JP6879528B2 - Biometric information detection system and biometric information detection method - Google Patents

Description

The present invention relates to a biological information detection system that detects biological information of a living body, and a biological information detection method.

Conventionally, a technique has been developed in which radio waves such as microwaves irradiated to the human body are detected and biological information such as heartbeats is non-invasively detected based on the detected radio waves.

For example, in Patent Document 1, a predetermined portion of a measurement target is irradiated with microwaves, microwaves transmitted through the body of the measurement target are detected, and the heartbeat of the measurement target is measured based on the detected microwaves. A heart rate detection device for calculation is disclosed.

Further, Patent Document 2 includes biological information including an electromagnetic wave oscillating unit that irradiates a living body with an electromagnetic wave and a scattered electromagnetic wave receiving unit that receives an electromagnetic wave having a plane of polarization rotated by 90 ° with respect to the plane of polarization of the irradiated electromagnetic wave. The detection system is described. The biological information detection system described in Patent Document 2 has a configuration in which a scattered electromagnetic wave receiving unit detects minute fluctuations in the body surface from electromagnetic waves received and calculates physiological indexes of the living body such as heartbeat appearing in the minute fluctuations in the body surface. Is disclosed.

Japanese Unexamined Patent Publication No. 2013-153783 Japanese Unexamined Patent Publication No. 2014-90877

However, in the heartbeat detection device of Patent Document 1 described above, not only the transmitted wave transmitted through the body of the measurement target, but also the diffracted wave diffracted outside the body and the surface wave propagated along the surface of the body (hereinafter, this). Such surface waves are called body surface waves) and are included in the received microwaves. Therefore, the transmitted wave, the diffracted wave, and the body surface wave interfere with each other, and it may be difficult to stably detect the heartbeat.

Specifically, when a diffracted wave that fluctuates due to body movement but does not contain biological information is received, the biological information contained in the transmitted wave is suppressed according to the intensity of the diffracted wave. Therefore, as the intensity of the diffracted wave increases, it becomes more difficult to detect biological information, and only body movement can be detected.

In addition, the above-mentioned body surface waves are subject to fluctuations due to body movements and respiration that appear largely on the body surface. For example, when a heartbeat is detected using a transmitted wave, if a breathing wave, which is a component of a body surface wave that has been changed by breathing, is received, not only the breathing wave and the transmitted wave interfere with each other, but also the breathing wave. Interference with the transmitted wave due to the harmonics of is also possible. Such effects of body movement and respiration become greater as the intensity of body surface waves increases, and it becomes difficult to stably detect heartbeats.

Further, since the scattered electromagnetic wave receiving unit in the biological information detection system of Patent Document 2 described above receives the reflected wave reflected on the body surface, it is more susceptible to the influence of the body movement having a larger fluctuation range than the minute fluctuation of the body surface. When trying to improve the detection characteristics of information indicating physiological indicators such as heartbeat, it is easy to be restricted by the installation position of the antenna.

The present invention provides a biological information detection system capable of stably detecting biological information such as heartbeat, respiration, and pulse wave, and improving the degree of freedom in the installation position of an antenna, and a biological information detection method. The purpose is to do.

The biological information detection system according to the present invention is arranged on one side of a living body and emits radio waves having a predetermined polarized wave to the living body, and is arranged on the other side of the living body and is predetermined in the process of penetrating the inside of the living body. Based on a reflecting part that reflects radio waves that are polarized perpendicular to the polarized radio waves of the above, a receiving antenna that is placed on one side of the living body and receives the radio waves reflected by the reflecting part, and the radio waves received by the receiving antenna. It also includes a detection unit that detects biological information.

Further, the biological information detection method according to the present invention includes a transmission step of radiating a radio wave having a predetermined polarization from one side of the living body to the living body and a bias orthogonal to the radio wave having a predetermined polarization in the process of passing through the body of the living body. It includes a receiving step of receiving a radio wave that becomes a wave and is reflected by a reflecting unit on one side of the living body, and a detection step of detecting biological information based on the radio wave received in the receiving step.

According to the present invention, it is possible to stably detect biological information such as heartbeat, respiration, and pulse wave, and to improve the degree of freedom in the installation position of the antenna.

The figure which shows an example of the structure of the biological information detection system which concerns on this invention. The figure explaining the outline of the biological information detection which concerns on Embodiment 1. The figure explaining the polarization state of the microwave in Embodiment 1. The figure explaining the polarization state of the microwave in Embodiment 1. The figure explaining the outline of the biological information detection which concerns on Embodiment 2. The figure explaining the polarization state of the microwave in Embodiment 2. The figure explaining the polarization state of the microwave in Embodiment 2. The figure explaining the outline of the biological information detection which concerns on Embodiment 3. The figure explaining the polarization state of the microwave in Embodiment 3. The figure explaining the polarization state of the microwave in Embodiment 3. The figure explaining the outline of the biological information detection which concerns on Embodiment 4. The figure explaining the polarization state of the microwave in Embodiment 4. The figure explaining the polarization state of the microwave in Embodiment 4. Diagram illustrating an overview of biometric information detection for vehicle drivers and passengers Diagram explaining the outline of biological information detection during human sleep

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same components are designated by the same reference numerals. In addition, the drawings schematically show each component for ease of understanding.

Hereinafter, a case where the target for which the biological information is detected by the biological information detection system is a human and the detected biological information is the heartbeat will be described, but the present invention is not limited to this, and the present invention is not limited to the human. It can be widely applied to the detection of living organisms and other biological information such as pulse waves and respiration.

The heartbeat is the heartbeat. The pulse wave is a waveform showing a change in blood vessel volume or a change in blood pressure that occurs with the beating of the heart. Heartbeat detection detects the heartbeat, and pulse wave detection detects changes in blood vessel volume and blood pressure.

FIG. 1 is a diagram showing an example of the configuration of the biological information detection system 10 according to the present invention. As shown in FIG. 1, the biometric information detection system 10 includes a transmission device 10a having a transmission antenna 11, a transmission unit 13 and a control unit 16, a reflection unit 35, a reception antenna 12, a reception unit 14, and a signal processing unit 15. And a receiving device 10b having a determination unit 17.

The transmitting antenna 11 is an antenna that radiates microwaves having a predetermined polarization to a person. The predetermined polarized wave is, for example, linearly polarized wave such as horizontally polarized wave or vertically polarized wave, or right-handed circularly polarized wave or left-handed circularly polarized wave. Here, the linearly polarized wave means that the plane of polarization of the electromagnetic wave is in one plane.

Horizontally polarized waves are linearly polarized waves in which the vibration direction of the electric field is horizontal to the ground. Vertically polarized waves refer to linearly polarized waves in which the vibration direction of the electric field is perpendicular to the ground.

Right-handed circularly polarized waves are circularly polarized waves in which the plane including the traveling direction of the electromagnetic wave and the vibration direction of the electric field rotates, and the rotation direction of the polarization plane is clockwise when viewed from the direction facing the traveling direction of the electromagnetic wave. Say something. Left-handed circularly polarized wave means that the plane including the traveling direction of the electromagnetic wave and the vibration direction of the electric field rotates. In circularly polarized wave, the rotation direction of the polarization plane is counterclockwise when viewed from the direction facing the traveling direction of the electromagnetic wave. The thing.

The shape of the transmitting antenna 11 is not particularly limited, but when the transmitting antenna 11 emits circularly polarized microwaves, it is preferable that the transmitting antenna 11 emits circularly polarized waves having excellent axial ratio characteristics. The transmitting antenna 11 is, for example, a helical antenna or a patch antenna.

The transmission unit 13 is a device that radiates microwaves through the transmission antenna 11.

The control unit 16 is a control device that controls the transmission unit 13. The control unit 16 causes the transmission unit 13 to transmit microwaves. Further, the control unit 16 sets the frequency of the microwave emitted by the transmission unit 13. It is not essential that the transmission device 10a is provided with the control unit 16, and the transmission unit 13 may be configured to radiate a predetermined microwave.

As will be described later in the first and second embodiments, when the receiving antenna is not installed on the back side of the person, the reflecting unit 35 has, for example, polarization selectivity to reflect microwaves of a specific polarization. It is a reflector of. Further, the reflecting unit 35 may be a reflecting plate having no polarization selectivity.

Further, as described in the third and fourth embodiments, when the receiving antenna is installed on the back side of a person, the reflecting unit 35 transmits microwaves of a specific polarized wave and other than the specific polarized wave. It is a polarization filter that reflects the microwaves of.

When the linearly polarized microwave is reflected by the reflection unit 35, the polarization state of the linearly polarized microwave does not change, and when the circularly polarized microwave is reflected by the reflection unit 35, the circularly polarized wave is circularly polarized. The polarization state of the microwave is reversed.

The receiving antenna 12 is an antenna that receives microwaves radiated from the transmitting antenna 11. The microwave radiated from the transmitting antenna 11 passes through the human body, is reflected by the reflecting unit 35, and then passes through the human body again and reaches the receiving antenna 12.

The shape of the receiving antenna 12 is not particularly limited, but the receiving antenna 12 is, for example, a patch antenna.

The receiving unit 14 is a device that receives microwaves via the receiving antenna 12. The receiving unit 14 sets the frequency of the microwave to be received.

The signal processing unit 15 is a detection unit that detects a person's heartbeat by extracting heartbeat information from the analog waveform of the microwave received by the receiving unit 14. Since the technique of radiating microwaves to a person to detect a heartbeat is known, detailed description thereof will be omitted here.

The determination unit 17 is a processing unit that makes various determinations based on the heartbeat of the person detected by the signal processing unit 15. The determination unit 17 determines, for example, whether the heart rate of a person exceeds or falls below a predetermined threshold value. In the present invention, the signal processing unit 15 and the determination unit 17 function as detection units.

(Embodiment 1)
Here, the outline of the biological information detection according to the first embodiment of the present invention will be described. FIG. 2 is a diagram illustrating an outline of biological information detection according to the first embodiment.

The transmitting antenna 11 is arranged on one side of the person 20. The one side is, for example, the front side of the person 20. The receiving antenna 12 is arranged side by side with the transmitting antenna 11 on one side of the person 20. The reflector 40 is arranged on the other side of the person 20. The other side is, for example, the back side of the person 20. That is, the reflector 40 is arranged so as to face the transmitting antenna 11 and the receiving antenna 12 with the person 20 in between.

The transmitting antenna 11 and the receiving antenna 12 and the reflecting plate 40 may be arranged so as to face each other with the person 20 in between, and the transmitting antenna 11 and the receiving antenna 12 are arranged on the back side of the person 20 and the reflecting plate is arranged. 40 may be arranged on the front side of the person 20.

The transmitting antenna 11 is an antenna that radiates linearly polarized microwaves toward the person 20.

The receiving antenna 12 is an antenna that receives a microwave having a polarization orthogonal to the microwave radiated from the transmitting antenna 11.

The reflector 40 reflects polarized microwaves orthogonal to the linearly polarized microwaves radiated from the transmitting antenna 11, except for polarized waves orthogonal to the linearly polarized microwaves radiated from the transmitting antenna 11. It is a reflecting plate having polarization selectivity that does not reflect polarized microwaves.

By using such a polarization-selective reflector 40, the transmitted wave 31 that has passed through the human body and propagated is reflected, and the body surface waves 30 and the human 20 that have propagated along the surface of the human body 20 are reflected. It is possible to prevent the diffracted wave 32 that has been diffracted and propagated outside the body of the body from being reflected. This will be described in detail later.

The reflector 40 is formed, for example, by fixing a large number of linear conductive members arranged parallel to each other to a frame member. The linear members of the reflector 40 form slits together with the linear members that are close to each other.

By using the reflecting plate 40 having such a configuration, it is possible to reflect microwaves having a polarization parallel to the linear conductive member and to transmit microwaves having a polarization perpendicular to the linear conductive member. it can.

When linearly polarized microwaves are radiated from the transmitting antenna 11, the body surface wave 30 propagates along the surface of the human body 20, the transmitted wave 31 propagating through the human body 20, and the human 20. The diffracted wave 32 diffracted and propagated outside the body reaches the reflecting plate 40.

Here, some microwaves among the transmitted waves 31 transmitted through the body are repeatedly reflected or diffracted at the boundary surface of the organ 20a having a difference in dielectric constant in the process of transmitting through the body, so that the inside of the human body 20 It is radiated from the body in a polarized state orthogonal to the polarized state when it is incident on.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 is reflected by the reflector 40. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 are not reflected by the reflecting plate 40.

The transmitted wave 31 reflected by the reflector 40 is incident on the body of the person 20 again. The transmitted wave 31 incident on the body of the person 20 repeatedly reflects and diffracts inside the body of the person 20, passes through the body, and reaches the receiving antenna 12.

As described above, when the microwave passes through the body of the human 20, the polarization state of a part of the microwave becomes the polarization orthogonal to the polarization state when it is incident on the body of the person 20.

Therefore, the transmitted wave 31 reaching the receiving antenna 12 has a microwave having a polarization orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11 and a microwave having the same polarization as the linearly polarized microwave emitted by the transmitting antenna 11. Includes microwaves.

The receiving antenna 12 is an antenna that receives the polarized microwaves orthogonal to the linearly polarized microwaves radiated by the transmitting antenna 11. Therefore, the receiving antenna 12 receives the transmitted wave 31 which has reached the polarization orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11.

Further, among the linearly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is linearly polarized, the reflected wave 33 having the same polarization as the microwave radiated from the transmitting antenna 11 reaches the receiving antenna 12.

Since the receiving antenna 12 is an antenna that receives the polarized microwaves orthogonal to the polarized microwaves radiated by the transmitting antenna 11, it does not receive the reflected waves 33 reflected by the body surface of the person 20.

As a result, the receiving antenna 12 can receive only the transmitted wave 31 which has reached the polarization orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11.

As a result, the biological information detection system 10 according to the first embodiment suppresses the influence of interference with the body surface wave 30, the diffracted wave 32, and the reflected wave 33, and stabilizes the transmitted wave 31 including the biological information. Can be received. In other words, in the biological information detection system 10 according to the first embodiment, microwaves propagating through a specific path and reaching the receiving antenna 12 are selectively received, and heartbeat information is stably transmitted from the microwaves. Can be extracted.

Further, since the biological information detection system 10 of the first embodiment has the transmitting device 10a and the receiving device 10b installed on the front side of the person 20, the receiving device 10b or the receiving device 10b is supplied with electric power on the back side of the person 20. There is no need to provide a power supply or wiring to supply. Therefore, the configuration of the biological information detection system 10 can be simplified to improve convenience and reduce the total cost.

Next, the polarization state in the process of reaching the receiving antenna 12 of the linearly polarized microwaves radiated from the transmitting antenna 11 will be specifically described. FIG. 3 is a diagram for explaining the polarization state of the microwave in the first embodiment.

When the transmitting antenna 11 radiates a vertically polarized microwave, the reflecting plate 40 has a vertically polarized body surface wave 30, a vertically polarized diffracted wave 32, and a transmission that becomes vertically polarized in the process of passing through the body. The wave 31 and the transmitted wave 31 which has become horizontally polarized in the process of passing through the body arrive.

As described above, since the reflecting plate 40 is a reflecting plate that reflects microwaves of polarization orthogonal to the microwaves of linearly polarized waves radiated from the transmitting antenna 11, it becomes horizontally polarized in the process of passing through the body. Only the transmitted wave 31 that has become is reflected.

The horizontally polarized transmitted wave 31 reflected by the reflector 40 passes through the body of the person 20 again. The receiving antenna 12 includes a transmitted wave 31 that has become horizontally polarized in the process of penetrating the body, a transmitted wave 31 that has become vertically polarized in the process of passing through the body, and a reflection of the vertically polarized wave reflected on the body surface. Wave 33 arrives.

Since the receiving antenna 12 is an antenna that receives the microwave having a polarization orthogonal to the microwave emitted by the transmitting antenna 11, the receiving antenna 12 receives the transmitted wave 31 having a horizontally polarized wave.

On the other hand, when the transmitting antenna 11 emits horizontally polarized microwaves, the reflecting plate 40 has a horizontally polarized body surface wave 30, a horizontally polarized diffracted wave 32, and horizontally polarized waves in the process of passing through the body. The transmitted wave 31 and the transmitted wave 31 that has become vertically polarized in the process of transmitting through the body arrive.

As described above, since the reflecting plate 40 is a reflecting plate that reflects microwaves of polarized waves orthogonal to the microwaves of linearly polarized waves radiated from the transmitting antenna 11, it becomes vertically polarized in the process of passing through the body. Only the transmitted wave 31 that has become is reflected.

The vertically polarized transmitted wave 31 reflected by the reflector 40 passes through the body of the person 20 again. The receiving antenna 12 includes a transmitted wave 31 that becomes vertically polarized in the process of penetrating the body, a transmitted wave 31 that becomes horizontally polarized in the process of passing through the body, and a reflection of horizontally polarized waves reflected on the body surface. Wave 33 arrives.

Since the receiving antenna 12 is an antenna that receives the microwave having a polarization orthogonal to the microwave emitted by the transmitting antenna 11, the receiving antenna 12 receives the transmitted wave 31 having a vertically polarized wave.

As described above, in the invention according to the first embodiment, the receiving antenna 12 is polarized in the body of the person 20 and is orthogonal to the linearly polarized microwaves radiated by the transmitting antenna 11 and becomes the receiving antenna 12. The transmitted transmitted wave 31 that has arrived is received. On the other hand, the receiving antenna 12 does not receive the body surface wave 30, the diffracted wave 32, the reflected wave 33, and the transmitted wave 31 having the same polarization as the linearly polarized wave radiated by the transmitting antenna 11.

Therefore, in the first embodiment, the transmitted wave 31 including the biological information can be stably received, and further, the configuration of the biological information detection system 10 is simplified to improve convenience and reduce the total cost. Can be planned.

In the first embodiment described above, the reflecting plate 40 having polarization selectivity is used for the reflecting portion 35, but the reflecting portion 35 is a reflecting plate 40 formed of a metal plate or the like having no polarization selectivity. There may be.

In this case, the reflector 40 reflects the microwave that has reached the reflector 40 regardless of the polarization state of the microwave.

When a reflecting plate 40 having no polarization selectivity is used for the reflecting unit 35, the polarization state that appears in the process in which the linearly polarized microwaves radiated from the transmitting antenna 11 reach the receiving antenna 12 is concrete. Explain to. FIG. 4 is a diagram for explaining the polarization state of microwaves when the reflector 40 having no polarization selectivity is used in the first embodiment.

When the transmitting antenna 11 radiates a vertically polarized microwave, the reflecting plate 40 has a vertically polarized body surface wave 30, a vertically polarized diffracted wave 32, and a transmission that becomes vertically polarized in the process of passing through the body. The wave 31 and the transmitted wave 31 which has become horizontally polarized in the process of passing through the body arrive.

Since the reflector 40 has no polarization selectivity, it reflects these microwaves that have reached the reflector 40.

The vertically polarized transmitted wave 31 and the horizontally polarized transmitted wave 31 again enter the body of the human 20. These transmitted waves 31 incident on the human body 20 reach the receiving antenna 12 as vertically polarized or horizontally polarized microwaves (transmitted waves 31) in the process of passing through the body.

Since the receiving antenna 12 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, the microwave that reaches the receiving antenna 12 in the horizontally polarized state ( Receives the transmitted wave 31).

Some microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflecting plate 40 become the body surface wave 30 or the diffracted wave 32 again and reach the receiving antenna 12 in a vertically polarized state. However, since the receiving antenna 12 is an antenna that receives the microwaves of polarization orthogonal to the microwaves of linearly polarized waves radiated from the transmitting antenna 11, these microwaves (body surface wave 30, diffracted wave 32). Do not receive.

Some of the other microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflector 40 are incident on the human body 20, and some of the microwaves incident on the body are inside the body. In the process of transmission, it becomes horizontally polarized and reaches the receiving antenna 12.

Since the receiving antenna 12 is an antenna that receives the microwave having a polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, the receiving antenna 12 becomes horizontally polarized in the process of passing through the body. The reached microwave (transmitted wave 31) is received.

Further, among the vertically polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is linearly polarized, the reflected wave 33 reaches the receiving antenna 12 with a microwave having the same polarization as the microwave radiated by the transmitting antenna 11.

Since the receiving antenna 12 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20.

Next, when the transmitting antenna 11 radiates a horizontally polarized microwave, the reflecting plate 40 has a horizontally polarized body surface wave 30, a horizontally polarized diffracted wave 32, and a horizontally polarized wave in the process of passing through the body. The transmitted wave 31 that has become and the transmitted wave 31 that has become vertically polarized in the process of transmitting through the body arrives.

Since the reflector 40 does not have polarization selectivity, it reflects these microwaves that have reached the reflector 40.

The horizontally polarized transmitted wave 31 and the vertically polarized transmitted wave 31 again enter the body of the human 20. These transmitted waves 31 incident on the human body 20 reach the receiving antenna 12 as vertically polarized or horizontally polarized microwaves (transmitted waves 31) in the process of passing through the body.

Since the receiving antenna 12 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, the microwave that reaches the receiving antenna 12 in the vertically polarized state ( Receives the transmitted wave 31).

Some microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflecting plate 40 become the body surface wave 30 or the diffracted wave 32 again and reach the receiving antenna 12 in a horizontally polarized state. However, since the receiving antenna 12 is an antenna that receives the microwaves of polarization orthogonal to the microwaves of linearly polarized waves radiated from the transmitting antenna 11, these microwaves (body surface wave 30, diffracted wave 32). Do not receive.

Some of the other microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflector 40 are incident on the human body 20, and some of the microwaves incident on the body are inside the body. In the process of transmission, it becomes vertically polarized and reaches the receiving antenna 12.

Since the receiving antenna 12 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, it becomes vertically polarized in the process of passing through the body and becomes the receiving antenna 12. The reached microwave (transmitted wave 31) is received.

Further, among the horizontally polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is linearly polarized, the reflected wave 33 reaches the receiving antenna 12 with a microwave having the same polarization as the microwave radiated by the transmitting antenna 11.

Since the receiving antenna 12 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20.

As described above, in the invention according to the first embodiment, even when the reflector 40 having no polarization selectivity is used, the receiving antenna 12 stably receives the transmitted wave 31 including the biological information. can do.

When the reflector 40 having no polarization selectivity is used, the body surface wave 30 and the diffracted wave 32, which are microwaves having unintended polarization, reach the receiving antenna 12. Therefore, when the reflector 40 having no polarization selectivity is used, the degree of suppression of the receiving antenna 12 against unintended polarization is higher than when the reflector 40 having polarization selectivity is used. Is desired.

Further, the antenna used in the biological information detection system 10 of the first embodiment is preferably an antenna having a sharp directivity.

(Embodiment 2)
Next, the outline of the biological information detection in the second embodiment will be described. FIG. 5 is a diagram illustrating an outline of biological information detection according to the second embodiment.

The transmitting antenna 11 is arranged on one side of the person 20. The one side is, for example, the front side of the person 20. The receiving antenna 12 is arranged side by side with the transmitting antenna 11 on one side of the person 20. The reflector 40 is arranged on the other side of the person 20. The other side is, for example, the back side of the person 20. That is, the reflector 40 is arranged so as to face the transmitting antenna 11 and the receiving antenna 12 with the person 20 in between.

The transmitting antenna 11 and the receiving antenna 12 and the reflecting plate 40 may be arranged so as to face each other with the person 20 in between, and the transmitting antenna 11 and the receiving antenna 12 are arranged on the back side of the person 20 and the reflecting plate is arranged. 40 may be arranged on the front side of the person 20.

The transmitting antenna 11 is an antenna that radiates circularly polarized microwaves toward the person 20.

The receiving antenna 12 is an antenna that receives microwaves having the same circularly polarized waves as the microwaves emitted by the transmitting antenna 11. When the transmitting antenna 11 emits a circularly polarized microwave, the polarized state of the microwave emitted by the transmitting antenna 11 and the polarized state of the microwave received by the receiving antenna 12 are the same. The antenna may be common.

The reflector 40 reflects polarized microwaves orthogonal to the circularly polarized microwaves radiated from the transmitting antenna 11, except for polarized waves orthogonal to the circularly polarized microwaves radiated from the transmitting antenna 11. It is a reflecting plate having polarization selectivity that does not reflect polarized microwaves. When the circularly polarized microwave is reflected by the reflector 40, the rotation direction of the circularly polarized wave is reversed.

When a circularly polarized microwave is radiated from the transmitting antenna 11, the body surface wave 30 propagates along the surface of the human body 20, the transmitted wave 31 propagating through the human body 20, and the human 20. The diffracted wave 32 diffracted and propagated outside the body reaches the reflecting plate 40.

Here, some microwaves among the transmitted waves 31 transmitted through the body are repeatedly reflected or diffracted at the boundary surface of the organ 20a having a difference in dielectric constant in the process of transmitting through the body, so that the inside of the human body 20 It is radiated from the body in a polarized state orthogonal to the polarized state when it is incident on.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 is reflected by the reflector 40. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 are not reflected by the reflecting plate 40.

The microwave reflected by the reflector 40 is incident on the body of the person 20 again. The transmitted wave 31 incident on the body of the person 20 repeatedly reflects and diffracts inside the body of the person 20, passes through the body, and reaches the receiving antenna 12.

As described above, when the microwave passes through the body of the human 20, the polarization state of a part of the microwave becomes the polarization orthogonal to the polarization state when it is incident on the body of the person 20.

Therefore, the transmitted wave 31 reaching the receiving antenna 12 includes a microwave having a polarization orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11 and a microwave having the same polarization as the circularly polarized microwave emitted by the transmitting antenna 11. Waves are included.

The receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized wave emitted by the transmitting antenna 11. Therefore, the receiving antenna 12 receives the transmitted wave 31 that has reached the same polarization as the circularly polarized microwave emitted by the transmitting antenna 11.

Further, among the circularly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is circularly polarized, the reflected wave 33 reaches the receiving antenna 12 in a polarized wave orthogonal to the microwave of the polarized wave radiated by the transmitting antenna 11.

Here, since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the polarization radiated by the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20.

As a result, the receiving antenna 12 can receive only the transmitted wave 31 that has reached the same polarization as the circularly polarized wave radiated by the transmitting antenna 11.

Thereby, the present invention can stably receive the transmitted wave 31 including the biological information by suppressing the influence of the interference with the body surface wave 30, the diffracted wave 32, and the reflected wave 33.

Further, in the biological information detection system 10 of the second embodiment, since the transmitting device 10a and the receiving device 10b are installed on the front side of the person 20, power is applied to the receiving device 10b or the receiving device 10b on the back side of the person 20. There is no need to provide a power supply or wiring to supply. Therefore, the configuration of the biological information detection system 10 can be simplified to improve convenience and reduce the total cost.

Next, the polarization state in the process of reaching the receiving antenna 12 of the circularly polarized microwaves radiated from the transmitting antenna 11 will be specifically described. FIG. 6 is a diagram for explaining the polarization state of the microwave in the second embodiment.

When the transmitting antenna 11 radiates microwaves with right-handed circularly polarized waves, the reflector 40 has a right-handed circularly polarized body surface wave 30, a right-handed circularly polarized diffracted wave 32, and the right in the process of passing through the body. The transmitted wave 31 that has become circularly polarized and the transmitted wave 31 that has become left-handed circularly polarized in the process of penetrating the body arrives.

As described above, since the reflector 40 is a reflector that reflects the microwaves of polarization orthogonal to the microwaves of circularly polarized waves radiated from the transmitting antenna 11, it is left-handed circularly polarized waves in the process of passing through the body. Only the transmitted wave 31 that has become is reflected. When the transmitted wave 31 of the left-handed circularly polarized wave is reflected by the reflecting plate 40, the rotation direction of the circularly polarized wave is reversed, and the transmitted wave 31 becomes a microwave of right-handed circularly polarized wave.

The transmitted wave 31, which is reflected by the reflector 40 and becomes right-handed circularly polarized wave, passes through the body of the person 20 again. The receiving antenna 12 has a transmitted wave 31 that has become right-handed circularly polarized wave in the process of penetrating the body, a transmitted wave 31 that has become left-handed circularly polarized wave in the process of passing through the body, and a left-handed wave that is reflected by the body surface. The circularly polarized reflected wave 33 arrives.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the microwave emitted by the transmitting antenna 11, the receiving antenna 12 receives the transmitted wave 31 having a right-handed circularly polarized wave.

On the other hand, when the transmitting antenna 11 radiates microwaves with left-handed circularly polarized waves, the reflector 40 has a left-handed circularly polarized body surface wave 30, a left-handed circularly polarized diffracted wave 32, and a left-handed circularly polarized wave in the process of passing through the body. The polarized wave 31 and the transmitted wave 31 that has become right-handed circularly polarized in the process of penetrating the body arrive.

As described above, since the reflecting plate 40 is a reflecting plate that reflects microwaves of polarization orthogonal to the circularly polarized microwaves radiated from the transmitting antenna 11, it passes through the body and is right-handed circularly polarized waves. Only the transmitted wave 31 that has become is reflected.

The transmitted wave 31, which is reflected by the reflector 40 and becomes left-handed circularly polarized wave, passes through the body of the person 20 again. The receiving antenna 12 has a transmitted wave 31 that becomes left-handed circularly polarized wave in the process of penetrating the body, a transmitted wave 31 that becomes right-handed circularly polarized wave in the process of passing through the body, and a transmitted wave 31 that is reflected on the body surface and is right The reflected wave 33 that has become circularly polarized waves arrives.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the microwave emitted by the transmitting antenna 11, the receiving antenna 12 receives the transmitted wave 31 having left-handed circularly polarized waves.

As described above, in the invention according to the second embodiment, the receiving antenna 12 is a transmitted wave that has passed through the body of the person 20 and has the same polarization as the circularly polarized wave radiated by the transmitting antenna 11 and has reached the receiving antenna 12. 31 is received. On the other hand, the receiving antenna 12 is polarized so as to pass through the body surface wave 30, the diffracted wave 32, the reflected wave 33, and the human body 20 and be orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11. The transmitted wave 31 is not received.

Therefore, in the invention according to the second embodiment, the transmitted wave 31 including the biological information can be stably received, the configuration of the biological information detection system 10 is simplified, the convenience is improved, and the total cost is improved. Can be reduced.

In the second embodiment described above, the reflecting plate 40 having polarization selectivity is used for the reflecting portion 35, but the reflecting portion 35 is a reflecting plate 40 formed of a metal plate or the like having no polarization selectivity. There may be.

In this case, the reflector 40 reflects the microwave that has reached the reflector 40 regardless of the polarization state of the microwave.

When a reflecting plate 40 having no polarization selectivity is used for the reflecting unit 35, the polarization state shown in the process in which the circularly polarized microwaves radiated from the transmitting antenna 11 reach the receiving antenna 12 is concrete. Explain to. FIG. 7 is a diagram for explaining the polarization state of microwaves when the reflector 40 having no polarization selectivity is used in the second embodiment.

When the transmitting antenna 11 radiates microwaves with right-handed circularly polarized waves, the reflector 40 has a right-handed circularly polarized body surface wave 30, a right-handed circularly polarized diffracted wave 32, and the right in the process of passing through the body. The transmitted wave 31 that has become circularly polarized and the transmitted wave 31 that has become left-handed circularly polarized in the process of penetrating the body arrives.

Since the reflector 40 does not have polarization selectivity, it reflects these microwaves that have reached the reflector 40. When the transmitted wave 31 of right-handed circularly polarized waves is reflected by the reflecting plate 40, the rotation direction of circularly polarized waves is reversed to become left-handed circularly polarized microwaves.

The transmitted wave 31 that is reflected by the reflector 40 and becomes left-handed circularly polarized wave and the transmitted wave 31 that is reflected by the reflector 40 and becomes right-handed circularly polarized wave are incident on the body of the person 20 again. These transmitted waves 31 incident on the human body 20 reach the receiving antenna 12 as microwaves (transmitted waves 31) of right-handed circularly polarized waves or left-handed circularly polarized waves in the process of passing through the body.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, the microwaves reaching the receiving antenna 12 in a right-handed circularly polarized state. (Transmitted wave 31) is received.

Some microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflecting plate 40 become the body surface wave 30 or the diffracted wave 32 again and reach the receiving antenna 12 in a left-handed circularly polarized state. However, since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, these microwaves (body surface wave 30, diffracted wave 32) are used. Do not receive.

Some of the other microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflector 40 are incident on the human body 20, and some of the microwaves incident on the body are inside the body. In the process of transmission, it becomes right-handed circularly polarized wave and reaches the receiving antenna 12.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, the receiving antenna 12 becomes right-handed circularly polarized in the process of passing through the body. Receives the microwave (transmitted wave 31) that has reached.

Further, among the right-handed circularly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is circularly polarized, the reflected wave 33 reaches the receiving antenna 12 as a microwave having a polarized wave orthogonal to the microwave radiated by the transmitting antenna 11.

Since the receiving antenna 12 is an antenna that receives the microwave having the same polarization as the circularly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20.

Next, when the transmitting antenna 11 emits microwaves with left-handed circularly polarized waves, the reflector 40 has a left-handed circularly polarized body surface wave 30, a left-handed circularly polarized diffracted wave 32, and left-handed in the process of passing through the body. The circularly polarized transmitted wave 31 and the right-handed circularly polarized transmitted wave 31 arrive in the process of penetrating the body.

Since the reflector 40 does not have polarization selectivity, it reflects these microwaves that have reached the reflector 40. When the transmitted wave 31 of the left-handed circularly polarized wave is reflected by the reflecting plate 40, the rotation direction of the circularly polarized wave is reversed, and the transmitted wave 31 becomes a microwave of right-handed circularly polarized wave.

The transmitted wave 31 that is reflected by the reflector 40 and becomes left-handed circularly polarized wave and the transmitted wave 31 that is reflected by the reflector 40 and becomes right-handed circularly polarized wave are incident on the body of the person 20 again. These transmitted waves 31 incident on the human body 20 reach the receiving antenna 12 as microwaves (transmitted waves 31) of right-handed circularly polarized waves or left-handed circularly polarized waves in the process of passing through the body.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, the microwaves reaching the receiving antenna 12 in a left-handed circularly polarized state ( Receives the transmitted wave 31).

Some microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflecting plate 40 become the body surface wave 30 or the diffracted wave 32 again and reach the receiving antenna 12 in a right-handed circularly polarized state. However, since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, these microwaves (body surface wave 30, diffracted wave 32) are used. Do not receive.

Some of the other microwaves of the body surface wave 30 and the diffracted wave 32 reflected by the reflector 40 are incident on the human body 20, and some of the microwaves incident on the body are inside the body. In the process of transmission, it becomes left-handed circularly polarized wave and reaches the receiving antenna 12.

Since the receiving antenna 12 is an antenna that receives microwaves having the same polarization as the circularly polarized microwaves radiated from the transmitting antenna 11, it becomes left-handed circularly polarized waves in the process of passing through the body and becomes the receiving antenna 12. The reached microwave (transmitted wave 31) is received.

Further, among the left-handed circularly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves reach the receiving antenna 12 as reflected waves 33 that are reflected and propagated on the body surface of the person 20. When the microwave radiated from the transmitting antenna 11 is circularly polarized, the reflected wave 33 reaches the receiving antenna 12 as a microwave having a polarized wave orthogonal to the microwave radiated by the transmitting antenna 11.

Since the receiving antenna 12 is an antenna that receives the microwave having the same polarization as the circularly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20.

As described above, in the invention according to the second embodiment, even when the reflector 40 having no polarization selectivity is used, the receiving antenna 12 stably receives the transmitted wave 31 including the biological information. can do.

When the reflector 40 having no polarization selectivity is used, the body surface wave 30 and the diffracted wave 32, which are microwaves having unintended polarization, reach the receiving antenna 12. Therefore, when the reflector 40 having no polarization selectivity is used, the degree of suppression of the receiving antenna 12 against unintended polarization is higher than when the reflector 40 having polarization selectivity is used. Is desired. In other words, it is desirable that the receiving antenna 12 is an antenna that receives microwaves having excellent axial ratio characteristics.

Further, the antenna used in the biological information detection system 10 of the present embodiment is preferably an antenna having a sharp directivity.

(Embodiment 3)
Next, the outline of the biological information detection in the third embodiment will be described. FIG. 8 is a diagram illustrating an outline of biological information detection according to the third embodiment. The biological information detection system 10 according to the third embodiment has a first receiving antenna 45 and a second receiving antenna 46, and switches between these two receiving antennas to receive microwaves. In the following, a mode in which the second receiving antenna 46 receives the microwave and then switches to the first receiving antenna 45 to receive the microwave will be described.

The transmitting antenna 11 is arranged on one side of the person 20. The one side is, for example, the front side of the person 20. The first receiving antenna 45 is on one side of the person 20 and is arranged side by side with the transmitting antenna 11. The polarization filter 41 is arranged on the other side of the person 20. The other side is, for example, the back side of the person 20. That is, the polarization filter 41 is arranged so as to face the transmitting antenna 11 and the first receiving antenna 45 with the person 20 in between. The second receiving antenna 46 is arranged so as to face the person 20 with the polarization filter 41 interposed therebetween.

The transmitting antenna 11 and the first receiving antenna 45, the polarization filter 41, and the second receiving antenna 46 need only be arranged so as to face each other with the person 20 in between, and the transmitting antenna 11 and the first receiving antenna 11 and the first receiving antenna 46 need to be arranged so as to face each other. The antenna 45 may be arranged on the back side of the person 20, and the polarization filter 41 and the second receiving antenna 46 may be arranged on the front side of the person 20.

The transmitting antenna 11 is an antenna that radiates linearly polarized microwaves toward the person 20. The transmitting antenna 11 can switch the polarization state of the microwave and radiate it. As a result, the antenna that receives the microwave radiated from the transmitting antenna 11 can be switched between the first receiving antenna 45 and the second receiving antenna 46. This will be described in detail later.

The first receiving antenna 45 is an antenna that receives a microwave having a polarization orthogonal to the microwave emitted by the transmitting antenna 11.

When the second receiving antenna 46 receives the microwave, the polarization filter 41 transmits the polarized microwave orthogonal to the linearly polarized microwave radiated by the transmitting antenna 11 and transmits the first receiving antenna 45. Is a filter that reflects polarized microwaves orthogonal to the linearly polarized microwaves emitted by the transmitting antenna 11 when it receives microwaves.

The second receiving antenna 46 is an antenna that receives the transmitted wave 31 that has passed through the person 20 and the polarization filter 41.

When a microwave having a predetermined linearly polarized wave is radiated from the transmitting antenna 11, the body surface wave 30 propagating along the surface of the body, the transmitted wave 31 propagating through the body of the person 20, and the person 20 The diffracted wave 32 diffracted and propagated outside the body reaches the polarization filter 41.

Here, some microwaves among the transmitted waves 31 transmitted through the body are repeatedly reflected or diffracted at the boundary surface of the organ 20a having a difference in dielectric constant in the process of transmitting through the body, so that the inside of the human body 20 It is radiated from the body in a polarized state orthogonal to the polarized state when it is incident on.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 passes through the polarization filter 41. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 do not pass through the polarization filter 41.

The transmitted wave 31 that has passed through the polarization filter 41 reaches the second receiving antenna 46.

Since the second receiving antenna 46 is an antenna that receives the microwave having the polarization orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11, the transmitted wave 31 that has reached the second receiving antenna 46 is received. To do.

Therefore, the second receiving antenna 46 can receive only the transmitted wave 31 which has reached the polarization orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11.

Next, when the transmitting antenna 11 switches from the predetermined linearly polarized light to the polarized light orthogonal to the predetermined linearly polarized microwave and radiates the microwave, the body surface wave 30 propagating along the surface of the body and the body surface wave 30 The transmitted wave 31 that has passed through the body of the person 20 and propagated, and the diffracted wave 32 that has been diffracted and propagated outside the body of the person 20 reach the polarization filter 41. Since the technique for switching the polarization state of linearly polarized waves is known, detailed description thereof will be omitted here.

As described above, some microwaves among the transmitted waves 31 transmitted through the body are repeatedly reflected or diffracted at the interface of the organs 20a having different dielectric constants in the process of transmitting through the body, so that the person 20 It is radiated from the body in a polarized state that is orthogonal to the polarized state when it enters the body.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 is reflected by the polarization filter 41. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 are not reflected by the polarization filter 41.

The transmitted wave 31 reflected by the polarization filter 41 is incident on the human body 20 again. The transmitted wave 31 incident on the body of the person 20 repeatedly reflects and diffracts inside the body of the person 20, passes through the body, and reaches the first receiving antenna 45.

As described above, when the microwave passes through the body of the human 20, the polarization state of a part of the microwave becomes the polarization orthogonal to the polarization state when it is incident on the body of the person 20.

Therefore, the microwave reaching the first receiving antenna 45 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The first receiving antenna 45 is an antenna that receives microwaves having a polarization orthogonal to the polarization of the microwaves emitted by the transmitting antenna 11. Therefore, the first receiving antenna 45 receives the transmitted wave 31 which has reached the polarization orthogonal to the polarization of the microwave emitted by the transmitting antenna 11.

Further, among the microwaves of the predetermined linearly polarized waves radiated by the transmitting antenna 11, some of the microwaves are reflected on the body surface of the person 20 and are the first in the same polarized state as the microwaves radiated by the transmitting antenna 11. Reach the receiving antenna 45 of.

Here, since the first receiving antenna 45 is an antenna that receives the microwave having a polarization orthogonal to the polarization of the microwave emitted by the transmitting antenna 11, the reflected wave 33 reflected by the body surface of the person 20 is used. Do not receive.

As a result, the first receiving antenna 45 can receive only the transmitted wave 31 which has become polarized orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11 and has reached the first receiving antenna 45. ..

By switching the polarization state of the microwave radiated by the transmitting antenna 11 in this way, the microwave radiated by the transmitting antenna 11 is switched between the first receiving antenna 45 and the second receiving antenna 46 for reception. can do.

The method of switching the receiving antenna is not limited to the method of changing the polarization state of the microwave emitted by the transmitting antenna 11. For example, the polarization filter 41 may be rotated 90 degrees around an axis extending in the direction connecting the transmitting antenna 11 and the second receiving antenna 46.

In this case, the polarization that is transmitted or reflected by the polarization filter 41 can be changed without changing the polarization state of the microwave emitted by the transmitting antenna 11. Therefore, the configuration of the transmitting antenna 11 can be simplified.

Next, the polarization state of the microwave when the linearly polarized microwave radiated from the transmitting antenna 11 is received by the second receiving antenna 46 and then switched to the first receiving antenna 45 to be received is concrete. Explain to.

First, the transmitting antenna 11 radiates vertically polarized microwaves, and then horizontally polarized microwaves so that the antenna that receives the microwaves is changed from the second receiving antenna 46 to the first receiving antenna 45. The mode of switching to is described. FIG. 9 is a diagram for explaining the polarization state of the microwave in the third embodiment.

When the transmitting antenna 11 emits a vertically polarized microwave, the polarization filter 41 has a vertically polarized body surface wave 30 and a diffracted wave 32, a vertically polarized transmitted wave 31, and a horizontal in the process of passing through the body. The polarized transmitted wave 31 arrives.

The polarization filter 41 is a filter that transmits horizontally polarized microwaves and reflects microwaves other than horizontally polarized waves. Therefore, the polarization filter 41 transmits only the transmitted wave 31 that has become horizontally polarized in the process of transmitting through the body of the person 20.

The second receiving antenna 46 is an antenna that receives a microwave having a polarization orthogonal to the microwave emitted by the transmitting antenna 11, and the second receiving antenna 46 receives a transmitted wave 31 having a horizontally polarized wave.

When the transmitting antenna 11 changes the microwave radiated toward the person 20 from the vertically polarized microwave to the horizontally polarized microwave, the polarization filter 41 is subjected to the horizontally polarized body surface wave 30 and the diffracted wave 32. The horizontally polarized transmitted wave 31 and the vertically polarized transmitted wave 31 in the process of penetrating the body arrive.

Here, the polarization filter 41 is a filter that transmits horizontally polarized microwaves and reflects microwaves of polarization other than horizontally polarized waves. Therefore, the polarization filter 41 reflects the transmitted wave 31 that has become vertically polarized in the process of passing through the body of the person 20.

The vertically polarized wave 31 reflected by the polarization filter 41 passes through the body of the person 20 again. The vertically polarized transmitted wave 31, the horizontally polarized transmitted wave 31 in the process of passing through the body, and the horizontally polarized reflected wave 33 reflected on the body surface reach the first receiving antenna 45. ..

Since the first receiving antenna 45 is an antenna that receives the vertically polarized microwaves, it receives the vertically polarized transmitted waves 31 that have passed through the body.

Further, among the horizontally polarized microwaves radiated by the transmitting antenna 11, some of the microwaves become reflected waves 33 that are reflected and propagated on the body surface of the person 20 and reach the first receiving antenna 45. .. When the microwave radiated from the transmitting antenna 11 is linearly polarized, the reflected wave 33 becomes a microwave having the same polarization as the microwave radiated by the transmitting antenna 11 and reaches the first receiving antenna 45.

Since the first receiving antenna 45 is an antenna that receives the polarized microwaves orthogonal to the linearly polarized microwaves radiated from the transmitting antenna 11, it receives the reflected waves 33 reflected by the body surface of the person 20. do not.

As described above, by switching the microwave emitted by the transmitting antenna 11 from vertically polarized waves to horizontally polarized waves, the antenna that receives the microwaves including biological information is changed from the second receiving antenna 46 to the first receiving antenna 45. Can be switched.

Next, the transmitting antenna 11 radiates horizontally polarized microwaves, and then vertically polarized microwaves so that the antenna that receives the microwaves is changed from the second receiving antenna 46 to the first receiving antenna. A mode of switching to 45 will be described. FIG. 10 is a diagram for explaining the polarization state of the microwave in the third embodiment.

When the transmitting antenna 11 emits horizontally polarized microwaves, the polarization filter 41 is vertically polarized with a horizontally polarized body surface wave 30 and a diffracted wave 32, a horizontally polarized transmitted wave 31, and a process of passing through the body. The polarized transmitted wave 31 arrives.

The polarization filter 41 is a filter that transmits vertically polarized microwaves and reflects microwaves other than vertically polarized microwaves. Therefore, the polarization filter 41 transmits only the transmitted wave 31 that has passed through the body of the person 20 and has become vertically polarized.

The second receiving antenna 46 is an antenna that receives a microwave having a polarization orthogonal to the microwave emitted by the transmitting antenna 11, and the second receiving antenna 46 receives a transmitted wave 31 having a vertically polarized wave.

When the transmitting antenna 11 changes the microwave radiated toward the person 20 from the horizontally polarized microwave to the vertically polarized microwave, the polarization filter 41 is subjected to the vertically polarized body surface wave 30 and the diffracted wave 32. The vertically polarized transmitted wave 31 and the horizontally polarized transmitted wave 31 in the process of penetrating the body arrive.

Here, the polarization filter 41 is a filter that transmits vertically polarized microwaves and reflects microwaves of polarization other than vertically polarized waves. Therefore, the polarization filter 41 reflects the transmitted wave 31 that has become horizontally polarized in the process of passing through the body of the person 20.

The horizontally polarized transmitted wave 31 reflected by the polarization filter 41 passes through the body of the person 20 again. The horizontally polarized transmitted wave 31, the vertically polarized transmitted wave 31 in the process of passing through the body, and the vertically polarized reflected wave 33 reflected on the body surface reach the first receiving antenna 45. ..

Since the first receiving antenna 45 is an antenna that receives horizontally polarized microwaves, it receives horizontally polarized transmitted waves 31 that have passed through the body.

Further, among the vertically polarized microwaves radiated by the transmitting antenna 11, some of the microwaves become reflected waves 33 that are reflected and propagated on the body surface of the person 20 and reach the first receiving antenna 45. .. When the microwave radiated from the transmitting antenna 11 is linearly polarized, the reflected wave 33 becomes a microwave having the same polarization as the microwave radiated by the transmitting antenna 11 and reaches the first receiving antenna 45.

Since the first receiving antenna 45 is an antenna that receives the polarized microwaves orthogonal to the linearly polarized microwaves radiated from the transmitting antenna 11, it receives the reflected waves 33 reflected by the body surface of the person 20. do not.

As described above, by switching the microwave emitted by the transmitting antenna 11 from the horizontally polarized wave to the vertically polarized wave, the antenna for receiving the microwave containing the biological information is changed from the second receiving antenna 46 to the first receiving antenna 45. Can be switched.

In the invention according to the third embodiment, the second receiving antenna 46 passes through the body of the person 20 and becomes a polarized wave orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11, and is the second receiving antenna. The transmitted wave 31 that has reached 46 is received. On the other hand, the body surface wave 30 and the microwave 32 which is the diffracted wave 32 are not received.

Therefore, in the invention according to the third embodiment, the influence of the interference with the body surface wave 30, the diffracted wave 32, and the reflected wave 33 is suppressed, and the transmitted wave 31 including the biological information is stably received. Can be done.

Further, the first receiving antenna 45 is transmitted through the body of the person 20, and the transmitted wave 31 reaches the first receiving antenna 45 in a polarized wave orthogonal to the linearly polarized microwave emitted by the transmitting antenna 11. To receive. On the other hand, the first receiving antenna 45 does not receive the reflected wave 33 that is reflected by the body surface of the person 20 and reaches the first receiving antenna 45.

Therefore, in the invention according to the third embodiment, the influence of the interference between the transmitted wave 31 and the reflected wave 33 can be suppressed, and the transmitted wave 31 including the biological information can be stably received.

In the biological information detection system 10 of the third embodiment, the detection of biological information is continued even if a problem occurs in one of the first receiving antenna 45 and the second receiving antenna 46. can do.

For example, when the second receiving antenna 46 is receiving microwaves, the voltage of the power supply device that supplies the power of the second receiving antenna 46 drops, and the second receiving antenna 46 cannot receive the microwaves. In some cases. In this case, by changing the polarization state of the microwave transmitted from the transmitting antenna 11, the first receiving antenna 45 can receive the microwave.

As a result, the biological information detection system 10 can continuously detect the heartbeat of the person 20.

The antenna used in the biological information detection system 10 of the present invention is preferably an antenna with sharp directivity.

(Embodiment 4)
Next, the outline of the biological information detection in the fourth embodiment will be described. FIG. 11 is a diagram illustrating an outline of biometric information detection according to the fourth embodiment. The biological information detection system 10 according to the fourth embodiment has a first receiving antenna 45 and a second receiving antenna 46, and switches between these two receiving antennas to receive microwaves. In the following, a mode in which the second receiving antenna 46 receives the microwave and then switches to the first receiving antenna 45 to receive the microwave will be described.

The transmitting antenna 11 is arranged on one side of the person 20. The one side is, for example, the front side of the person 20. The first receiving antenna 45 is on one side of the person 20 and is arranged side by side with the transmitting antenna 11. The polarization filter 41 is arranged on the other side of the person 20. The other side is, for example, the back side of the person 20. That is, the polarization filter 41 is arranged so as to face the transmitting antenna 11 and the first receiving antenna 45 with the person 20 in between. The second receiving antenna 46 is arranged so as to face the person 20 with the polarization filter 41 interposed therebetween.

The transmitting antenna 11 and the first receiving antenna 45, the polarization filter 41 and the second receiving antenna 46 may be arranged so as to face each other with the person 20 in between, and the transmitting antenna 11 and the first receiving antenna 11 and the first receiving antenna 46 need to be arranged so as to face each other. The antenna 45 may be arranged on the back side of the person 20, and the polarization filter 41 and the second receiving antenna 46 may be arranged on the front side of the person 20.

The transmitting antenna 11 is an antenna that radiates circularly polarized microwaves toward the person 20. The transmitting antenna 11 can switch the polarization state of the microwave and radiate it. As a result, the antenna that receives the microwave radiated from the transmitting antenna 11 can be switched between the first receiving antenna 45 and the second receiving antenna 46. This will be described in detail later.

The first receiving antenna 45 is an antenna that receives microwaves having the same polarization as a predetermined circularly polarized wave radiated by the transmitting antenna 11. When the transmitting antenna 11 emits a circularly polarized microwave, the polarized state of the microwave emitted by the transmitting antenna 11 and the polarized state of the microwave received by the first receiving antenna 45 are the same. , These antennas may be common.

When the second receiving antenna 46 receives the microwave, the polarization filter 41 transmits the polarized microwave orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11 and transmits the first receiving antenna 45. Is a filter that reflects polarized microwaves orthogonal to the circularly polarized microwaves emitted by the transmitting antenna 11 when it receives microwaves. When the circularly polarized microwave is reflected by the polarization filter 41, the rotation direction of the circularly polarized wave is reversed.

The second receiving antenna 46 is an antenna that receives the transmitted wave transmitted through the person 20 and the polarization filter 41.

When a microwave having a predetermined circularly polarized wave is radiated from the transmitting antenna 11, the body surface wave 30 propagating along the surface of the body, the transmitted wave 31 propagating through the body of the person 20, and the person 20 The diffracted wave 32 diffracted and propagated outside the body reaches the polarization filter 41.

Here, some microwaves among the transmitted waves 31 transmitted through the body are repeatedly reflected or diffracted at the boundary surface of the organ 20a having a difference in dielectric constant in the process of transmitting through the body, so that the inside of the human body 20 It is radiated from the body in a polarized state orthogonal to the polarized state when it is incident on.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 passes through the polarization filter 41. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 do not pass through the polarization filter 41.

The transmitted wave 31 that has passed through the polarization filter 41 reaches the second receiving antenna 46.

Since the second receiving antenna 46 is an antenna that receives the microwave having a polarization orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11, the transmitted wave 31 that has reached the second receiving antenna 46 is received. To do.

Therefore, the second receiving antenna 46 can receive only the transmitted wave 31 which has reached the polarization orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11.

Next, when the transmitting antenna 11 switches from a predetermined circularly polarized wave to a polarized wave orthogonal to the predetermined circularly polarized wave and emits microwaves, the body surface wave 30 propagating along the surface of the body and the person 20 The transmitted wave 31 that has passed through the body and propagated, and the diffracted wave 32 that has been diffracted and propagated outside the body of the person 20 reach the polarization filter 41. Since the technique for switching the polarization state of circularly polarized waves is known, detailed description thereof will be omitted here.

As described above, some of the transmitted waves 31 that pass through the body, of which microwaves, are repeatedly reflected or diffracted at the interface of the organs 20a having different dielectric constants in the process of passing through the body, so that the person 20 It is radiated from the body in a polarized state that is orthogonal to the polarized state when it enters the body.

Therefore, the transmitted wave 31 transmitted through the body of the human 20 includes a microwave having the same polarization as the microwave emitted by the transmitting antenna 11 and a microwave having a polarization orthogonal to the microwave.

The transmitted wave 31 whose polarization is orthogonal to the microwave emitted by the transmitting antenna 11 is reflected by the polarization filter 41. On the other hand, the transmitted wave 31, the body surface wave 30, and the diffracted wave 32 having the same polarization as the microwave emitted by the transmitting antenna 11 are not reflected by the polarization filter 41.

The transmitted wave 31 reflected by the polarization filter 41 is incident on the human body 20 again. The transmitted wave 31 incident on the body of the person 20 repeatedly reflects and diffracts inside the body of the person 20, passes through the body, and reaches the first receiving antenna 45.

As described above, when the microwave passes through the body of the human 20, the polarization state of a part of the microwave becomes the polarization orthogonal to the polarization state when it is incident on the body of the person 20.

Therefore, the microwave reaching the first receiving antenna 45 includes a microwave having a predetermined circular polarization and a microwave having a polarization orthogonal to the microwave having a predetermined circular polarization.

Since the first receiving antenna 45 is an antenna that receives microwaves having the same polarization as the microwave having the same polarization as the microwave of the predetermined circular polarization radiated by the transmitting antenna 11, it is the same as the predetermined circular polarization radiated by the transmitting antenna 11. The polarized transmitted wave 31 is received.

Further, among the microwaves having polarized waves orthogonal to the predetermined circularly polarized microwaves emitted by the transmitting antenna 11, some of the microwaves are reflected by the body surface of the person 20 and are emitted by the transmitting antenna 11. The polarization becomes orthogonal to the polarization state of the above and reaches the first receiving antenna 45.

Here, since the first receiving antenna 45 is an antenna that receives microwaves having the same polarization as the microwave emitted by the transmitting antenna 11, it receives the reflected wave 33 reflected by the body surface of the person 20. do not.

As a result, the first receiving antenna 45 can receive only the transmitted wave 31 that has reached the first receiving antenna 45 in the same polarization state as the circularly polarized wave radiated by the transmitting antenna 11.

By switching the polarization state of the microwave radiated by the transmitting antenna 11 in this way, the microwave radiated by the transmitting antenna 11 is switched between the first receiving antenna 45 and the second receiving antenna 46 for reception. can do.

Next, after receiving the circularly polarized microwaves radiated from the transmitting antenna 11 by the second receiving antenna 46, the polarization state of the microwaves when switching to the first receiving antenna 45 and receiving the microwaves is concrete. Explain to.

First, the transmitting antenna 11 radiates microwaves of right-handed circularly polarized waves, and then emits microwaves of left-handed circularly polarized waves, so that the antenna that receives the microwaves is selected from the second receiving antenna 46 to the first. A mode of switching to the receiving antenna 45 will be described. FIG. 12 is a diagram for explaining the polarization state of the microwave in the fourth embodiment.

When the transmitting antenna 11 radiates microwaves of right-handed circularly polarized waves, the polarization filter 41 has a right-handed circularly polarized body surface wave 30 and a diffracted wave 32, a right-handed circularly polarized transmitted wave 31, and an internal body. The transmitted wave 31 that has become left-handed circularly polarized light arrives in the process of transmitting through.

The polarization filter 41 is a filter that transmits microwaves of left-handed circularly polarized waves and reflects microwaves of polarized waves other than left-handed circularly polarized waves. Therefore, the polarization filter 41 transmits only the transmitted wave 31 that has become left-handed circularly polarized wave in the process of transmitting through the body of the person 20.

The second receiving antenna 46 is an antenna that receives the microwave having a polarized wave orthogonal to the microwave emitted by the transmitting antenna 11. Therefore, the second receiving antenna 46 receives the transmitted wave 31 of left-handed circularly polarized waves.

When the transmitting antenna 11 changes the microwave radiated toward the person 20 from a right-handed circularly polarized wave to a left-handed circularly polarized microwave, the polarization filter 41 is charged with a left-handed circularly polarized body surface wave 30. The diffracted wave 32, the left-handed circularly polarized transmitted wave 31, and the right-handed circularly polarized transmitted wave 31 arrive in the process of passing through the body.

Here, the polarization filter 41 is a filter that transmits microwaves of left-handed circularly polarized waves and reflects microwaves of polarized waves other than left-handed circularly polarized waves. Therefore, the polarization filter 41 reflects the transmitted wave 31 that has passed through the body of the person 20 and has become right-handed circularly polarized waves. When the right-handed circularly polarized microwave is reflected by the polarization filter 41, the rotation direction of the circularly polarized wave is reversed, and the microwave becomes a left-handed circularly polarized microwave.

The right-handed circularly polarized wave 31 reflected by the polarization filter 41 passes through the body of the person 20 again. The first receiving antenna 45 includes a right-handed circularly polarized wave 31, a transmitted wave 31 that becomes left-handed circularly polarized wave in the process of passing through the body, and a reflection of right-handed circularly polarized wave reflected on the body surface. Wave 33 arrives.

Since the first receiving antenna 45 is an antenna that receives the left-handed circularly polarized microwave, it receives the left-handed circularly polarized transmitted wave 31 that has passed through the body.

Further, among the right-handed circularly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves become reflected waves 33 that are reflected and propagated on the body surface of the person 20 and become the first receiving antenna 45. To reach. When the microwave radiated from the transmitting antenna 11 is circularly polarized, the reflected wave 33 becomes a polarized microwave orthogonal to the microwave radiated by the transmitting antenna 11 and reaches the first receiving antenna 45.

Since the first receiving antenna 45 is an antenna that receives the microwave having the same polarization as the circularly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20. ..

As described above, by switching the microwave emitted by the transmitting antenna 11 from the right-handed circularly polarized wave to the left-handed circularly polarized wave, the antenna that receives the microwave containing the biological information is first received from the second receiving antenna 46. It can be switched to the antenna 45.

Next, the transmitting antenna 11 radiates microwaves of left-handed circularly polarized waves, and then emits microwaves of right-handed circularly polarized waves, so that the antenna that receives the microwaves is first from the second receiving antenna 46. A mode of switching to the receiving antenna 45 of the above will be described. FIG. 13 is a diagram for explaining the polarization state of the microwave in the fourth embodiment.

When the transmitting antenna 11 emits left-handed circularly polarized microwaves, the polarization filter 41 transmits left-handed circularly polarized body surface waves 30 and diffracted waves 32, left-handed circularly polarized transmitted waves 31, and the body. In the process of doing so, the transmitted wave 31 that has become right-handed circularly polarized waves arrives.

The polarization filter 41 is a filter that transmits microwaves of right-handed circularly polarized waves and reflects microwaves other than right-handed circularly polarized waves. Therefore, the polarization filter 41 transmits only the transmitted wave 31 that has become right-handed circularly polarized wave in the process of transmitting through the body of the person 20.

The second receiving antenna 46 is an antenna that receives the microwave having a polarized wave orthogonal to the microwave emitted by the transmitting antenna 11. Therefore, the second receiving antenna 46 receives the transmitted wave 31 of right-handed circularly polarized waves.

When the transmitting antenna 11 changes the microwave radiated toward the person 20 from the left-handed circularly polarized wave to the right-handed circularly polarized microwave, the polarization filter 41 is subjected to the right-handed circularly polarized body surface wave 30. The diffracted wave 32, the right-handed circularly polarized transmitted wave 31, and the left-handed circularly polarized transmitted wave 31 arrive in the process of passing through the body.

Here, the polarization filter 41 is a filter that transmits microwaves of right-handed circularly polarized waves and reflects microwaves of polarized waves other than right-handed circularly polarized waves. Therefore, the polarization filter 41 reflects the transmitted wave that has passed through the body of the person 20 and has become left-handed circularly polarized wave. When the left-handed circularly polarized microwave is reflected by the polarization filter 41, the rotation direction of the circularly polarized light is reversed, and the microwave becomes a right-handed circularly polarized microwave.

The transmitted wave 31 reflected by the polarization filter 41 passes through the body of the person 20 again. The first receiving antenna 45 reflects the right-handed circularly polarized wave 31 that has passed through the body of the person 20, the left-handed circularly polarized wave 31 that has passed through the body, and the body surface. , The reflected wave 33, which is polarized in a left-handed circle, arrives.

Since the first receiving antenna 45 is an antenna that receives microwaves of right-handed circularly polarized waves, it receives transmitted waves 31 of right-handed circularly polarized waves that have passed through the body.

Further, among the left-handed circularly polarized microwaves radiated by the transmitting antenna 11, some of the microwaves become reflected waves 33 that are reflected and propagated on the body surface of the person 20 and reach the first receiving antenna 45. To do. When the microwave radiated from the transmitting antenna 11 is circularly polarized, the reflected wave 33 becomes a polarized microwave orthogonal to the microwave radiated by the transmitting antenna 11 and reaches the first receiving antenna 45.

Since the first receiving antenna 45 is an antenna that receives the microwave having the same polarization as the circularly polarized microwave radiated from the transmitting antenna 11, it does not receive the reflected wave 33 reflected by the body surface of the person 20. ..

As described above, by switching the microwave emitted by the transmitting antenna 11 from the left-handed circularly polarized wave to the right-handed circularly polarized wave, the antenna that receives the microwave containing the biological information is received from the second receiving antenna 46 to the first. It can be switched to the antenna 45.

In the invention according to the fourth embodiment, the second receiving antenna 46 passes through the body of the person 20 and becomes a polarized wave orthogonal to the circularly polarized microwave emitted by the transmitting antenna 11, and is the second receiving antenna. The transmitted wave 31 that has reached 46 is received. On the other hand, the body surface wave 30 and the microwave 32 which is the diffracted wave 32 are not received.

Therefore, in the invention according to the fourth embodiment, the influence of the interference with the body surface wave 30, the diffracted wave 32, and the reflected wave 33 is suppressed, and the transmitted wave 31 including the biological information is stably received. Can be done.

Further, the first receiving antenna 45 transmits the transmitted wave 31 that has passed through the body of the person 20 and has the same polarization as the circularly polarized wave radiated by the transmitting antenna 11 and has reached the first receiving antenna 45. On the other hand, the first receiving antenna 45 does not receive the reflected wave 33 that is reflected by the body surface of the person 20 and reaches the first receiving antenna 45.

Therefore, in the invention according to the fourth embodiment, the influence of the interference between the transmitted wave 31 and the reflected wave 33 can be suppressed, and the transmitted wave 31 including the biological information can be stably received.

In the biological information detection system 10 of the fourth embodiment, the detection of biological information is continued even if a problem occurs in one of the first receiving antenna 45 and the second receiving antenna 46. can do.

As a result, the biological information detection system 10 can continuously detect the heartbeat of the person 20.

For example, when the second receiving antenna 46 is receiving microwaves, the voltage of the power supply device that supplies power to the second receiving antenna 46 drops, and the second receiving antenna 46 can receive the microwaves. It may disappear. In this case, by changing the polarization state of the microwave transmitted from the transmitting antenna 11, the first receiving antenna 45 can receive the microwave.

The antenna used in the biological information detection system 10 of the present invention is preferably an antenna with sharp directivity.

The biometric information detection system 10 of the first to fourth embodiments can be used, for example, to detect heartbeat information necessary for estimating fatigue and drowsiness of a vehicle driver and passenger. FIG. 14 is a diagram illustrating an outline of biometric information detection of the driver and passenger of the vehicle 50.

Here, when the biometric information detection system 10 is mounted on the vehicle 50 to detect biometric information, it is desirable to stably receive the biometric information of the driver and all passengers. However, if the receiving device 10b including the receiving antenna 12 is installed in all the seats, the cost of the entire system increases.

Therefore, it is preferable to provide the receiving antenna 12 only in the driver's seat where it is necessary to stably receive the heartbeat information, and to install an inexpensive reflector 40 in the other seats. Thereby, it is possible to provide the biological information detection system 10 in which the function and the cost are well-balanced.

The vehicle 50 includes, for example, a console unit (not shown), a driver's seat 51, a passenger seat 52, a left rear seat 53, and a right rear seat 54.

The console unit includes a transmitting antenna 11 and a receiving antenna 12. The backrest portion of the driver's seat 51 is provided with a polarization filter 41 and a second receiving antenna 46. Further, the backrests of the passenger seat 52, the left rear seat 53, and the right rear seat 54 are provided with a reflector 40.

When the transmitting antenna 11 emits a microwave having a predetermined polarization, the polarization filter 41 transmits a transmitted wave 31 having a polarization orthogonal to the microwave having a predetermined polarization in the process of passing through the body of the person 20. The second receiving antenna 46 receives the transmitted wave 31 having a polarized wave orthogonal to the microwave having a predetermined polarized wave.

Further, the reflector 40 reflects a transmitted wave 31 having a polarized wave orthogonal to a microwave having a predetermined polarized wave in the process of transmitting through the body of the person 20, and the first receiving antenna 45 reflects the transmitted wave 31. To receive.

The transmitting / receiving device including the transmitting antenna 11 and the receiving antenna 12 and the receiving device including the second receiving antenna 46 are connected by a CAN (Control Area Network). Further, the transmission / reception device and the reception device are communicably connected to the ECU (Engine Control Unit) of the vehicle 50, and the ECU detects the heartbeat information. Here, the ECU corresponds to the signal processing unit 15 and the determination unit 17 shown in FIG.

As a result, the biometric information detection system 10 detects the biometric information of the driver and the biometric information of the occupant while driving the vehicle 50, and determines whether or not an abnormality has occurred in the driver or the occupant, and the fatigue of the driver or the occupant. The degree can be detected.

Further, in this example, the driver's seat 51 is provided with the polarization filter 41 and the second receiving antenna 46, and the passenger seat 52, the left rear seat 53, and the right rear seat 54 are provided with the reflector 40. I made it. Therefore, the cost of the entire biometric information detection system 10 can be kept low as compared with the case where the second receiving antenna 46 is provided in all the seats.

The biological information detection system 10 of the first embodiment or the second embodiment can be used, for example, to detect the biological information of the person 20 during sleep. FIG. 15 is a diagram illustrating an outline of detection of biological information during sleep of a person.

The transmitting antenna 11 and the receiving antenna 12 are arranged above the person 20. The reflection portion 35 is arranged below the person 20. It is assumed that the person 20 is covered with, for example, a futon 71.

A polarization-selective reflective sheet 42 is used for the reflective unit 35. The reflective sheet 42 is formed of, for example, metal fibers woven into the sheets 70. Further, the reflective sheet 42 may be a metal film formed on a polyethylene sheet bonded to the sheets 70 for the purpose of waterproofing.

The reflective sheet 42 may be provided, for example, on a portion corresponding to the chest of the person 20. In this case, it is preferable to use an antenna having a sharp directivity such as a helical antenna as the transmitting antenna 11 and to concentrate the radiation range of the microwave radiated from the transmitting antenna 11 toward the reflection sheet 42.

The reflecting unit 35 may be a polarization-selective reflector 40. In this case, the reflector 40 is arranged on, for example, a bed, a mattress, or a mattress.

Further, the reflecting unit 35 may be a reflecting sheet 42 or a reflecting plate 40 having no polarization selectivity. In this case, it is desired that the receiving antenna 12 is an antenna having a high degree of suppression against unintended polarization. In particular, when the receiving antenna 12 receives the circularly polarized microwaves, it is desirable that the receiving antenna 12 is an antenna that receives the microwaves having excellent axial ratio characteristics.

The present invention is suitable for use in a biological information detection system that detects biological information of a living body.

10 Biometric information detection system 10a Transmitter 10b Receiver 11 Transmitter antenna 12 Receiving antenna 13 Transmitter 14 Receiver 15 Signal processing unit 16 Control unit 17 Judgment unit 20 people 20a Organ 35 Reflector 40 Reflector 41 Polarization filter 42 Reflection sheet 45 First receiving antenna 46 Second receiving antenna 50 Vehicle 51 Driver's seat 52 Passenger seat 53 Left rear seat 54 Right rear seat 70 Sheets 71 Duvet

Claims (5)

It is a biological information detection system that detects biological information of living organisms.
A transmitting antenna that is placed on one side of the living body and radiates radio waves of predetermined polarization to the living body.
A reflecting unit that is arranged on the other side of the living body and reflects a radio wave having a polarized wave orthogonal to the radio wave of the predetermined polarized wave in the process of passing through the body of the living body.
A receiving antenna arranged on one side of the living body and receiving the radio wave reflected by the reflecting portion, and a receiving antenna.
A detection unit that detects the biological information based on the radio wave received by the receiving antenna, and
A biological information detection system characterized by being equipped with. The biometric information detection system according to claim 1, wherein the reflective unit is a reflector having polarization selectivity. The biometric information detection system according to claim 1, wherein the reflecting unit is a polarization filter that transmits radio waves of the predetermined polarization. A second receiving antenna that receives radio waves of the predetermined polarization that has passed through the polarization filter is further provided.
The biometric information detection system according to claim 3, wherein the detection unit detects the biometric information based on the radio wave of the predetermined polarized wave received by the second receiving antenna. It is a biological information detection method that detects biological information of a living body.
A transmission step of radiating a radio wave having a predetermined polarization from one side of the living body to the living body,
In the process of transmitting through the body of the living body, the polarization becomes orthogonal to the radio wave of the predetermined polarized wave, and the radio wave reflected by the reflecting portion is received by one side of the living body.
A biological information detection method comprising a detection step for detecting the biological information based on the radio wave received in the reception step.

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