JP2008288699A - Portable radio device, and switching method for antenna matching circuit of portable radio device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable radio device capable of improving return loss characteristics when used nearby the head of a human body, and a switching method for an antenna matching circuit of the portable radio device. <P>SOLUTION: Disclosed is the portable radio device capable of changing matching characteristics of the antenna matching circuit 2. The portable radio device has a control unit which switches the antenna matching circuit 4 from matching characteristics 13 for free space to matching characteristics 15 for proximity of a human head part by detecting a predetermined tilt state of a portable radio device case by an angle sensor 6 etc., and also detecting a speech communication state from an opening state etc., of a path of a microphone 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a portable wireless device and a switching method of an antenna matching circuit of the portable wireless device, and more particularly to a portable wireless device such as a mobile phone and a switching method of an antenna matching circuit of the portable wireless device.

  In recent years, portable wireless devices tend to be multifunctional, and many components must be mounted in order to cope with them. Therefore, it is necessary to simplify the circuit configuration and downsize components including the antenna so as to effectively utilize the limited mounting space.

  On the other hand, it is known that the input impedance of the antenna changes when the portable wireless device is brought close to the human head. In particular, since portable wireless devices in recent years have been downsized, the distance between the human head and the antenna has become shorter, and the amount of change in input impedance has increased. As a result, there arises a problem that mismatch loss between the antenna and the radio circuit is increased.

  FIG. 8 is a diagram illustrating an example of characteristic deterioration when the portable wireless device is used near the human head. It is an example of the characteristic in the conventional portable radio | wireless machine, A horizontal axis shows the frequency and the vertical axis | shaft has shown the return loss characteristic. Here, the return loss is the ratio of reflected power (reflection coefficient) to the power input to the antenna, expressed in decibels. The smaller the return loss value, the greater the power radiated from the antenna.

  The dotted line of the characteristic shown in FIG. 8 shows the return loss characteristic in free space, and the solid line shows the return loss characteristic near the human head. As can be seen from the figure, the return loss characteristic in the free space is −10 dB or less in the operating frequency range, whereas the return loss value increases near the human head, which is inconsistent with the radio circuit. There was a problem that the alignment loss increased.

In addition, there has been proposed a mobile phone having a configuration in which impedance matching between the antenna unit and the radio unit is performed depending on whether or not the user is using the mobile phone with his / her ear (see Patent Document 1). This mobile phone detects the presence / absence of D / A conversion or A / D conversion of audio data and whether or not the earphone microphone is attached, performs the D / A (A / D) conversion, and does not attach the earphone microphone. In this case, it is determined that the mobile phone is being used by placing it on the ear, and impedance matching is performed according to the state in which the mobile phone is in close contact with the human body.
JP 2002-152078 A (see FIG. 3)

  As described above, the return loss characteristic of the antenna of a portable radio device is large in the vicinity of the human head even if it is good within a usable frequency range in a free space, and the mismatch loss with the radio circuit becomes large. was there.

  For this reason, in order to control impedance matching between the antenna unit and the radio unit in accordance with the usage status of the portable radio device, a cellular phone configured to determine the usage state applied to the ear is proposed in Patent Document 1. However, in this mobile phone, the usage state applied to the ear is determined by detecting the presence or absence of audio signal processing and the presence or absence of the earphone microphone. In the function of handling audio signals in a separated state and using a microphone and a speaker, it is impossible to perform appropriate impedance matching.

  An object of the present invention is to solve the above problems, and provide a portable wireless device capable of improving the return loss characteristics when used near the human head and a method for switching the antenna matching circuit of the portable wireless device. There is to do.

  Another object of the present invention is to provide a portable radio capable of reliably switching a matching circuit between free space and the vicinity of the human head in order to reduce mismatch loss between the antenna input impedance and the circuit side impedance. An object of the present invention is to provide a method for switching an antenna matching circuit of a portable wireless device.

  The first portable wireless device of the present invention detects a predetermined inclination state of the portable wireless device housing, and detects a call state to switch the antenna matching circuit to matching characteristics for the vicinity of the human head (control circuit). Part or control circuit part and external logic circuit).

  According to the first method for switching an antenna matching circuit of a portable wireless device according to the present invention, when the portable wireless device is in a predetermined tilt state and in a talking state, the antenna matching circuit is made to have matching characteristics for the vicinity of the human head. Switch.

  ADVANTAGE OF THE INVENTION According to this invention, the return loss characteristic at the time of use near a human body head can be improved, and it is possible to improve the antenna characteristic of a portable radio.

  In addition, by applying it to a foldable portable wireless device, it is possible to talk even in a folded state (closed state), and in this case, it is possible to improve the antenna characteristics of the portable wireless device when used near the human head It is.

Example 1
One embodiment of the portable wireless device and the antenna matching circuit of the portable wireless device of the present invention will be described with reference to an example of a folding portable wireless device.

  FIG. 1 is a diagram showing the configuration of this embodiment. The foldable portable wireless device according to the present embodiment includes an upper case and a lower case each configured by engaging a front (front) case and a rear (back) case, and hinges the upper and lower cases at the ends of the two front cases. A cylindrical binge portion to be joined is formed. In addition, the lower housing is provided with a lower substrate 8, and an antenna 1, a matching circuit 2, a feeding terminal 12, a wireless circuit portion 3, a microphone 5 on the lower end side, a control signal line B11, and the like are provided on the lower housing. An upper substrate 7 is provided therein, and a control circuit unit 4, an angle sensor 6, a control signal line A 10, a speaker (not shown) on the upper end side and the like are provided, and in order to connect the lower substrate 8 and the upper substrate 7, The upper and lower substrate connecting portions 9 such as a flexible printed wiring board wound once are provided.

  FIG. 2 is a diagram showing a circuit configuration of this embodiment. Antenna 1, matching circuit 2, wireless circuit unit 3, control circuit unit 4, microphone 5, angle sensor 6, control signal line A10, control signal line B11, free space matching circuit 13, human head vicinity matching circuit 14, The switch 15 includes an AND circuit A16 and a control signal line D18.

  In this embodiment, the antenna 1 is mounted in the vicinity of the hinge portion of the lower housing, and is connected to the matching circuit 2 through the power supply terminal 12 mounted on the lower substrate 8. The matching circuit 2 includes a free space matching circuit 13 mounted on the lower substrate 8, a human head vicinity matching circuit 14, and a switch 15, and is connected to the radio circuit unit 3.

  The matching circuit 2 is a circuit for performing impedance matching between the antenna 1 and the radio circuit unit 3, and the free space matching circuit 13 and the human head vicinity matching circuit 14 are provided between two switching switches 15. Are connected to each other in parallel. The two switches 15 select the matching circuit 13 for free space when the output of the AND circuit A16 is Low, and select the matching circuit 14 for the vicinity of the human head when the output of the AND circuit A16 is High. To do.

  The angle sensor 6 is a device for recognizing a predetermined inclination (rotation) angle in the lateral direction of the portable wireless device with respect to the vertical direction as an angle detection means. When tilted in the lateral direction, data representing the tilted state is output. The angle sensor can be configured using an acceleration sensor.

  The control circuit unit 4 is connected to the radio circuit unit 3 and performs communication control and call control such as incoming and outgoing calls and videophones by wireless communication, browser control such as connection and control of Web and e-mail, transmission and reception, display, etc. Functions such as key input and display control not performed, detection of a call state, generation of a path opening / closing signal of the microphone 5, and connection with the microphone 5 by an audio signal line and a control signal line B11, and an AND circuit A15 Are connected by the control signal line B11 and the control signal line A10, are connected by the angle sensor 6 and the control signal line D18, and a driving signal for operating the microphone by the opening / closing signal is output to the microphone 5 to open / close the path. The AND circuit A16 is controlled based on the data representing the tilt state from the angle sensor 6, and the matching characteristic of the matching circuit 2 is controlled.

  That is, in controlling the matching characteristics of the control circuit unit 4, the call state is determined, the switching signal is generated, the voltage of the control signal line B11 is set high, the path of the microphone 5 is opened, and the angle A table for writing data indicating the tilt state of the portable wireless device input from the sensor 6 is built in, and based on this data, the longitudinal direction (upper and lower casing direction) of the portable wireless device is ± θ or ± θ in the lateral direction with respect to the vertical direction. Is detected and the voltage of the control signal line A10 is output as a High (Low for other data) state, and the control signal lines B11 and A10 are output. The matching characteristic is switched by setting the output of the AND circuit A16 to the high state according to the high state of the voltage.

  In order to realize the above functions, the control circuit unit 4 includes a CPU (Central Processing Unit), a RAM and a ROM storing a program and the like. The CPU reads a program stored in the ROM, and the CPU is controlled by the read program. The respective units can be controlled to realize the respective functions. In this embodiment, the control circuit unit 4 and the AND circuit A16 constitute the control unit of the present invention.

(Description of operation)
Next, the operation principle of the present embodiment will be described in detail with reference to FIGS.
FIG. 3 is a diagram illustrating a usage state of the portable wireless device of the present embodiment, and FIG. 4 is a diagram illustrating an example of characteristics when the portable wireless device is used in the vicinity of the human head of the present embodiment.

  First, the standby state of the portable wireless device will be described. In the standby state, the data indicating the inclination state of the portable wireless device is written in the table in the control circuit unit 4 via the control signal line D18 according to the inclination angle of the portable wireless device (casing) in the side surface direction. Since any inclination angle is obtained in the standby state, the voltage of the control signal line A10 is in a high or low state. On the other hand, in the standby state, the microphone path is closed, and the voltage of the control signal line B11 is low. Accordingly, the output of the AND circuit A16 is in a low state, and the two switches 15 select the matching circuit 13 for free space. As a result, the reflection loss between the antenna 1 and the radio circuit unit 3 can be minimized.

  Next, the call state of the portable wireless device will be described. In a call state, the user tilts the portable wireless device near the human head, so that the voltage of the control signal line A10 is in a high state. Further, the microphone path is open, and the voltage of the control signal line B11 is High. Therefore, since the output of the AND circuit A16 is in a high state, the two switches 15 select the human body matching circuit 14. As a result, the return loss characteristic as shown by the solid line in FIG. 4 is obtained, and the reflection loss can be made smaller than in the case of the free space matching circuit as shown by the dotted line.

  Next, the usage state of the TV phone function and the mail function will be described. The antenna input impedance when using the TV phone function or the mail function is substantially the same as the antenna input impedance in free space because it is away from the human head. Therefore, the antenna 1 and the radio circuit unit 3 can be impedance matched by the free space matching circuit 13.

  When the TV phone function is used, it is assumed that there is no state in which the portable wireless device is tilted in the ± θ direction shown in FIG. 3, and the voltage of the control signal line A10 is in the Low state. On the other hand, the path of the microphone is opened, and the voltage of the control signal line B11 is in a high state. Accordingly, since the output of the AND circuit A16 is in a low state, the two switches 15 are switched to the free space matching circuit 13 side. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  Further, when the mail function is used, the microphone path is closed and the output of the AND circuit A16 is in a low state, so that the two switches 15 select the free space matching circuit 13 side. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  FIG. 5 is a diagram illustrating a circuit state of each unit in a usage state of each function of the portable wireless device. Control signal line A10 based on the output of the sensor 6 in each use state of the portable wireless device, e-mail, telephone call and TV phone, the output of the control signal line B11 for opening and closing the microphone path, the output of the AND circuit A16, matching Each state of the switching of the circuit 2 and the return loss RL is shown.

  As can be seen from the figure, when the output of the AND circuit A16 is in a high state and the switch 15 of the matching circuit 2 is switched and the matching circuit 14 for the vicinity of the human head is selected, the user places the portable radio device on his / her ear. This is only when making a call, and in this case as well, return loss can be minimized as in the case of using standby, e-mail, videophone, and the like. Therefore, even if the impedance changes when the portable wireless device is used in free space or near the human head, matching can be achieved in each case, thereby reducing mismatch loss due to impedance changes that occur during use near the human head. Therefore, the return loss characteristic can be improved, and the antenna characteristic of the portable wireless device can be improved.

(Example 2)
A second embodiment 2 of the present invention will be described in detail with reference to FIGS. The second embodiment is applied to a foldable portable wireless device, and is configured as a portable wireless device capable of making a call even in a folded state.

  FIG. 6 is a diagram showing the configuration of the second embodiment 2 of the portable wireless device and the antenna matching circuit switching method of the portable wireless device of the present invention, and FIG. 7 is a diagram showing the circuit configuration of the second embodiment. is there. In the second embodiment, the Hall IC 19, the control signal line C 17 and the magnet 21 are added to the embodiment shown in FIG. 1, and the circuit configuration thereof is the Hall IC 19, the control signal line C 17, the circuit configuration shown in FIG. E22 and AND circuit 20 are added.

  The Hall IC 19 according to the second embodiment is present in the upper casing, the magnet 21 is present in the lower casing, and the Hall IC 19 and the magnet 21 are arranged so as to approach each other and face each other when the portable wireless device is folded. The Hall IC 19 includes a Hall element as a magnetic sensor and an output shaping circuit, and is an IC device in which the output voltage becomes Low when the magnet 21 approaches, and the output voltage becomes High when the magnet 21 leaves. As a result, when the portable wireless device is in the unfolded state (open state), the magnet 21 and the Hall IC 19 are separated from each other, so the control signal line C17 is in a high state, and when the portable wireless device is folded, they are close to each other. The control signal line C17 is in a low state. The operation of this embodiment will be described below.

  Now, when the portable wireless device is in the open state and in the standby state, the voltage of the control signal line A10 is High or Low depending on the inclination angle of the mobile phone. Since the output of the Hall IC 19 is in a high state in the open state, the output of the AND circuit B20 is in a high or low state. Further, the voltage of the control signal line B11 is always in a low state, and the path of the microphone 5 is closed. Therefore, the output of the AND circuit A16 is in a low state, and the two switches 15 select the matching circuit 13 for free space. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  Next, when a call is made with the cellular phone open, the voltage of the control signal line A10 is in a high state in order to tilt the portable wireless device to the inclination angle θ in the vicinity of the human head. Further, the voltage of the control signal line C17 connected to the Hall IC 19 is in a high state because the portable wireless device is in an open state. For this reason, the output of the AND circuit B20 becomes High. Further, the voltage of the control signal line B11 is High and the microphone path is open. Accordingly, since the output of the AND circuit A16 is in a high state, the two switches 15 select the matching circuit for the vicinity of the human head. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  When the TV phone function is used, it is assumed that the portable wireless device is not tilted in the ± θ direction shown in FIG. 3, and the voltage of the control signal line A10 is in a low state. Further, since the portable wireless device is in the open state, the voltage of the control signal line C17 is in a high state. Therefore, the output of the AND circuit B20 is always in a low state. On the other hand, the voltage of the control signal line B is in a high state and the microphone path is open. Accordingly, since the output of the AND circuit A16 is in a low state, the two switches 15 select the free space matching circuit 13 side. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  Next, when the e-mail function is used, the voltage of the control signal line B is low, the microphone path is closed, and the output of the AND circuit A16 is low. The free space matching circuit 13 side is selected. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  Furthermore, in the second embodiment, it is possible to make a call with the portable wireless device folded. When calling with the portable wireless device folded, the distance between the antenna 1 and the human head can be increased by placing the upper housing between the lower housing containing the antenna 1 and the human head. There is almost no change in antenna impedance between the use of and the use in the vicinity of the human head. In this case, since the portable wireless device is tilted in the vicinity of the human head, the voltage of the control signal line A10 is in a high state. Further, the voltage of the control signal line C17 connected to the Hall IC 19 is in a Low state because the portable radio is folded. For this reason, the output of the AND circuit B20 is in a low state. Further, the voltage of the control signal line B11 is always high, and the microphone path is open. Accordingly, since the output of the AND circuit A16 is in a low state, the two switches 15 select the matching circuit 13 for free space. As a result, the reflection loss between the antenna 1 and the radio circuit can be minimized.

  Even if it is a portable wireless device that can talk in the folded state as described above, it is applied to a portable wireless device that can suppress or prevent the influence of the one housing approaching the head of the human body on the antenna built into the other housing during a call. Is possible. As described above, the application to the folding portable wireless device enables a call even in a folded state, and in this case, it is possible to reduce mismatch loss due to a change in impedance that occurs during use in the vicinity of the human head. It is possible to improve the antenna characteristics of the radio.

(Other examples)
As described above, the present invention has been described based on the first and second embodiments. However, the present invention is not limited to the above-described embodiments, and in order to reduce mismatch loss between the antenna input impedance and the circuit side impedance, Various modifications can be made without departing from the gist of the invention of switching the matching circuit between the vicinity of the human head. For example, although an example of a folding portable wireless device having a casing has been described, the present invention is applicable to a portable wireless device that is not a folding type. In addition, the angle sensor can be installed at an arbitrary position of the upper casing or the lower casing instead of being installed on the upper substrate. Further, instead of detecting the call state / non-call state by the open / close signal of the path of the microphone 5, it is possible to detect the call state / non-call state by the operating state of the voice circuit indicating the call state. In addition, the control by the output of the Hall IC 19 is performed by adding the function of the AND circuit B20 in the control circuit unit 20 instead of adding the AND circuit B20 to control the switching of the matching circuit, and changing the AND circuit B20 from the control circuit unit 20 to the AND circuit. A control signal can be directly output to A16 for control. Further, the function of the AND circuit 16 can be added to the control circuit unit 20 to control switching of the matching circuit 2 from the control circuit unit 20 with a single control signal line. That is, the control circuit unit 4 or the control circuit unit 4 and the external logic circuit (AND circuit A16, AND circuit B20) can constitute the control unit of the present invention. Furthermore, the Hall IC and the magnet can be arranged at arbitrary positions facing each other when the upper and lower housings are closed, and the upper and lower housings are opened and closed using mechanical switches instead of using the Hall ICs. It is also possible to use detection means. Further, in order to enable a call in the folded state in the second embodiment, a speaker and a microphone can be additionally installed on the rear case side of the chassis that approaches the human head during a call.

It is a figure which shows the structure of 1st Example 1 of the portable radio | wireless machine of this invention. 1 is a diagram illustrating a circuit configuration of a first embodiment. It is a figure which shows the use condition of the portable wireless apparatus of the present Example 1, It is a figure which shows the example of a characteristic at the time of use of the portable radio | wireless machine of the human body head vicinity of the present Example 1. FIG. It is a figure which shows the circuit state of each part in each use condition of the portable radio | wireless machine of the present Example 1. FIG. It is a figure which shows the structure of the 2nd Example 2 of this invention. It is a figure which shows the circuit structure of the present Example 2. It is a figure which shows the example of the characteristic degradation at the time of use in the human body head vicinity of a portable radio | wireless machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Matching circuit 3 Wireless circuit part 4 Control circuit part 5 Microphone 6 Angle sensor 7 Upper board 8 Lower board 9 Upper and lower board connection part 10 Control signal line A
11 Control signal line B
12 Feeding terminal 13 Free space matching circuit (element)
14 Matching circuit (element) for human head vicinity
15 switch 16 AND circuit A
17 Control signal line C
18 Control signal line D
19 Hall IC
20 AND circuit B
21 Magnet 22 Control signal line E

Claims (12)

A portable wireless device capable of changing the matching characteristics of the antenna matching circuit, detecting a predetermined tilt state of the portable wireless device housing, and detecting a call state to make the antenna matching circuit a matching characteristic for the vicinity of the human head A portable wireless device comprising a switching control unit. The portable wireless device according to claim 1, wherein the control unit detects the predetermined tilt state based on an output of an angle sensor provided in a portable wireless device housing. The portable wireless device according to claim 1, wherein the control unit detects the call state based on an open state of a microphone path. The said portable radio | wireless machine is a foldable portable radio | wireless machine, The said control part switches the said antenna matching circuit in the expansion | deployment state of the housing of this foldable portable radio | wireless machine. Portable radio. 5. The portable wireless device according to claim 4, wherein a call can be made in a folded state of the folding housing. 6. The portable wireless device according to claim 5, wherein a microphone and a speaker are provided on a rear case side of one housing, and an antenna is provided on the other housing. The portable wireless device according to any one of claims 1 to 6, wherein the inclined state is a predetermined angle state in a longitudinal direction of the casing with respect to a vertical direction. A method for switching an antenna matching circuit of a portable radio, characterized in that the antenna matching circuit is switched to a matching characteristic for the vicinity of the human head when the portable radio is in a predetermined tilt state and in a talking state. 9. The method of switching an antenna matching circuit of a portable wireless device according to claim 8, wherein the portable wireless device is a foldable portable wireless device, and the antenna matching circuit is switched in a deployed state of the casing of the portable wireless device. . 10. The method of switching an antenna matching circuit of a portable wireless device according to claim 9, wherein the portable wireless device is capable of making a call with the housing folded. The method for switching an antenna matching circuit of a portable wireless device according to claim 10, wherein the portable wireless device includes a microphone and a speaker on a rear case side of one housing and an antenna on the other housing. 12. The method for switching an antenna matching circuit of a portable radio device according to claim 8, wherein the predetermined tilt state is a predetermined angle state in a longitudinal direction of the casing with respect to a vertical direction. .

Images