KR20170113135A - Sensor module - Google Patents

Abstract

The present invention relates to a sensor module, and more particularly, to a sensor module that includes a microwave sensor that outputs a signal to the outside, receives a signal reflected from a subject, and outputs information on a frequency difference; And a processor for receiving a signal output from the microwave sensor and calculating a measurement distance.

Description

Sensor module {SENSOR MODULE}

The present invention relates to a sensor module, and more particularly, to a sensor module for measuring a distance to an external subject.

Recently, in order to secure the competitiveness of the convergence industry and the future industry, the development of smart sensor technology is actively proceeding. However, in Korea, smart sensor base technology is very scarce and vulnerable, and more than 70% of sensor demand is imported, and a large number of small-lot production is avoided.

In addition, as the Internet of objects is getting attention, the development of sensors of key technologies of the Internet of things is becoming important, and miniaturized and lightweight sensors are required to be applied to the Internet market of things.

However, conventional sensors have limitations in miniaturization and weight reduction while maintaining their functions, and the function is also a major function of recognizing the subject simply, the image processing is not possible, the detection distance is short, There is a demand for a sensor capable of securing it.

Korean Patent No. 10-0781577

An object of the present invention is to provide a miniaturized and lightweight sensor module for a K-band capable of recognizing the presence or absence of a subject and the size of a subject using a microwave sensor and an antenna.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sensor module that minimizes transmission loss caused by designing a K-band band on a PCB substrate.

According to a first aspect of the present invention, there is provided a sensor module comprising: a microwave sensor for outputting a signal to the outside, receiving a signal reflected from a subject, and outputting information about a frequency difference; And a processor for receiving a signal output from the microwave sensor and calculating a measurement distance.

Preferably, the microwave sensor includes a first antenna for outputting a part of signals generated by the signal generator through a signal distributor to the outside; A second antenna for receiving a return signal reflected from an external subject; A first amplifier for amplifying a signal input by the second antenna; A signal mixer for mixing the signal amplified through the first amplifier and the remaining signal distributed through the signal distributor; A filter for receiving a mixed signal from the signal mixer and detecting a signal corresponding to a specific frequency; A second amplifier receiving a signal detected from the filter and amplifying the signal at an input level that the digital converter can receive; And a digital converter receiving the amplified signal from the second amplifier and converting the amplified signal into digital signal.

Preferably, the first antenna and the second antenna may be microstrip array antennas.

Preferably, the distance between the first antenna and the second antenna is a distance d between the center and the center of the first antenna and the second antenna, and d may be? / 2. Where λ is the wavelength.

Preferably, the processor may calculate a difference frequency using the following equation based on a signal received from the microwave sensor.

[Equation]

Here, f _r is the difference frequency, B is the sweep bandwidth, T _m is the sweep time, and c is the round trip delay.

Preferably, the processor can calculate a distance to an external subject based on the difference frequency using the following equation.

[Equation]

Where R is the distance, B is the sweep bandwidth, T _m is the sweep time, c is the round trip delay, and f _r is the frequency shift due to the time delay.

The apparatus may further include an external connector for receiving a measured distance calculated from the processor and transmitting the measured distance to an external device.

As described above, according to the present invention, since the microwave sensor and the antenna are used, the transmission loss can be minimized and the sensor module can be miniaturized and lightweight.

In addition, since the signal is output to the outside through the antenna and is received from the outside, power consumption of the oscillator inside the microwave sensor can be reduced to reduce the current consumption and improve the recognition distance of the sensor.

Therefore, according to the present invention, it is possible to provide an indoor sensor module capable of distinguishing between a person and an animal by recognizing the presence or absence of the subject and the size of the subject.

1 is a block diagram of a sensor module according to a preferred embodiment of the present invention.
2 is a block diagram of the microwave sensor of FIG.
3 is an exemplary diagram showing the design of the first and second antennas.
4 is an exemplary view showing a design of a filter.
5 is an exemplary diagram showing a design of an amplifier.
6 is an exemplary view showing a link budget of the microwave sensor module.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will be more apparent from the following detailed description taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification. "And / or" include each and every combination of one or more of the mentioned items.

Although the first, second, etc. are used to describe various elements, components and / or sections, it is needless to say that these elements, components and / or sections are not limited by these terms. These terms are only used to distinguish one element, element or section from another element, element or section. Therefore, it goes without saying that the first element, the first element or the first section mentioned below may be the second element, the second element or the second section within the technical spirit of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

1 is a block diagram of a sensor module according to a preferred embodiment of the present invention. Referring to FIG. 1, the sensor module 100 includes a microwave sensor 110 and a processor 120, and may preferably include an external connector 130 for transmitting data to an external device.

Preferably, the microwave sensor 110 outputs a signal to the outside, and when the signal is reflected from an external subject and returns, the signal is processed and then transmitted to the processor 120. The processor 120 may receive the processed signal from the microwave sensor 110 and calculate a distance corresponding to a distance from an external subject. In addition, the data on the measured distance calculated in the processor 120 can be transmitted to the external device by the external connector 130, and the external device can receive data on the measured distance and utilize it in various ways.

Hereinafter, the microwave sensor will be described in more detail with reference to FIG. 2 is a block diagram of a microwave sensor.

2, the microwave sensor 110 includes a first antenna 211, a second antenna 212, a signal generator 230, a signal distributor 240, a signal mixer 250, a filter 260 A first amplifier 271, a second amplifier 272, and a digital converter 280. The first amplifier 271, the second amplifier 272,

The microwave sensor 110 of the present invention includes a first antenna 211 and a second antenna 211. The first antenna 211 is for outputting signals to the outside and the second antenna 212 is for inputting signals from the outside. And 212 can be used to improve the recognition distance with an external subject.

3 is an exemplary diagram showing the design of the first and second antennas. 3, the first antenna 211 and the second antenna 212 may be designed as a microstrip 2X1 phased array antenna, and the radiation characteristics of the antenna may be in the form of an array, The radiation pattern of each device, and the relative magnitude and phase of the unit device current.

Referring to FIG. 3, L of the first antenna 211 and the second antenna 212, which are designed as patch antennas, may have a half wavelength. The distance between the first antenna 211 and the second antenna 212 is the distance d between the center and the center of the first antenna 211 and the second antenna 212, Or from λ / 5 to λ / 7 (where λ is the wavelength), depending on the permittivity or the environment.

The distance between the first antenna 211 and the second antenna 212 when forming the first antenna 211 and the second antenna 212 is one of the important factors that greatly affects the efficiency of the antenna, a beam width, a position of a grating lobe, and the like. For example, if the distance between the first antenna 211 and the second antenna 212 is too close to each other, mutual coupling may occur and the gain and efficiency of the antenna may deteriorate. That is, the side lobe level may be increased, And a null may be generated. Therefore, since the antenna characteristic change and the gain difference are generated due to the mutual interference between the first antenna 211 and the second antenna 212, the characteristics of the change are analyzed, and the first antenna 211 and the second antenna 212, The spacing between the second antennas 212 can be determined.

The microwave sensor 110 may be designed to minimize the matching loss by optimizing the impedance matching between the first antenna 211 and the second antenna 212 when the sensor module 100 is designed.

The first antenna 211 outputs a part of signals generated by the signal generator 230 through the signal distributor 240 to the outside. A signal output to the outside by the first antenna 211 is reflected from an external subject and returns. The second antenna 212 receives a signal that is reflected from an external subject and returns.

The first amplifier 271 amplifies the signal input by the second antenna 212. Since the size of a signal reflected from an external subject such as a person or an object is very small and the Doppler effect is used, the number of frequencies of the signal is only KHz, so that the first amplifier 271 is input by the second antenna 212 Amplifies the frequency level of the received signal. Preferably, the first amplifier 271 and the second amplifier 272 described below may be designed as shown in FIG.

The signal mixer 250 mixes the amplified signal through the first amplifier 271 with the residual signal distributed through the signal distributor 240. That is, the signal mixer 250 mixes the signal transmitted through the microwave sensor 110 with the received signal. The signal mixer 250 mixes signals received through the signal distributor 240 among the signals generated by the signal generator 230, 1 mixer 211 mixes the remaining signal that is not output to the outside with the signal that is input through the second antenna 212 and amplified through the amplifier 271. Here, the frequency difference between the two signals can be obtained by mixing the transmitted signal and the signal reflected from the external subject, and if it is used, information on the distance to the external object through the processor 120, which will be described below, Can be obtained.

The filter 260 receives the mixed signal from the signal mixer 250 and detects a signal corresponding to a specific frequency. Preferably, the filter 260 detects only a desired frequency to remove a spurious signal generated by the harmonic frequency of the oscillator, and may be designed as a low pass filter (LPF) as shown in FIG.

The second amplifier 272 receives the signal corresponding to the specific frequency detected from the filter 260 and amplifies the frequency of the signal to an input level that the digital converter 280 can receive.

The digital converter 280 receives the amplified signal from the second amplifier 272 and converts the amplified signal into a digital signal.

Referring again to FIG. 1, the digital signal output from the microwave sensor 110 is input to the processor 120. As described above, the microwave sensor 110 outputs a part of the signals generated by the signal generator 230 to the outside, receives a signal reflected from an external subject, and outputs a signal generated by the signal generator 230 Mix with the rest of the. Here, the mixed signal has information on the frequency difference between the externally transmitted signal and the externally received signal, and the measured distance can be calculated on the basis of the difference. Accordingly, the mixed signal is processed through the filter 260, the second amplifier 272, and the digital converter 280, and then supplied to the processor 120 to calculate the distance to the external object, i.e., .

The processor 120 receives the digitally converted signal by the digital converter 280 of the microwave sensor 110 and calculates the measured distance. Preferably, the processor 120 calculates a difference frequency using an FFT (Fast Fourier Transform) based on a signal supplied from the microwave sensor 110, and calculates a measurement distance based on the difference frequency. Here, the difference frequency corresponds to the frequency difference between the signal transmitted through the microwave sensor 110 and the received signal.

Preferably, the method of calculating the difference frequency is performed by, for example, assuming that an external subject is stopped at a distance R from the sensor module 100, the microwave sensor 110 of the sensor module 100 When a frequency-modulated signal is transmitted linearly, it is reflected on a subject at a distance R and is received by the microwave sensor 110 of the sensor module 100 after a time delay of 2R / c. When the transmitted signal and the received signal, that is, the signal output from the outside through the first antenna 211 and the signal input from the outside through the second antenna 212 are mixed, the processor 120 The difference frequency can be calculated as shown in the following Equation 1 by receiving the output signal of the microwave sensor 110.

[Formula 1]

Here, f _r is a frequency shift due to the time delay (frequency shift), that is, a difference between the frequency, B is the sweep bandwidth (sweep bandwidth), T _m is the sweep time (sweep time), c is the round trip delay (round trip delay.

Then, the processor 120 can calculate the distance R from the external object through the following Equation 2 based on the difference frequency value calculated by the above-mentioned [Equation 1].

[Formula 2]

R is the distance, B is the sweep bandwidth, T _m is the sweep time, c is the round trip delay, and f _r is the frequency shift due to the time delay.

6 is an exemplary view showing a link budget of the microwave sensor module.

6, the output level of the sensor module should be 0 dBm or more when the height of the inside of the building is 3 m, the gain of the transmission / reception antenna is 10 dBi, and the level of the minimum detection signal (MDS) of the receiver is -70 dBm. The sensor module 100 of the sensor module 100 minimizes the loss generated in the sensor module 100 and thus lowers the output level generated by the microwave sensor 110. Accordingly, There is an effect.

Although the preferred embodiments of the sensor module according to the present invention have been described above, the present invention is not limited thereto, but can be variously modified and embodied within the scope of the claims, the detailed description of the invention, Also belong to the present invention.

100: sensor module 110: microwave sensor
120: processor 130: external connector
211: first antenna 212: second antenna
230: Signal generator 240: Signal distributor
250: Signal mixer 260: Filter
271: first amplifier 272: second amplifier
280: Digital Converter

Claims (7)

A microwave sensor for outputting a signal to the outside, receiving a signal reflected from a subject and outputting information about a frequency difference; And
And a processor for receiving a signal output from the microwave sensor and calculating a measurement distance.
The microwave sensor according to claim 1, wherein the microwave sensor
A first antenna for outputting a part of signals generated by the signal generator through a signal distributor;
A second antenna for receiving a return signal reflected from an external subject;
A first amplifier for amplifying a signal input by the second antenna;
A signal mixer for mixing the signal amplified through the first amplifier and the remaining signal distributed through the signal distributor;
A filter for receiving a mixed signal from the signal mixer and detecting a signal corresponding to a specific frequency;
A second amplifier receiving a signal detected from the filter and amplifying the signal at an input level that the digital converter can receive; And
And a digital converter receiving the amplified signal from the second amplifier and converting the amplified signal to digital.
3. The method of claim 2,
Wherein the first antenna and the second antenna are microstrip array antennas.
The method of claim 3,
Wherein a distance between the first antenna and the second antenna is a distance d between a center and a center of the first antenna and the second antenna, and d is? / 2. Where λ is the wavelength.
2. The apparatus of claim 1, wherein the processor
Wherein the difference frequency is calculated based on a signal input from the microwave sensor using the following equation.
[Equation]

Here, f _r is the difference frequency, B is the sweep bandwidth, T _m is the sweep time, and c is the round trip delay.
6. The apparatus of claim 5, wherein the processor
And calculates a distance to an external subject based on the difference frequency using the following formula.
[Equation]

Where R is the distance, B is the sweep bandwidth, T _m is the sweep time, c is the round trip delay, and f _r is the frequency shift due to the time delay.
The method according to claim 1,
And an external connector for receiving a measured distance calculated from the processor and transmitting the measured distance to an external device.

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