阅读说明：本技术 一种基于fbar振荡器的微波传感器 (Microwave sensor based on FBAR oscillator ) 是由 尹汐漾 霍新平 何婉婧 于 2020-07-10 设计创作，主要内容包括：本发明公开了一种基于FBAR振荡器的微波传感器,包括信号收发单元、混频器单元和基于FBAR谐振器的振荡器单元；所述振荡器单元,用于产生单频点信号,并分别传输给信号收发单元和混频器单元；所述信号收发单元,将来自振荡器单元的信号对外发送,并接收检测对象的反射信号,传输给混频器单元；所述混频器单元,将来自振荡器单元和信号收发单元的信号进行混频后对外输出；所述振荡器单元包括FBAR谐振器U1、三级管Q1、电感L1、第一电阻R1~第六电阻R6,以及第一电容C1~第三电容C3。本发明提供了一种基于FBAR振荡器的微波传感器,具有高Q值,高精度等优势。(The invention discloses a microwave sensor based on an FBAR (film bulk acoustic resonator), which comprises a signal transceiving unit, a mixer unit and an oscillator unit based on the FBAR; the oscillator unit is used for generating single-frequency point signals and respectively transmitting the single-frequency point signals to the signal transceiving unit and the mixer unit; the signal receiving and transmitting unit is used for sending a signal from the oscillator unit to the outside, receiving a reflected signal of a detection object and transmitting the reflected signal to the mixer unit; the mixer unit is used for mixing the signals from the oscillator unit and the signal transceiving unit and then outputting the mixed signals to the outside; the oscillator unit comprises an FBAR resonator U1, a triode Q1, an inductor L1, first to sixth resistors R1 to R6 and first to third capacitors C1 to C3. The invention provides a microwave sensor based on an FBAR oscillator, which has the advantages of high Q value, high precision and the like.)

1. A microwave sensor based on FBAR oscillator, its characterized in that: the frequency mixer comprises a signal transceiving unit, a mixer unit and an oscillator unit based on an FBAR resonator;

the oscillator unit is used for generating single-frequency point signals and respectively transmitting the single-frequency point signals to the signal transceiving unit and the mixer unit;

the signal receiving and transmitting unit is used for sending a signal from the oscillator unit to the outside, receiving a reflected signal of a detection object and transmitting the reflected signal to the mixer unit;

the mixer unit is used for mixing the signals from the oscillator unit and the signal transceiving unit and then outputting the mixed signals to the outside;

the oscillator unit includes: FBAR resonator U1 and triode Q1; the FBAR resonator U1 is connected to the base electrode of the triode Q1 through a fourth resistor R4 and a first capacitor C1 in sequence, and the collector electrode of the triode Q1 is connected to a VCC power supply port through a third resistor R3; the common end of the third resistor R3 and the VCC power supply port is grounded through a second resistor R2 and a first resistor R1 in sequence; the common end of the first resistor R1 and the second resistor R2 is connected to the base electrode of a triode Q1; an emitter of the triode Q1 is grounded through a sixth resistor R6 and an inductor L1 in sequence; the collector of the triode Q1 is also connected with a second capacitor C2 which is grounded, and the emitter of the triode Q1 is also connected with a third capacitor C3 and a fifth resistor R5 which are grounded in parallel; and the collector of the triode Q1 is used as the output end of the oscillator unit and is respectively connected with the signal transceiving unit and the mixer unit.

2. A FBAR oscillator based microwave sensor as claimed in claim 1 wherein: the signal transceiving unit is an antenna unit.

3. A FBAR oscillator based microwave sensor as claimed in claim 1 wherein: the mixer unit comprises a mixer, a filter and an intermediate-frequency signal output port, one input end of the mixer is connected with the output end of the oscillator unit, the other input end of the mixer is connected with the output end of the signal receiving and transmitting unit, and the output end of the mixer is connected with the intermediate-frequency signal output port through the filter.

4. A FBAR oscillator based microwave sensor as claimed in claim 1 wherein: in the oscillator unit, the connection among the elements is realized through microstrip lines to form a microstrip oscillator circuit.

Technical Field

The invention relates to the technical field of microwaves, in particular to a microwave sensor based on an FBAR oscillator.

Background

With the rise of smart homes in recent years, more and more smart devices enter all corners of the society. In the application of the smart device, sensing of a moving object and measuring of the speed of the object are one of the key fields of the application of the smart device (such as an intelligent sensing lamp, doppler radar speed measurement, etc.). For the measurement of a moving target, a doppler radar is currently used to measure the velocity of the moving target, and the velocity information of the moving target can be obtained through different calculations. For the conventional doppler radar sensor at present, a combination of a microstrip oscillator, a passive mixer and an antenna is often adopted to form a sensor front end. The single frequency point signal is generated by the microstrip oscillator and is transmitted out through the mixer and the antenna. When the signal returns, the return signal and the signal generated by the oscillator are mixed in the mixer, and the intermediate frequency signal generated after mixing is sent to the back end signal processing part for calculation, so that the speed information of the target is obtained.

However, in the current doppler radar sensor, because the Q value of the microstrip line is not high, the phase noise performance of the oscillator designed by using the microstrip line is not good enough, and generally, an RC oscillator is used to generate a signal required for testing, and an RC phase shift network is used as a feedback loop, the frequency of the oscillator depends on the value of the RC, because the RC oscillator has larger discrete resistance and capacitance, and meanwhile, the accuracy of the whole temperature and the working power supply voltage range is poorer, and the output error is larger.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a microwave sensor based on an FBAR oscillator, which has the advantages of high Q value, high precision and the like.

The purpose of the invention is realized by the following technical scheme: a microwave sensor based on an FBAR oscillator comprises a signal transceiving unit, a mixer unit and an oscillator unit based on an FBAR resonator;

the oscillator unit is used for generating single-frequency point signals and respectively transmitting the single-frequency point signals to the signal transceiving unit and the mixer unit;

the signal receiving and transmitting unit is used for sending a signal from the oscillator unit to the outside, receiving a reflected signal of a detection object and transmitting the reflected signal to the mixer unit;

the mixer unit is used for mixing the signals from the oscillator unit and the signal transceiving unit and then outputting the mixed signals to the outside;

the oscillator unit includes: FBAR resonator U1 and triode Q1; the FBAR resonator U1 is connected to the base electrode of the triode Q1 through a fourth resistor R4 and a first capacitor C1 in sequence, and the collector electrode of the triode Q1 is connected to a VCC power supply port through a third resistor R3; the common end of the third resistor R3 and the VCC power supply port is grounded through a second resistor R2 and a first resistor R1 in sequence; the common end of the first resistor R1 and the second resistor R2 is connected to the base electrode of a triode Q1; an emitter of the triode Q1 is grounded through a sixth resistor R6 and an inductor L1 in sequence; the collector of the triode Q1 is further connected with a second grounded capacitor C2, the emitter of the triode Q1 is further connected with a third grounded capacitor C3 and a fifth grounded resistor R5 in parallel, and the collector of the triode Q1 is used as the output end of the oscillator unit and is respectively connected with the signal transceiving unit and the mixer unit.

Preferably, the signal transceiving unit is an antenna unit, and the antenna unit may adopt one of a microstrip antenna, a dipole antenna, a monopole antenna and a helical antenna.

The mixer unit comprises a mixer, a filter and an intermediate-frequency signal output port, one input end of the mixer is connected with the output end of the oscillator unit, the other input end of the mixer is connected with the output end of the signal receiving and transmitting unit, and the output end of the mixer is connected with the intermediate-frequency signal output port through the filter.

Preferably, in the oscillator unit, the connection between the elements is realized by a microstrip line, so as to form a microstrip oscillator.

The invention has the beneficial effects that: based on the high Q value characteristic of the FBAR, the phase noise of an oscillator unit (FBAR oscillator) is low, the detection precision of the sensor is effectively improved, and the FBAR oscillator has the advantages of simple structure and convenience in integration; meanwhile, the microstrip antenna is adopted to transmit and receive signals, has the advantages of ground profile, high efficiency, easy processing and the like, and effectively simplifies the circuit.

Drawings

FIG. 1 is a functional block diagram of the present invention;

FIG. 2 is a circuit schematic of an oscillator unit;

FIG. 3 is a schematic diagram of one embodiment of a microwave sensor;

FIG. 4 is a diagram illustrating harmonic frequency simulation results of an oscillator unit;

FIG. 5 is a diagram illustrating phase noise simulation results of an oscillator unit;

in the figure, 1-mixed oscillation layer, 2-metal grounding layer, 3-antenna layer.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.

As shown in fig. 1, a microwave sensor based on an FBAR oscillator includes a signal transceiving unit, a mixer unit, and an oscillator unit based on an FBAR resonator;

the oscillator unit is used for generating single-frequency point signals and respectively transmitting the single-frequency point signals to the signal transceiving unit and the mixer unit;

the signal receiving and transmitting unit is used for sending a signal from the oscillator unit to the outside, receiving a reflected signal of a detection object and transmitting the reflected signal to the mixer unit;

the mixer unit is used for mixing the signals from the oscillator unit and the signal transceiving unit and then outputting the mixed signals to the outside;

as shown in fig. 2, the oscillator unit includes: FBAR resonator U1 and triode Q1; the FBAR resonator U1 is connected to the base electrode of the triode Q1 through a fourth resistor R4 and a first capacitor C1 in sequence, and the collector electrode of the triode Q1 is connected to a VCC power supply port through a third resistor R3; the common end of the third resistor R3 and the VCC power supply port is grounded through a second resistor R2 and a first resistor R1 in sequence; the common end of the first resistor R1 and the second resistor R2 is connected to the base electrode of a triode Q1; an emitter of the triode Q1 is grounded through a sixth resistor R6 and an inductor L1 in sequence; the collector of the triode Q1 is further connected with a second grounded capacitor C2, the emitter of the triode Q1 is further connected with a third grounded capacitor C3 and a fifth grounded resistor R5 in parallel, and the collector of the triode Q1 is used as the output end of the oscillator unit and is respectively connected with the signal transceiving unit and the mixer unit.

In the oscillator unit, the connection among all elements is realized through microstrip lines to form a microstrip circuit, and the whole circuit is a negative resistance oscillator circuit, consists of a negative resistance device and a frequency selection network and respectively corresponds to a triode and an FBAR resonator; resistors R1, R2 and R3 are bias resistors of a triode Q1, the triode works in an amplification area, the triode adopts BFP520, the working point is IC =20mA, VCE =2V, VCC is used for supplying power to the triode, and the power supply voltage is 5V; c1 is a coupling capacitor, C2 is used to eliminate the effect of the bias circuit on the oscillator at radio frequency, and C2 is implemented with a sectorial microstrip. C3, R5, R6 and L1 form a regulating circuit and can be realized by adopting microstrip lines; the triode works in an unstable state by adjusting the microstrip line of the emitter of the triode, and the sum of the phases of the triode and the FBAR can meet the phase stability condition of the oscillator and simultaneously change the working frequency of the oscillator by adjusting the length of the microstrip line of the base of the triode.

The signal receiving and transmitting unit is an antenna unit, and the antenna unit can adopt one of a microstrip antenna, a dipole antenna, a monopole antenna and a helical antenna.

The mixer unit comprises a mixer, a filter and an intermediate-frequency signal output port, one input end of the mixer is connected with the output end of the oscillator unit, the other input end of the mixer is connected with the output end of the signal receiving and transmitting unit, and the output end of the mixer is connected with the intermediate-frequency signal output port through the filter. In the embodiment of the present application, the mixer unit adopts a microstrip structure, wherein the mixer adopts a mixing ring diode for mixing, specifically, a diode mixer HSMS2862 is adopted; the mixer, the filter and the intermediate frequency output port are connected through a microstrip line; and the filter can adopt a fan-shaped microstrip filter to filter the influence of the radio frequency signal on the intermediate frequency.

As shown in fig. 3, in some embodiments, the whole microwave sensor is a multi-layer integrated structure, which includes a top-down mixing oscillation layer 1, a metal ground layer 2 and an antenna layer 3, and the multi-layer structure may be fixed by common means such as adhesion, pressing, welding, etc.; the frequency mixing oscillation layer comprises a dielectric substrate, and the oscillator unit and the mixer unit are integrated on the upper surface of the dielectric substrate in a microstrip circuit mode; the metal grounding layer is a metal sheet; the antenna layer 3 comprises an FR4 dielectric slab with the thickness of 1mm and a radiation patch arranged on the lower surface of the dielectric slab, and the dielectric slab, the radiation patch and the metal grounding layer form a microstrip antenna; the radiation patch is electrically connected with the oscillator unit and the mixer unit by penetrating through the frequency mixing oscillation layer 1, the metal grounding layer 2, the antenna layer 3 and the via hole, namely, the connection of the microstrip antenna with the mixer unit and the oscillator unit is realized; in other embodiments, the microwave sensor may also be a split structure, and the microstrip antenna is formed by a metal ground layer, an FR4 dielectric board and a radiation patch in the same manner, and the oscillator unit and the mixer unit are integrated on another dielectric board, and the microstrip antenna is connected with the mixer unit and the oscillator unit by a feeder line. In other embodiments, the antenna may be another type of antenna (e.g., a dipole antenna, a monopole antenna, a helical antenna, etc.), and is electrically connected to the mixer unit and the oscillator unit through the metalized vias.

As shown in fig. 4, which is a harmonic frequency table of simulation results of the oscillator unit in the present application, the frequency at the fundamental frequency is 6GHz, that is, the oscillation frequency of the oscillator is 6GHz, as shown in fig. 5, which is a phase noise simulation diagram of the oscillator unit, the phase noise of the output signal at the position of 100kHz is-144 dBc @100kHz, and the phase noise is good, so that the detection accuracy of the sensor is high.

The foregoing is a preferred embodiment of the present invention, it is to be understood that the invention is not limited to the form disclosed herein, but is not to be construed as excluding other embodiments, and is capable of other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.