High-isolation miniaturized double-panel circular antenna and application

Abstract

The invention relates to a high-isolation miniaturized double-panel circular antenna and application. According to the low-power-consumption Doppler effect radar sensor, the length and the position of the feedback short line are adjusted, the shape of the antenna oscillator is adjusted, in addition, the length of the transmitting feeder line is limited, the antenna isolation degree is finally improved, the performance of the low-power-consumption Doppler effect radar sensor is improved, and the low-power-consumption Doppler effect radar sensor is suitable for a low-cost double-panel radar module and can be used for multiple scenes such as low-cost radars and RFID transceivers. Compared with the prior art, the antenna has the beneficial effects that the isolation degree of the antenna is improved while the small size is provided, the noise of the radar module is greatly reduced, and the induction distance is greatly increased. The problem that the 1mA low-power-consumption radar module is applied to the bulb lamp is solved, the production cost is greatly reduced, and the high commercial value is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of electronic equipment and electronic devices, in particular to a high-isolation miniaturized double-panel circular antenna and its application. Background Art

[0002] The cost of 5.8GHz Doppler effect radar sensor chips is close to or even lower than that of discrete radar solutions, and radar solutions are more suitable for bulbs than infrared pyroelectric solutions. However, the power supply of the radar module restricts the cost of radar sensor lights. Under normal circumstances, a DC-DC switching power supply chip with a voltage resistance of more than 300V is required, combined with a freewheeling inductor, to obtain 5V DC power for the radar module. This power supply solution requires an additional cost of about 1 yuan, which limits the widespread use of radar modules of about 2 yuan in bulbs. Figure 6 As shown, if the radar module consumes 1mA, then a resistor RL of about 300k ohms is used to draw power from the high-voltage direct current (about 300V, i.e. 220V*1.414) output by the silicon bridge (four rectifier diodes), and a diode (voltage regulator diode, clamping diode or protection transistor) and a low-voltage filter capacitor (generally with a withstand voltage value of less than or equal to 50V) are used. When the current is less than 1mA, the power consumption is less than 300mW. Under the condition that the radar sensor light is powered on 24 hours a day, the power consumption of 300mW is less than 1 kWh in 138 days. If a 10W radar sensor light saves electricity for 4 hours a day (the actual power saving time in a public corridor with fewer people can reach more than 6 hours a day), 1 kWh of electricity can be saved in 25 days, which can not only make up for the power supply loss, but also save nearly 1 kWh of electricity every quarter.

[0003] However, a low-power radar chip of about 1mA is generally the same chip as a radar chip of about 50uA in a battery-powered product, except that the duty cycle of the intermittent operation of the RF circuit is different (the 50uA radar chip uses a duty cycle of 1 / 500 to 1 / 1000, and the 1mA radar chip uses a duty cycle of 1 / 25 to 1 / 50). In order to support ultra-low power consumption, the operating current of the intermediate frequency amplifier on the radar chip is generally less than 10uA. With such low power consumption, it is difficult for the intermediate frequency amplifier to maintain extremely high common-mode rejection ratio and open-loop gain. Therefore, whether it is a differential active mixer plus a differential amplifier solution or a passive double-balanced mixer plus a differential transconductance amplifier solution, it is difficult to maintain high common-mode rejection capability to eliminate common-mode interference caused by power supply interference (the interference path is generally electromagnetic field interference through the frequency source, namely the internal inductive coupling of the chip of the voltage-controlled oscillator (VCO)). Generally, in this low-cost bulb power solution, the rectifier silicon bridge, high-voltage filter capacitor (usually 3.3uF aluminum electrolytic capacitor with a withstand voltage of 400V), LED driver chip, freewheeling inductor and about 10 LED lamp beads are all welded on the circuit board made of aluminum substrate. Even if the four-layer back-fed antenna itself has a high transmit-receive isolation, because the chip on the four-layer board is on the back of the antenna, that is, very close to the power board with LED lamp beads (the distance between the radar module and the power board is generally less than or equal to 5 mm), this low-cost power solution has a lot of interference and it is extremely difficult to meet the detection requirements of 3 meters hanging height and 3 meters sensing radius.

[0004] Antennas are often used in the transmitting and receiving ports of SOC chips with integrated radio frequency. For situations where cost requirements are relatively high, double-sided boards are a cost-effective choice because they are cheaper than four-layer boards. Moreover, because the radar chip of the double-sided board radar module is on the antenna surface, it is isolated from the LED driver power supply by a layer of ground (the chip is also isolated again by the heat dissipation pad). However, the conventional double-sided board edge-fed antenna is large in size and poor in isolation, resulting in its cost being comparable to that of a four-layer board. In addition, the oversized size easily blocks the light of the lamp beads in the bulb and creates a shadow in the center. If the size of the double-layer circuit board is the same as that of the four-layer board, in general, the double-sided board antenna cannot meet the requirements of a hanging height of 3 meters and a sensing radius of 3 meters due to the low isolation between the transmitter and the receiver.

[0005] The reasons why the radar module sensing distance is too close when the antenna isolation is poor are as follows: Doppler sensing radar belongs to a self-mixing system, and transmission and reception are carried out simultaneously. Because the system's transmission and reception isolation is limited, part of the transmission signal will directly return to the receiving end, forming a self-mixing DC level. Although the DC level can be eliminated by a DC blocking capacitor, because the Doppler frequency is very low, the phase noise of the frequency source will form low-frequency noise through the self-mixing effect, becoming the main noise source of the radar system. Although this low-frequency noise is partly derived from the 1 / f noise of the mixer and the intermediate frequency amplifier, the main source of noise is the near-end phase noise of the voltage-controlled oscillator. Even if the phase-locked loop technology is used to greatly improve the phase noise in the loop at a slightly farther position, it is difficult to reduce the near-end phase noise. Doppler sensing radar chips with phase-locked loops have high power consumption and high cost, and require external crystal oscillators, which are at a cost and power consumption disadvantage in low-end applications of smart lighting. For example, for a 5.8GHz Doppler radar module, when a person walks at 1 meter per second, the Doppler frequency is 38Hz. This low-frequency phase noise is difficult to improve by optimizing the voltage-controlled oscillator. The main method in the industry is to improve the isolation between transmitters and receivers. For low-power radar modules of around 1mA, the market urgently needs a double-layer circuit board transceiver integrated antenna with an isolation of more than 40dB. Summary of the invention

[0006] The purpose of the present invention is to provide a high-isolation miniaturized double-panel circular antenna for use in Doppler effect radar sensors. It achieves an isolation effect similar to a 4-port bridge through the feeder length and antenna shape, improves antenna isolation, and improves the performance of low-power Doppler effect radar sensors. It is suitable for low-cost double-panel radar modules and can be used in multiple scenarios such as low-cost radars and RFID transceivers.

[0007] The present invention is implemented by the following technical scheme: a high-isolation miniaturized double-panel circular antenna, characterized in that: it includes a PCB board 9, and the PCB board 9 is divided into a top layer and a bottom layer; the top layer is formed by copper plating to form an antenna vibrator 1, a feed line, a chip pin and a ground line, and the remaining area is a blank area for green oil and silk screen printing, and the bottom layer is a whole layer of ground copper foil;

[0008] The antenna vibrator 1 is circular, and two feeding points are provided on the antenna vibrator 1, wherein the angle between the two feeding points and the line connecting the center of the antenna vibrator 1 is 90 degrees; a slot 11 is opened in the antenna vibrator 1 starting from the feeding point and along the radius of the circle, wherein an antenna transmitting feed line 2 connected to the feeding point and extending from the antenna vibrator 1 is provided in one of the slots 11, and an antenna receiving feed line 3 connected to the feeding point and extending from the antenna vibrator 1 is provided in the other slot 11; antenna grounding vias 12 are provided on both sides of any slot 11, and the two antenna grounding vias 12 corresponding to any slot 11 are located at the bottom layer of the PCB board 9 and connected through the copper sheet 8;

[0009] The antenna receiving feeder 3 is adjacent to the receiving pin 41 of the chip pin and connected to the receiving pin 41, and the transmitting pin 42 of the chip pin is also connected to a transmitting feeder, wherein the transmitting feeder is further divided into a transmitting feeder section A 51, a transmitting feeder section B 52, a transmitting feeder section C 53, and a transmitting feeder section D 54; the transmitting feeder section A 51 is connected to the transmitting pin 42, and the transmitting feeder section A 51 overlaps with the tangent line of the circle passing through the transmitting pin 42 in the antenna vibrator 1, the transmitting feeder section C 53 is a straight line and parallel to the side of the PCB board 9, the transmitting feeder section B 52 is an arc segment and its two ends are respectively connected to the transmitting feeder section A 51 and the transmitting feeder section C 53, and the transmitting feeder section D 54 is an arc segment and its two ends are respectively connected to the transmitting feeder section C 53 and the antenna transmitting feeder 2; both sides of the transmitting feeder are ground wires with multiple coplanar line grounding vias 6;

[0010] A feedback short line 7 is connected to the antenna grounding via 12 on one side of the antenna receiving feeder 3. The size of the feedback signal is adjusted by adjusting the length of the feedback short line 7 and the distance between the feedback short line 7 and the transmitting feeder so that the size of the feedback signal is equal to the size of the leakage signal from the antenna to the receiver.

[0011] Furthermore, the antenna transmitting feeder line 2 is laid in the slot 11 so that a gap is formed between the antenna transmitting feeder line 2 and the antenna vibrator 1, and the width of the gap is 1 / 3 of the width of the antenna transmitting feeder line 2; the antenna receiving feeder line 3 is laid in the slot 11 so that a gap is formed between the antenna receiving feeder line 3 and the antenna vibrator 1, and the width of the gap is 1 / 3 of the width of the antenna receiving feeder line 3.

[0012] Furthermore, the transmitting feeder, the copper sheet 8, the antenna transmitting feeder 2, and the antenna receiving feeder 3 are all of equal width to ensure the same characteristic impedance.

[0013] Furthermore, the total length of the transmitting feed line is equal to 1 / 2 wavelength.

[0014] Furthermore, the chip pin is also provided with a chip grounding via 43; or a center via is provided at the center of the antenna element 1 for grounding.

[0015] Furthermore, the PCB board 9 is a double-sided board with a thickness of 1.6±0.1 mm.

[0016] Furthermore, the length of the outer end of the antenna transmission feed line 2 extending from the edge of the antenna element 1 is 3±1 mm.

[0017] The application of the high-isolation miniaturized double-panel circular antenna in a low-power radar module.

[0018] Compared with the previous technology, the beneficial effects of the present invention are:

[0019] 1. While providing a small size, it improves the isolation of the antenna, greatly reduces the noise of the radar module, and greatly increases the sensing distance.

[0020] 2. It solves the problem of applying 1mA low-power radar module to bulb lamps and greatly reduces production costs, which has high commercial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the outline of the high-isolation circular antenna before the feedback signal size on the top layer of the antenna is adjusted.

[0022] Figure 2 This is the outline diagram of the high-isolation circular antenna after the feedback signal size on the top layer of the antenna is adjusted.

[0023] Figure 3 This is the outline diagram of the high isolation circular antenna at the bottom layer of the antenna.

[0024] Figure 4 The radar module noise floor (left half white) and hand-wave Doppler (right half white) waveforms before the feedback signal size is adjusted.

[0025] Figure 5 The radar module noise floor (left half white) and hand-wave Doppler (right half white) waveforms after the feedback signal size is adjusted.

[0026] Figure 6 Schematic diagram of the circuit for the radar sensor light powered by resistor voltage divider.

[0027] Explanation of the reference numbers: 1-antenna vibrator, 11-slot, 12-antenna ground via, 2-antenna transmitting feeder, 3-antenna receiving feeder, 41-receiving pin, 42-transmitting pin, 43-chip ground via, 51-transmitting feeder section A, 52-transmitting feeder section B, 53-transmitting feeder section C, 54-transmitting feeder section D, 6-coplanar line ground via, 7-feedback short line, 8-copper sheet, 9-PCB board DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings:

[0029] like Figure 1-3 As shown: a high-isolation miniaturized double-panel circular antenna, including a PCB board 9, the PCB board 9 is divided into a top layer and a bottom layer; the top layer is formed by copper plating to form an antenna vibrator 1, a feed line, a chip pin and a ground line, the remaining area is a blank area for green oil and silk screen printing, and the bottom layer is a whole layer of ground copper foil;

[0030] The antenna vibrator 1 is circular, and two feeding points are provided on the antenna vibrator 1, wherein the angle between the two feeding points and the line connecting the center of the antenna vibrator 1 is 90 degrees; a slot 11 is opened in the antenna vibrator 1 starting from the feeding point and along the radius of the circle, wherein an antenna transmitting feed line 2 connected to the feeding point and extending from the antenna vibrator 1 is provided in one of the slots 11, and an antenna receiving feed line 3 connected to the feeding point and extending from the antenna vibrator 1 is provided in the other slot 11; antenna grounding vias 12 are provided on both sides of any slot 11, and the two antenna grounding vias 12 corresponding to any slot 11 are located at the bottom layer of the PCB board 9 and connected through the copper sheet 8;

[0031] The antenna receiving feeder 3 is adjacent to the receiving pin 41 of the chip pin and connected to the receiving pin 41, and the transmitting pin 42 of the chip pin is also connected to a transmitting feeder, wherein the transmitting feeder is further divided into a transmitting feeder section A 51, a transmitting feeder section B 52, a transmitting feeder section C 53, and a transmitting feeder section D 54; the transmitting feeder section A 51 is connected to the transmitting pin 42, and the transmitting feeder section A 51 overlaps with the tangent line of the circle passing through the transmitting pin 42 in the antenna vibrator 1, the transmitting feeder section C 53 is a straight line and parallel to the side of the PCB board 9, the transmitting feeder section B 52 is an arc segment and its two ends are respectively connected to the transmitting feeder section A 51 and the transmitting feeder section C 53, and the transmitting feeder section D 54 is an arc segment and its two ends are respectively connected to the transmitting feeder section C 53 and the antenna transmitting feeder 2; both sides of the transmitting feeder are ground wires with multiple coplanar grounding vias 6;

[0032] A feedback short line 7 is connected to the antenna grounding via 12 on one side of the antenna receiving feeder 3. The size of the feedback signal is adjusted by adjusting the length of the feedback short line 7 and the distance between the feedback short line 7 and the transmitting feeder so that the feedback signal size is equal to the leakage signal size from the antenna's transmission to the reception.

[0033] The antenna vibrator of the present invention is circular, and the radius of the antenna vibrator is determined by the simulation of the electromagnetic wave wavelength of the antenna operating frequency. The position of the feeding point is similar to that of the ordinary four-layer back-fed antenna, the angle between the feeding point and the center of the antenna vibrator circle is 90 degrees, and the distance between the feeding point and the center of the antenna vibrator circle is determined by the simulation of the electromagnetic wave wavelength of the antenna operating frequency.

[0034] The antenna transmitting feeder line 2 is laid in the slot 11 so that a gap is formed between the antenna transmitting feeder line 2 and the antenna vibrator 1, and the width of the gap is 1 / 3 of the width of the antenna transmitting feeder line 2; the antenna receiving feeder line 3 is laid in the slot 11 so that a gap is formed between the antenna receiving feeder line 3 and the antenna vibrator 1, and the width of the gap is 1 / 3 of the width of the antenna receiving feeder line 3.

[0035] Furthermore, the transmitting feeder, the copper sheet 8, the antenna transmitting feeder 2, and the antenna receiving feeder 3 are all of equal width to ensure the same characteristic impedance.

[0036] from Figure 1 It can be seen that, starting from the feeding point, slots are made along the radius of the circle. In addition, the feed line uses coplanar lines and microstrip lines for impedance transformation. Because slotting destroys the problem of electromagnetic waves moving along the metal edge, it is necessary to provide antenna grounding vias 12 on both sides of the slot. The antenna grounding vias 12 are connected with copper foil on the reverse side (bottom layer) of the antenna vibrator. The width of the connecting copper foil is the same as the width of the feed line (including the transmitting feed line, antenna transmitting feed line 2, and antenna receiving feed line 3), that is, the characteristic impedance is the same, and both are designed according to 50 ohms.

[0037] During the design process, the antenna receiving feed line 3 is very close to the receiving pin 41 of the chip pin in the radar chip, which is beneficial to reducing the receiving insertion loss and improving the receiving signal amplitude.

[0038] The total length of the transmitting feed line is equal to 1 / 2 wavelength.

[0039] It should be noted that the shape and length of the transmitting feeder of the present invention are very critical. The transmitting feeder starts from the transmitting pin 42 and is divided into four sections: transmitting feeder section A 51, transmitting feeder section B 52, transmitting feeder section C 53, and transmitting feeder section D 54. Among them, the transmitting feeder section A extends outward in a straight line close to the tangent of the circle to improve the antenna isolation; to further improve the isolation; the transmitting feeder is designed according to the 50 ohm impedance matching of the coplanar line (the internal impedance of the transmitting port of the chip is 50 ohms). The transmitting feeder section B is connected to the C section with an arc line, and the C section is a straight line parallel to the edge of the radar module PCB board to reduce the size. The transmitting feeder section D is connected to the transmitting feeder of the antenna with an arc line.

[0040] In addition, the length of the outer end of the antenna transmission feed line 2 extending from the edge of the antenna vibrator 1 is 5±1 mm. Specifically, the antenna transmission feed line 2 extends outwardly about 5 mm along the circular diameter direction, further improving the isolation.

[0041] Both sides of the transmitting feed line are ground wires with multiple coplanar line ground vias 6; laying ground wires can also be used here.

[0042] Another key link of the present invention is the feedback short line. When the total length of the transmission feed line is approximately equal to 1 / 2 wavelength, the transmission feed line has a phase shift of about 180 degrees. In addition, the transmission to reception leakage of the antenna has a phase shift of about 90 degrees. Therefore, the feedback signal coupled by the parasitic capacitance between the feedback short line and the transmission feed line has a phase shift of about 90 degrees; that is, at the receiving point, the leakage signal of the transmission signal through the antenna is 180 degrees out of phase with the feedback signal.

[0043] By adjusting the length of the feedback short line and the distance between the feedback short line and the transmitting feed line, the size of the feedback signal can be adjusted. In actual design, two solutions can be used for adjustment design.

[0044] Solution 1: Under the condition of antenna simulation, the short feedback line is appropriately made a little longer. After the PCB antenna is processed, the length of the feedback antenna is manually shortened to adjust it to the appropriate feedback size. Finally, the PCB antenna is processed according to the hand-cut feedback line length.

[0045] Solution 2 is to process about 5 different lengths of feedback line PCB boards at one time, and select the feedback short line with the most appropriate length after testing.

[0046] Furthermore, the chip pin is also provided with a chip grounding via 43 (there is a grounding balun inside the chip); or a center via is provided at the center of the antenna element 1 for grounding. This design can eliminate the accumulation of electrostatic charge.

[0047] Furthermore, the PCB board 9 is a double-sided board with a thickness of 1.6±0.1 mm. The present invention is a double-sided board, which can effectively reduce the production cost. Figure 1-2 The medium-dark color is the top layer of the antenna, which is made of copper foil. The light-colored area is a blank area on the top layer, without copper, and has nothing else except green paint and silk screen. Figure 3 The bottom layer is a whole layer of ground copper foil. Because the board thickness has a great influence on the antenna Q value, and the thicker the circuit board, the lower the antenna Q value and the flatter the isolation curve, so the antenna is preferably 1.6mm thick.

[0048] The effects of the present invention are as follows Figure 4 and Figure 5 shown. Figure 4 It is the radar intermediate frequency signal before the feedback signal size is adjusted, and the white curve on the left is the noise when there is no Doppler signal; Figure 5 It is the radar intermediate frequency signal when the feedback signal size (that is, the feedback line length) is adjusted to the optimal feedback state (the feedback signal size is equal to the leakage signal size transmitted from the antenna to the receiver). The white curve on the left is the noise when there is no Doppler signal. Figure 5 The gray "Z" waveform in the lower middle is the trigger signal for turning on the light. Figure 4 and Figure 5 It can be seen that the noise is reduced by about half, which means that the signal-to-noise ratio is improved by about 6dB. During the light-on test, the power frequency interference amplitude is smaller than that of the four-layer board module with a back-feed antenna of the same size, and the distance measurement is farther than that of the four-layer board module.

[0049] A 1.6 mm thick common FR4 epoxy resin glass fiber 2-layer board designed in the manner described in the present invention is welded with a 50 ohm coaxial line with an SMA head at the chip pin position and connected to a network analyzer to test the standing wave and isolation (S21). The isolation of the antenna at the center of the working frequency is higher than 40 dB; taking a 5.8 GHz antenna as an example, the isolation is higher than 30 dB within the range of + and -75 MHz on both sides of the working frequency. Therefore, the antenna of the present invention has a good application effect.

[0050] The following is an explanation of the application of the high-isolation miniaturized double-panel circular antenna in a low-power radar module with reference to a specific case.

[0051] Take the 5.8GHz motion-triggered radar module as an example. The motion-sensing radar trigger chip designed and manufactured using CMOS technology is small in size, low in cost and low in power consumption. It is made into a radar module with a PCB board antenna and can be installed in LED lamps to realize intelligent lighting that turns on the light when people come and turns off the light when people leave, saving overall social electricity consumption. At present, the infrared sensing automatic lights installed in the corridors of buildings rely on Fresnel lenses to partition the space and use differential input thermopiles to identify human infrared thermal radiation. Although the cost is low, the infrared sensing probe needs to be installed independently because the LED emits light and heat, which interferes with the work of the infrared detector. Infrared sensing lamps are only suitable for installation when new houses and new buildings are renovated, and are not convenient for entering thousands of households. In addition, the Fresnel lens made of organic glass is prone to aging over time, which will reduce the sensitivity of the infrared sensor. In addition, in summer, the ambient temperature in buildings in the south is close to the human body temperature, which can easily lead to the inability to recognize human movement and make it difficult to turn on the light when people come.

[0052] The radar sensing module is manufactured by using the motion sensing chip based on the Doppler speed measurement principle. It has the advantage of working around the clock and can be placed directly in lamps, especially bulbs and T8 tubes. The original problem was that the radar module consumed more than 10mA and needed an independent switching power supply chip with a withstand voltage of more than 300V to power the radar module. The switching power supply chip requires a filter freewheeling inductor, which increases the cost and increases the interference. In order to save costs, the industry began to use a resistor voltage division scheme to directly draw power from the high-voltage voltage division of more than 300V output by the rectifier silicon bridge. This scheme requires that the radar module consumes less than 1.5mA, otherwise the heat dissipation problem cannot be solved. The performance of the double-layer circuit board radar module of this scheme is not lower than that of the four-layer board radar module. Moreover, because of the isolation effect of the double-layer board, the radar chip is farther away from the freewheeling inductor and filter capacitor of the LED driver power supply (separated by a layer of ground), and when used in a bulb, the power frequency interference is smaller than that of the four-layer board module. The double-layer plate antenna of the present invention can allow a radar module of about 1 mA to meet the application requirements of a hanging height of 3 meters and a sensing radius of more than 3 meters, thereby reducing material costs and patch costs, and allowing the radar module to be more widely used.

[0053] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-isolation miniaturized double-panel circular antenna, characterized in that: It comprises a PCB board (9), wherein the PCB board (9) is divided into a top layer and a bottom layer; the top layer is formed by copper plating to form an antenna vibrator (1), a feed line, a chip pin and a ground line, the remaining area is a blank area for green oil and silk screen printing, and the bottom layer is a whole layer of ground copper foil; The antenna vibrator (1) is circular, and two feeding points are provided on the antenna vibrator (1), wherein the angle between the two feeding points and the line connecting the center of the antenna vibrator (1) is 90 degrees; a slot (11) is provided in the antenna vibrator (1) starting from the feeding point and along the radius of the circle, wherein one of the slots (11) is provided with an antenna transmitting feed line (2) connected to the feeding point and extending from the antenna vibrator (1), and the other slot (11) is provided with an antenna receiving feed line (3) connected to the feeding point and extending from the antenna vibrator (1); antenna grounding vias (12) are provided on both sides of any slot (11), and the two antenna grounding vias (12) corresponding to any slot (11) are located at the bottom layer of the PCB board (9) and connected through the copper sheet (8); The antenna receiving feeder (3) is adjacent to the receiving pin (41) of the chip pin and connected to the receiving pin (41); the transmitting pin (42) of the chip pin is also connected to a transmitting feeder, wherein the transmitting feeder is further divided into a transmitting feeder section A (51), a transmitting feeder section B (52), a transmitting feeder section C (53), and a transmitting feeder section D (54); the transmitting feeder section A (51) is connected to the transmitting pin (42), and the transmitting feeder section A (51) is connected to the antenna vibrator (1). The tangent lines of the circle passing through the transmitting pin (42) overlap, the transmitting feed line section C (53) is a straight line and parallel to the side of the PCB board (9), the transmitting feed line section B (52) is an arcuate line segment and its two ends are respectively connected to the transmitting feed line section A (51) and the transmitting feed line section C (53), and the transmitting feed line section D (54) is an arcuate line segment and its two ends are respectively connected to the transmitting feed line section C (53) and the antenna transmitting feed line (2); both sides of the transmitting feed line are ground wires with a plurality of ground vias (6); A feedback short line (7) is connected to the antenna grounding via (12) on one side of the antenna receiving feeder (3). The size of the feedback signal is adjusted by adjusting the length of the feedback short line (7) and the distance between the feedback short line (7) and the transmitting feeder so that the size of the feedback signal is equal to the size of the leakage signal from the transmitting to the receiving of the antenna.

2. According to claim 1, a high isolation miniaturized double-panel circular antenna, characterized in that: The antenna transmission feeder (2) is laid in the slot (11) so that a gap is formed between the antenna transmission feeder (2) and the antenna vibrator (1), and the width of the gap is 1 / 3 of the width of the antenna transmission feeder (2); the antenna reception feeder (3) is laid in the slot (11) so that a gap is formed between the antenna reception feeder (3) and the antenna vibrator (1), and the width of the gap is 1 / 3 of the width of the antenna reception feeder (3).

3. According to claim 1, a high isolation miniaturized double-panel circular antenna, characterized in that: The transmitting feeder, the copper sheet (8), the antenna transmitting feeder (2), and the antenna receiving feeder (3) are all of equal width to ensure the same characteristic impedance.

4. According to claim 1, a high isolation miniaturized double-panel circular antenna, characterized in that: The total length of the transmitting feed line is equal to 1 / 2 wavelength.

5. According to claim 1, a high isolation miniaturized double-panel circular antenna, characterized in that: The chip pin is also provided with a chip grounding via (43); or the center of the antenna element (1) is provided with a center via for grounding.

6. The high-isolation miniaturized double-panel circular antenna according to claim 1, characterized in that: The PCB board (9) is a double-sided board with a thickness of 1.6±0.1 mm.

7. The high-isolation miniaturized double-panel circular antenna according to claim 1, characterized in that: The length of the outer end of the antenna transmission feed line (2) extending from the edge of the antenna vibrator (1) is 3±1 mm.

8. Application of the high-isolation miniaturized double-panel circular antenna according to any one of claims 1 to 7 in a low-power radar module.

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