Radio frequency signal receiver module and wireless microwave gateway

Abstract

The utility model discloses a radio frequency signal receiver module and a wireless microwave gateway, and belongs to the technical field of wireless monitoring. A radio frequency signal receiver module comprises a passive down-conversion mixer, a band-pass filter, a first low-pass filter and an analog-to-digital converter which are connected in sequence. The wireless microwave gateway provided by the utility model comprises the radio frequency signal receiver module. According to the passive tag return signal receiver module of the utility model, the passive down-conversion mixer is matched with the band-pass filter to eliminate a large direct-current component generated after a leakage carrier is subjected to down-conversion, so that the influence on a post-stage circuit of the receiver module can be reduced, and therefore, the sensitivity of the receiving module can be improved; the receiver module is prevented from being blocked, the obtained intermediate frequency signal has high fidelity, and the demodulation precision is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of wireless monitoring technology, specifically to a radio frequency signal receiver module and a wireless microwave gateway. Background Technology

[0002] In 5G-A passive IoT applications, a passive IoT system can be built using a wireless microwave gateway and wireless tags. The wireless microwave gateway continuously transmits wireless carrier signals to provide power to the passive tags. However, the wireless microwave gateway includes a transmitter and a receiver. During communication, the carrier signal transmitted by the wireless microwave gateway can leak to the receiver. The downlink signal strength of this leaked carrier is much greater than the uplink signal strength of the passive tag, which interferes with the uplink signal of the passive tag and reduces the communication performance of the passive IoT system. Specifically:

[0003] Since passive tags have no power source, their internal circuitry needs to rectify the continuous carrier waves generated by the wireless microwave gateway transmitter to provide the voltage necessary for normal operation. Simultaneously, the tag transmits its return signal via backscatter modulation. Therefore, while the reader's receiver is receiving the tag's return signal, the transmitter is continuously emitting a high-power carrier wave. For a single-antenna passive microwave gateway, the isolation of the transceiver isolation devices (such as circulators and directional couplers) cannot reach theoretical infinity. Consequently, a portion of the transmitted RF carrier signal leaks to the receiver. Depending on the isolation and transmission power, the leakage power is typically between 0 and 10 dBm, while the power of the passive tag's return signal is usually no higher than -50 dBm. Therefore, the power of the leaked carrier signal is much greater than the power of the passive tag's return signal, negatively impacting the receiver's sensitivity and potentially even blocking it.

[0004] In addition, traditional receivers typically use superheterodyne, zero-IF receiver architectures for downconversion processing of tag return signals. These receiver modules usually include low-noise amplifiers, RF bandpass filters, and downconverters. The above architecture has drawbacks such as difficulty in effectively suppressing the DC component generated by the leakage carrier and intrinsic signal, high power consumption, poor linearity, and inability to withstand large leakage signal power. Utility Model Content

[0005] The purpose of this invention is to provide an RF signal receiver module and a wireless microwave gateway to solve the problem that existing wireless microwave gateway receivers suffer from carrier leakage when receiving passive tag return signals, which negatively affects the receiver's sensitivity and may even block the receiver.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0007] A radio frequency (RF) signal receiver module includes: a passive downconverter mixer, a bandpass filter, a first low-pass filter, and an analog-to-digital converter connected in sequence; the passive downconverter mixer is used to receive the RF signal returned by a passive tag and the leaked carrier signal and convert the RF signal into an intermediate frequency (IF) signal; the passive downconverter mixer and the bandpass filter are used to eliminate DC components; the first low-pass filter is used to enhance the attenuation of the RF signal and its harmonic components; and the analog-to-digital converter is used to convert the IF signal into an IF digital signal for external output.

[0008] Furthermore, the aforementioned passive downconverter mixer includes a coupler, a first capacitor, a second capacitor, a first inductor, a second inductor, a first Schottky diode, a second Schottky diode, and a second low-pass filter;

[0009] Port P1 of the coupler is used to receive the radio frequency signal returned by the passive tag and the leaked carrier signal, and port P2 of the coupler is connected to the local oscillator.

[0010] The first terminal and the second terminal of the first capacitor are respectively connected to the first terminal of the coupler and the first terminal of the first inductor, and the second terminal of the first inductor is grounded; the first terminal and the second terminal of the second capacitor are respectively connected to the first terminal of the coupler and the first terminal of the second inductor, and the second terminal of the second inductor is grounded.

[0011] The first terminal and the second terminal of the first Schottky diode are respectively connected to the first terminal of the first inductor and the input port of the second low-pass filter; the first terminal and the second terminal of the second Schottky diode are respectively connected to the first terminal of the second inductor and the input port of the second low-pass filter.

[0012] The output port P3 of the second low-pass filter is connected to the band-pass filter.

[0013] Furthermore, the aforementioned bandpass filter is a capacitively coupled LC resonant circuit.

[0014] Furthermore, the aforementioned bandpass filter includes a fourth port P4, a first LC resonant circuit, a fifth capacitor, a second LC resonant circuit, and a fifth port P5 connected in sequence; the fourth port P4 is connected to the output port P3, and the fifth port P5 is connected to the analog-to-digital converter.

[0015] Furthermore, the aforementioned first LC resonant circuit includes a third inductor and a third capacitor, both of which are grounded; the third inductor is connected to port four P4, and the third capacitor is connected to the first terminal of the third inductor and the fifth capacitor.

[0016] The second LC resonant circuit includes a fourth inductor and a fourth capacitor, both of which are grounded. The fourth inductor is connected to port 5 P5, and the fourth capacitor is connected to the second terminal of the fourth inductor and the fifth capacitor.

[0017] Furthermore, the aforementioned first low-pass filter is a second-order RC low-pass filter.

[0018] Furthermore, the aforementioned first low-pass filter includes a first resistor, a second resistor, a sixth capacitor, and a seventh capacitor;

[0019] The first end of the first resistor is connected to port 6 P6, which is connected to the bandpass filter. The second end of the first resistor is connected to the first end of the sixth capacitor, which is grounded. The first end of the second resistor is connected to port 7 P7, which is connected to the analog-to-digital converter. The first end of the second resistor is also connected to the first end of the seventh capacitor, which is grounded. The second end of the second resistor is connected to the second end of the first resistor.

[0020] Furthermore, the structure of the second low-pass filter is the same as that of the first low-pass filter; port six P6 of the second low-pass filter is the input port of the second low-pass filter, and port seven P7 of the second low-pass filter is the output port of the second low-pass filter.

[0021] A wireless microwave gateway includes: a gateway antenna, a 5G gateway module, a baseband processing module, a transmitter module, a circulator, and a first antenna connected in sequence, as well as the aforementioned radio frequency signal receiver module; a passive downconverter mixer and an analog-to-digital converter are respectively connected to the circulator and the baseband processing module; the gateway antenna is used to receive control commands sent by a remote control platform; the baseband processing module is used to generate baseband data after receiving the control commands sent by the remote control platform, and to receive intermediate frequency digital signals and transmit the parsed data to the 5G gateway module 502; the first antenna is used to radiate downlink signals into free space and receive passive tag return signals.

[0022] Furthermore, the transmitter module includes a digital-to-analog converter, a driver, and a power amplifier connected in sequence. The digital-to-analog converter is connected to the baseband processing module, and the power amplifier is connected to the circulator.

[0023] This utility model has the following beneficial effects:

[0024] (1) Since the wireless microwave gateway transmits and receives at the same frequency or with a close frequency interval, the leakage carrier and local oscillator signal mix to generate a DC component. The DC component may be as large as several hundred millivolts. The DC component must be eliminated, otherwise the receiver module will not work properly. Therefore, after the passive tag return signal receiver module of this utility model receives the carrier signal leaked from the transmitter and the passive tag return signal, it first passes through a passive downconverter mixer and then through a bandpass filter. The passive downconverter mixer and the bandpass filter work together to effectively eliminate the large DC component generated by the leakage carrier after downconversion, reduce the impact on the subsequent circuits of the receiver module, thereby improving the sensitivity of the receiver module, avoiding blockage and clogging of the receiver module, and the obtained intermediate frequency signal has high fidelity, which greatly improves the demodulation accuracy.

[0025] (2) The present invention provides a first low-pass filter between the bandpass filter and the analog-to-digital converter. The first low-pass filter is a second-order RC low-pass filter, which can increase the attenuation of the radio frequency signal and its harmonic components, and make the intermediate frequency signal obtained by down-conversion as pure as possible.

[0026] (3) The passive tag return signal receiver module of this utility model has good linearity and dynamic range, which enables the passive tag return signal receiver module to work normally when a high-power leakage carrier exists, and has good scene adaptability and scalability. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the passive tag return signal receiver module of this utility model;

[0028] Figure 2 This is a circuit diagram of the passive downconverter mixer of this utility model;

[0029] Figure 3 This is a circuit diagram of the bandpass filter of this utility model;

[0030] Figure 4 This is a circuit diagram of the first low-pass filter of this utility model;

[0031] Figure 5 This is a schematic diagram of the structure of the wireless microwave gateway of this utility model.

[0032] In the diagram: 101-First antenna; 102-Circulator; 201-Passive downconverter mixer; 202-Bandpass filter; 203-First low-pass filter; 204-Analog-to-digital converter; 301-Power amplifier; 302-Driver; 303-Digital-to-analog converter; 304-Baseband processing module; 400-Baseband processing module; 501-Gateway antenna; 502-5G gateway module; 2010-Coupled; 2011-First capacitor; 201 2-Second capacitor; 2013-First inductor; 2014-Second inductor; 2015-First Schottky diode; 2016-Second Schottky diode; 2017-Second low-pass filter; 2020-Fifth capacitor; 2021-Third inductor; 2022-Fourth inductor; 2023-Third capacitor; 2024-Fourth capacitor; 2031-First resistor; 2032-Sixth capacitor; 2033-Second resistor; 2034-Seventh capacitor. Detailed Implementation

[0033] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0034] Example 1:

[0035] Please refer to Figures 1 to 4 This embodiment provides a passive tag return signal receiver module. This module receives the radio frequency (RF) signal and leaked carrier signal returned by a passive tag. After eliminating the large DC component generated by the leaked carrier signal, it converts the RF signal into an intermediate frequency (IF) digital signal for output. This passive tag return signal receiver module effectively eliminates the large DC component generated by the leaked carrier after down-conversion, reducing the impact on subsequent circuitry and improving the receiver module's sensitivity. It also avoids blocking or clogging the receiver module, resulting in a high-fidelity IF signal and significantly improving demodulation accuracy.

[0036] Specifically, the passive tag return signal receiver module in this embodiment includes a passive down-conversion mixer 201, a bandpass filter 202, and an analog-to-digital converter 204 connected in sequence. Because the wireless microwave gateway transmits and receives on the same frequency or at close frequency intervals, the leakage carrier and local oscillator signal mix, generating a DC component. This DC component can be as large as several hundred millivolts and must be eliminated; otherwise, the receiver module will malfunction. In this embodiment, the passive down-conversion mixer 201 receives the radio frequency signal returned by the passive tag and the leaked carrier signal, converting the radio frequency signal into an intermediate frequency (IF) signal. The passive down-conversion mixer 201 and the bandpass filter 202 work together to eliminate the DC component. The analog-to-digital converter 204 converts the IF signal into an IF digital signal for external output.

[0037] In order to increase the attenuation of radio frequency signals and their harmonic components and to make the intermediate frequency signal obtained by downconversion as pure as possible, in this embodiment, the passive tag return signal receiver module further includes a first low-pass filter 203, which is connected to the band-pass filter 202 and the analog-to-digital converter 204 respectively.

[0038] Please refer to Figure 2 The passive downconverter mixer 201 includes a coupler 2010, a first capacitor 2011, a second capacitor 2012, a first inductor 2013, a second inductor 2014, a first Schottky diode 2015, a second Schottky diode 2016, and a second low-pass filter 2017.

[0039] Port P1 of coupler 2010 is used to receive the radio frequency signal returned by the passive tag and the leaked carrier signal, and port P2 of coupler 2010 is connected to the local oscillator.

[0040] The first terminal and the second terminal of the first capacitor 2011 are respectively connected to the first terminal of the coupler 2010 and the first terminal of the first inductor 2013, and the second terminal of the first inductor 2013 is grounded; the first terminal and the second terminal of the second capacitor 2012 are respectively connected to the first terminal of the coupler 2010 and the first terminal of the second inductor 2014, and the second terminal of the second inductor 2014 is grounded.

[0041] The first terminal and the second terminal of the first Schottky diode 2015 are respectively connected to the first terminal of the first inductor 2013 and the input port of the second low-pass filter 2017; the first terminal and the second terminal of the second Schottky diode 2016 are respectively connected to the first terminal of the second inductor 2014 and the input port of the second low-pass filter 2017.

[0042] The output port P3 of the second low-pass filter 2017 is connected to the band-pass filter 202.

[0043] Please refer to Figure 3 The bandpass filter 202 is a capacitively coupled LC resonant circuit, which includes a fourth port P4, a first LC resonant circuit, a fifth capacitor 2020, a second LC resonant circuit, and a fifth port P5 connected in sequence; the fourth port P4 is connected to the output port P3, and the fifth port P5 is connected to the first low-pass filter 203.

[0044] Specifically, the first LC resonant circuit includes a third inductor 2021 and a third capacitor 2023, both of which are grounded; the third inductor 2021 is connected to port four P4, and the third capacitor 2023 is connected to the first end of the third inductor 2021 and the fifth capacitor 2020.

[0045] The second LC resonant circuit includes a fourth inductor 2022 and a fourth capacitor 2024, both of which are grounded. The fourth inductor 2022 is connected to port 5 P5, and the fourth capacitor 2024 is connected to the second terminal of the fourth inductor 2022 and the fifth capacitor 2020.

[0046] Please refer to Figure 4 The first low-pass filter 203 is a second-order RC low-pass filter, which includes a first resistor 2031, a second resistor 2033, a sixth capacitor 2032 and a seventh capacitor 2034.

[0047] The first terminal of the first resistor 2031 is connected to port 6 P6, which is connected to port 5 P5 of the bandpass filter 202. The second terminal of the first resistor 2031 is connected to the first terminal of the sixth capacitor 2032, which is grounded. The first terminal of the second resistor 2033 is connected to port 7 P7, which is connected to the analog-to-digital converter 204. The first terminal of the second resistor 2033 is also connected to the first terminal of the seventh capacitor 2034, which is grounded. The second terminal of the second resistor 2033 is connected to the second terminal of the first resistor 2031.

[0048] In this embodiment, the circuit structure of the second low-pass filter 2017 can be the same as or different from that of the first low-pass filter 203; no specific limitation is made here. When the circuit structure of the second low-pass filter 2017 is the same as that of the first low-pass filter 203, port P6 of the second low-pass filter 2017 is the input port of the second low-pass filter 2017, and port P7 of the second low-pass filter 2017 is the output port of the second low-pass filter 2017.

[0049] Obviously, in other embodiments of this utility model, the circuit structure of the second low-pass filter 2017 may not be the same as that of the first low-pass filter 203, and a low-pass filter that can achieve the corresponding function can be used.

[0050] The passive tag return signal receiver module in this embodiment has good linearity and dynamic range, enabling it to operate normally in the presence of high-power leaky carriers, and has good scene adaptability and scalability.

[0051] Example 2:

[0052] Please refer to Figure 5 This embodiment provides a wireless microwave gateway, including: a gateway antenna 501, a 5G gateway module 502, a baseband processing module 400, a transmitter module, a circulator 102, and a first antenna 101 connected in sequence, as well as the radio frequency signal receiver module of Embodiment 1. The passive downconverter mixer 201 and the analog-to-digital converter 204 of the radio frequency signal receiver module are respectively connected to the circulator 102 and the baseband processing module 400.

[0053] in:

[0054] After receiving control commands from the remote control platform, the gateway antenna 501 transmits them to the 5G gateway module 502. The 5G gateway module 502 controls the baseband processing module 400 to generate baseband data and transmits it to the transmitter module. The transmitter module generates a modulated carrier from the baseband data and couples the carrier to the first antenna 101 via the circulator 102 before radiating it into free space. The remote passive tag receives the signal and responds by generating a radio frequency signal (i.e., a backlink uplink signal). The returned radio frequency signal passes through the first antenna 101 and the circulator 102 before reaching the passive downconversion mixer 201, where it enters the passive downconversion mixer. The device 201 receives both returned radio frequency (RF) signals and leaked carrier signals. The passive downconverter mixer 201 converts the RF signals into intermediate frequency (IF) signals. Simultaneously, the passive downconverter mixer 201 and the bandpass filter 202 filter out the DC component. The RF signal and its harmonic components are then filtered out by the first low-pass filter 203. The adjusted IF signal is converted into an IF digital signal by the analog-to-digital converter 204 and sent to the baseband processing module 400. The baseband processing module 400 reports the parsed data to the 5G gateway module 502. The 5G gateway module 502 then sends the data to the remote control platform via the gateway antenna 501.

[0055] In this embodiment, the transmitter module includes a digital-to-analog converter 303, a driver 302 and a power amplifier 301 connected in sequence. The digital-to-analog converter 303 is connected to the baseband processing module 400 and the power amplifier 301 is connected to the circulator 102.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A radio frequency signal receiver module, characterized in that, include: A passive downconverter mixer (201), a bandpass filter (202), a first low-pass filter (203), and an analog-to-digital converter (204) are connected in sequence. The passive downconverter mixer (201) is used to receive the radio frequency signal and the leaked carrier signal returned by the passive tag and convert the radio frequency signal into an intermediate frequency signal. The passive downconverter mixer (201) and the bandpass filter (202) are used to eliminate the DC component. The first low-pass filter (203) is used to enhance the attenuation of the radio frequency signal and its harmonic components. The analog-to-digital converter (204) is used to convert the intermediate frequency signal into an intermediate frequency digital signal for external output.

2. The radio frequency signal receiver module according to claim 1, characterized in that, The passive downconverter mixer (201) includes a coupler (2010), a first capacitor (2011), a second capacitor (2012), a first inductor (2013), a second inductor (2014), a first Schottky diode (2015), a second Schottky diode (2016), and a second low-pass filter (2017). Port P1 of the coupler (2010) is used to receive the radio frequency signal returned by the passive tag and the leaked carrier signal, and port P2 of the coupler (2010) is connected to the local oscillator. The first terminal and the second terminal of the first capacitor (2011) are respectively connected to the first terminal of the coupler (2010) and the first terminal of the first inductor (2013), and the second terminal of the first inductor (2013) is grounded; the first terminal and the second terminal of the second capacitor (2012) are respectively connected to the first terminal of the coupler (2010) and the first terminal of the second inductor (2014), and the second terminal of the second inductor (2014) is grounded; The first terminal and the second terminal of the first Schottky diode (2015) are respectively connected to the first terminal of the first inductor (2013) and the input port of the second low-pass filter (2017); the first terminal and the second terminal of the second Schottky diode (2016) are respectively connected to the first terminal of the second inductor (2014) and the input port of the second low-pass filter (2017). The output port P3 of the second low-pass filter (2017) is connected to the band-pass filter (202).

3. The radio frequency signal receiver module according to claim 2, characterized in that, The bandpass filter (202) is a capacitively coupled LC resonant circuit.

4. The radio frequency signal receiver module according to claim 3, characterized in that, The bandpass filter (202) includes a fourth port P4, a first LC resonant circuit, a fifth capacitor (2020), a second LC resonant circuit, and a fifth port P5 connected in sequence; the fourth port P4 is connected to the output port P3, and the fifth port P5 is connected to the analog-to-digital converter (204).

5. The radio frequency signal receiver module according to claim 4, characterized in that, The first LC resonant circuit includes a third inductor (2021) and a third capacitor (2023) that are both grounded; the third inductor (2021) is connected to the fourth port P4, and the third capacitor (2023) is connected to the first end of the third inductor (2021) and the fifth capacitor (2020); The second LC resonant circuit includes a fourth inductor (2022) and a fourth capacitor (2024) that are both grounded. The fourth inductor (2022) is connected to port 5 P5, and the fourth capacitor (2024) is connected to the second end of the fourth inductor (2022) and the fifth capacitor (2020).

6. The radio frequency signal receiver module according to claim 2, characterized in that, The first low-pass filter (203) is a second-order RC low-pass filter.

7. The radio frequency signal receiver module according to claim 6, characterized in that, The first low-pass filter (203) includes a first resistor (2031), a second resistor (2033), a sixth capacitor (2032), and a seventh capacitor (2034). The first end of the first resistor (2031) is connected to port six P6, which is connected to the bandpass filter (202). The second end of the first resistor (2031) is connected to the first end of the sixth capacitor (2032), which is grounded. The first end of the second resistor (2033) is connected to port seven P7, which is connected to the analog-to-digital converter (204). The first end of the second resistor (2033) is also connected to the first end of the seventh capacitor (2034), which is grounded. The second end of the second resistor (2033) is connected to the second end of the first resistor (2031).

8. The radio frequency signal receiver module according to claim 7, characterized in that, The second low-pass filter (2017) has the same structure as the first low-pass filter (203); port six P6 of the second low-pass filter (2017) is the input port of the second low-pass filter (2017), and port seven P7 of the second low-pass filter (2017) is the output port of the second low-pass filter (2017).

9. A wireless microwave gateway, characterized in that, include: The gateway antenna (501), 5G gateway module (502), baseband processing module (400), transmitter module, circulator (102) and first antenna (101) are connected in sequence, as well as the radio frequency signal receiver module according to any one of claims 1 to 8; the passive downconverter mixer (201) and the analog-to-digital converter (204) are respectively connected to the circulator (102) and the baseband processing module (400); the gateway antenna (501) is used to receive control commands sent by the remote control platform; the baseband processing module (400) is used to generate baseband data after receiving the control commands sent by the remote control platform, and to receive intermediate frequency digital signals and transmit the parsed data to the 5G gateway module 502; the first antenna (101) is used to radiate downlink signals into free space and receive passive tag return signals.

10. The wireless microwave gateway according to claim 9, characterized in that, The transmitter module includes a digital-to-analog converter (303), a driver (302), and a power amplifier (301) connected in sequence. The digital-to-analog converter (303) is connected to the baseband processing module (400), and the power amplifier (301) is connected to the circulator (102).

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