Radio frequency signal receiver module and wireless microwave gateway

Abstract

The invention discloses a radio frequency signal receiver module and a wireless microwave gateway, and belongs to the technical field of wireless monitoring. The invention relates to a radio frequency signal receiver module, which receives a radio frequency signal returned by a passive tag and a leaked carrier signal, eliminates a large direct current component generated by the leaked carrier signal, and then converts the radio frequency signal into an intermediate frequency digital signal to be output. The wireless microwave gateway provided by the invention comprises the radio frequency signal receiver module. According to the passive tag return signal receiver module, 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, and the influence on a post-stage circuit of the receiver module is reduced, so that the sensitivity of the receiving module is improved, the receiver module is prevented from being blocked, and the service life of the receiver module is prolonged. The obtained intermediate frequency signal has high fidelity, and the demodulation precision is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless monitoring, and particularly relates to a radio frequency signal receiver module and a wireless microwave gateway. Background Art

[0002] In 5G-A passive Internet of Things applications, a passive Internet of Things system can be formed by using a wireless microwave gateway and wireless tags. The wireless microwave gateway continuously transmits a wireless carrier signal to provide energy for the passive tags. However, the wireless microwave gateway includes a transmitter end and a receiver end. During the communication process, the carrier signal transmitted by the transmitting end of the wireless microwave gateway will leak to the receiver end, and the downlink signal strength of the leaked carrier is much greater than the uplink signal strength of the passive tag's backhaul. The leaked carrier will interfere with the passive tag's backhaul uplink signal and reduce the communication performance of the passive Internet of Things system. Specifically:

[0003] Since the passive tag has no power supply, its internal circuit needs to rectify the continuous carrier generated by the wireless microwave gateway transmitter to provide the voltage for its normal operation. At the same time, the tag completes the transmission of the return signal through backscatter modulation. Therefore, when the receiver of the reader-writer receives the tag return signal, the transmitter has been transmitting a high-power carrier. For a single-antenna passive microwave gateway, since the isolation degree of the transceiver isolation device (such as a circulator, a directional coupler) cannot reach theoretically infinite, a part of the transmitted radio frequency carrier signal will leak to the receiving end. With the change of the isolation degree and the transmission power, the leakage power is usually between 0 and 10 dBm, while the power of the passive tag return signal is usually not higher than -50 dBm. Therefore, the power of the leaked carrier signal is much greater than the power of the passive tag return signal, and the leaked carrier will have a negative impact on the sensitivity of the receiver and may even block the receiver.

[0004] In addition, the traditional down-conversion processing of the tag return signal by the receiver usually adopts superheterodyne and zero-IF receiver architectures. These receiver modules usually include a low-noise amplifier, a radio frequency band-pass filter, and a down-converter. The above architectures have defects such as difficulty in effectively suppressing the DC components generated by the leaked carrier and the intrinsic signal, high power consumption, poor linearity, and difficulty in withstanding large leaked signal power. Summary of the Invention

[0005] The purpose of the present invention is to provide a radio frequency signal receiver module and a wireless microwave gateway to solve the problem that when the receiver of the existing wireless microwave gateway receives the passive tag return signal, there will be carrier leakage, which will have a negative impact on the sensitivity of the receiver and may even block the receiver.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A radio frequency signal receiver module receives the radio frequency signal returned by the passive tag and the leaked carrier signal, eliminates the large DC component generated by the leaked carrier signal, and then converts the radio frequency signal into an intermediate frequency digital signal for external output.

[0008] Further, the above radio frequency signal receiver module includes: a passive down-conversion mixer, a band-pass filter, and an analog-to-digital converter connected in sequence; the passive down-conversion mixer is used to receive the radio frequency signal returned by the passive tag and the leaked carrier signal and convert the radio frequency signal into an intermediate frequency signal; the passive down-conversion mixer and the band-pass filter are used to eliminate the DC component; the analog-to-digital converter is used to convert the intermediate frequency signal into an intermediate frequency digital signal for external output.

[0009] Further, the above passive down-conversion 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;

[0010] 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 source;

[0011] The first end and the second end of the first capacitor are respectively connected to the coupler and the first end of the first inductor, and the second end of the first inductor is grounded; the first end and the second end of the second capacitor are respectively connected to the coupler and the first end of the second inductor, and the second end of the second inductor is grounded;

[0012] The first end and the second end of the first Schottky diode are respectively connected to the first end of the first inductor and the input port of the second low-pass filter, and the first end and the second end of the second Schottky diode are respectively connected to the first end of the second inductor and the input port of the second low-pass filter;

[0013] The output port P3 of the second low-pass filter is connected to the band-pass filter.

[0014] Further, the above band-pass filter is a capacitive-coupled LC resonance circuit.

[0015] Further, the above band-pass filter includes a port P4, a first LC resonance circuit, a fifth capacitor, a second LC resonance circuit, and a port P5 connected in sequence; port P4 is connected to output port P3, and port P5 is connected to the analog-to-digital converter.

[0016] Further, the above first LC resonance circuit includes a third inductor and a third capacitor both grounded; the third inductor is connected to port P4, and the third capacitor is connected to the first ends of the third inductor and the fifth capacitor;

[0017] The second LC resonance circuit includes a fourth inductor and a fourth capacitor both grounded, the fourth inductor is connected to port five P5, and the fourth capacitor is connected to the second ends of the fourth inductor and the fifth capacitor.

[0018] Further, the above further includes: a first low-pass filter, which is respectively connected to the band-pass filter and the analog-to-digital converter, and is used to enhance the attenuation of the radio frequency signal and its harmonic components.

[0019] Further, the above first low-pass filter is a second-order RC low-pass filter, which includes a first resistor, a second resistor, a fifth capacitor and a sixth capacitor;

[0020] The first end of the first resistor is connected to port six P6, port six P6 is connected to the band-pass filter, the second end of the first resistor is connected to the first end of the fifth capacitor, and the second end of the fifth capacitor is grounded; the first end of the second resistor is connected to port seven P7, port seven P7 is connected to the analog-to-digital converter, the first end of the second resistor is also connected to the first end of the sixth capacitor, the second end of the sixth capacitor is grounded, and the second end of the second resistor is connected to the second end of the first resistor.

[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, and the above radio frequency signal receiver module; a passive down-conversion 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 instructions sent by a remote control platform; the baseband processing module is used to generate baseband data after receiving control instructions sent by the remote control platform, and is used to receive intermediate frequency digital signals and transmit the parsed data to the 5G gateway module 502; the first antenna is used to radiate a downlink signal into free space and receive a signal returned by a passive tag.

[0022] Further, the above 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] The present invention has the following beneficial effects:

[0024] (1) Since the wireless microwave gateway has the same transmitting and receiving frequency or a relatively close frequency interval, the leaked carrier wave and the local oscillator signal are mixed to generate a DC component, which 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 the present invention receives the leaked carrier signal from the transmitter and the passive tag return signal, it first passes through a passive down-conversion mixer and then through a band-pass filter. The passive down-conversion mixer and the band-pass filter cooperate well to eliminate the large DC component generated after the leaked carrier wave is down-converted, reduce the impact on the subsequent circuit of the receiver module, thereby improving the sensitivity of the receiving module, avoiding blocking and jamming the receiver module, and the obtained intermediate frequency signal has high fidelity, greatly improving the demodulation accuracy.

[0025] (2) The present invention is provided with a first low-pass filter between the band-pass filter and the analog-to-digital converter. The first low-pass filter adopts 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 the present invention has good linearity and dynamic range, enabling the passive tag return signal receiver module to work normally in the presence of a high-power leaked carrier wave, and having good scene adaptability and scalability. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the passive tag return signal receiver module of the present invention;

[0028] Figure 2 is a circuit structure diagram of the passive down-conversion mixer of the present invention;

[0029] Figure 3 is a circuit structure diagram of the band-pass filter of the present invention;

[0030] Figure 4 is a circuit structure diagram of the first low-pass filter of the present invention;

[0031] Figure 5 is a schematic structural diagram of the wireless microwave gateway of the present invention.

[0032] In the figure: 101 - first antenna; 102 - circulator; 201 - passive down-conversion mixer; 202 - band-pass 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 - coupler; 2011 - first capacitor; 2012 - 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 manners

[0033] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0034] Example 1:

[0035] Please refer to Figures 1 to 4 , this example provides a passive tag return signal receiver module. This passive tag return signal receiver module receives the radio frequency signal and the leaked carrier signal returned by the passive tag, eliminates the large DC component generated by the leaked carrier signal, and then converts the radio frequency signal into an intermediate frequency digital signal for external output. This passive tag return signal receiver module can preferably eliminate the large DC component generated after down-conversion of the leaked carrier, reduce the impact on the subsequent circuit of the receiver module, thereby improving the sensitivity of the receiving module, avoiding blocking and jamming of the receiver module, and the obtained intermediate frequency signal has high fidelity, greatly improving the demodulation accuracy.

[0036] Specifically, the passive tag return signal receiver module of this example includes: a passive down-conversion mixer 201, a band-pass filter 202, and an analog-to-digital converter 204 connected in sequence. Since the wireless microwave gateway transmits and receives at the same frequency or with a close frequency interval, the leaked carrier and the local oscillator signal are mixed to generate a DC component, and 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. In this example, the passive down-conversion 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 down-conversion mixer 201 and the band-pass filter 202 cooperate to eliminate the DC component; the analog-to-digital converter 204 is used to convert the intermediate frequency signal into an intermediate frequency digital signal for external output.

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

[0038] Please refer to Figure 2 , the passive down-conversion 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 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 source;

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

[0041] The first end and the second end of the first Schottky diode 2015 are respectively connected to the first end of the first inductor 2013 and the input port of the second low-pass filter 2017, and the first end and the second end of the second Schottky diode 2016 are respectively connected to the first end 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 band-pass filter 202 is a capacitive-coupled LC resonance circuit, which includes a port P4, a first LC resonance circuit, a fifth capacitor 2020, a second LC resonance circuit, and a port P5 connected in sequence; port P4 is connected to the output port P3, and port P5 is connected to the first low-pass filter 203.

[0044] Specifically, the first LC resonance circuit includes a third inductor 2021 and a third capacitor 2023 both grounded; the third inductor 2021 is connected to port 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 resonance circuit includes a fourth inductor 2022 and a fourth capacitor 2024 that are both grounded. The fourth inductor 2022 is connected to port five P5, and the fourth capacitor 2024 is connected to the second ends 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 end of the first resistor 2031 is connected to port six P6. Port six P6 is connected to port five P5 of the band-pass filter 202. The second end of the first resistor 2031 is connected to the first end of the sixth capacitor 2032, and the second end of the sixth capacitor 2032 is grounded; The first end of the second resistor 2033 is connected to port seven P7. Port seven P7 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, and the second end of the seventh capacitor 2034 is grounded. The second end of the second resistor 2033 is connected to the second end of the first resistor 2031.

[0048] In this embodiment, the circuit structure of the second low-pass filter 2017 may be the same as or different from that of the first low-pass filter 203, and 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 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.

[0049] The passive tag return signal receiver module of this embodiment has good linearity and dynamic range, enabling the passive tag return signal receiver module to work properly in the presence of high-power leakage carriers, and having good scene adaptability and scalability.

[0050] Embodiment 2:

[0051] 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 that are connected in sequence, and the radio frequency signal receiver module of Embodiment 1. The passive down-conversion 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.

[0052] Wherein:

[0053] After receiving the control instruction sent by the remote control platform, the gateway antenna 501 transmits it to the 5G gateway module 502. The 5G gateway module 502 controls the baseband processing module 400 to generate baseband data and transfers 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 through the circulator 102 for radiation into free space. After receiving the signal, the passive tag at the remote end responds and generates a radio frequency signal (i.e., the backhaul uplink signal). The returned radio frequency signal reaches the passive down-conversion mixer 201 after passing through the first antenna 101 and the circulator 102. At this time, both the returned radio frequency signal and the leaked carrier signal enter the passive down-conversion mixer 201. The passive down-conversion mixer 201 converts the radio frequency signal into an intermediate frequency signal. At the same time, the passive down-conversion mixer 201 and the band-pass filter 202 filter out the DC component, and then the first low-pass filter 203 filters out the radio frequency signal and its harmonic components. The adjusted intermediate frequency signal is converted into an intermediate frequency 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, and the 5G gateway module 502 then sends the data to the remote control platform through the gateway antenna 501.

[0054] 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.

[0055] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A radio frequency signal receiver module, characterized in that: The radio frequency signal receiver module receives the radio frequency signal returned by the passive tag and the leaked carrier signal, eliminates the large DC component generated by the leaked carrier signal, and then converts the radio 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: include: A passive down-conversion mixer (201), a bandpass filter (202) and an analog-to-digital converter (204) are connected in sequence; the passive down-conversion mixer (201) is used to receive a radio frequency signal and a leaked carrier signal returned by a passive tag and convert the radio frequency signal into an intermediate frequency signal; the passive down-conversion mixer (201) and the bandpass filter (202) are used to eliminate a direct current component; and the analog-to-digital converter (204) is used to convert the intermediate frequency signal into an intermediate frequency digital signal for external output.

3. The radio frequency signal receiver module according to claim 2, characterized in that: The passive down-conversion mixer (201) comprises 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 1 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 2 P2 of the coupler (2010) is connected to the local oscillator source; The first end and the second end of the first capacitor (2011) are respectively connected to the first end of the coupler (2010) and the first end of the first inductor (2013), and the second end of the first inductor (2013) is grounded; the first end and the second end of the second capacitor (2012) are respectively connected to the first end of the coupler (2010) and the second inductor (2014), and the second end of the second inductor (2014) is grounded; The first end and the second end of the first Schottky diode (2015) are respectively connected to the first end of the first inductor (2013) and the input port of the second low-pass filter (2017); the first end and the second end of the second Schottky diode (2016) are respectively connected to the first end 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).

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

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

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

7. The radio frequency signal receiver module according to any one of claims 2 to 6, characterized in that: Also includes: A first low-pass filter (203), the first low-pass filter (203) is connected to the band-pass filter (202) and the analog-to-digital converter (204) respectively, and is used to enhance the attenuation of the radio frequency signal and its harmonic components.

8. The radio frequency signal receiver module according to claim 7, characterized in that: The first low-pass filter (203) is a second-order RC low-pass filter, comprising 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 a port six P6, the port six P6 is connected to the band-pass filter (202), the second end of the first resistor (2031) is connected to the first end of the sixth capacitor (2032), and the second end of the sixth capacitor (2032) is grounded; the first end of the second resistor (2033) is connected to a port seven P7, the port seven P7 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), the second end of the seventh capacitor (2034) is grounded, and the second end of the second resistor (2033) is connected to the second end of the first resistor (2031).

9. A wireless microwave gateway, characterized in that: include: 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, and a radio frequency signal receiver module as claimed in any one of claims 2 to 8; the passive down-conversion 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 instructions sent by a remote control platform; the baseband processing module (400) is used to generate baseband data after receiving control instructions sent by a remote control platform, and is used 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 comprises 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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