CN113267672B

CN113267672B - 6G communication microwave power detection system based on radio frequency diode

Info

Publication number: CN113267672B
Application number: CN202110489491.0A
Authority: CN
Inventors: 郭巧彤; 吴梓境; 王志; 任青颖; 王德波
Original assignee: Nanjing University of Posts and Telecommunications
Current assignee: Nanjing University of Posts and Telecommunications
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2022-08-30
Anticipated expiration: 2041-05-06
Also published as: CN113267672A

Abstract

The invention discloses a 6G communication microwave power detection system based on a radio frequency diode, wherein a through rectangular cavity is transversely formed in a substrate integrated waveguide, a microstrip patch antenna fed by a coaxial line is arranged in the rectangular cavity, the microstrip patch antenna is electrically connected with the substrate integrated waveguide through an impedance matching network equivalent to a band-pass filter, the substrate integrated waveguide is electrically connected with the radio frequency diode and a low-pass filter through the impedance matching network, the low-pass filter is electrically connected with a data processing module, and the radio frequency diode rectifies received microwave signals in a 6G communication frequency band. The system can detect the microwave power of a 6G communication low frequency band, and has the advantages of high integration level, low cost and simple structure.

Description

6G communication microwave power detection system based on radio frequency diode

Technical Field

The invention relates to a 6G communication microwave power detection system based on a radio frequency diode, and belongs to the technical field of microwave power detection.

Background

Fields closely related to 6G communication in life are developed under the research of 6G communication, and microwave power detection plays an important role in level detection, power monitoring and gain control. Most of microwave power detection equipment available in the market is very expensive and adopts discrete components and parts more, and is large in size and large in power consumption, not beneficial to carrying, and is mainly used for laboratory measurement, and the detection system reaching the 6G communication detection frequency band is few and few, and the cost is very high. Most detection systems use complex antenna designs and ready-made detection chips, the existing chips can detect less than 6G (100 GHz-10 THz), the bandwidth range which can be detected by the existing envelope/peak detector ADL6012 with the highest detection frequency is GHz-67 GHz, and the frequency range which can be detected by a Root Mean Square (RMS) response power detector LTC5597 is 100 MHz-70 GHz.

In the field of microwave signal detection, a thermoelectric microwave power sensor detects microwave power by utilizing the Seebeck effect, the sensitivity can reach 0.671mV/mW, but the dynamic measurement range is only about 20dB (the source is 'Suspended thermal for microwave power Sensors based on bulk MEMS and GaAs MMIC technology,' IEEE Sensors Journal, vol.15, No.4, pp. 2019-; the capacitive microwave power sensor is based on sensing of electrostatic force generated between a transmission line and a cantilever beam, and has the advantage of X-waveband online detection. But the dynamic measurement range is only 20dB, the detection resolution is 100mW, and the comparison is poor (the source is 'Bent mirror radio frequency micro electromechanical system power detector with improved linearity up to 1W.' IET Microwaves Antennas & Propagation, vol.13, No.10, pp.1732-1736); the dynamic measurement range of the coupled microwave power sensor is optimized to be 32dB, and the sensitivity in the X-band is only 0.124mV/mW (from the sources of 'A shielded measuring-type and capacitive-type power sensor for-10-to 22-dBm application.' IEEE Electron devices Letters, vol.37, No.4, pp.489-491). However, most microwave power sensors are concentrated on the X-band (8-12 GHz) and are hardly used for detecting the 6G communication band (100 GHz-10 THz).

In the current solution, aiming at the microwave signal detection of a lower frequency band (1.5 GHz-5.3 GHz), the method comprises the following steps: ZL202010464745.9, wherein a core technology module adopts a logarithmic detection chip AD8318 chip, the input bandwidth is 1M-8 GHz, the input power range is-65-5 dBm, the detection chip AD8318 converts the input microwave power into direct current voltage, the low-frequency microwave signal can be detected, and the detection of 6G microwave power cannot be directly completed by the AD detection chip; in addition, microwave signals in 2G-5G frequency bands in a communication frequency band are received by adopting a planar wide slot antenna and a coplanar waveguide matching branch, signals in a 6G communication frequency band cannot be detected, and the millimeter wave substrate integrated waveguide is a novel planar circuit structure for a millimeter wave frequency band, has the characteristics of waveguide and can be realized on a PCB (printed circuit board).

In the era of 6G communication to be popularized, a microwave power detection system with equivalent detection frequency band and low cost needs to be researched as an adaptive scheme.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art, and provide a 6G communication microwave power detection system based on a radio frequency diode, so that the power of a received microwave signal is detected, and the processing and visualization of the detected microwave signal are realized.

In order to achieve the above purpose, the invention provides a microstrip patch antenna comprising a coaxial line feed, an impedance matching network equivalent to a band-pass filter, a substrate integrated waveguide, a radio frequency diode, a low-pass filter and a data processing module, wherein the substrate integrated waveguide is transversely provided with a through rectangular cavity, the microstrip patch antenna is arranged in the rectangular cavity, the microstrip patch antenna is electrically connected with the substrate integrated waveguide through the impedance matching network, the substrate integrated waveguide is electrically connected with the radio frequency diode and the low-pass filter through the impedance matching network, the low-pass filter is electrically connected with the data processing module, and the radio frequency diode rectifies a received microwave signal in a 6G communication frequency band; the output signal of the radio frequency diode is sent to a low-pass filter to filter out fundamental frequency and higher harmonic, and a direct current component in the voltage signal is output, the direct current component is sent to a data processing module to be converted into a digital signal, and serial port communication is completed through a universal synchronous/asynchronous serial receiving/sending interface of the data processing module.

Preferably, the impedance matching network comprises a first quarter-microstrip line transformer of 50 Ω, a second quarter-microstrip line transformer of 50 Ω and a quarter-microstrip line transformer of 80 Ω, the microstrip patch antenna, the first quarter-microstrip line transformer of 50 Ω and the quarter-microstrip line transformer of 80 Ω are electrically connected in series with the substrate integrated waveguide, the second quarter-microstrip line transformer of 50 Ω and the radio frequency diode are grounded after being connected in series, and the microstrip line transformers are electrically connected with the low-pass filter.

Preferably, the low pass filter includes a resistor Rg, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor RQ, a resistor RF1, a resistor RF2, a capacitor C1, a capacitor C2, a filter A1, a filter A2 and a filter A3,

an input end 1 of a filter A1 is electrically connected after an arbitrary point series resistor Rg on a wire is connected between a quarter microstrip line transformer II of 50 omega and a radio frequency diode, an input end 2 of a filter A1 is grounded after being connected with a series resistor RQ in series, an input end 2 of a filter A1 is grounded after being connected with a series resistor R3 in series, an input end 1 of a filter A1 is electrically connected with an output end LPout, an input end 1 of a filter A1 is electrically connected with an output end 3 of a filter A1 after being connected with a series resistor R2 in series, and an input end 2 of a filter A1 is electrically connected with an output end 3 of a filter A2 after being connected with a series resistor R4 in series;

the output end 3 of the filter A1 is electrically connected with the input end 1 of the filter A2 after being connected with a resistor RF1 in series, the input end 1 of the filter A2 is electrically connected with the output end 3 of the filter A2 after being connected with a capacitor C1 in series, and the input end 2 of the filter A2 is grounded;

the output end 3 of the filter A2 is electrically connected with the input end 1 of the filter A3 after being connected with the resistor RF2 in series, the input end 1 of the filter A3 is electrically connected with the output end 3 of the filter A3 after being connected with the capacitor C2 in series, the input end 2 of the filter A3 is grounded, and the output end 3 of the filter A3 is electrically connected with the output end LPout.

Preferably, the analog-to-digital conversion module includes an ADR421 chip, a capacitor C4, a capacitor C5, and an analog-to-digital converter AD7887, where the ADR421 chip is electrically connected to a pin 8 of the analog-to-digital converter AD7887, a pin 1 of the analog-to-digital converter AD7887 is electrically connected to the output terminal LPout, the analog-to-digital converter AD7887 is electrically connected to the control processor, a pin 6 of the analog-to-digital converter AD7887 is electrically connected to the power VCC, a pin 6 of the analog-to-digital converter AD7887 is connected in series with the capacitor C4 and then grounded, a pin 6 of the analog-to-digital converter AD7887 is connected in series with the capacitor C5 and then grounded, and a pin 7 of the analog-to-digital converter AD7887 is grounded.

Preferably, the analog-to-digital conversion module further includes a resistor R11, a resistor R12, a resistor R13, and a resistor R14, the control processor is an STM32 microcontroller, a pin 2 of the analog-to-digital converter AD7887 is electrically connected with a pin PA6 of the STM32 microcontroller after being connected in series with a resistor R11, a pin 3 of the analog-to-digital converter AD7887 is electrically connected with a pin PA7 of the STM32 microcontroller after being connected in series with a resistor R12, a pin 4 of the analog-to-digital converter AD7887 is electrically connected with a pin PA5 of the STM32 microcontroller after being connected in series with a resistor R13, and a pin 5 of the analog-to-digital converter AD7887 is electrically connected with a pin PA4 of the STM32 microcontroller after being connected in series with a resistor R14.

Preferably, the chip further comprises a capacitor C11, a capacitor C12 and a capacitor C3, pin 1 of the ADR421 chip is electrically connected to the power VCC, pin 1 of the ADR421 chip is connected in series with the capacitor C11 and then grounded, the capacitor C12 is connected in parallel with the capacitor C11, pin 2 of the ADR421 chip is grounded, pin 3 of the ADR421 chip is connected in series with the capacitor C3 and then grounded, and pin 3 of the ADR421 chip is electrically connected to the pin of the analog-to-digital converter AD 7887.

Preferentially, the intelligent terminal also comprises a Bluetooth transmission module and a display screen, wherein the control processor is electrically connected with the display screen and wirelessly communicates with the terminal through the Bluetooth transmission module.

Preferably, a pin PB10 of the STM32 microcontroller is electrically connected with the Bluetooth transmission module, and a pin PB11 of the STM32 microcontroller is electrically connected with the display screen.

Preferably, the rf diode is of the schottky diode type MA4E1310, the maximum operating frequency can reach 110GHz, the reverse breakdown voltage is typically 7V, the minimum value is 4.5V, and the maximum input rf power is 20 dbm.

Preferentially, the frequency range of the microwave signal received by the microstrip patch antenna is 100 GHz-110 GHz of the frequency bandwidth of 6G communication, and the resonance center point of the microstrip patch antenna is 108 GHz.

The invention achieves the following beneficial effects:

the impedance matching network is connected with a low-pass filter, the low-pass filter is connected with an analog-to-digital conversion AD7887, and the output end of the data processing module is connected with the input end of a Bluetooth transmission module and the input end of a display screen, namely a display module. The output signal of the diode is sent to a main low-pass filter for filtering, fundamental frequency and higher harmonic waves are filtered, a direct current component in a voltage signal is output, the direct current component (an analog voltage signal) is sent to an analog-to-digital converter AD7887 and then converted into a digital signal, the digital signal is processed in an STM32 microcontroller, serial port communication is completed through a universal synchronous/asynchronous serial receiving/sending interface of the STM32 microcontroller, processed data are displayed on an LCD display screen, or the processed signal is wirelessly transmitted to a terminal through Bluetooth, and reading and recording of detection data are facilitated.

(1) The technology is novel: compared with the traditional microwave power sensor, the invention can be suitable for detecting the signal power of a microwave higher frequency band (100 GHz-110 GHz), and has the advantages of small volume, high integration level and the like.

(2) The performance is good: the traditional microstrip low-pass filter adopts the open-circuit stub as a branch line, the structure principle is simple, the design is easy, but the size and the wavelength are strictly related due to the fact that the Richard conversion is adopted for the traditional straight stub, and when the frequency is low, the size is too large, and the application is inconvenient. The low-pass filter designed by the invention can improve the performance of the filter while reducing the circuit size.

(3) The cost is low: the chip capable of directly detecting the microwave power in the market is expensive, and the frequency band capable of being detected is not high enough. The low cost is mainly reflected in the cost of components used by the system, and the main components of the microwave power detection circuit system are a Schottky diode, passive components such as a resistor, a capacitor, an inductor and the like, an amplifier and the like, so the cost of the whole system is relatively low.

Drawings

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

FIG. 2 is a circuit diagram of a low pass filter in the system of the present invention;

FIG. 3 is a schematic diagram of a microstrip patch antenna fed by a coaxial line in the system of the present invention;

FIG. 4 is a plot of the results of a sweep of the return loss S11 of the antenna in the system of the present invention;

FIG. 5 is a 3D pattern of an antenna in the system of the present invention;

FIG. 6 is a graph showing the voltage variation across the load when the load resistance is 50-3000 Ω in the system of the present invention;

FIG. 7 is a graph showing the variation of the impedance of the RF diode at 108GHz fundamental frequency at various input powers in the system of the present invention;

FIG. 8 is a schematic diagram of a microstrip patch antenna-substrate integrated waveguide-microstrip line transformer in the system of the present invention;

fig. 9 is a circuit diagram of the analog-to-digital conversion module and the control processor in the system of the present invention.

Detailed Description

The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The 6G communication microwave power detection system based on the radio frequency diode comprises a microstrip patch antenna fed by a coaxial line, an impedance matching network equivalent to a band-pass filter, a substrate integrated waveguide, the radio frequency diode, a low-pass filter and a data processing module, wherein a through rectangular cavity is transversely formed in the substrate integrated waveguide, the microstrip patch antenna is arranged in the rectangular cavity, the microstrip patch antenna is electrically connected with the substrate integrated waveguide through the impedance matching network, the substrate integrated waveguide is electrically connected with the radio frequency diode and the low-pass filter through the impedance matching network, the low-pass filter is electrically connected with the data processing module, and the radio frequency diode rectifies received microwave signals in a 6G communication frequency band. The output signal of the radio frequency diode is sent to a low-pass filter to filter out fundamental frequency and higher harmonic, and a direct current component in the voltage signal is output, the direct current component is sent to a data processing module to be converted into a digital signal, and serial port communication is completed through a universal synchronous/asynchronous serial receiving/sending interface of the data processing module.

Further, the impedance matching network comprises a first quarter microstrip line transformer of 50 omega, a second quarter microstrip line transformer of 50 omega and a quarter microstrip line transformer of 80 omega, the microstrip patch antenna, the first quarter microstrip line transformer of 50 omega and the quarter microstrip line transformer of 80 omega are electrically connected in series with the substrate integrated waveguide, the second quarter microstrip line transformer of 50 omega and the radio frequency diode are grounded after being connected in series, and the microstrip line transformer is electrically connected with the low-pass filter.

Further, the low-pass filter in this embodiment includes a resistor Rg, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor RQ, a resistor RF1, a resistor RF2, a capacitor C1, a capacitor C2, a filter a1, a filter a2, and a filter A3,

the output end 3 of the filter A2 is electrically connected with the input end 1 of the filter A3 after being connected with the resistor RF2 in series, the input end 1 of the filter A3 is electrically connected with the output end 3 of the filter A3 after being connected with the capacitor C2 in series, the input end 2 of the filter A3 is grounded, and the output end 3 of the filter A3 is electrically connected with the output end LPout. And the low-pass filter UAF42 filters out fundamental waves and higher harmonics and outputs a direct-current signal to be sent to data processing.

Furthermore, the analog-to-digital conversion module in this embodiment includes an ADR421 chip, a capacitor C4, a capacitor C5, and an analog-to-digital converter AD7887, where the ADR421 chip is electrically connected to a pin 8 of the analog-to-digital converter AD7887, a pin 1 of the analog-to-digital converter AD7887 is electrically connected to the output terminal LPout, the analog-to-digital converter AD7887 is electrically connected to the control processor, a pin 6 of the analog-to-digital converter AD7887 is electrically connected to the power VCC, a pin 6 of the analog-to-digital converter AD7887 is connected in series with the capacitor C4 and then is grounded, a pin 6 of the analog-to-digital converter AD7887 is connected in series with the capacitor C5 and then is grounded, and a pin 7 of the analog-to-digital converter AD7887 is grounded.

Further, in this embodiment, the analog-to-digital conversion module further includes a resistor R11, a resistor R12, a resistor R13, and a resistor R14, the control processor is an STM32 microcontroller, a pin 2 of the analog-to-digital converter AD7887 is electrically connected to a pin PA6 of the STM32 microcontroller after being connected in series with a resistor R11, a pin 3 of the analog-to-digital converter AD7887 is electrically connected to a pin PA7 of the STM32 microcontroller after being connected in series with a resistor R12, a pin 4 of the analog-to-digital converter AD7887 is electrically connected to a pin PA5 of the STM32 microcontroller after being connected in series with a resistor R13, and a pin 5 of the analog-to-digital converter AD7887 is electrically connected to a pin PA4 of the STM32 microcontroller after being connected in series with a resistor R14.

Further, the present embodiment further includes a capacitor C11, a capacitor C12, and a capacitor C3, pin 1 of the ADR421 chip is electrically connected to the power VCC, pin 1 of the ADR421 chip is connected in series with the capacitor C11 and then grounded, the capacitor C12 is connected in parallel to the capacitor C11, pin 2 of the ADR421 chip is grounded, pin 3 of the ADR421 chip is connected in series with the capacitor C3 and then grounded, and pin 3 of the ADR421 chip is electrically connected to the pin of the analog-to-digital converter AD 7887.

Further, still include bluetooth transmission module and display screen in this embodiment, the control treater electricity is connected the display screen, and the control treater passes through bluetooth transmission module and terminal wireless communication.

Further, in this embodiment, a pin PB10 of the STM32 microcontroller is electrically connected to the bluetooth transmission module, and a pin PB11 of the STM32 microcontroller is electrically connected to the display screen.

Further, in the present embodiment, the type of the rf diode is schottky diode MA4E1310, the maximum operating frequency can reach 110GHz, the typical value of the reverse breakdown voltage is 7V, the minimum value is 4.5V, and the maximum inputtable rf power is 20 dbm.

The frequency range of the micro-strip patch antenna for receiving the microwave signals is the frequency bandwidth of 6G communication and ranges from 100GHz to 110GHz, and the resonance center point of the micro-strip patch antenna is 108 GHz.

The microstrip patch antenna comprises a microstrip patch antenna fed by a coaxial line, a microstrip line converter, a substrate integrated waveguide, a resistor Rg, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor RQ, a resistor RF1, a resistor RF2, a capacitor C1, a capacitor C2, a filter A1, a filter A2, a filter A3, a capacitor C4, a capacitor C5, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, wherein the types of the components can be adopted in the prior art.

The terminal is a computer or a server, and the Substrate Integrated Waveguide (SIW) is a new microwave transmission line form, which uses metal through holes to realize the field propagation mode of the waveguide on the dielectric Substrate. In this embodiment, a substrate integrated waveguide in the prior art is adopted, and the structure of the substrate integrated waveguide is as follows:

1, two rows of metal through holes are realized by adopting a PCB, LTCC or film process.

2, the electromagnetic wave is limited in a rectangular cavity formed by two rows of metal holes and upper and lower metal boundaries.

3, due to the via holes on the sides, the transverse magnetic wave (TM) does not exist, and the transverse electric wave TE10 mode is the main mode.

The microstrip antenna generally comprises a dielectric substrate, a radiator and a ground plate. The thickness of the dielectric substrate is far smaller than the wavelength, the metal thin layer at the bottom of the substrate is connected with the grounding plate, and the metal thin layer with a specific shape is manufactured on the front surface of the substrate through a photoetching process to be used as a radiator. The shape of the radiating fins can be varied in many ways according to requirements. Microstrip antennas are generally classified into three types, that is, microstrip patch antennas, microstrip slot antennas, and microstrip antenna arrays (mainly, microstrip traveling wave antennas). Classified by shape, there are circular, rectangular, annular microstrip antennas, and the like. The microstrip antenna can be classified into a resonant type (standing wave type) microstrip antenna and a non-resonant type (traveling wave type) microstrip antenna according to the working principle. In the device, a rectangular microstrip patch antenna is adopted.

The resistance of the resistor R1 is 50K omega, the resistance of the resistor R2 is 50K omega, the resistance of the resistor R3 is 50K omega, the resistance of the resistor R4 is 50K omega, the resistance of the capacitor C1 is 1000PF, and the resistance of the capacitor C2 is 1000 PF.

The models of the filter A1, the filter A2 and the filter A3 are universal filter chips UFA 42.

The general implementation method of the invention is as shown in fig. 1, a microwave signal of a 6G communication frequency band (100 GHz-110 GHz) is received by a microstrip patch antenna, the microwave signal collected by the microstrip patch antenna in a coupling way is conducted to a low-pass filter by a microstrip line-substrate integrated waveguide-microstrip line converter, and a direct-current voltage signal LP out is output after low-frequency filtering by a low-pass filter composed of a rectification radio-frequency diode and a universal filter chip UFA 42. The output direct current voltage signal LP out is transmitted to a data processing module, the data processing module comprises an analog-to-digital converter AD7887 and an STM32 microcontroller, the analog voltage signal is converted into a digital signal which can be processed by the STM32 microcontroller after passing through the analog-to-digital converter AD7887, the digital signal is sent into the STM32 microcontroller for processing, serial port communication is completed with a data processing part through a universal synchronous/asynchronous serial receiving/sending interface of the STM32 microcontroller, an LCD screen is called, and the processed data is displayed on the LCD screen; or the processed voltage signal and the corresponding microwave signal power data are wirelessly transmitted to the terminal through the RXD and TXD serial port communication, so that the reading and the recording of the detection data are facilitated. The microwave signal detection method can realize detection of the microwave signal of the lower frequency band of the 6G communication.

The core part of the invention is a microwave power detection circuit based on a Schottky diode MA4E1310, and as shown in figure 2, the microwave power detection circuit consists of the Schottky diode, a low-pass filter for filtering fundamental frequency and higher harmonic and a load R. The microwave signal coupled to the antenna is sent to a matched Schottky (rectifying) diode, then a direct current voltage signal mixed with higher harmonics is output through rectification, the diode output signal is sent to a low-pass filter mainly composed of three UFA42 amplifiers for filtering, and a direct current component in the voltage signal is output, so that the detection of the microwave signal is completed. The performance of the whole rectifying circuit is influenced by the selection of the diode, and in a frequency band with extremely high frequency, the Schottky diode with low conduction voltage and short switching time is selected as the rectifying diode, the load R and the power supply are grounded, and the other end of the load R is electrically connected with the output end LPout.

Microwave signal reception of the 6G communication low frequency band is completed by using a microstrip patch antenna fed by a coaxial line. According to the working principle of the microstrip patch antenna, the working frequency is preset to be 108GHz, the formula for calculating the size of the antenna is substituted, the parameters of the antenna are simulated and optimized in the HFSS, and the length of a radiation element is 0.293mm according to the calculation formula and the optimized parameter values; the equivalent radiation gap length is Δ L of 0.410 mm; the width of the radiating element is 1.174 mm; the effective dielectric constant is 2.2 mm; the position of the coaxial line feed point is 0.113 mm; the relative dielectric constant is 1.693. A coaxial-fed microstrip patch antenna model designed according to the parameters is shown in fig. 3. The resonance center point of the simulated antenna is 108GHz, the frequency sweeping result of the return loss S11 of the antenna is shown in FIG. 4, and the return losses in the frequency bands (100 GHz-110 GHz) near the resonance center are all less than-10 dB. The result of the 3D directional diagram simulation of the microstrip patch antenna is shown in fig. 5, the gain of the microstrip patch antenna along a specific direction reaches about 6.4dB, no measurement blind area in a large range exists, and the initial design requirements are met.

Deducing and establishing a closed formula of a Schottky diode parallel rectifier circuit under an ideal condition, and qualitatively analyzing the influence of input power on diode input impedance and direct-current voltage on a load in the rectifier circuit to obtain that when the input power of a source is constant, the voltage on the load of the rectifier circuit is monotonically increased along with the increase of the load; when the load resistance is constant, the voltage on the load increases with the input power of the source. Establishing a model of the Schottky diode in the ADS, simulating the Schottky diode parallel rectification circuit, and testing the Schottky diode parallel rectification circuit of each load under the frequency of 108 GHz. When the load resistance is 50-3000 Ω, the voltage across the load changes as shown in fig. 6, and the voltage across the load increases with the increase of the input power, but when the power increases to a certain value, the diode breaks down in the reverse direction, and the voltage across the load is maintained at about 3.2V and does not change. Under the same power, the larger the resistance value of the load is, the larger the voltage drop at two ends of the load is, but when the resistance value of the load is larger than 1000 Ω, the increasing amplitude of the voltage drop at two ends of the load along with the increase of the resistance value is gradually no longer obvious. Therefore, in order to take power and voltage drop at two ends of the load into account, the load resistance value is not too large, and is about 1000 Ω. And (3) solving a change curve of 108GHz fundamental frequency impedance of the diode under each input power according to the voltage at the nodes at the two ends of the diode and the current flowing through the diode, and further designing an impedance matching network and a rectifying circuit. Simulation results as shown in fig. 7, as the input power increases, the diode can turn on, the resistance thereof decreases, and the reactance decreases. The impedance matching design of the next rectifying circuit is carried out by taking the reactance value of the diode near 1.26 mW of input power, and the impedance of the diode is taken as 130-125 omega. The microstrip patch antenna couples the energy of the microwave signal to the lower substrate integrated waveguide through the slot on the substrate integrated waveguide, and the substrate integrated waveguide transmits the signal to the rectifying circuit established based on the microstrip line impedance matching network to rectify the signal, thereby finally realizing the conversion of the microwave signal into a direct current signal which can be conveniently read. The impedance matching network is designed to use a substrate integrated waveguide-microstrip line structure, as shown in fig. 8. The substrate integrated waveguide is equivalent to a band-pass filter, only allows electromagnetic waves with the frequency higher than the cut-off frequency of the substrate integrated waveguide to pass, conducts high-frequency electromagnetic waves received by the antenna to a quarter microstrip line with the impedance of 50 omega, and then is connected to a quarter microstrip line converter with the impedance of 80 omega to complete impedance matching with a rectifier diode.

Finally, the detected microwave signals are visually displayed through an analog-to-digital converter AD7887 and an STM32 microprocessor chip, a rectifier diode is connected with the tail end of an impedance matching network and a low-pass filter, and the upper fundamental frequency and higher harmonics are filtered out and then data processing is carried out on the direct current signals. As shown in fig. 9, the 2.5V reference voltage generated by ADR421 is connected to 8 ports through grounded capacitor C3, i.e. 3 ports, to provide a reference voltage for AD 7887. The direct-current voltage output after being filtered by the low-pass filter enters an analog-to-digital converter AD7887 from a port 1, and then the analog-to-digital converter AD7887 converts an input analog signal into a digital signal; finally, the analog-to-digital converter AD7887 transmits the digital signals to the STM32 microprocessor through R11-R14, and data processing and analysis are achieved in the STM 32. R11-R14 are 100 omega resistors, so that digital noise can be reduced, and a sampling result is more stable; the C3 value is 100nF, and the ripple of the reference voltage can be reduced. C11, C12, C4 and C5 are two pairs of bypass capacitors connected to VCC, with C11 and C12 values of 10 μ F and C4 and C5 values of 100 nf. After the digital signals are sent to an STM32 microcontroller through R11-R14, codes are compiled to process and display the signals, and visualization of detection data is achieved. And the Bluetooth connection can be completed with other terminals to transmit signals in a wireless transmission mode, and finally, the real-time display and recording of detection signals are realized.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. The 6G communication microwave power detection system based on the radio frequency diode is characterized by comprising a microstrip patch antenna fed by a coaxial line, an impedance matching network equivalent to a band-pass filter, a substrate integrated waveguide, the radio frequency diode, a low-pass filter and a data processing module, wherein the substrate integrated waveguide is transversely provided with a through rectangular cavity, the microstrip patch antenna is arranged in the rectangular cavity, the microstrip patch antenna is electrically connected with the substrate integrated waveguide through the impedance matching network, the substrate integrated waveguide is electrically connected with the radio frequency diode and the low-pass filter through the impedance matching network, the low-pass filter is electrically connected with the data processing module, and the radio frequency diode rectifies received microwave signals in a 6G communication frequency band; the output signal of the radio frequency diode is sent to a low-pass filter to filter out fundamental frequency and higher harmonic, and a direct current component in a voltage signal is output, the direct current component is sent to a data processing module to be converted into a digital signal, and serial port communication is completed through a universal synchronous/asynchronous serial receiving/sending interface of the data processing module;

the impedance matching network comprises a first quarter microstrip line transformer of 50 omega, a second quarter microstrip line transformer of 50 omega and a quarter microstrip line transformer of 80 omega, the microstrip patch antenna, the first quarter microstrip line transformer of 50 omega and the quarter microstrip line transformer of 80 omega are electrically connected in series with the substrate integrated waveguide, the second quarter microstrip line transformer of 50 omega and the radio frequency diode are grounded after being connected in series, and the second quarter microstrip line transformer of 50 omega is electrically connected with the low-pass filter.

2. The RF diode-based 6G communication microwave power detection system of claim 1,

the low-pass filter comprises a resistor Rg, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor RQ, a resistor RF1, a resistor RF2, a capacitor C1, a capacitor C2, a filter A1, a filter A2 and a filter A3,

the second quarter microstrip line transformer with the voltage of 50 ohms is electrically connected with the input end 1 of the filter A1 after being connected with the series resistor Rg at any point on an electric wire between the second quarter microstrip line transformer and the radio frequency diode, the input end 2 of the filter A1 is grounded after being connected with the series resistor RQ in series, the input end 2 of the filter A1 is grounded after being connected with the series resistor R3 in series, the input end 1 of the filter A1 is electrically connected with the output end LPout, the input end 1 of the filter A1 is electrically connected with the output end 3 of the filter A1 after being connected with the series resistor R2 in series, and the input end 2 of the filter A1 is electrically connected with the output end 3 of the filter A2 after being connected with the series resistor R4 in series;

3. The RF diode-based 6G communication microwave power detection system of claim 2,

the data processing module comprises an analog-to-digital conversion module, the analog-to-digital conversion module comprises an ADR421 chip, a capacitor C4, a capacitor C5 and an analog-to-digital converter AD7887, the ADR421 chip is electrically connected with a pin 8 of the analog-to-digital converter AD7887, a pin 1 of the analog-to-digital converter AD7887 is electrically connected with an output end LPout, the analog-to-digital converter AD7887 is electrically connected with the control processor, a pin 6 of the analog-to-digital converter AD7887 is electrically connected with a power VCC, a pin 6 of the analog-to-digital converter AD7887 is connected with a capacitor C4 in series and then grounded, a pin 6 of the analog-to-digital converter AD7887 is connected with a capacitor C5 in series and then grounded, and a pin 7 of the analog-to-digital converter AD7887 is grounded.

4. The RF diode-based 6G communication microwave power detection system of claim 3,

the analog-to-digital conversion module further comprises a resistor R11, a resistor R12, a resistor R13 and a resistor R14, the control processor is an STM32 microcontroller, a pin 2 of the analog-to-digital converter AD7887 is electrically connected with a pin PA6 of the STM32 microcontroller after being connected with a resistor R11 in series, a pin 3 of the analog-to-digital converter AD7887 is electrically connected with a pin PA7 of the STM32 microcontroller after being connected with a resistor R12 in series, a pin 4 of the analog-to-digital converter AD7887 is electrically connected with a pin PA5 of the STM32 microcontroller after being connected with a resistor R13 in series, and a pin 5 of the analog-to-digital converter AD7887 is electrically connected with a pin PA4 of the STM32 microcontroller after being connected with a resistor R14 in series.

5. The RF diode-based 6G communication microwave power detection system of claim 3,

the analog-to-digital conversion module further comprises a capacitor C11, a capacitor C12 and a capacitor C3, wherein a pin 1 of the ADR421 chip is electrically connected with a power supply VCC, a pin 1 of the ADR421 chip is connected with the capacitor C11 in series and then grounded, the capacitor C12 is connected with the capacitor C11 in parallel, a pin 2 of the ADR421 chip is grounded, a pin 3 of the ADR421 chip is connected with the capacitor C3 in series and then grounded, and a pin 3 of the ADR421 chip is electrically connected with a pin 8 of the analog-to-digital converter AD 7887.

6. The RF diode-based 6G communication microwave power detection system of claim 4,

the control processor is electrically connected with the display screen and is in wireless communication with the terminal through the Bluetooth transmission module; filter a1, filter a2, and filter A3 are UFA42 amplifiers.

7. The RF diode-based 6G communication microwave power detection system of claim 6,

the data processing module includes STM32 microcontroller, and the bluetooth transmission module is connected to STM32 microcontroller's pin PB10 electricity, and the display screen is connected to STM32 microcontroller's pin PB11 electricity.

8. The RF diode-based 6G communication microwave power detection system of claim 1,

the radio frequency diode is a Schottky diode MA4E1310, the highest working frequency can reach 110GHz, the typical value of reverse breakdown voltage is 7V, the minimum value is 4.5V, and the maximum input radio frequency power is 20 dbm.

9. The RF diode-based 6G communication microwave power detection system of claim 1,