Research On Broadband Microwave Front-end Technology

With the continuous innovation and improvement of communication technology,People increasingly rely on electronics.These include satellite communications,military radar,drones,driverless cars,mobile phone communications,smart homes,etc.However,in these devices that require information exchange or remote control,there must be an information transmission and reception system.The microwave RF frontend is a key component of the transceiver,and its circuit design is particularly important.Based on a surface wave transmission research project,this paper designs a C-band microwave transceiver front-end suitable,and completes the physical production and performance test of the transceiver front-end.This paper introduces the detailed theoretical basic knowledge of the structure of commonly used microwave radio frequency transceivers.The performance indicators of the receiver and the transmitter are analyzed,and according to actual needs,it is decided that both the receiving front end and the transmitting front end adopt superheterodyne structures.With the corresponding simulation software,the reasonable allocation and simulation of the gain and noise parameters of the transmit and receive front-end links are completed.In order to facilitate processing and testing,the receiving front end and the transmitting front end are designed separately,and a sub-module design is used in each design.The modules included filters,mixers,drive amplifiers,controllable attenuators,low noise amplifiers,power amplifiers,and local oscillator frequency synthesizers.This paper has completed the design and processing of the microwave transceiver front-end and the circuit board of the local frequency synthesizer.The cavity design and processing of each module were completed,and the assembly,debugging and testing of each module were completed.For the receiving front-end system,the continuous wave power that can stably output is 0dBm ± 2dB,the channel gain can reach 50 dB ± 2dB,and the gain flatness is less than or equal to 3.0dBp-p / 200 MHz.The controllable range of the channel gain is 30 dB,and the step range is 1dB.The spurious suppression is more than 70 dBc,and the noise figure is less than 2dB.For the transmitting front-end system,the continuous wave power that can be stably output is 24 ± 2dB dBm,the channel gain can reach 45 dB,the gain controllable range is 30 dB,the step range is 1dB,and the spurious suppression is greater than 30 dBc.For the local oscillator frequency synthesizer,the stable local oscillator signal power is 0dBm ± 2dB,and the gain can be adjusted from-4dBm to 5dBm.The design of this paper covers the important components of the microwave RF transceiver front-end,and a lot of debugging,testing and improvement work have been done during the design process.Test results show that this microwave transceiver front end fully meets the design requirements.