Research And Design Of Active Link In Ka Band

Millimeter wave technology has a wide range of applications in areas such as communications,radar,and imaging.Millimeter wave signals have the advantages of high bandwidth and high data transmission rate,which can be used for high-speed wireless communication and high-resolution imaging.Millimeter wave radar can be used to detect long-distance targets and provide high-resolution imaging,such as applications in security detection,traffic monitoring and other fields.Millimeter wave imaging technology can be used in medical,security,geological exploration and other fields.The millimeter-wave active link is a key component of millimeter-wave technology,and its performance has a significant impact on the performance and reliability of the entire system.This paper designs and implements a Ka-band active link with adjustable phase,frequency and amplitude,which is used as a millimeterwave signal source for millimeter-wave array antenna microwave anechoic chamber testing.The main research contents and results are as follows:(1)Based on the high-performance DDS chip and sub-harmonic mixer based on the principle of direct digital frequency synthesis,a millimeterwave active link implementation scheme is designed,which consists of a highly integrated baseband module and a Ka-band multi-channel mixing module and a phase correction module.The test results have verified the effectiveness of the scheme,realizing eight-channel broadband millimeterwave signal output with an output frequency range of 25.4GHz-27.4GHz.The frequency modulation accuracy is 1Hz,the amplitude modulation accuracy is 1dB,and the phase modulation accuracy is 1°,where the amplitude modulation error is less than 0.5dB,and the phase correction module correction error is less than 2°.(2)Based on the single-chip microcomputer and high-performance DDS chip,a high-precision and high-integration baseband module is designed,and the single-chip microcomputer is used to control the logic of the DDS chip.The test results show that the module can generate a frequency range of 10MHz-200MHz,a frequency modulation accuracy of 1Hz,and output A multi-channel baseband signal with a maximum power of-8dBm and a phase modulation accuracy of 1°.(3)The Ka-band multi-channel mixing module is designed based on the subharmonic mixer.In order to save costs and meet the miniaturization requirements,a 12GHz-14GHz broadband one-to-eight microstrip Tshaped power division structure is researched and designed.Plywood processing with the mixing module PCB RF board.After testing and verification,the results show that the frequency mixing module can generate 25.4GHz-27.4GHz multi-channel millimeter-wave signals,and the signal amplitude can be adjusted precisely,which is consistent with the theoretical calculation results,and the error is less than 0.5dB.(4)Based on the I/Q down-converter and 90° electric bridge,a multichannel radio frequency signal phase correction method was proposed and the phase correction module was built.This method overcomes the millimeter-wave image interference and realizes millimeter-wave Wave phase correction function.After testing,the effectiveness of this method for millimeter wave phase correction is verified,and the phase correction error is less than 2°.