K-band Mirror Frequency Mixer Research To Suppress Harmonic Wave

Mixers are the important components of the microwave communication, remotesensing, remote control, radar and microwave measurement systems, characteristics ofthe mixer, such as conversion loss, image rejection, noise, impact on the performance ofthe electronic system.This thesis introduces the domestic and international developments of the mixer,the mixer’s basic theories, analytical methods, the characteristics of the different mixersand the differences between them are also analyzed. According to the foregoing analysisand the actual requirements of the subject indexes, harmonic image rejection mixer isused in this thesis.This thesis gives the detailed simulation optimization steps. A secondary harmonicimage rejection mixer and a fourth harmonic image rejection mixer are simulated usingADS and HFSS. Each of the proposed mixers consists of two harmonic mixer units, aRF (radio frequency) orthogonal power divider, an IF (intermediate frequency)orthogonal power combiner, and a LO (local oscillation) in-phase divider. Anti-parallelpair of diodes is used in harmonic mixers to achieve frequency conversion. The RForthogonal power divider consists of a Wilkinson power divider and a microstrip linewhich is1/4wavelength of the RF frequency. An advanced Wilkinson power divider isused in this thesis to avoid strong coupling between the two embranchments of the RFpower divider. Besides, the LO in-phase power divider is a Wilkinson power divider;the IF orthogonal power combiner consists of a lumped phase shifter and a lumpedWilkinson power divider.In the thesis, two mixers which are fabricated using hybrid microwave integratedcircuit (HMIC) process based on substrate Rogers RT/Duriod5880are realized. At theRF bandwidth of20~21GHz, conversion loss of the secondary harmonic imagerejection mixer is lower than11.8dB, it’s image rejection is better than20dB;conversion loss of the fourth harmonic image rejection mixer is lower than14dB, andit’s image rejection is better than21dB. All of the experimental results meet goodagreement with the design index requirement, so the feasibility of the development program and the correctness of theoretical analysis are verified.