W-band Sub-harmonic Mixing Technology

Mixers are indispensable in millimeter wave systems, which are extensivelyapplied in millimeter-wave communication systems, military radars, informationcountermeasure and related measure systems.The performance of millimeter-wave mixers could be excellent. The LO sources atthat frequency band, however, are expensive and hard-to-get, which are bad forengineering use. Harmonic mixers could employ the harmonics of LO sources to mixwith RF signals and then get the IF frequency, which would markedly lower therequired frequency of LO sources. The application of harmonic mixers could overcomethe difficulty of achieving millimeter-wave LO sources and reduce the cost of systems.The design of harmonic mixers featured by wide-band and low-loss seems to be animportant research area in the future.In this thesis, the microstrip-line is applied because of its planar construction、smallsize and compatibility with semiconductor devices. The UMS company DBE105a seriesdiode is selected as the mixer diode. The circuit analysis and design are guided byHarmonic balance method which is theoretical basis of mixers. Using electromagneticsimulation software HFSS and circuit simulation software ADS, design waveguide tomicrostrip probe transition of RF, LO duplex (IF low-pass filter, LO low-pass filter andthe LO transition) and Relateda matching circuit. Sub-harmonic mixer is finished byoverall circuit optimization and simulation with the passive part of the circuit and thediode model. Test results show that the W-band sub-harmonic mixer gets a less than10dB conversionloss in the band of88~99GHz, with the conversion of7.3dB at94GHz.