Systematic design of 7-to-40-GHz on-chip mixer based on optimal impedance deviation coefficient

摘要

In this article, a 7-GHz to 40-GHz ultra-wideband passive double-balancedmixer MMIC using compact wideband Marchand balun (CWMB) is presented.The CWMB is analyzed and designed by introducing a novel optimal impedancedeviation coefficient. A trade-off between the needed bandwidth and theacceptable insertion loss in an ultra-wideband passive-doubly-balanced mixerdesign can be made through introducing the optimal impedance deviation coefficient.Finally, to verify the proposed methodology, a compact wideband passivedouble-balanced mixer monolithic microwave integrated circuit (MMIC) wasdesigned and fabricated using a standard gallium arsenide (GaAs) pHEMT technologyaccording to the process characteristics. Experimental results show that anultra-wideband mixer MMIC is realized from 7 GHz to 40 GHz (140% fractionalbandwidth) with a measured conversion loss between 9.5 dB~12.5 dB (in-bandfluctuation less than 3 dB) and a LO-to-RF isolation larger than 34 dB. The measurementresults are in good agreement with the simulation results.