A broadband doubly balanced monolithic ring mixer with a compact intermediate frequency (IF) extraction

To meet the requirements for broadband operation, high port-to-port isolation, and miniature chip area, a doubly balanced monolithic microwave ring mixer with an advanced IF extraction fabricated using 0.15 μm GaAs pHEMT process is presented. A miniature Marchand-like spiral balun with low-pass filter is used to extract IF signals and maintain balun performance simultaneously. The low-pass filter can filter out both the RF and LO signals. This miniaturized mixer design can mitigate layout complexity, improve port-to-port isolations suitable for ultra-broadband Ku-, K-, and Ka- band applications. Subsequently, the LO/RF-to-IF isolations are greater than 43.2 and 32 dB from 11 to 40 GHz, respectively. The LO-to-RF isolation is between 26.9 and 50.7 dB within the same swept range. The conversion loss is 7.2-12.4 dB within the operating bandwidth.