A CMOS doubly balanced monolithic ring mixer with an advanced IF extraction

A CMOS doubly balanced monolithic microwave ring mixer fabricated through 0.18 μm TSMC CMOS process is presented. The main design objective is to satisfy broadband operations with a compact and advanced IF extraction and to shrink the chip area. A miniature Marchand-like spiral balun with a low-pass filter is used to extract IF signals and maintain balun performance simultaneously. This design can mitigate layout complexity and promote port-to-port isolations. The CMOS ring DBM exhibits an operating bandwidth of 7-23 GHz at an LO power of 11 dBm with the smallest chip area of 0.76 × 0.51 mm². Moreover, the LO/RF-to-IF isolations levels are both higher than 31 dB. This outcome is primarily caused by the utilization of an offset overlayed stacked spiral balun.