A Passive X-Band Double Balanced Mixer Utilizing Diode Connected SiGe HBTs

摘要

In this paper, a passive double balanced mixer in SiGe HBT technology is presented. Due to lack of suitable passive mixing elements in the technology, the mixing elements are formed by diode connected HBTs. The mixer is optimized for use in doppler radars and is highly linear with 1 dB compression point above 12 dBm. The conversion gain at the center frequency of 8.5 GHz is -9.8 dB with an LO drive level of 15 dBm. The mixer is very broadband with 3 dB bandwidth from 7-12 GHz covering the entire X-band. The LO-IF and RF-IF isolation is better than 46 dB and 36 dB, respectively, in the entire band of operation.