Wide-IF-Band CMOS Mixer Design

A wide-IF-band transistor mixer has been designed using a 0.13-¿m RF-CMOS process where its RF frequency is 8.7-17.4 GHz, local oscillator (LO) fixed at 17.4 GHz, and IF up to 8.7 GHz. Proper layout arrangement for the Marchand balun has been discussed and then implemented; the output amplitude and phase imbalance are less than 0.5 dB and 1°measured in the RF bandwidth. Related theories for the core mixing circuit are explored extensively and verified through simulation; broad bandwidth of the resistive double-balanced mixer is then confirmed in the IF aspect. The designed mixer has more than 10-dB conversion gain, matched RF, IF, and LO ports, and good port isolation over the intended wide bandwidth. The input-referred P1 dB is -17.5 dBm at 9 GHz and -16 dBm at 13 GHz. The third-order input intercept point is -6 dBm at 9 GHz and -5 dBm at 13 GHz. The noise figure is 7 dB at 9 GHz and 12.6 dB at 13 GHz. The power consumption is 40 mW for this 1.3-mm2mixer chip.