Design of a Broadband HEMT Mixer for UWB Applications

This paper presents the design of a novel distributed HEMT mixer for ultrawide-band (UWB) receivers. Artificial transmission lines are incorporated in the distributed mixer to absorb the parasitic capacitances. With a local oscillator power of 12 dBm, and RF power of -20 dBm, the proposed mixer has a Conversion Gain of 0 ~ 4 dB(without IF signal amplification), LO-to-RF isolation better than 32 dB and 130 mW DC power consumption. The designed mixer is capable of covering the RF and LO frequencies over a wide range of frequencies from 5-25 GHz. Mixer operation is demonstrated both for downconversion to fixed IF and for broadband conversion using fixed LO frequencies. This mixer utilized a new distributed topology with single-gate HEMTs and achieved a vary broadband performance comparable to the cascode or dual-gate distributed mixers. The topology of this mixer is suitable for monolithic implementation.

Keywords:

distributed mixer , ultra-wideband , HEMT mixer , wireless communication , millimeter-wave (MMW)