Compact Down-Conversion mixer design employing a wide and deep Stop-Band DGS-LPF

Abstract

This paper investigates a compact 24-GHz hybrid down-conversion mixer. The proposed mixer is based on a wide and deep stop-band low pass filter, four Schottky diodes, two hybrid couplers and an open stub. The unwanted harmonics are rejected by means of a filter based on three uniforms dumbbell-shaped defected ground structure and a compensated microstrip line. A good conversion loss of 2.19dB, 1-dB compression point of 3-dBm and an LO-to-RF isolation better than 35dB are obtained. The validity of the mixer configuration and the design procedure are confirmed by a comparison between simulation results and measurements data reported in literature