Abstract

For LMDS and MVDS systems, a compact Image Rejection Star Mixer has been developed for use as both up-and down converter.The circuit has been designed in order to ease the integration,to reduce the size and finally to reach the cost requirements for such systems.The MMIC is fabricated on UMS commercially available PH25 GaAs PHEMT processes.At 40-GHz LO-frequency,the up conversion losses are only 7 dB for an LO power of 18 dBm and 1.5-GHz IF.The image rejection is better than –25 dB and the LO/RF isolation is better than 25 dB.With a chip area of only 2 mm 2,compared to previously reported results for image rejection double balanced mixer MMICs operating in the 35-45-GHz frequency range,this represents a chip size reduction by more than 30 %.