Balun design for uniplanar broad band double balanced mixer

A novel balun based on an asymmetric coplanar waveguide with finite ground plane (ASYCPWFGP) to coplanar strip (CPS) transition is presented. A return loss better than 16 dB is obtained up to 50 GHz. The baluns are combined with four silicon Schottky barrier crossover diodes to yield a planar double-balanced mixer (DBM) which demonstrates an ultra-broadband performance up to 40 GHz.