Compact double-balanced star mixers with novel dual 180° hybrids

Compact double-balanced monolithic star mixers using 0.25 μm GaAs pHEMT process are presented. These star mixers adopt two novel types of the dual 180° hybrid structure, thereby reducing the chip size and eliminating complex layout. With multi-coupled lines technology, the proposed dual 180° hybrids are produced and applied to star mixers successfully. Furthermore, the proposed hybrids simplifies the star mixer´s IF extraction circuit to reduce the chip size and enhance the IF bandwidth. The results demonstrate wide operation bandwidth, low conversion loss and good port-to-port isolations with a size dimension of less than 0.81 mm², could thus be obtained.