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.