Ka-Band CMOS Hybrids Miniaturization Incorporating Multilayer Synthetic Quasi-TEM Transmission Lines

Multilayer synthetic quasi-TEM transmission lines (TLs) are applied to the CMOS hybrids miniaturization. Two meandered synthetic quasi-TEM TLs are integrated in the form of CMOS multilayer structure and shielded by the mesh ground plane. Theoretical analyses are performed to extract the guiding properties of the multilayer synthetic quasi-TEM TLs. The extracted results are applied to the CMOS hybrid designs. The prototypes of
Ka
-band power divider and 180-degree hybrid (rat-race hybrid) are implemented by using the standard 0.18-mum 1P6M CMOS technology, achieving the circuit sizes of 180.0 mum times 180.0 mum and 210.0 mum times 480.0 mum, respectively. The experiments show intrinsic loss of power divider is less than 5.26 dB over a bandwidth of 10-GHz when the input return loss is kept higher than 10.0 dB. In the rat-race design, the measured insertion loss is 4.98 dB and the isolation is higher than 17.0 dB.