A novel six-port circuit based on four quadrature hybrids

A novel six-port circuit is proposed and demonstrated. The circuit is based on four quadrature hybrids. A prototype circuit is fabricated and characterized with microstrip lines. Reflection coefficients for a few loads are measured with the fabricated circuit to evaluate its performance. The results agree with those from an HP8510C network analyzer reasonably well. Using active inductors and varactors, the six-port circuit is also designed with a 0.13 μm CMOS process. The simulation results show that the operating frequency is tunable from 1 to 6.8 GHz.