A Novel Tunable Phase Shifter with Distributed Capacitive Loading

A novel but simple design of transmission line with a parasitic patch that works as a phase shifter at the frequency range of 1.5 - 3 GHz is presented. Variable capacitors attached to a parasitic element above the transmission line change the phase of the propagating wave with minimum reflection. A 90 degree of phase shift is achieved with capacitance of 4.5 pF variation.