Enhancement Phase-shifting Nonreciprocity by Asymmetry Series Interdigital Capacitors in Normally Magnetized Ferrite Microstrip Lines

Periodic insertion of asymmetric interdigital capacitors (IDCS) in a series branch of normally magnetized ferrite microstrip lines is proposed. Two types of IDCS, 2-staged IDC and tapered IDC, are numerically and experimentally investigated. The numerical and measured results were in good agreement. The prototype circuits were fabricated, and the measured results agree with the simulations. The nonreciprocal phase shifts for both types of IDCS increase monotonically as the operating frequency increases within the transmission bands.