Periodic Structure on the Slot Resonators in Microstrip Transmission Line

In this paper, scattering and phase-shift characteristics of 1-D periodic structures based on slot resonators in a ground plane of a microstrip line were studied. The scattering matrix of a slot resonator in a microstrip line ground plane was calculated by the two methods: using from scattering matrix of microstrip-slotline transition, and rigorous calculation of slot resonator in microstrip line. Both matrices were obtained by a transverse resonance technique. Amplitude characteristics and phase shift on period were studied for one-, two-, and three-stages periodic structures. As an example of possible application, the high-order harmonics filter based on a three-stage periodic structure was designed, which has a phase of a reflection coefficient equal to 0 and pi on the second and third harmonic, respectively. Such values of the phase find application in the output network of inverse class F power amplifiers.