Abstract
In this paper, a band pass filter with adjustable transmission zeros is presented. The proposed filter structure is based on a non-degenerate dual-mode resonator loaded by either varactor diodes or open circuit stubs at its opposite corners. These loading techniques allow adjusting the transmission zeros either on the upper stopband or on the lower stopband. The effect of open stubs and varactor diodes loading is inspected and design curves for the proposed structure are deduced. Based on that, a filter is designed and implemented on Duroid substrate with 10.3 dielectric constant and 0.635 mm thickness to validate the proposed concept. Simulation and experimental results are, then, analyzed and compared.