Dual band high selective compact transmission line gap resonator

This paper presents, for the first time, a coupled gap transmission line resonator based on dual composite right/left handed microstrip structure. This introduced topology proposes dual band with high selective sharp band pass response. The whole structure is designed using only one cell comprised using a shunt tank of interdigital capacitor and strip inductor, and series tank formed using patch capacitor with small strip inductor. Moreover, the paper elaborates the equivalent circuit model, analytical study, 3D full wave simulation and fabrication measurement results. The results exhibit two sharp insertion loss resonances at 5.8 GHz and 7.7 GHz with associated return loses better than 10 dB. Furthermore, the quality factor demonstrates very high selectivity and equals 194.3 and 142.3 at the two bands, respectively.