Dual-band filters using complementary split-ring resonator and capacitive loaded half-mode substrate-integrated-waveguide

Novel dual-band bandpass filters are implemented for 3.5GHz and 5.8GHz operation by using the half-mode substrate integrated-waveguide (HMSIW) loaded with a complementary split-ring resonator (CSRR) and a capacitive metal patch. Forward electromagnetic wave transmission below the characteristic waveguide cutoff frequency is achieved at two arbitrary frequency bands. Relatively independent control of the resonance frequencies, external Q factor and mutual coupling are possible. A dual band resonator and a two-pole miniaturized bandpass filter are demonstrated. The external and internal mutual coupling variations are fully investigated. Full wave structure simulation and measurement results are provided.