Output coupled line wavelength hybrid ring resonator centered at 3 GHz for bandpass filter applications

Abstract

An output coupled line wavelength ring resonator centered at 3 GHz operating frequency for bandpass filter application is presented in this paper. The proposed ring resonator demonstrates a single mode resonant frequency at 3 GHz with a pair of transmission zeroes. This ring resonator consists of even and odd mode line impedance, and coupled to the output feed lines along a quarter-wavelength of its side to generate a single-mode bandpass response with two transmission zeroes at 2 GHz and 3.5 GHz. The design of the resonator filter is simulated in Microwave Office (AWR Design Environment) based on the design specification and fabricated on Flame Retardant Type-4 (FR4) microstrip substrate with dielectric constant, ε_r=4 and height of thickness, H = 4 mm. All the simulation and measurement results are presented and discussed in this paper to show its feasibility.

Keywords: line wavelength; ring resonator; two transmission zeroes; microwave filter; bandpass filter