Abstract
Various bandpass filters using stub resonators have been proposed to realize attenuation poles near the desired passband. However, designers have had to set the location of the attenuation poles by trial and error so as to use the attenuation pole effectively.
In this paper, we propose and design bandpass filters using stub resonators in order to decide the location of the attenuation poles and the sidelobe level in the stopband near the passband by using the elliptic function characteristic. The effectiveness of the designed filters is evaluated by circuit simulation, electromagnetic simulation, and experiment. We have also confirmed the realization of the sidelobe level in the stopband near the passband that is larger than the basic elliptic function characteristic by the appropriate choice of first and third resonators.
