A microstrip UWB bandpass filter using a stub-loaded dual-mode ring resonator and a step impedance two-mode resonator

A novel UWB bandpass filter is developed by taking advantages of both the microstrip stub-loaded dual-mode ring resonator and the step-impedance resonator added with low-impedance sections. A frequency response having sharp attenuations near the passband and large attenuations over a wide stopband is realized, which satisfies quite well Japan's low-band limit for UWB applications.