122 / 2019-06-03 21:00:13

A Microstrip Lowpass Filter with Compact Size and Wide Stopband

Compact, wide stopband, lowpass filter, radial stub

This paper presents a compact wide stopband microstrip lowpass filter using novel stepped impedance hairpin resonators. By embedding a radial stub inside the stepped impedance hairpin resonator, the resulting resonator can achieve a compact size and wide stopband simultaneously. To validate the designed approach, a microstrip lowpass filter is implemented, and tested. The filter features a compact size of 0.158λg × 0.126λg, where λg is the waveguide length at the cutoff frequency of 1.9 GHz. The measurements demonstrate that the filter offers a wide stopband from 2.45 GHz to 16.3 GHz with a suppression level better than 20 dB.