Miniature microstrip wideband band-pass filter

This paper presents a simple method to design miniature wideband band-pass filters. In order to verify this method, we designed a miniature microstrip wideband band-pass filter by using open-loop resonators. Eventually we achieved a 10th-order miniature wideband band-pass filter with center frequency 2 GHz, bandwidth 1 GHz and the relative bandwidth 50%, passband insertion loss less than 7.3 dB, stop-band rejection better than 42.6 dB when frequency lower than 1.4 GHz and more than 36.6 dB when frequency higher than 2.6 GHz. Its total size is 20.01 mm×16.22 mm.