Wideband and miniaturized lumped‐element low temperature co‐fired ceramic filter Using size reduced resonators for very high frequency applications

Abstract

A wideband and miniaturized bandpass filter (BPF) is proposed using size reduced resonator (SRR) for the very high frequency band applications. The proposed SRR places vertically interdigital-capacitor inside spiral inductor, thus two L-C elements only take up one inductor's area. Therefore, significant size reduction and integration increment are both achieved without increasing the number of substrate layers. The BPF is built on a 10-layer thickness low temperature cofired ceramic substrate and has the smallest reported size of only 0.00 7 λg × 0.004 λg × 0.0005 λg. Moreover, the BPF also achieved a wide fractional bandwidth of 97.2%, a low in-band insertion loss of only 0.7 dB, a great selectivity BW20 dB/BW3 dB of 1.23 and a wide stopband up to 2.2f0 with 20 dB suppression. Furthermore, comparisons and discussions are also implemented.