High Selectivity BPF With Wideband and Stopband Exploiting 3-D CRLH-SIW in Through Glass via (TGV)-Based Package

A high selectivity band-pass filter (BPF) with wide passband and out-of-band suppression based on through glass vias (TGV) technology is presented in this brief. By embedding three-dimensional (3D) composite right-/left-handed (CRLH) structure into the substrate integrated waveguide (SIW) resonator or connecting short-circuit 3D CRLH to feeding lines (FLs), the equivalent dual-CRLH effect is achieved by the parasitic right-handed capacitances between TGVs, leading to high-Qquasi-bound states in the continuum (Q-BIC) and eliminating the need for discrete capacitive and inductive elements. Consequently, four independently adjustable transmission zeros (TZs) are produced at both lower and upper passband, enabling broadband operation, sharp selectivity, and extended stopband suppression. The measured center frequency of the BPF isf0=42.15 GHz with a -3 dB fractional bandwidth (FBW) of 37.3%. The rectangle coefficient of BW-30 dB/BW-3 dB equals 1.41. The out-of-band suppression is better than-20 dB with frequencies more than 110 GHz.