Compact On-Chip Half-Mode SIW-Based Dual-Band Bandpass Filter Using 3-D Stacked Inductors With Controllable Transmission Zero

A compact half-mode substrate-integrated waveguide (HMSIW) dual-band bandpass filter (BPF) is proposed based on the through silicon vias (TSVs) technology in this brief. The two pass bands of the filter operating at 14.02 and 21.46 GHz with the 3-dB fractional bandwidth (FBW) of 32.2% and 27.5% are constructed by the quasi-TEM and TE102 modes, respectively. 3-D-stacked inductors utilizing TSVs and redistribution layers (RDLs) are employed to induce mixed couplings, thereby generating a transmission zero (TZ) above the passband, which are analyzed by the equivalent circuit of the filter. The circuit size of the fabricated prototype of the dual-band HMSIW BPF is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18\lambda _{g}^{2}$ </tex-math></inline-formula>. The in-band insertion losses (ILs) are 1.37 and 1.33 dB, severally. Measurement results agree well with the electromagnetic (EM) simulation results.