A Novel Cross-Coupled Substrate Integrated Waveguide Bandpass Filter for 5G Upper Band Application

This paper introduces a bandpass filter (BPF) designed using the substrate integrated waveguide (SIW) technique, targeting the 5 G upper band frequency range. The filter is designed based on cross-coupled structure. The filter have mainly two part of consideration, one is novel proposed mixed coupling design loaded cavity and second part is cross-coupling cavities. Both part of design contribute transmission zero's (TZ) formation to improve the stopband performance and selectivity of the filter. Proposed filter design simulated and fabricated for the validation of the concept. The filter center frequency is 26 GHz with 930 MHz bandwidth along five TZ's. The measured minimum insertion loss (IL) is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1. 9 ~ d B}$</tex>, and return loss (RL) is better than 18 dB. The filter model demonstration use PCB fabrication process and due to this it is cost-effective and suitable for large production of 5 G application.