3.4/4.0 GHz Tunable Resonant Cavity in SIW Technology Using Metal Post and PIN Diode on a Low-Cost Biasing Network for 5G Applications

Abstract This paper presents a dual-band resonant cavity in Substrate Integrated Waveguide (SIW) technology to operate in the range from 3.3 GHz to 4.2 GHz, spectrum considered for the Fifth Generation (5G) network. The cavity was designed to operate at 3.4 GHz and 4.0 GHz. To achieve different states, a jumper and a PIN diode switch are considered as switching elements, connecting and disconnecting the bottom and the upper walls of the SIW resonant cavity through a metal post inserted inside its internal volume. A fitting equation is proposed to predict the maximum resonance frequency caused by the insertion of a single metal post inside the internal volume of the SIW resonant cavity and a new low-cost biasing network is designed on a thin dielectric substrate allocated on the upper wall of the SIW resonant cavity, using transmissions lines and a single capacitor, reducing the final cost and the insertion losses. Good agreement was observed among the fitting equation, computational electromagnetic simulations, and experimental results, validating the proposed methods.