Mechanical Tuning of Air‐Filled Substrate Integrated Waveguide Cavities by Employing Dielectric Rods

This study presents a simple method to obtain tunable cavity resonators in air‐filled substrate integrated waveguide (AFSIW) technology. It is based on the insertion of a dielectric rod from an opening placed on a side of the SIW cavity, whose resonance frequency is varied by changing the penetration depth of the rod. To avoid power leakage, a short SIW section below cutoff is connected to the opening. The applications of this method include postproduction compensation for manufacturing inaccuracies and possibly the tuning of cavity filters. The proposed method is numerically and experimentally demonstrated through a frequency reconfigurable filter, operating at 5 GHz with a tuning range of ±200 MHz (8%).