Design of SIW Frequency Agile Antenna Based on a Varactor Loaded on U-Slot

This work describes a new kind of frequency reconfigurable antenna loaded by two varactor diodes. The proposed structure is designed on hexagonal SIW cavity radiating through a U-slot, integrated in the lower face of the SIW. The antenna is fed by a grounded coplanar transmission line attached to a 50 O microstrip line. The simulation results show that the resonance frequency is varied from 10.4 GHz to 10.76 GHz when the two BBY31 diodes are controlling. The radiation pattern is not affected during the variation of the resonance frequency. This is a suitable propriety for several wireless applications.