Design of a frequency reconfigurable patch antenna using capacitive loading and varactor diode

A frequency reconfigurable antenna optimized to operate at 2.45 GHz was presented. The antenna consists on a square patch excited by a coaxial probe. The frequency agility was achieved by integrating a varactor diode between the patch and the ground plane, which reduces the antenna size. A broad tuning range of 0.5 - 2.43 GHz is realized using a varactor diode (biasing voltage is varying from 0 to 20V). Prototypes were realized and characterized for both cases (with lumped capacitors and a varactor diode). Simulated and measured results are presented and discussed.