Frequency Reconfigurability in a Multi-Band Antenna Using Varactor Diode Integration

This research introduces an innovative method for achieving frequency reconfigurability in reference antennas by employing a specially designed antenna structure and optimizing it with HFSS Software. The proposed approach reduces the need for incorporating numerous switched elements into the reference structure while simultaneously enhancing the antenna performance in terms of S
11
values and bandwidth across various operating frequency bands. The proposed antenna has a small size with dimensions of 20 × 20 × 0.8 mm
³
. Simulated results of the frequency-reconfigurable antenna are presented and discussed, demonstrating that integrating a single varactor diode on the ground plan of the antenna structure allows for bi-band operating behaviour with resonant frequencies of f1= 4.52 GHz and f2=5.35 GHz. Furthermore, by controlling the capacitance of the varactor diode electronically, the antenna demonstrates the capability of frequency shifting, resulting in a versatile multi-band performance with improved bandwidth and reflection coefficient characteristics centred around each operating frequency.