Spectrum-Aware Compact Reconfigurable UHF Antenna for Interweave Cognitive Radio

This paper presents a compact ultra-high frequency (UHF) folded antenna design that relies on a single radio frequency micro-electro-mechanical switch (RF-MEMS) to reconfigure its frequency of operation between 575 MHz and 760 MHz. The reconfigurable multi-layered antenna design has a volumetric folded topology with total dimensions of 40×40mm2; equivalent to 0.11λx0.11λ at 575 MHz. The antenna is fabricated and tested where the measurements agree well with the simulation results. The antenna exhibits a radiation efficiency of 40% at 575 MHz and 62% at 760 MHz. Furthermore, the proposed antenna is tested in a cognitive radio environment to validate its ability to adapt to cognitive input and tune its performance across white space within the UHF band. This is achieved by relying on a trained classifier model that is embedded within a microcontroller to autonomously control the state of the integrated switch based on which channel is idle.