Design of UHF Band Microstrip Antenna for Recovering Resonant Frequency and Return Loss Automatically

Abstract

This paper presents a microstrip antenna which recovers its resonant frequency and impedance shifted automatically by the approach of other objects such as hands. This can be used for telemetry sensor applications in the ultrahigh frequency(UHF) industrial, scientific, and medical(ISM) band. It is the key element that an frequency-reconfigurable antenna could be electrically controlled. This antenna is miniaturized by loading the folded plates at both radiating edges, and varactor diodes are installed between the radiating edges and the ground plane to control the resonant frequency by adjusting the DC bias asymmetrically. Using this voltage-controlled antenna and the micro controller peripheral circuits of reading the returned level, the antenna is designed and fabricated which recovers its resonant frequency and impedance automatically. Designed frequency auto recovering antenna is conformed to be recovered within a few seconds when the resonant frequency and impedance are shifted by the approach of other objects such as hand, metal plate, dielectric and so on.

Effects of Substrates and Shapes of Cavities on the Gain and Directivity of a Dipole Antenna

“…The researchers used micro-controllers for reading, voltage-controlled antenna for recovery. As a result, their design microstrip antenna can automatically recover the resonant frequency and impedance in a matter of seconds [24]. The designed micropatch antenna by the researchers is revolutionary as it can automatically restore its previous state of optimized working conditions.…”