Frequency self-compensating technique for mitigating detuning effects due to bending for wearable patch antennas

Abstract

This paper presents the design analysis and measurement of a linearly polarized microstrip patch antenna resonating in the X-band regime with a self-compensating mechanism to mitigate the detuning effects due to bending. The antenna is studied for its variation in the resonant frequency for bending radii up to 20mm and a compensation of ≈ 50% is achieved as compared to its counterpart. The compensation technique is realized by altering the effective dielectric constant of the substrate by injecting dielectric fluids into the grooves incorporated in the substrate, supplemented by a shape variation of the grooves due to bending. The antennas demonstrated in the current work exhibit a gain of more than 7 dBi throughout along with a consistent -10 dB impedance bandwidth.