Analytical Modeling of Resonance Frequency Shifts Induced by Mechanical Strain in Stretchable Rectangular Patch Antennas

The increasing demand for wearable electronics has emphasized the need for flexible antennas capable of maintaining stable electromagnetic performance under mechanical deformation. This paper presents a universal theoretical framework for predicting resonance frequency shifts in stretchable rectangular patch antennas subjected to uniaxial tensile stress. By extending the cavity model theory to accommodate mechanically deformed configurations, closed-form expressions are derived to explicitly correlate the strain magnitude and Poisson’s ratio with intrinsic resonance frequency deviations. The proposed model reveals, for the first time, the electromechanical coupling mechanism that governs patch antenna performance degradation. A robustness metric (Ξf) is introduced to quantitatively evaluate the resonance frequency stability of the antenna under strain. The model is systematically validated through eigenmode simulations, full-wave electromagnetic analysis, and prototype measurements, demonstrating its broad applicability to various material platforms. This study provides fundamental insights into strain-antenna coupling phenomena, facilitating more efficient design processes by reducing unnecessary computational costs.