Design Methodology for Conformal U‐Shaped Series‐Fed Microstrip Antenna Array

Abstract

ABSTRACT The manuscript presents a methodical framework for conceptualizing a conformal U‐shaped series‐feed microstrip antenna array (US‐SFMA) that employs true‐time delay phase shifters. The research elucidates the design methodology of the conformal US‐SFMA array, which is devoid of supplementary elements intended to adjust its spectral and radiation characteristics. This approach effectively restores the resonant frequency, and consequently, the spectral response of the array when it is conformed to a cylindrical geometry through a phase compensation technique, thereby optimizing its gain. The analytical equation quantifies the incremental modification in the length of the U‐shaped feedline, facilitating phase advancement for sequential elements. The proposed phase advancement mitigates the spatial phase delay of radiations from the respective elements when they are conformed to a curved surface, thereby restoring their operational frequency and efficiency optimally. A design of the conformal US‐SFMA array on a cylindrical surface with a radius of r = 50 mm has been introduced to substantiate the proposed methodology. The enhancement in the spectral performance of the design at a frequency of 10 GHz yields a gain improvement of 2.16 dB for a 5‐element US‐SFMA array conforming to a radius of curvature of r = 50 mm. The 5‐element US‐SFMA array and its conformed counterpart have been fabricated and measured, with the overall response demonstrating concordance. The conformal series‐fed antenna array is anticipated to be advantageous for airborne communication systems targeting high gain and low RCS applications since being better by 26.25% or 3 dB () in the direction of incidence.