Mechanical Tension Effects on Cylindrical Probe-Fed Circularly Polarized Microstrip Antennas

The experimental characterization of the mechanical tension effects on a 2.2 GHz probe fed circularly polarized rectangular microstrip antenna conformed on a cylindrical surface is presented in this work. Two prototypes were designed and built for a metallic cylinder with a radius of 25 centimeters and height of 1.5 meters. The first antenna was used to characterize the effects of mechanical tension, also considering permittivity uncertainty and the manufacture after etch stress relief effect. A comparison between numerical and experimental results from the first prototype showed that the conformed patch is elongated along the curvature of the metallic cylinder approximately by 0.15 millimeters. The patch elongation was compensated on the second prototype. Experimental measurements showed that the elongation was predicted accurately.