A Conformal Circularly Polarized Series-Fed Microstrip Antenna Array Design

A conformal circularly polarized (CP) series-fed microstrip array design for broadside radiation is presented. The array aperture under design is conformal to a cylindrical surface of a given radius. The approach we present primarily addresses focusing of the CP major lobe of the conformal array by proper dimensioning of the aperture spacings. The proposed analytical models yield the values of the element spacings within the series-fed conformal array aperture and element-specific spacings of the patch radiators within each CP element. These spacings are critical to produce a broadside CP major lobe at the design frequency. Subsequently, each array element is equipped with an in-line matching quarter wave transformer. The measured characteristics of the X-band conformal array validate the proposed design approach.