Effect of superstrate material on a high‐gain antenna using array of parasitic patches

Abstract

Abstract This article highlights the effect of superstrate material on a high‐gain antenna using array of parasitic patches for wireless applications. The antenna structure consists of a microstrip antenna, which feeds an array of square parasitic patches fabricated on a ceramic or FR4 superstrate. The patches on a superstrate are suspended in air at λ 0 /2. The spacing between parasitic patches and patch dimensions decrease with dielectric constant and, thus, a compact antenna with almost same gain can be designed with high dielectric superstrate. The structures with 5 × 5 array of square parasitic patches provide a gain of 17.5 dB on infinite ground plane in both the cases but the array dimension is 55 × 55 mm 2 in ceramic as compared to 115 × 115 mm 2 Antenna with ceramic superstrate on finite ground requires 25% less ground plane size as compared to FR4. Structure with FR4 superstrate is designed, fabricated, and tested. The measured VSWR is <2 over 5.725–5.875 GHz frequency band. The antenna with 5 × 5 array of square parasitic patches provides a gain of 18.0 dB with 92% efficiency, SLL of −18.4 dB, and front to back lobe ratio of more than 20 dB. The proposed structure can be packaged inside an application platform. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 82–88, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24850