A Wideband Single Polarization Antenna for Precision Cosmology in S-Band

In this paper we present a prototype antenna design for the Array of Precision Spectrometers for the Epoch of RecombinAtion(APSERa), a future ground-based radio array with a primary science goal of detecting faint spectral distortions in the Cosmic Microwave Background. The printed planar monopole antenna backed by a square metallic reflector operates over 2.7 to 4 GHz. It is designed to be nominally achromatic and easy to fabricate in large numbers to form an array of over 100 identical antennas. The antenna presented herein has nominal maximum gain towards the zenith, wide half power beam widths (HPBW) of mean value~ 56° in E-plane and ~ 113° in H-plane and a smooth return-loss with just one inflection. These are all desirable characteristics for APSERa. The antenna was designed and optimized in CST microwave studio. The antenna structure is fabricated and characterized in anechoic chamber. The measured antenna properties are compared with simulation results. We conclude with discussions on suitability of the designed antenna for APSERa and suggest improvements toward the same.