Theoretical Analysis and Design of Metasurface Antennas for Wide Beamwidth and Dual Circularly Polarized High Gain

This paper presents an in-depth study on the design and analysis of metasurface (MTS) antennas optimized for high gain and wide beamwidth performance in X-band applications. The proposed MTS antennas are comprehensively analyzed using impedance layer models with Sommerfeld-type integrals and image theory. The proposed MTS can function as a Perfect Magnetic Conductor (PMC), Perfect Electrical Conductor (PEC), or Reactive Impedance Surface (RIS) depending on the conditions. In high gain configurations, the MTS antenna is 26.5×26.5×2.52mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and achieves a peak boresight gain of 10.1 dBi at 9 GHz under PMC, with boresight gain reduction observed at 11 GHz as it transitions towards PEC. The -10 dB impedance bandwidth exceeds 25%, covering the 6.7 ~ 8.7 GHz range. For wide beamwidth applications, the antenna is 16.5×16.5×3.04mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and incorporates a RIS to mitigate ground plane effects, resulting in a 3-dB beamwidth of 140° (H-plane) and 104° (E-plane). Additionally, a dual circular polarization (CP) MTS antenna is proposed, utilizing a cascaded hybrid coupler to achieve a maximum gain of 14 dBic at 8.35 GHz in a 2×2 array configuration, while maintaining an axial ratio (AR) below 1.5 dB across the specified X-band frequencies.