A Simplified Configuration of Beam-Steerable Risley Prism Antennas: Principles and Validation
Junbo Wang, Yahya Rahmat‐Samii
Abstract
Beam-steerable Risley prism antennas (RPAs) typically require at least three separated components, including a stationary feed source and two independently rotatable gradient-phase-shift surfaces. In this letter, we propose a simplified two-component RPA configuration that employs a gradient-phase feed source and a gradient-phase transmitarray. The proposed configuration is validated by a novel circularly polarized (CP) RPA in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> -band through simulations. It consists of an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{8}\times \text{8}$</tex-math></inline-formula> gradient-phase CP patch array feed and a 10 cm diameter CP transmitarray. The total height of this system is 14.6 mm, which is less than one wavelength at 19 GHz. A left-hand CP beam scan from broadside to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{55}^\circ$</tex-math></inline-formula> is demonstrated. The simulated RPA achieved a broadside directivity of 22.3 dBi at 19 GHz (42.7% aperture efficiency) and a 3 dB directivity bandwidth of 9.2%.