Optimal Dimensions and Performance Evaluation of a Truncated Spherical Dielectric Lens Antenna at X-Band Frequencies

Abstract

This study presents the design and development of a truncated spherical dielec-tric lens antenna. The objective was to enhance and optimize the directivity and beamwidth of the feed antenna by adjusting the feed position around the focal point of the lens. Polyetrafluoroethylene (PTFE), with a dielectric constant of 2.1, was chosen as the lens medium. Simulations were conducted using CST Studio Suite over a frequency range of 8 to 12 GHz. Experimental validation was performed using a vector network analyzer (VNA) and an anechoic chamber. The optimized dimensions of the dielectric lens antenna were determined as follows: lens thickness (T) = 24.34 mm, center of curvature (R) = 55 mm, and lens aperture (L) = 110 mm. This configuration achieved a directivity of 21.9 dBi and a beamwidth of 13.1°. The resulting dielectric lens antenna exhibits a compact size, simple geometric shape, and ease of design and construction. These characteristics make it highly suitable for RF applications, particularly when energy concentration is required.