Analysis and design of inhomogeneous single layer slotted dielectric flat lens

This paper presents the design and results of low cost, light weight, planar, high gain, no feed blockage and single layer slotted dielectric flat lens for high gain antenna applications at 73.5 GHz. The proposed flat lens is completely dielectric where no metal used to construct it so the ohmic losses, mutual coupling and the surface waves are expected to be lower. The unit cell that forming the lens is based on cutting slots having same depth in the both sides of a commercial non magnetic low loss host dielectric substrate to produce a phase compensation from 0° → 360° by controlling the width of the cut slot with losses less than -1dB. A 21 cell × 21 cell lens that is occupied an area of 42 mm × 42 mm and illuminated by a pyramidal horn antenna is designed and simulated. A peak gain of 28dBi is achieved at the design frequency with almost flat gain from 71GHz to 76GHz, beamwidth of 5.1° and aperture efficiency of 47.41%. The radiation characteristics of the lens are calculated using Finite integral technique (CST Microwave Studio) and finite element method (HFSS).