Design and Optimization of Spherical Lens Antennas Including Practical Feed Models

Abstract

Abstract-A novel approach for the design and optimization of spherical lens antennas (SLAs) including practical feed model (PFM) is proposed. The vector spherical wave function expansions (VSWE) combined with differential evolution (DE) algorithm is adopted for the optimal design of SLAs. Moreover, the near-field aperture distributions of a Ku band dielectric loaded horn feed and a Ka band corrugated horn feed were obtained using the full wave simulation and were then taken into account in the DE optimization. The performances of the optimized 2-layer design are compared with previous works, higher directivity is obtained. Additionally, the radiation characteristics of an optimized SLA are presented, and numerical results of a 650 mm diameter 2-layer hemispherical lens antenna (HLA) with ground plane are compared to the experimental results, and good agreements are obtained. An investigation of the influence of the various lens-to-feed distances as well as aperture sizes of SLA on the aperture efficiency for a 2-layer design is also proposed.

Multiobjective Optimization and Design of a Luneberg Lens Antenna With Multiband Multi-Polarized Feed-System

“…It is desired to maximize aperture efficiencies at separated frequency bands simultaneously, while keeping the SLL lower enough to satisfy the specific needs of broadband satellite communication. As compared with methods in previous works [16][17][18][19][20], the proposed design procedure provides much better radiation performances and greater design freedom to the designers, as a group of Pareto-optimal LLA solutions can be readily obtained with just one simulation. This paper is organized as follows.…”

“…For instance, H. Mosallaei employed genetic algorithm (GA) to control the gain and SLL envelope for a 5-layer 30λ diameter LLA, which offers gain of 37.47 dBi (η ap = 63%) with −17.5 dB SLL, yet the optimal solution is largely dependent on the values of the weights specified [16]. Moreover, most of the previous works usually design LLA by using single-objective optimization techniques, such as GA [16], particle swarm optimization (PSO) algorithm [17], differential evolution (DE) algorithm [18,19], or minmax optimization (MO) algorithm [20], where all the objectives were combined into a single fitness function by adding different weighting factors to different objectives and the selection of the weighting factors depends highly on the rule of thumb. LLAs reported so far are rarely dealt with multiobjective optimization algorithm.…”

“…Another key challenge in the design of an optimal LLA is to adopt as fewer as possible for the number of lens layers while maintaining higher aperture efficiency at each band and acceptable low sidelobe level (SLL) performance. In the past decades, many analysis methods [14][15][16][17][18][19][20][21][22][23][24][25] and fabrication techniques [26][27][28][29][30][31][32][33] for lens antennas have been developed. For instance, H. Mosallaei employed genetic algorithm (GA) to control the gain and SLL envelope for a 5-layer 30λ diameter LLA, which offers gain of 37.47 dBi (η ap = 63%) with −17.5 dB SLL, yet the optimal solution is largely dependent on the values of the weights specified [16].…”

A K-Band Flat Transmitarray Antenna With a Planar Microstrip Slot-Fed Patch Antenna Feeder

“…Like traditional dielectric lens [1][2][3][4][5], the microwave and millimeter-wave flat transmitarray [6][7][8] can transform quasi-spherical waves from a feeding source at the focal point to quasi-plane waves by adjusting the phase distributions across the surface of the transmitarray. There are two basic types of transmitarrays: one is based on the transparent-opaque Fresnel zone plate, and the other is designed using phase-correcting techniques.…”

A Comparison of the Performance of Cylindrical Lens Reflectors and Stepped-Indexed Cylindrical Luneburg Lens Reflectors: Simpler Is Better?

“…Most investigations on lens reflectors are concerned with the Spherical Lens Reflectors (SLR) [1][2][3][4][5][6][7][8][9][10] in the form of a stepped-index Luneburg Lens (LL) with attached perfectly electric conducting (PEC ) spherical cap. The stepped-index LL has been extensively used as a focusing device as an approximation to the ideal LL with continuously varying dielectric constant.…”