Double-shell axial-symmetric imaging lens antenna for space applications (original) (raw)

Evaluation of a double-shell integrated scanning lens antenna

This paper presents the design and evaluation of a high dielectric constant double-material integrated lens antenna for multi-beam or scanning applications. The lens is formed by two shaped embedded shells of different material permittivity to enhance both power transmission across the lens interfaces and the lens scanning characteristics over a broad frequency range, when the feeds are integrated at the lens base. Design is based on Geometrical Optics formulation and the lens performance is evaluated using the classic hybrid Geometrical Optics / Physical Optics approach (GO/PO). The proposed lens concept is experimentally validated with a fabricated MACOR/Acrylic prototype, showing less than 1 dB scan loss up to ±20º with Gaussissity better than 95% over 40% frequency band at millimeter-waves.

Modern Lens Antennas for Communications Engineering

2013

The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/ Microwave professionals the design insights in order to make full use of lens antennas. Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.

Double-shell modified extended hemispherical lens feed for reflectors in scanning applications

European Conference on Antennas and Propagation, 2011

A new dielectric lens antenna configuration is described, intended to feed a quasi-optical imaging reflector system. The lens is fed at its base by a 5 pixel array, each one producing an output beam after the reflector with near 61 dBi directivity. The lens is designed in such a way that it produces virtual foci outside the lens body, close to the reflector focal arch. The lens plus reflector system provides a maximum scanning angle of α = ±0.36º in elevation with gain scan loss below 1.1dB, while a mechanical rotation of the reflector produces azimuth scan.

Focal-Plane Multibeam Dual-Band Dielectric Lens for Ka-Band

2017

A shaped double-shell dielectric lens is evaluated as a primary feed for a multibeam single-reflector system operating in the satellite uplink and downlink Ka-bands, complying with gain and edge-of-coverage (EoC) directivity requirements. An assembly of dual-band printed feeds is integrated at the base of a single lens, each feed producing a virtual focus far behind the lens base and coincident with the reflector focal arch. The used double-shell lens approach, instead of a single-material lens, allows an extra degree of freedom to accommodate an aberration mitigation condition. This primary feed system is proposed as a low-complexity solution to enable fitting more beams per solid angle than conventional single-feed-per-beam systems based on a cluster of focal-plane horns. A proof-of-concept lens prototype with 87 mm diameter and 62 mm height, fed by a linear arrangement of five dual-band printed feeds, was fabricated and tested at the Ka-band. The lens measured radiation patterns were post-processed to evaluate the combined performance of the lens with an offset F/D 1 reflector system designed for 45-dBi EoC directivity. It is shown that it duplicates the reflector aperture efficiency compared to horn-fed systems with same feed separation. Index Terms—Dual-band antenna, multibeam antennas, reflector antennas, shaped double shell-lens antenna.

Analysis of a Lens Based Antenna Using Spherical Modes

2011

A fixed shaped beam antenna offers an excellent compromise between cost and system performance in high data rate systems operating in the frequency range of 565 GHz. Shaped Dielectric Lenses perform the task of collimation and shaping, along with physically small feed antennas, to obtain multiple and shaped beams in a fixed set of directions. Lenses are inherently broadband, easy to fabricate, have lower dimensional tolerances, cost effective and act as radome for the primary radiators that are embedded inside or placed behind the lens. Earlier techniques for the analysis of shaped dielectric lenses, employed ray tracing methods of GO and PO, that are valid only in the far field of a primary point source type of radiator. But the dielectric lens is in the near field of finite sized primary radiators oriented at different angles and at different distances from the lens center. In this paper we discuss, a new accurate analytical procedure for the radiation pattern of a spherical lens ...

Two-shell circularly-layered dielectric lens antennas: Design and characterization

The paper describes a procedure for designing two-shell circularly-layered dielectric lens antennas (DLA) with radiation characteristics compatible with conventional multi-layer uniformly-layered Luneburg lens (LL) antennas. It is demonstrated that a two-shell lens with the favorable collimating capabilities can be designed using standard low-permittivity materials provided the proper selection of shells thickness. Analysis is performed in the 2-D formulation using the exact Mie-type series approach. The outlined recommendations are then validated on the example of two-shell spherical DLAs excited by a horn antenna modelled using commercial software.

Compact Ka-band lens antennas for LEO satellites

Antennas and …, 2008

This paper presents and compares two new compact lens antenna configurations for data link communications with LEO satellites at 26 GHz. These lenses match a secant type radiation pattern template in the elevation plane while having a mechanically scanned sector beam in azimuth to enhance gain as much as possible. No rotary joints or multiple feeds are required and emphasis is put also on the compactness of the proposed solutions (< 6 lambda). Two alternative lens configurations are evaluated numerically and experimentally: one is based on modified axial-symmetric dome lens geometry, and the other one consists of a full 3-D double-shell lens antenna. In contrast to current nearly omnidirectionnal antennas, the directivity of our lens prototypes is above 15.4 dBi. Up to 4.2 dB loss obtained in the prototypes can be significantly reduced by using lower loss dielectrics and matching layers, without affecting the conclusions. The numerical and experimental results are in good agreement with the radiation specifications given the compact size of the antennas.