Quasi axis-symmetric integrated lens antennas: Design rules and experimental/manufacturing trade-offs at millimeter-wave frequencies

Abstract

Integrated lens antennas (ILAs) are of paramount importance for millimeter-wave shaped-beam applications. Although the design techniques of electrically-large shaped ILAs are rather well established, very little data are available in the academic literature about the influence of all the key parameters involved in their design procedure, namely, from the early lens synthesis based on geometrical optics (GO) principles, to the final characterization of the prototype. These issues are discussed throughout this paper for the V-band, by considering an ILA excited by a probe-fed microstrip-patch antenna array. The lens shape is designed to transform the primary feed pattern into a circularly symmetric Gaussian power template. The synthesized lens shape is nearly axis-symmetric because of the slight dissymmetry of the feed pattern. The design rules are based on the implementation of the conventional GO synthesis method of axis-symmetric ILAs. This technique is applied independently in several vertical cut-planes in order to generate the 3D lens shape. The synthesis algorithm is briefly described. We also investigate theoretically and experimentally at 58.5 GHz the influence of the synthesis parameters (initial lens contour, lens dielectric constant), as well as the effects of the manufacturing and assembly parameters (accuracy in the fabrication of the lens body and primary source, misalignment between the feed and the lens), on the radiation performance of the lens prototype. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 20–29, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21251