On the Actual Possibilities of Applying the Composite Right/Left-Handed Waveguide Technology to Slot Array Antennas

Abstract

The novelties offered by using a composite right/lefthanded (CRLH) waveguide as the feeding structure of a slot array antenna are surveyed for some common slot arrangements. Furthermore, a complete approach to the design of beam-steerable arrays using the CRLH waveguide technology and meeting a set of specific requirements is presented. To illustrate the proposed methodology, a 13-slot array antenna has been designed, built and measured. It provides a full-space beam scanning from 40 to +30 as the frequency changes over a 25% bandwidth with a good input match, narrow beamwidth, moderate side-lobe performance and acceptable gain values.Index Terms-Beam steering, composite right/left-handed (CRLH), corrugated waveguides, slot arrays, traveling wave antennas.

Electromagnetic Analysis on Propagation Characteristics of CRLH Waveguide Loaded With Double Ridge Corrugations

“…The waveguide CRLH TLs have higher power capacity than the planar ones, and they may satisfy the actual requirements for radar applications. The CRLH waveguide with dielectric-filled corrugations proposed in [11] has been applied to leaky-wave antennas (LWAs) [15,16]. However, the radiation efficiency is low due to high dielectric loss, thus this CRLH waveguide with dielectric-filled corrugations is not suitable for high performance LWAs.…”

Broadband slot array antenna with full‐space steerable pattern in a composite right/left‐handed waveguide

“…[8] A CRLH waveguide prototype has been designed to be operated within the monomode region, where the fundamental Bloch mode propagates. Although the dispersion diagram of the prototype has already been shown and explained in Navarro-Tapia et al [2012a], this content is also herein reproduced for the sake of completeness. The measurements of the propagation constant of the fundamental Bloch mode have been carried out by means of the method proposed by Bianco and Parodi [1975], which has been statistically improved by considering a large number of measurements [Navarro-Tapia et al, 2012b].…”

“…This way, the upper broad wall is left free, which is very appropriate for slotted antenna applications. Although an explanation of its geometry can be found in Navarro‐Tapia et al [], it has been also included here (see Figure ) for the sake of completeness. The waveguide (inner dimensions a × b and wall thickness t ) is air‐filled.…”

“…Although both designs remain well matched and efficient at its own design frequency (see Navarro‐Tapia et al , ; and Navarro‐Tapia , ), these features are unavoidably deteriorated when moving away from the working frequency. An attempt to enlarge the frequency band of operation has been made.…”

“…Particularly in CRLH waveguide technology, there are some achievements worthy of mention. The first one addresses the design of a slot array antenna resorting to an optimization process [ Liao et al , ]; the second one proposes some guidelines to adopt an engineering approach to successfully design an antenna of the kind [ Navarro‐Tapia et al , ]. However, despite these pioneering contributions in the design of slot array antennas on CRLH waveguides, some concerns on the subject still remain somewhat obscure and overlooked.…”