A Design of a Leaky Waveguide Crossed-Slot Linear Array with a Matching Element by the Method of Moments with Numerical-Eigenmode Basis Functions

Takuichi HIRANO
Jiro HIROKAWA
Makoto ANDO

Publication
IEICE TRANSACTIONS on Communications   Vol.E88-B    No.3    pp.1219-1226
Publication Date: 2005/03/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.3.1219
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antennas and Propagation
Keyword: 
crossed-slot,  slotted leaky waveguide arrays,  circularly polarized wave,  finite element method,  method of moments,  eigenmode basis functions,  

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Summary: 
A waveguide crossed-slot linear array with a matching element is accurately analyzed and designed by the method of moments using numerical-eigenmode basis functions developed by the authors. The rounded ends of crossed-slots are accurately modeled in the analysis. The initial values of the slot parameters determined by a model with assumption of periodicity of field are modified and refined by the full-wave finite-array analysis for uniform excitation and small axial ratio. As an example, an 8-element linear array is designed at 11.85 GHz, which radiates a circularly polarized wave at a beam-tilting angle of 50 degrees. The radiation pattern, the frequency characteristics of the reflection and the axial ratio are compared between the analysis and the measurement and they agree very well. The calculated and measured axial ratio at the beam direction are 0.1 dB and 1.7 dB, respectively. This method provides a basic and powerful design tool for slotted waveguide arrays.