A Simple Mutual Coupling Compensation Technique in Array of Single-Mode Elements by a Weighted Mutual Coupling Matrix Based on the Impedance Matrix

Hiroyoshi YAMADA  Masayuki MORISHITA  Yoshio YAMAGUCHI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E90-B   No.9   pp.2288-2296
Publication Date: 2007/09/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.9.2288
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Smart Antennas
Keyword: 
array calibration,  mutual coupling compensation,  DOA estimation,  superresolution technique,  

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Summary: 
High-resolution Direction-of-Arrival (DOA) estimation techniques for antenna arrays have been widely desired in many applications such as smart antennas, RF position location, and RFID system. To realize high-resolution capability of the techniques, precise array calibration is necessary. For an array of single-mode elements, a calibration matrix derived by the open-circuit method is the simplest one. Unfortunately, calibration performance of the method is not enough for the high-reslution DOA estimation techniques. In this paper, we consider problems of the calibration matrix derived by the method, and show that errors in the matrix can be effectively removed by an optimal diagonal weight coefficient. In the proposed compensation technique, the number of newly introduced parameters, or unknowns, is only one for an array of the identical elements. Performance of the simple compensation technique is verified numerically and experimentally.