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Mutual Coupling Reduction for Two Closely Spaced Meander Line Antennas Using Metamaterial Substrate

Two closely spaced printed meander line antennas (MLAs) are developed by using metamaterial loading techniques with reduced mutual coupling. The antenna array built on the metamaterial substrate showed significant size reduction and less mutual coupling compared to similar arrays on conventional substrates. Demonstrated to have left-handed magnetic characteristics, the methodology uses elliptical split-ring resonators (E-SRRs) placed horizontally between the patch and the ground plane with a row of the same type between antenna elements. Measured return loss of the printed antenna with this technique is less than -10 dB from 5.1-5.9 GHz which covers the IEEE 802.11a (5.15-5.35 GHz and 5.47-5.725 GHz) American standard and HIPPER LAN/2 (5.15-5.35 GHz and 5.725-5.825 GHz) European standard. Also this antenna has an omnidirectional radiation pattern, high gain, and very good pattern stability over the operating band. It is shown to have great impact on the antenna performance enhancement in terms of high efficiency, low voltage standing wave ratio, good bandwidth and less mutual coupling between two antennas with a very close separation of about 0.073λ0. Experimental data show a reasonably good agreement between the simulation and measured results.