Isolation improvement of 5 GHz WLAN antenna array using metamaterial absorber

Abstract

In this paper, isolation between planar inverted-F antenna (PIFA) array elements is improved by using an array of metamaterial unit cell for 5 GHz WLAN applications. The designed antenna element is of 12 × 5 mm2 size with an overall antenna height of 5.8 mm over a ground plane of 100 × 40 mm2. The proposed dual band absorber unit cell is of size 13 × 12 × 0.8 mm3 and a 4 × 2 array of this unit cell is used as an isolator. Isolation increases from 22.5 dB to 33 dB and 32.5 dB in its best cases for band 1 (5.15 – 5.35 GHz) and band 2 (5.725 – 5.825 GHz), respectively. The absorption mechanism of the absorber array is explained with surface current distribution plot. The proposed array is fabricated. The measured and simulated results are found in good agreement. The radiation pattern shows pattern diversity and the lower values of envelope correlation coefficient make it suitable for MIMO application. Suitable calculated values of peak realized gain and radiation efficiency are obtained.