Gain enhancement and mutual coupling reduction of multiple‐intput multiple‐output antenna for millimeter‐wave applications using two types of novel metamaterial structures

Abstract

A method to significantly increase the gain and reduce the mutual coupling of microstrip multiple-intput multiple-output (MIMO) antenna based on metamaterial concept is presented. The μ-negative and ε-negative features of the proposed modified peace-logo planar metamaterial (MPLPM) and two-sided MPLPM (TSMPLPM) structures are calculated. The antenna structure consists of eight MPLPM slabs and two TSMPLPM, which are embedded in azimuth plane of a MIMO antenna vertically. The dimensions of MIMO antenna are 28 × 16 × 6.3 mm3 at 40 GHz. As a result, a compact MIMO antenna is simulated in comparison with primary microstrip structures. The corresponding return-loss of the antenna is better than 10 dB over 34.5 to 45.5 GHz for Ka-band applications. Good consent between the measured and simulated result is tacked. The maximum simulated gain of the structure is 15.5 dB at 40 GHz, creating a maximum gain improvement of 11.5 dB in comparison with a MIMO antenna without any metamaterial combinations. The value of the insertion-loss (isolation) is 33 dB, which has improved by more than 25 dB compared to the conventional sample.