The Effect of Parasitic Patches Addition on Bandwidth Enhancement and Mutual Coupling in 2 × 2 Sub-Arrays

Abstract

This paper presents a 2x2 sub-array design with elements having parasitic patches (PPs) for massive MIMO applications. We show that with greater number PPs, bandwidth can be increased considerably with respect to previous designs. The increase in element dimension and, consequentially, element spacings reduces the mutual coupling in the sub-array. The frequency chosen for the design is 3.5 GHz, one of the 5G frequency allocations. For each sub-array element, multiple PPs are placed on the top layer, aimed to enhance the bandwidth. A coaxial feeding probe is employed. Two types of single element antenna with 5 and 10 PPs exhibit a bandwidth of more than 600 MHz and 700 MHz or a fractional bandwidth of about 17% and 20%, respectively. Simulation results and measurements of the 2x2 sub-arrays with 5 PPs and 10 PPs elements show that the antennas meet the desired performance because the return loss is less than dB in a bandwidth of 567 MHz and 730 MHz, respectively. Mutual coupling effects can be suppressed down to less than dB in the frequency range of 3.202 GHz 3.934 GHz.