A compact 13-port circularly polarized antennas for MIMO communication systems

Abstract

Antenna diversity is a well-known technique to enhance the performance of wireless communication systems and quality of services by increasing channel capacity. To overcome the physical limitation of diversity antenna due to strong mutual coupling between adjacent antennas, there are still much work in progress. The purpose of this paper is to design a compact integrated broadband and circularly polarized diversity antenna that has 13 feed ports with more than 15 dB isolation between them. Several methods were used for that purpose. More specifically, printed quadrifilar spiral antenna which has good axial ratio characteristics against size of ground plane was selected and optimum simulation for structure of MIMO antenna was conducted. It finds that antenna has an impedance bandwidth of 700MHz ranging from 2.2GHz to 2.9GHz (S11 < 10dB) and 13 ports antenna is integrated in half wavelength volume (0.5λ * 0.5λ * 0.5λ). The proposed antenna shows 74.54 b/s/Hz estimated channel capacity at an SNR of 20 dB.