A broadside three-port antenna for 5G massive MIMO antenna systems

This paper presents a broadside antenna with three ports operating at the same frequency. The TM030 and TM003 modes of a patch are excited by two coaxial cables to generate two orthogonal linear polarizations. The patch can be transformed into a slotted SIW cavity whose TE201 and TE102 modes are jointly excited by the third cable. A matching cavity and a matching patch are introduced to broaden the impedance bandwidth of the third port. The simulated results show that the isolations between these three ports are higher than 18 dB, even though the radiation patterns of the three ports are all broadside. The proposed three-port antenna can provide a solution to increase the number of the ports per unit area in outdoor massive MIMO antennas