CSRR and Stub Loaded Miniaturised Tri-band Patch Antenna for 5G Base Station Application

In this paper, a complementary split ring resonator (CSRR) and stub-loaded miniaturized tri-band microstrip patch antenna is proposed for sub-6 GHz 5G base-station application. First, a CSRR loading is used on a square microstrip patch antenna to achieve dual-band response and antenna miniaturization simultaneously. Next, the tri-band response is achieved by adding two differently sized stubs. The proposed tri-band antenna works at 3.59 GHz, 3.85 GHz and 4.44 GHz, sub-6 GHz operating frequencies having peak gains of 4.8 dBi, 5.5 dBi and 6.7 dBi respectively. In order to reduce the cross-polarization levels at the operating frequencies, a rectangular slot is etched from the ground plane. The proposed antenna exhibits co-polarization to the cross-polarization separation of 20 dB, 11 dB and 17 dB at 3.59 GHz, 3.85 GHz and 4.44 GHz respectively. A prototype of the antenna is fabricated and measured results are compared with the simulated ones.