In this study, a dual-feed polarization diversity antenna with a broadside or conical radiation pattern is proposed for fifth-generation (5G)-NR applications.The antenna’s design incorporates a radiator created using a circular slot, segmented into two semicircular slots by a protruding stub.By adjusting the phase difference applied to these two semi-circular slots, different radiation patterns within the Journal same frequency band can be achieved.A modified 180° rat-race coupler served as the feed structure.By analyzing current distribution and E-field distribution, the phase difference formed in the two semi-circular slots according to the input terminal is confirmed.
The measurement results showed that the proposed antenna exhibited polarization diversity characteristics across a bandwidth of 12.7% ( $3.24sim 3.7$ GHz), with isolation exceeding 25 dB between the two input terminals.In this case, the measured gains are 5.
2 dBi Motorcycle Kit for Port 1 and 3.5 dBi for Port 2.