A Highly Isolated Co-Polarized Co-Located Electric and Magnetic Dipoles and Its MIMO Performance

In this paper, a co-polarized, co-located electric and magnetic dipoles (CCEMD) with high isolation is presented. The antenna consists of a loop based on segmented line and two independent feeding ports. Two modes of the antenna are exited separately, the first one has a radiation pattern equivalent to an electric dipole by exciting anti-phase current with symmetric distribution, and the second one is like a magnetic dipole by exciting uniform and in-phase currents along the loop. The antenna is fabricated and tested. Its measured common -10 dB impedance bandwidth at two ports is 280 MHz (2.32 -2.6 GHz) with isolation better than 41 dB. Its MIMO performance in terms of capacity gain (CG) over the SISO system is investigated in a multipath rich environment containing two parallel PEC planes by both measurements and image theory based simulations. Results show that, in free space, the CG results are just slightly larger than 1, however, in the multipath rich channel, the CG values are very close to 2, which indicates that two separate subchannels can be achieved by the proposed CCEMD. The measured results of CG agree well with that obtained by simulation.