Dual polarized semi-circular MIMO/diversity antenna based on LTCC technology

In this paper, we present simulated design of two antennas intended for Ultra-wideband Radio Frequency Identification (UWB-RFID) applications. Both antennas present multiple-input-multiple-output (MIMO) capabilities with dual polarization. The antennas have planar structure with semicircular radiating patches within a circular slot. To achieve dual polarization, both antenna designs with semi-circular patches are fed orthogonally via Co-Planar Waveguide (CPW) transmission lines. Numerical optimization, detailed design and analysis are presented and discussed which are carried out via electromagnetic simulation tools. The results obtained reveal that the antennas are matched over a wideband covering the band of interest i.e. UWB-RFID band (6-8 GHz). Exciting the first antenna with two semicircular patches achieves an impedance bandwidth of 58% (6.05-10.1 GHz) and maximum gain of 9.26 dBi. Similarly, excitation of the second antenna with four elements achieve an impedance bandwidth of 114 % (5-13 GHz) with maximum gain of 6.8 dBi. Diversity performance in terms of envelope correlation coefficient (ECC) for both antenna designs are also studied.