A Miniaturized 8x8 Dual-layer EBG Slotted Circularly Polarized Patch Antenna Array for mMIMO

This paper proposes a novel dual-layer electromagnetic bandgap slotted circularly polarized patch antenna to design an 8x8 antenna array for massive MIMO operating at 3.5GHz. The antenna element structure achieves a bandwidth of 250 MHz (7.1% at 3.5GHz). It has a gain of 5.1dB, a directivity of 6.1dB, and a 3dB-beamwidth of 94 degrees. With EBG elements underneath, the radiating patch size can be reduced by 65% while the top EBG layer provides a high surface impedance and an isolation of 14.3dB between radiating patches with a separation distance of 0.32 wavelength. Simulation and measured results of the designed 8x8 antenna array on return loss, radiation patterns, mutual coupling, and beamforming performance in different scenarios are discussed and shown to be in good agreement.