Sustaining the Radiation Properties of a 900-MHz-Band Planar LoRa Antenna Using a 2-by-2 Thin EBG Ground Plane

In this work, a 2-by-2 array of a low-profile EBG ground plane is used as a means of sustaining the radiation performance of a 900-MHz LoRa antenna that could be installed at various construction sites. The proposed semi-circles added mushroom (SAM) structure enables a thin EBG height of 0.02λg on an FR-4 substrate at 900 MHz frequencies. A planar electric meander antenna for the 900-MHz LoRa band is integrated with the proposed 2-by-2 SAM plane. From a simulation and demonstration, it is found that the impedance and radiation properties of the integrated prototype in free space are well maintained with a minimum degradation even when it is placed on a concrete medium.