A 28 GHz mmWave Circular Microstrip Antenna with Rectangular Slots on Air-Substrate

This paper presents a circular-shaped copper (Cu)-based antenna for 28 GHz mmWave applications. The proposed design employs air as a substrate to substantially reduce the manufacturing cost. The coaxial probe feed technique was utilized to excite the system. Experimental results confirm that, by integrating a pair of rectangular slots at one of the radiating elements, wide bandwidth can be achieved. The optimum configuration occupied 324 sq. mm area and functioned with a bandwidth of 3.10 GHz, gain of 8.92 dBi and efficiency of 96.05%.