Compact Circular Millimeter-Wave Parasitic Antenna for 5G-II Band Application

A compact parasitic antenna operating within the millimeter-wave frequency range for applications in the 5G-II band. The primary goal of the antenna design is to achieve a balance between complexity and size efficiency. The front side of the antenna showcases a rectangular patch at its center, which consists of a parasitic circular element, complemented by two parasitic pendulum shapes positioned on top. The central feed mechanism employs a 50-ohm strip line that connects to a microstrip line. Meanwhile, the back side of the antenna incorporates three circular slots on the bottom plane, along with two vertical strips connected to a single circular element to enhance performance at higher frequencies. For performance evaluation, the antenna is subjected to simulations using CST Microwave Studio, utilizing an FR-4 substrate with dimensions measuring 12×10×1.5 cubic millimeters with electrical size of .06A * .05A *. 008λ. The simulation results reveal remarkable attributes, including an impressive impedance bandwidth of 85.7% and a return loss of -18 dB across the frequency range spanning from 16 to 40 GHz, with a central frequency at 28 GHz. The radiation patterns exhibit consistency throughout its operational range, maintaining stable polar patterns and delivering efficient performance. The antenna demonstrates a wide gain of 3.89 dBi and an efficiency of 81.9%. Given these results, it is evident that the proposed antenna is well-suited for microwave applications in the Millimeter-wave and 5G-II bands.