Design and analysis of a low profile, high gain rectangular microstrip patch antenna for 28 GHz applications

This paper presents a simple, low-profile rectangular microstrip patch antenna for applications in the 28 GHz band. A regular rectangular microstrip patch antenna is initially designed. The antenna is then modified to perfectly resonate at 28 GHz and improve antenna performance in terms of S11, radiation gain, and impedance bandwidth. The antenna is optimized using inset feed to enhance the matching between the radiating patch and the feeding line. Then, a rectangular slit on the front edge of the patch is inserted with altering the antenna's dimensions to reduce its size. The suggested antenna uses a Rogers RT/Duroid-5880 substrate with a dielectric constant of 2.2, a thickness of 0.508 mm, and a loss tangent of 0.0009. The final design is small, measuring 8 × 8.489 × 0.508 mm3 (≈ 0.75λ × 0.79λ × 0.05λ), having a maximum S11 value of - 45 dB and an impedance bandwidth of 1.43 GHz, extending from 27.28 GHz to 28.71 GHz. The radiation gain is nearly consistent over the operating band, with above 8 dBi is achieved. Besides, the proposed antenna achieves a radiation efficiency of about 99% across the band. HFSS is employed for the design, simulations, and optimizations, while CST is used to validate the HFSS simulation findings. The simulation results from both simulators indicate a high level of agreement.