Design of circular patch antennas at mmWave

Recently, the increasing demands of 5G of higher data rates, and lower latency have been progressively investigated to cater the modernization and technology development. In order to achieve higher data rates, it is important to improve the bandwidth as well its gain. The antenna performance is crucial to determine the achievable bandwidth and gain. One of the parameters that influence the antenna performance is the thickness of the substrate. In this paper, a circular patch antenna is designed by using Rogers RT5880 of dielectric constant 2.2, and loss tangent 0.0009. The substrate thickness has been varied in order to investigate its effect to antenna performance i.e. return loss. The substrate thickness that has been investigated are 0.127 mm, 0.381 mm, 0.508 mm, 0.787 mm, and 1.575 mm, which are the standard thickness of Rogers RT5880. The simulation works are performed by CST Microwave Studio. The tasks are divided into two parts; i) the different substrates thickness are investigated while other parameters remain constant and ii) the radius of the circular patch of the antennas have been optimized in order to achieve the resonance frequency at 28 GHz based on the abovementioned substrate thickness used. The performance of the antenna is described in terms of its return loss, bandwidth, and gain. In (i), the results show that as the substrate thickness increases, the resonant frequency decreases under conditions of other fixed parameters value. The highest bandwidth is 1.17 GHz for substrate thickness of 0.508 mm while the highest gain is 7.52 dB for substrate thickness of 0.381 mm. For (ii), the highest bandwidth is 1.37 GHz for substrate thickness of 0.508 mm meanwhile the highest gain is 7.56 dB for substrate thickness of 0.381 mm at the resonant frequency of 28GHz.