New design of a broadband PBG-based antenna for THz band applications

In this contribution, a new optimized photonic bandgap (PBG) based antenna is proposed for broadband applications of the terahertz spectrum. First, the reference antenna is designed and optimized using a parametric study to operate at the resonance frequency of 0.3 THz. Then, the optimization is performed with a novel technique, called segmented objects technique (SOT), to guide the optimization of the PBG based substrate using genetic algorithms (GA). SOT permits to automatically change the geometry of the design space and guide the optimization through the evolutionary algorithms (EA) simply, efficiently and it is less expensive in terms of simulation time in order to explore the design space. Genetic algorithms are used for the optimization purpose in order to find the best PBG configuration of the antenna substrate for an optimal solution between bandwidth, gain, and frequency invariance. During this optimization, different PBG configurations are designed and analyzed using Ansoft High-Frequency Structure Simulator (HFSS). The antenna has a size of 118×118×100 µm 3 and covers a bandwidth of 133 GHz that ranges from 255 GHz to 388 GHz with a return loss of −58.70 dB and a gain of 9.43 dBi. The enhancement in terms of gain, bandwidth, and return loss after optimization was 3.74%, 104.62%, and 208.94% respectively. Various electrical parameters of these optimized antennas have been compared with reported literature over the past few years. The achieved results of the optimized PBG structure make the proposed design a viable candidate to meet the demand for high-speed data in the next cellular mobile system. • The characteristics of the microstrip antenna are enhanced for THz applications by the optimization of the PBG structure. • Genetic algorithms and segmented objects guiding technique (SOT) are applied in order to find the best PBG configuration. • SOT permits to guide the optimization of the PBG based substrate and to explore the design space. • The design space optimization aims to find the best air gap geometry and distribution in the antenna substrate. • The design parameters optimization is applied to determine the best dimensions of the new obtained configuration.