se antenna systems for terahertz communications, optimization algorithms are a well-promising design technique for these systems, offering comparative advantages compared to traditional antenna design techniques. Microstrip antennas or generally printed antennas with different shapes like E- shape are low-cost options, and they will be evaluated. Antenna design necessitates the optimization of numerous geometrical parameters at the same time. A appropri- ate strategy for solving this problem is to use an optimization method or technique. Several patch antenna designs utilizing various evolutionary algorithms (EAs) as the optimization method can be found in the literature. These design strategies include the following: particle swarm optimization (PSO) [15], differential evolution (DE) [22, 25], genetic algorithms (GA) [13, 23], and teaching-learning optimization (TLBO)[11]. In this context, we use the salp swarm algorithm (SSA), a recently introduced algorithm [20]. SSA is a mathematical model that simulates salps' swarming behavior while navigating and hunting in oceans. This is the first time, to the best of the authors' knowledge, that SSA has been used to solve a design problem in THz antennas. The use of SSA is further motivated by the fact that it is parameter-free, which means it does not require parameter fine-tuning to perform well. 10 THz Antenna Design Using SSA for 6G In this chapter, we use the SSA for 6G antenna design. We design a half E- shaped patch antenna for operation at 300 GHz. This antenna design can be used for operation in the whole low THz frequency band from 252 to 325 GHz as defined in [1]. We design this antenna on a Rogers RT/duroid 5880 laminate with 2.2 dielectric constant and t = 0.127 mm thickness. A single microstrip feed is used, which simplifies the design process even more. The suggested antenna is circularly polarized with an acceptable operating frequency bandwidth. Additionally, in order to achieve wide bandwidth, we introduce an additional design parameter by using not a 