## 1 Introduction  
The high gain beam steering antennas are widely used in 5G wireless mobile communications, radio frequency (RF) wireless power transmission, and satellite communications [1; 2; 3]. In order to obtain high gain and beam steering characteristics, traditionally, antennas of the same type as phased array antennas, reflectarray antennas, and parabolic antennas have been designed [4; 5; 6]. However, these types of antennas have some disadvantages despite their excellent characteristics since the parabolic antenna and the dielectric lens antenna have a curved shape (i.e., non-planar structures), are expensive, and difficult to manufacture. In addition, a planar phased array antenna with high gain characteristics in the millimeter-wave band may have a complex feeding structure with losses that might influence the antenna's overall radio performance. Transmitarrays also considered as lens arrays or lenses were first presented in [7] by achieving control on EM waves. A lens antenna was proposed in [8] with a characteristic change that can control the wavefront of transmitted and reflected electromagnetic waves. Using a simple microwave lens antenna to attach two patch antennas with a center probe to transfer electromagnetic (EM) energy, the configuration was able to perform characteristics of scanning and focusing of an EM beam by microwave lens antenna. Microwave lenses obtained more interest when researchers achieved a better understanding of planar antennas and microstrip patch antennas [9]. Transmitarray uses a simple Snell's law for working operation, which causes a narrow bandwidth and time-consuming structures. All dielectric and all metal structures are adopted to improve their capabilities for these disadvantages. All dielectric structures are widely utilized for transmitarrays due to their high transmittance, low cost, easy fabrication, and lightweight qualities [10; 11; 12]. TA structures develop with all dielectric materials, while a genetic algorithm (GA) and practical swarm optimization algorithm (PSO) are applied to optimize each pillar unit cell [13; 14]. The integrated optimization strategy increases design reliability while freeing up human effort and time. Furthermore, in order to achieve wideband characteristics, the optimizing goal is to design a rectangular area to accommodate the source antenna's shifting phase center. As we develop all dielectric TA designs, 3D printing technology can easily fabricate designs and provides advantages of being lightweight, low cost, and easy to fabricate. All dielectric TAs have some disadvantages as compared to all metal TAs such as high profile, low machining accuracy, and electromagnetic properties of high power microwave applications [15]. Furthermore, for some applications, TAs are utilized in harsh working environments such as space. In these conditions, TAs without dielectric materials adapt to environmental conditions better than dielectric materials and reduce fabrication cost. Dielectric materials are not appropriate for high frequencies, whereas metals have low-frequency electromagnetic effects on high frequencies. Many studies have been proposed in the literature for all metal transmitarrays [16; 17; 18; 19]. Most of them adopt the multilayer method to obtain 360 degrees phase shift and low losses amplitude. Many improvements deliver for all metal TAs but their bandwidth is still relatively low. The transmitarray (TA) has attracted more and more interest from researchers due to its low profile, affordable cost, lower losses, low design complexity, and ease of fabrication. These have become popular solutions due to their remarkable applications, for instance, in biomedical systems (Brain and Breast Cancer Detection), civil and military radar systems, imaging systems, satellite communications, direct broadcasting services, and 6G/5G communication systems, etc. [20; 21; 22; 23; 24; 25; 26].