# The Uses of a Dual-Band Corrugated Circularly Polarized Horn Antenna for 5G Systems
## 5 Conclusions  
The dual-band corrugated circularly polarized horn antenna has been successfully designed, fabricated, and analyzed. By using a circularly polarization converter, the antenna achieved an axial ratio of 3-5 dB. The antenna has a broad beam width of 105 degrees and 77 degrees by using two different gap sizes of corrugated structure. The resulting measurement of the antenna satisfied the requirements of the 5G indoor coverage environment. The novelty of the proposed antenna is a multi-requested feature for the application of 5G communications, e.g., dual-band, circularly polarization, and broad beam width. The existing work developed a dual-band horn antenna suitable for satellite communication, but not for 5G communications. The fabrication complexity of horn antennas for satellite application is high with high manufacturing costs. The proposed antenna is easy to manufacture and assemble. Figure 23 illustrates the parts of the antenna made using conventional CNC machining, and wire electrical discharge machining, with a tolerance of \(+/-0.01\) mm. It is easy to assemble this antenna engineering design since there are aligned markers on the ridge structure as well as markers for the location of the screw holes on each section. The material used to make this antenna is brass in order for the antenna to withstand high power input flow. Depending on its application, the material can be changed to one with a low loss metal or coating surface. Even in the 5G products,  
Figure 21: 3D Radiation Efficiency. Figure 22: (a) Cross section of circularly polarization converter and (b) optimized axial ratio result. the antenna can be combined with the thermal sink on a one-piece molding [6]. This design reduces the cost of the antenna's production. In previous research, various horn antennas have been studied with different features, such as broad beam width [10] and circularly polarization [8; 9; 17; 18; 19]. In [20], metasurface was designed to create a circular polarization antenna. The concept of metasurface antenna is phase manipulation of electromagnetic wave. The material of antenna is a PCB or a plastic plane that is easy to fabricate. The height of the metasurface antenna is low, but the bandwidth was designed to meet a specific frequency band. This reconfigurable antenna technology can also be used to mimic the characteristics of circular polarization. In the study in [21], it was found that antenna can have three different polarizations by rotating the SSPP element. The performance of the antenna is determined by its broadband bandwidth and good axial ratio. For it to be high performing, the antenna structure will be complex and expensive. As listed in Table 4, the proposed antenna has a better beam width and a good axial ratio on both bands compared to other previously proposed antenna designs. Due to these improvements in performance, the antenna proposed in this study can effectively use 5G in an indoor coverage environment. In future works, the authors aim to study a reconfigurable ridge that is combined with a stepper motor and switch circuit to allow the antenna a better axial ratio on a specific scenario and frequency band. The current design in this study is a single antenna design that is designed to be suitable for 5G repeater products. Future work will include the implementation of a multi-antenna MIMO system, which will be another key technological research.