Coaxially Fed Circular Waveguide Antenna and Performance Optimisation

Electronic devices such as Wi-Fi and Bluetooth often experience signal attenuation due to obstacles like walls and metal objects. This issue can be mitigated by designing a waveguide antenna to enhance signal directionality, improving performance in environments with obstructions. In this study, a circular waveguide antenna was designed with a coaxial feed, optimized for an operating frequency of 2.45 GHz. The antenna design focused on controlling internal radiation and assessing the effects of various parameters on performance. To further improve directionality, a conical horn structure was added at the open end of the waveguide, transforming it into a horn antenna. The conical horn increased the antenna’s gain and directivity, making it more suitable for applications requiring focused radiation, though it came at the cost of increased return loss. Simulations were performed to determine the optimal antenna parameters, including waveguide length, coaxial insertion depth, and horn dimensions. The final design achieved excellent return loss performance, with -53 dB at 2.45 GHz for the basic circular waveguide antenna. After the conical horn addition, the return loss was reduced to -25 dB, but the directionality significantly improved, enhancing signal strength in the desired direction. Overall, the design trade-off between return loss and directivity makes this antenna practical for environments that prioritize focused signal radiation over minimal signal loss.