Design of KU-band slotted waveguide antenna array

Abstract

The Ku-band, defined as electromagnetic spectrum ranging from 12 GHz up to 18 GHz, is generally utilized for satellite communication, radio navigation, and earth exploration purposes. Recently, parts of the spectrum ranging from 13.4 GHz to 14 GHz has been listed as a possible candidate for future 5G communication system. In order to utilize the frequency band, an antenna capable of working in said frequency band must be designed. For this purpose, a slotted waveguide array antenna structure is chosen. A slotted array antenna has several distinct advantages, namely rugged structure, high gain, and high power handling capability.

For the antenna aperture distribution, a separable distribution is used. A Taylor Line Source distribution for low SLL level is combined with genetic algorithm to provide null filling capability. In order to suppress external mutual coupling between radiating slots, an open ended cavity structure is placed above each radiating slots. The dimensions of the radiating slots and coupling slots are determined by using Elliott`s design equation.

Two antennas are designed in this thesis. The first one utilizes $6\times 14$ elements array while the second one utilizes $6\times 16$ elements array. The antennas are designed to work from 13.75 GHz to 14 GHz. The antennas are first simulated using commercial CST Microwave Studio full wave simulation software. After the simulation shows satisfies the design specifications, the antennas are fabricated through milling process. The fabricated antennas are then measured inside an anechoic chamber to clarify their performance.

Measurement and simulation results show significant differences in term of return loss and gain. This is mainly due to imperfections in the antenna`s fabrication process. Solving these imperfections remain an issue for future works.