Abstract

The development of wireless and satellite communication systems has led to high demand for microwave and millimeter wave application components, which play an essential role in the upcoming 5G communication. The coverage area of such systems is control by transmitted power as well as the antenna gain of the system. Hence, it is essential to design a high gain antenna that can mitigate the losses and extend the system coverage area. Higher frequencies lead to smaller sizes of RF components including antennas. However, the implementation of passive components and guiding structure becomes difficult based on traditional guiding structures such as microstrip lines, and waveguides at millimeter wave bands. Microstrip line suffers from cavity modes, which leads to surface waves and has more losses at higher frequencies. The rectangular waveguide has high power handling capability, low losses, and high Q-factors which makes it very attractive for high-frequency applications. On the other hand, at high frequencies, the wavelengths become challenging to construct with current machining techniques as ensuring good electrical contact become very challenging.
In this thesis, planar high gain antennas are designed based on Printed Ridge Gap Waveguide (PRGW). The primary objective of this work is to develop high gain, wideband antennas that can support the future demand for high data transmission. Therefore, a detailed analysis for PRGW has been introduced as well as featured designs of the high gain antenna. This antenna array can perform for future 5G communication purpose, and it fulfills all the requirements of mm-wave bands.
In this work, a groove-based wideband bow-tie slot antenna array is designed at 30 GHz based on printed ridge gap waveguide technology (PRGW). A two-section T-shaped ridge is designed to feed a bow tie slot placed on the upper ground of PRGW. The gain of the proposed slot antenna is enhanced by using a horn-like groove. Then, the proposed high gain element is deployed to build up a 1 x 4 bow-tie slot antenna array loaded with three-layer groove antenna. The proposed antenna array is fabricated and measured, where the measured results show a -10 dB impedance bandwidth from 29.5 to 37 GHz (22%). The fabricated prototype achieves a high gain of 15.5 dBi and a radiation efficiency higher than 80% over the operating frequency bandwidth. Besides, to reduce the edge diffraction in the E-plane, an artificial corrugation ring is deployed with a certain depth so that it can improve the overall antenna performance.