Abstract
The main objective of this thesis is to manipulate electromagnetic (EM) waves in guided-wave and periodic structures to enhance the radiation characteristics of the corresponding beam. This is to regulate the performance of the structures in specific criteria including but not limited to controlling the direction of the beam, side-lobe-level (SLL), front-to-back ratio (F/B), and the number of beams.
A method is proposed to control both SLL and the tilt angle of the beam in a leaky-wave antenna (LWA) based on empty substrate integrated waveguides (ESIWs) with a low cross-polarization level. After that, the radiation characteristics of an edge-slotted LWA are controlled by presenting and applying a practical method. Research works on LWAs are then continued by utilizing the holographic technique to analyze and design a metal-strip LWA. The holography technique is then applied to a metasurface reflector to govern the beam directions. Finally, a combination of holography and phase compensations techniques is proposed in a SIW H-plane horn antenna to simultaneously enhance the gain, F/B, and SLL.
Overall, this thesis presents five LWAs, one holographic-based reflective metasurface, and one SIW H-plane horn antenna with enhanced radiation characteristics. All structures are fabricated and tested to showcase their performance in real-world scenarios.