Absorptive frequency-selective structures and their applications in antenna systems of low radar cross section

• Main Author: Huang, Hao
• Other Authors: Shen Zhongxiang
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: https://hdl.handle.net/10356/145121
• Institution: Nanyang Technological University

Microwave absorbers are widely used to reduce the overall reflection levels of a target or an object. For most of absorbers, they produce reflection bands out of their absorption bands due to the existence of impenetrable ground planes. On one hand, transmission band within the absorption band does not naturally exist in most absorbers. On the other hand, the reflection band of absorbers is fixed once they have been manufactured. These two issues have limited the application of absorbers in antenna systems, especially when the radiation efficiency is the major concern. To overcome these problems, absorptive frequency-selective reflection (AFSR) structures and absorptive frequency-selective transmission (AFST) structures are proposed in this thesis. Frequency responses of absorption-reflection-absorption and absorption-transmission-absorption are introduced, which provide more degrees of freedom in manipulating electromagnetic waves in the frequency domain. Following this, two specific types of absorptive FSSs are introduced and discussed, which are termed as AFST structure and AFSR structure, according to their frequency responses. The associated applications of AFST structures and AFSR structures are also presented with their applications in antenna systems for RCS reduction. In the end, this thesis is concluded by making suggestions for future research perspectives. With future research in functional electromagnetic surfaces or structures, more opportunities will be explained and more challenges will be attempted.