Microstrip Reflect Array Antenna Research And Design

With the rapid development of modern microwave communication, satellite communications and space technology, parabolic antennas are playing a more and more important role. However, according to the requirement of modern society for the flexibility of communication systems, parabolic antennas become get into trouble because of their traditional heavy, bulky structure. In order to break the restrictions of parabolic antennas, many foreign scholars put forward the low profile microstrip reflectarray antenna. Microstrip reflectarray antennas, which combine both characteristics of reflector antennas and microstrip array antennas, have many advantages such as light weights, small volumes, low prices, ease of manufacture and being especially prone to be conformed to other integrated circuits. They have attracted more and more attention and developed more and more rapidly since they were developed in 1978. Design of a microstrip reflectarray antenna has been systematically investigated in this thesis.Firstly, the functional principle and basic configurations have been analyzed. Then methods and principles to realize appropriate reflective phase compensation of the microstrip element have been discussed in detail. As a tool to obtain the phase shift of an element, the waveguide approach for calculating phase delay curves has been investigated intensively.Next, in order to break the limitation of their narrow bandwidth characteristic, bandwidth enhancement techniques of microstrip reflectarray antenna have been studied emphatically. A broadband double-layer patch element is developed to achieve broadband property. The phase shift characteristic of double-layer patch elements have been investigated by the numerical simulation software HFSS, which shows that good broadband performance can be achieved. Finally, a 161-element Ku-band offset-feed microstrip reflectarray has been developed, which has a main beam at 20°off broadside, and a gain of 25dB and a bandwidth of nearly 20%. Measured results have good agreement with simulation results.