Challenges and Issues in the Design of Micro-machined Antennas - A Review

Background: Patch antennas are composed of the substrate material with patch and ground plane on both sides of the substrate. The dimensions and performance characteristics of the antenna are highly influenced by choice of the appropriate substrate depending upon the value of their dielectric constant. Generally, low index substrate materials are used to design the patch antenna, but there are also some of the applications, which require the implementation of patch antenna design on high index substrates like silicon and gallium arsenide. Objective: The objective of this article was to review the design of antennas developed on high index substrate and the problems associated with the use of these materials as a substrate. Also, main challenges and solutions have been discussed to improve the performance characteristics while using the high index substrates. Methods: This review article is divided into various sections, including the solution of the problems associated with the high index substrates in the form of the micro-machining process. Along with this, types of micro-machining and its applications have been discussed in detail. Results: This review article investigates the various patch antennas designed with micro-machining technology and also discusses the impact of the micro-machining process on the performance parameters of the patch antennas designed on high index substrates. Conclusion: By using the micro-machining process, the performance of the patch antenna improves drastically, but fabrication and tolerances at such minute structures are very tedious task for the antenna designers.