Planar Reflector Design Using Metamaterials

Prof. Young Joong Yoon
Yonsei University

Reflectors are used in various microwave and millimeter-wave applications such as satellite antennas, broadcasting antennas, and military radars to direct beams to the target directions. Generally, the reflectors are designed with common metals but recent researches on metamaterials have been shown that conventional metallic reflectors can be replaced by planar metamaterials reflectors. The concept of metamaterials was first proposed in 1960s, and there have been various and intense researches on the field of electromagnetic metamaterials. So far, various types of metamaterials with diverse shapes and characteristics have been proposed, and their application areas are continuously expanding to microwave and millimeter-wave technologies. Among the many types of metamaterials, planar metamaterials called “artificial magnetic conductors (AMCs)” have been applied as reflectors by a number of researchers. AMCs have been drawn attentions due to the interesting reflection phase characteristic, i.e. no phase reversal of normally incident electric fields. Researchers also found that the reflection phase can be arbitrarily controlled by changing the unit cell structure of AMCs. The capability to attain any desired reflection phase enables the design of planar reflectors with desired reflection phase distribution. For instance, curved metallic reflectors (like parabolic reflectors) can be replaced by planar reflectors composed of metamaterials unit cells with required reflection phases to compensate the differences between the curved surfaces and the planar surfaces.

This course is about such various planar reflector design technology using metamaterials. In this course, after the brief introduction on electromagnetic metamaterials, the basic theory of AMCs will be overviewed. Next, various types of AMCs including a conventional mushroom type AMC and AMCs with various patch shapes or slot-loadings will be presented with their individual characteristics. Also, the methods of attaining desired reflection phases by modifying AMC structures will be presented. In the latter part of this course, various reflector applications (including low-profile reflector antennas, circular polarized antennas, reflectarrays and etc.) of metamaterials will be introduced. In the conclusion, the overall contents of the course will be summarized.

Young Joong Yoon received the B.S. and M.S. degrees in electronic engineering from Yonsei University, Seoul, Korea, in 1981 and 1986, respectively, and the Ph.D. degree in electrical engineering from the Georgia Institute of Technology, Atlanta, in 1991. From 1992 to 1993, he was a Senior Researcher with the Electronics and Telecommunications Research Institute (ETRI), Daejeon, Korea. In 1993, he joined the faculty of Yonsei University, where he is currently a Professor with the Department of Electrical and Electronics Engineering. He was a president at the Korean Institute of Electromagnetic Engineering & Science (KIEES) in 2011. His research interests are antennas, RF devices, metamaterials, and radio propagations.