Theory and applications of electromagnetic band-gap structures in microwaves

In recent years, there has been significant research interest in microwave applications of electromagnetic (photonic) band-gap structures. There has been much debate on the distinction of band-gap structures and the frequency selective surfaces or general periodic structures in microwaves. This paper provides an overview of the recent research effort on the new applications of microwave band-gap structures with emphasis on the integrated circuit applications. Examples of circuits on substrates without surface-waves are given to demonstrate the loss reduction. An example of the same structure for high-gain leaky-wave antenna is also shown.