Design of Compact Artificial Magnetic Conductor Using Planar Square Spiral

When a plane wave illuminates an electromagnetic band-gap (EBG) structure, the reflection phase continuously changes from 180° to -180° as the frequency increases. Especially at a certain frequency where the reflection phase is 0o, the surface shows the same property as a perfect magnetic conductor (PMC). The PMC material does not exist in nature, b u t an artificial magnetic conductor (AMC) can be realized by properly designing the EBG structure. The objective of this research is to design compact AMC using spiral geometry for wireless communication and RFID applications. Spiral geometry is investigated because it can increase the equivalent inductance, resulting in a lower resonant frequency. For the analysis of large periodic array of elements, the finite difference time domain algorithm is combined with the application of t he periodic boundary conditions such that only one unit cell (one element) needs to be analyzed. For the validity of the FDTD algorithm, commercial software, Ansoft Designer is also used.