High-Impedance Surfaces With Periodically Perforated Ground Planes

Because of the design limitations of conventional high-impedance surfaces (HIS), it is not possible to miniaturize the HIS and increase the bandwidth, simultaneously. To overcome this, a novel HIS is proposed with a periodically perforated ground plane. The magnetic flux flowing through the perforations results in an extra inductance which increases the fractional bandwidth and decreases the center frequency. Since the perforated HIS can also be considered as a defected ground structure (DGS), surface wave suppression can also be achieved by properly determining the geometry of the perforations. Therefore, a bandgap can be obtained without the need of vias, which considerably increase fabrication costs. It is also possible to tune and overlap the reflection phase and surface wave suppression bands. However, due to the rotational asymmetry of the structure, surface wave suppression is achieved in only one direction.