A high-impedance ground plane applied to a cellphone handsetgeometry

A high-impedance electromagnetic surface is a new type of metallic structure exhibiting high surface impedance and the suppression of propagating surface currents at a particular frequency band. We experimentally characterize such a high-impedance surface designed near 2.4 GHz. We describe an antenna built on such a surface, integrated into a printed circuit board that was designed for the form factor of a portable handset. Measurement shows high radiation efficiency near 2.4 GHz     

Hydroperoxidation of EPDM rubber using singlet oxygen: Synthesis and grafting studies

Chemically generated singlet oxygen hydroperoxidizes the ethylidene double bond in terpolymers of ethylene, propylene, and ethylidene norbornene (EPDM rubber). The EPDM–hydroperoxide was reduced exclusively to 2-(1-hydroxylethyl)-norborene-EPDM rubber using either triphenylphosphine or sodium sulfite. Thermal decomposition of EPDM–hydroperoxide in the presence of either methyl methacrylate or 2- or 4-vinyl pyridine free radically grafted these monomers to the rubber. In the absence of graftable monomer, however, thermal decomposition of EPDM-hydroperoxide generated an intractable polyether.     

High-impedance electromagnetic surfaces with a forbidden frequencyband

A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas     

An application of high-impedance ground planes to phased array antennas

The high-impedance surface was used as the antenna ground plane between two radiator elements to reduce the inter-element coupling between them. Measurement reveals the optimum performance occurred at the bandgap due to the suppression of surface currents in the ground plane.