It is known that if a conductor resides in the neighboring of an antenna with a small distance relative to the wavelength, it induces a reverse current on the conductor. This paper involves the unavoidable coupling effects on some common types of LF antennas, due to the large wavelength in this frequency band. In particular, after some discussions about top-loaded antennas, the coupling effect ...

We design, fabricate, and experimentally demonstrate an optically active metasurface of λ/50 thickness that rotates linearly polarized light by 45° over a broadband wavelength range in the near IR region. The rotation is achieved through the use of a planar array of plasmonic nanoantennas, which generates a fixed phase-shift between the left circular polarized and right circular polarized compo...

Recently, wireless-PAN systems using a UWB technique are considered. Antennas such as a planar trapezoidal monopole or dipole antenna for a UWB was developed.[1],[2] Since a 5 GHz band is allocated for wireless LAN service such as an IEEE802.11a, a UWB antenna should have a band notch to avoid an interference between two systems. To fulfil this requirement, several UWB antennas having a band no...

Planar inverted-F antennas (PIFA) are widely used in wireless hand-held devices due to their small-size, moderate bandwidth and radiation patterns. However, the radiation patterns of such antennas degrade when placed very close to a conductive finite ground plane. In this paper, an engineered magnetic superstrate is introduced to enhance the gain of PIFA antennas. The engineered magnetic supers...

The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spac...

Passive UHF RFID systems have drawn considerable attention because these can provide a long reading range, high data rate and small antenna size. However, a passive UHF RFID system has challenges in tagging a metallic object due to the effects of conducting materials on the tag antenna performance. This paper proposes two widely used label-type antennas: folded dipole antenna and meandered dipo...

Electromagnetic penetration through an aperture in an infinite, planar screen separating two half spaces of different electromagnetic properties, " American Geophysical Union, pp. 349-357, 1976. (also in the book Moment Methods in Antennas and Scattering. [7] D. T. Auckland and R. F. Hanington, " Electromagnetic transmission through a filled slit in a conducting plane of finite thickness, TE ca...

The paper provides an experimental comparison of four types of ultra-wideband coplanar-fed planar monopole antennas. Parameters of the open stub completed by an L-shaped monopole and the cross monopole were adopted from the literature. The forked monopole and the coplanar monopole were fabricated and measured. Monopoles were compared from the viewpoint of the impedance bandwidth, gain, directiv...

The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either para...