Coupling gaps of dipole radiating structures with implications for fabricating antennas using nanomaterials

Coupling gaps of dipole radiating structures with implications for fabricating antennas using nanomaterial

Loop antennas at microwave frequencies using nano-metamaterials

Loop antennas at microwave frequencies using nano-metamaterial

A metasurfaces review: Definitions and applications

This paper is a critical review of metasurfaces, which are planar metamaterials. Metamaterials offer bespoke electromagnetic applications and novel properties which are not found in naturally occurring materials. However, owing to their 3D-nature and resonant characteristics, they suffer from manufacturing complexity, losses and are highly dispersive. The 2-dimensional nature of metasurfaces allows ease of fabrication and integration into devices. The phase discontinuity across the metasurface offers anomalous refraction, thereby conserving the good metamaterial properties while still offering the low-loss characteristics. The paper discusses salient features and applications of metasurfaces; wavefront shaping; phase jumps; non-linear metasurfaces; and their use as frequency selective surfaces (FSS)

Microwave antennas and heterogeneous substrates using nanomaterial fabrication techniques (Invited paper for ICEA11)

By exploiting the enhanced physical properties of nanomaterials and the advancement in nanotechnology, alternative methods of fabricating microwave antennas can be conceived. This paper will discuss the potential manufacturing advantages as well as different fabrication methods. By controlling the location of metallic and dielectric particles, integrated antennas and substrates can be made in one process. Electromagnetic advantages result from being able to add inclusions with different electrical properties into the host substrate and thereby create a new effective permittivity and permeability. This paper will review and analyse methods for calculating these effective properties

A low-profile cavity-backed slot antenna loaded with an AMC reflector

A low profile printed slot antenna is presented with uni-directional radiation properties. The slot antenna radiates above a closely spaced artificial magnetic conducting (AMC) reflector. The electromagnetic band gap (EBG) performance was evaluated with an equivalent waveguide feed in place of one half-wavelength section of the slot antenna. Experimental results for the final antenna design (with a size of 1.02 0 × 0.82 0 × 0.063 0), mounted on 1.5 0 × 1.5 0 back plate, exhibit a 5% impedance bandwidth, maximum gain in excess of 10 dBi, low cross-polarization, and a front-to-back ratio of approximately 25 dB

Conservation practice could benefit from routine testing and publication of management outcomes

Effective conservation requires a step change in the way practitioners can contribute to science and can have access to research outputs. The journal Conservation Evidence was established in 2004 to help practitioners surmount several obstacles they face when attempting to document the effects of their conservation actions scientifically. It is easily and freely accessible online. It is free to publish in and it enables global communication of the effects of practical trials and experiments, which are virtually impossible to get published in most scientific journals. The driving force behind Conservation Evidence is the need to generate and share scientific information about the effects of interventions

A [SU(6)]4^4 FLAVOR MODEL WITHOUT MIRROR FERMIONS

We introduce a three family extension of the Pati-Salam model which is anomaly-free and contains in a single irreducible representation the known quarks and leptons without mirror fermions. Assuming that the breaking of the symmetry admits the implementation of the survival hypothesis, we calculate the mass scales using the renormalization group equation. Finally we show that the proton remains perturbatively stable.Comment: Z PHYS. C63, 339 (1994

Imprints of Short Distance Physics On Inflationary Cosmology

We analyze the impact of certain modifications to short distance physics on the inflationary perturbation spectrum. For the specific case of power-law inflation, we find distinctive -- and possibly observable -- effects on the spectrum of density perturbations.Comment: Revtex 4, 3 eps figs, 4 page