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A low-cost hybrid textile/PCB wearable rectenna is designed for smart on-body applications. It is an integration of a textile patch antenna and a highly efficient rectifier on a small PCB substrate, where the feeding aperture of the antenna is significantly miniaturized by exploiting an LC loading technique to have an effective integration with the rectifier. The feeding-rectifying circuitry is attached to the back of the antenna by normal sewing threads. The essential components are soldered on the small rigid PCB for a robust connection. The size of the rectenna is $0.817\times 0.817\,\,\lambda {0}^{2}$ while the rigid substrate area for the feeding-rectifying circuitry is only $0.278\times 0.147\,\,\lambda {0}^{2}$ ( $3.4\times1.8$ cm) at 2.45 GHz. The intrinsic dielectric/conduction loss of textile feedlines, the loss of antenna-to-rectifier interconnectors, the loss of soldering or gluing on textiles, and the loss due to body absorption from typical large feeding slots are constitutively reduced. The soldering points and the consequent hard-to-be-characterized parasitic effects on textiles are avoided. The proposed integration approach reduces the cost and eases the rectenna design, fabrication, and integration. As a result, the power conversion efficiency (PCE) of the rectifier reaches up to 39.5% at -20 dBm input power level whilst the experimental rectenna prototype achieves the state-of-the-art PCE of 41% at an extremely low incident power density of $0.4~\mu \text{W}$ /cm2. The maximum PCE is 56% at the -5 dBm input power. Finally, the possibility of harvesting datalink energy from PC/mobile phones as power source for wearable electronics is investigated.

In this communication, we propose a robust broadband anomalous refractor (BAR), which minimizes chromatic aberration. The design is based on engineering the dispersion curve of spoof surface plasmon polaritons (SSPPs) and manipulating the wavefront of the transmitted waves. We begin by deriving deflection conditions such that the discrete scatterers of the refractor need to have linear dispersion curves in the operating frequency band. The rich dispersion properties of the SSPP make it a good candidate for meeting the broadband deflection condition. Next, we design symmetric metallic blade structures (MBSs) to efficiently transform free-space waves into SSPPs and to realize the broadband linear dispersion relationship. The BAR is comprised of these MBSs with different strip heights. A prototype is designed, fabricated, and measured. Both the simulated and experimental results demonstrate excellent fixed-direction deflection in the 6.9–9.1 GHz band for the normal incidence case. Furthermore, the BAR still performs well when its outer profile is deformed to some extent, which is desirable in practical applications. This alternative approach to designing achromatic devices at microwave frequencies can be readily extended to higher frequencies.

© 1963-2012 IEEE. In this paper, we propose a general boundary integral equation (BIE) approach for solving both exterior (e.g., scattering) and interior (e.g., guided wave propagation) problems involving general plasmonic waveguiding structures with arbitrary cross-sectional geometries and with a continuous translational symmetry in the direction of wave propagation. Contrary to the field-based approach which deals with the electric and magnetic fields, we employ a potential-based formalism instead, involving vector and scalar potentials, and match them at the media interfaces. The proposed approach can handle not only conventional plasmonic waveguides on the order of a few hundred nanometers but also those whose critical sizes are a few nanometers and in which the nonlocal hydrodynamic effects need to be accounted for. The BIEs describing the interaction of light with the plasmonic waveguide are solved by the method of moments (MoM) algorithm. Two illustrative examples, the first one of which deals with the scattering problem, while the second computes the dispersion diagram of a plasmonic cylinder, are considered for both local and nonlocal cases. An excellent agreement is observed between the numerical and theoretical results, with the latter being derived from the generalized Mie theory. ispartof: IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION vol:67 issue:6 pages:3948-3960 status: published

Symmetry holds a prominent position in defining the optical response of a nanoantenna. In this work, we harness a mathematical tool, group representation theory, combine it with the eigenmode analysis for a nanoantenna, and illustrate how the symmetry allows or forbids the energetic coupling (i.e., interference) between a nanoantenna’s eigenmodes. We do this especially using a nanobar structure and a symmetric cross structure. Further, the consequence of symmetry-breaking is illustrated by an asymmetric cross-shaped nanostructure, i.e., a strong asymmetric Fano-type resonance line shape due to mode interference is observed with the physics behind elaborated. Both numerical and experimental evidences are provided.