A novel approach to broadband log-periodic antenna design is presented, where some of the most powerful evolutionary algorithms (EAs) are applied and compared for the optimal design of wire log-periodic dipole arrays (LPDA) using NEC (Numerical Electromagnetics Code). The target is to achieve an optimal antenna design with respect to maximum gain, gain flatness, Front to Rear ratio (F/R) and SW...

We investigate four types of gold nanoantennae (the monopole, the dipole, the cone-shaped, and the cone-bowtie antenna), under a fixed working wavelength. The finite-difference time-domain (FDTD) simulations show that the near-field enhancement values do not increase monotonously when the antennae sizes decrease, and optimization conditions vary with the antenna shapes. We also propose a distri...

This paper theoretically examines the key dipole antenna parameters that define their performances in terms of current distribution, radiation resistance, input impedance, radiation efficiency, size, bandwidth, quality factor and directivity. We have investigated how these parameters are related to each other and also how variation of one alters the overall performance of the antenna. Bandwidth...

Near-field dipolar plasmon interactions of multiple infrared antenna structures in the strong coupling limit are studied using scattering-type scanning near-field optical microscope (s-SNOM) and theoretical finite-difference time-domain (FDTD) calculations. We monitor in real-space the evolution of plasmon dipolar mode of a stationary antenna structure as multiple resonantly matched dipolar pla...

Abstract—This paper describes a wideband double-dipole Yagi-Uda antenna fed by a microstrip-slot coplanar stripline transition. The conventional dipole driver of a Yagi-Uda antenna is replaced by two parallel dipoles with different lengths to achieve multi-resonances, and a small, tapered ground plane is used to allow flexibility in the placement of a pair of reflectors for effective reflection...

The target of the paper is to provide guidelines for indoor antenna selection for passive distributed antenna system or radiating cable implementation. Distributed antenna systems are commonly used for indoor installations, and radiating cables are often used in tunnels, airplanes, or similar constricted areas. However, guidelines for optimizing WCDMA indoor network antenna configuration are la...

Bow-tie antenna is one of wideband antennas [1]. It has been reported that the bow-tie antenna has been miniaturized by adding folded elements [2]. In this paper, it is shown that bending the bow-tie antenna with folded elements is effective method for miniaturization. The bent bow-tie antenna with folded elements can be more miniaturized than conventional bow-tie antenna with folded elements, ...

Existing two-dimensional RFID tag antennas are orientation limited and material sensitive. This paper presents the novel designs of two three-dimensional tag antennas, the Albano-Dipole antenna and the Albano-Patch antenna and evaluates their performances in static and dynamic environments, examining specifically orientation and material sensitivity.

An antenna prototype utilizing artificial impedance surfaces to control the near field distribution is described. The antenna is a folded dipole placed above a finite-size artificial impedance surface. We have found that the field screening is most effective if the surface is a metal conductor. However, to achieve a reasonable value of the radiation resistance the dipole should be located far o...

Many of the technical requirements proposed for the LWA are significantly expanded compared with the LWDA. Among the most significant changes in requirements is the wider operating band of the LWA, nominally 20 MHz to 80 MHz [1], compared with 60 MHz to 80 MHz for the LWDA. This presents new challenges in designing many of the system components including the antenna. Requirements for an LWA ant...