Yoichi Ido

Wideband Planar Folded Dipole Antenna With Self-balanced Impedance Property

A planar folded dipole antenna that exhibits wideband characteristics is proposed. The antenna has simple planar construction without a ground plane and is easy to be assembled. Parameter values are adjusted in order to obtain wideband properties and compactness by using an electromagnetic simulator based on the method of moments. An experimental result centered at 1.7 GHz for 50 impedance matching shows that the antenna has bandwidth over 55% . The gains of the antenna are almost constant (2 dBi) in this frequency band and the radiation patterns are very similar to those of a normal dipole antenna. It is also shown that the antenna has a self-balanced impedance property in this frequency band.

Wideband Folded Loop and Folded Dipole Antennas

In this paper, the aim is to investigate the folded loop antenna (FLA) without ground plane (GP) in detail, and to find optimum antenna parameters for wideband characteristics. In the analysis, the electromagnetic simulator IE3D based on the method of moment (MoM) is used. Consequently, it is shown that the folded construction at both ends of the FLA is not necessary for wideband properties, and planar folded dipole antenna (FDA) also has wideband characteristics

Planar dual-band omni-directional UHF antennas employing a composite right/left-handed double-sided metal layer structure

This article presents planar dual-band omni-directional antennas employing a composite right/left-handed (CRLH) metamaterial for UHF applications. The antennas are compact and in a simple double-sided planar configuration without using vias or lumped-elements and have an omni-directional radiation pattern regardless of having a ground plane at the backside. A dual-band antenna operating at a pair of the negative (ƒ<inf>−1</inf>) and positive (ƒ<inf>+1</inf>) resonant frequencies is designed at 373/817MHz and the dual-band operation with omni-directional radiation patterns are demonstrated. The physical size of the presented antenna is λ<inf>−1</inf>/13 × λ<inf>−1</inf>/18 × λ<inf>−1</inf>/1005 at ƒ<inf>−1</inf>, and λ<inf>+1</inf>/8 × λ<inf>+1</inf>/6 × λ<inf>+1</inf>/459 at ƒ<inf>+1</inf>, where λ<inf>−1</inf> and λ<inf>+1</inf> are free space wavelengths at ƒ<inf>−1</inf> and ƒ<inf>+1</inf>, respectively. Maximum measured gains at ƒ<inf>−1</inf> and ƒ<inf>+1</inf> are −13.8dBi and −0.5dBi, respectively.