Principle, control theory, and application of the ESPAR (Electrically Steerable Parasitic Array Radiator) antenna are introduced. A typical ESPAR antenna consists of monopole or dipole elements, one of which is the radiator (fed element) and the others are the parasitic radiators with variable reactance devices loaded on them. It can provide a lower-cost solution as an adaptive array antenna or...

The complex antenna factor (CAF) introduced to measure transient electromagnetic fields or electromagnetic pulses and its applications are investigated. The equations of the three-antenna method for determining the CAF of a dipole antenna, a log-periodic dipole array antenna (LPDA), and a monopole antenna are derived. The results of the waveform reconstructions using the CAF are compared with t...

This paper describes the design of the disk-loaded monopole with a parasitic array for beam switching. Usually the radiation pattern of a single element such as a λ/4 monopole and the disk-loaded monopole provide low values of gain. The beamwidth is normally large and the coverage is wide. This may be appropriate in an on-body channel where the antenna orientation may not be easily controlled, ...

The diversity performance of the modurated scattering array antenna (MSAA) with various array spacing is measured in Rayleigh fading environment to investigate experimentally the relation between the array spacing and the diversity performance of the MSAA. A 2-element modulated scattering monopole array antenna with various array spacing which is supposed to be used for mobile handset applicati...

Butler Matrix is a beamforming network (BFN), functioning as a feeding network of antenna array. It provides multiple values of progressive phase different of excitation current to an antenna array. By integrating Butler Matrix with antenna array, multiple beams on radiation pattern could be created. In this work, three different types of antenna array have been integrated with the same Butler ...

Attempt is made to modify the radiation pattern of a patch antenna using a meta-structure consisting of an array of monopole antennas in the near field. The effect of the metastructure on the radiation characteristics of the patch antenna, for different angular arrangements of the metastructure plates, has been experimentally studied.

INTRODUCTION: By modifying the monopole antenna array (MA) for whole brain imaging, we developed extended and shielded monopole antenna array (ESMA) in order to enhance the uniformity of imaging at 7T MRI application. We compared the performance of this new coil with two different types of coils, namely, MA and extended monopole antenna array (EMA). The three coil types were evaluated for the t...