After the Federal Communication Commission (FCC)’s authorization of frequency band of 3.1 to 10.6 GHz for unlicensed radio applications, ultra-wideband (UWB) technology be‐ come the most promising candidate for a wide range of applications that will provide signif‐ icant benefits for public safety, business and consumers, and attracted a lot attention both in industry and academia. The antennas...

This paper introduces a moment-method formulation, which is capable of accurately modeling moderately thick cylindrical wire antennas. New algorithms are presented for the efficient computation of the cylindrical wire kernel and related impedance matrix integrals. These algorithms make use of exact series representations as well as efficient numerical procedures and lead to a significant reduct...

Folded monopole antennas have been used for many years in medium frequency amplitude modulation broadcast applications. These antennas offer a grounded radiating structure with a height approximating a quarter wavelength. Folded monopoles have been studied exhaustively during a recent effort in an attempt to characterize the input impedance and directivity characteristics as a function of monop...

A three left-handed metamaterial unit cell antenna is presented in this article for ultrawideband applications. Each left-handed metamaterial unit cell is a combination of a modified octagonal split-ring resonator, an octagonal spiral resonator, a capacitance-loaded strip, and a wire in order to achieve a design that simultaneously exhibits both negative electrical permittivity and negative mag...

Future base stations for Spatial Division Multiplex Access (SDMA) will utilize adaptive antenna arrays, capable of identifying the direction of the incoming signal and steering the transmitted beam in appropriate directions. The radiating elements that have been thus far considered for building the antenna array are typically wire dipoles or microstrip patches. This tutorial paper describes a n...

Calculation of electric field and potential inside a wire structured object in external pulse electromagnetic field of lightning discharge is presented in this paper. Conductive structure is solved as a receiving antenna using program SPAN [1,2] for an arbitrary antenna configuration, consisting of lineic cylindrical segments, in external electromagnetic field. One simple approximation [3] for ...

In this paper, circuital and numerical models of metal enclosure with apertures are considered for the purpose of accurate shielding effectiveness calculation. An improved circuital model is presented to account for the presence of receiving dipole antenna which is often used in practice to measure the level of electromagnetic field at selected points inside the enclosure. Receiving antenna of ...

Performance of a helical antenna designed for 2.4-GHz WLAN is experimentally investigated in terms of impedance matching. A section of the helical wire near the antenna feed point is replaced by a simple triangular copper strip. By deploying such technique, impedance matching can be achieved. Overall return loss is below −14 dB across entire WLAN frequency range. Moreover, overall return loss d...