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...

The efficiency of ground-based antennas is highly determined by the power dissipated in the ground plane, which can be separated into H-field and E-field losses. In this paper, a new approach is presented for the separation of ground losses that is based on Joule's law. It is theoretically valid at any frequency. Nevertheless, some simplifications can be applied in the lowand medium-frequency b...

Introduction: Millimetre-wave fibre wireless applications [1] could profit from a small antenna that can be fully integrated with the microwave and optical components of the system. This can lead to smaller and more cost-effective fibre-fed antenna units. Active integrated antennas [2] are another application that could benefit from a directly integrated antenna. Printed antennas are the obviou...

Electromagnetic waves are studied with applications to microstrip antennas, 1'2 geophysical subsurface probing,3' 4 scattering from helical structures5 '6 and Smith-Purcell radiation from metallic gratings.7 Radiation and resonance characteristics of two coupled circular microstrip disk antennas are studied rigorously using numerical techniques, matched asymptotic analysis, and the newly develo...

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...

Null steering to cancel interference at a given directions in adaptive arrays could be achieved efficiently using genetic algorithm (GA). Major deviations in the beam steering direction and large perturbation in the side lobe level could be the main limitations for placing nulls in the far field pattern. In this paper, null steering techniques for Dolph-Chebyshev and thinned antenna arrays usin...

Near Field Communication (NFC) is a short range radio frequency technology. Because of the short range, cloning attacks of NFC devices are impractical. To make this possible, you would need to be very close to the tag. Currently, a lot of research has been done on NFC range extension. However, almost all of this research is executed in a lab environment that is not comparable to a day-to-day wo...

A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmission system operating in a Rayleigh distributed environment at the 434 MHz ISM band are investigated. The two systems are simulated using the Finite Difference Time Domain (FDTD) method, which enables the simultaneous characterization of the propagation channel and the immersed wire dipoles antennas. ...

at the final stages of a coronary artery bypass graft operation on a 64-year-old man, an experienced physician attempted to insert an intra-aortic balloon pump into the femoral artery via the seldinger technique. however, while the balloon pump was being passed over the guide wire, the latter was completely lost. the guide wire should be held at the tip at all times to prevent passage into the ...