Direction finding by exploiting the directional radiation patterns of an Switched Parasitic Antenna (SPA) is considered. By employing passive elements (parasites), which can be shorted to ground using pin diodes, directional radiation patterns can be obtained. The direction finding performance of the SPA is examined by calculating a lower bound on the direction finding accuracy, the Cramér-Rao ...

In this paper, we define a simple discrete mathematical model for wireless ad-hoc sensor networks and study the problems of data distribution and data collection which arise in those networks. We show how those tasks can be optimally performed on tree sensor networks that use directional antennas. Furthermore we compare the performance of a network equipped with directional antenna elements wit...

Directional antennas have the potential to provide a fundamental breakthrough in ad hoc network capacity. Directional antenna systems are increasingly being recognized as a powerful way of increasing the capacity, connectivity, and covertness of MANETs. In this paper, we survey the state-ofthe-art routing protocols and give a comparison result of them with respect to the important challenging i...

Electronically Switched Directional (ESD) antennas allow software-based control of the direction of maximum antenna gain. ESD antennas are feasible for wireless sensor network. Existing studies with these antennas focus only on controllable directional transmissions. These studies demonstrate reduced contention and increased range of communication with no energy penalty. Unlike existing literat...

The theory, design, fabrication, and measurement of new uniform circular arrays (UCAs) for direction of arrival (DOA) estimation is presented in this report. In particular, the effect of directional antenna elements in UCAs for DOA estimation is studied in detail. While the vast majority of previous work assumes isotropic antenna elements or omnidirectional dipoles, this work demonstrates that ...

This paper presents the shaping optimization of an S-band cylindrical offset reflector antenna with cosecant-squared radiation pattern in elevation plane. The cross section of the antenna is mathematically modeled by a polynomial function and optimized by the genetic algorithm to obtain the desired pattern for both TE and TM polarizations. The physical optics method together with the uniform th...

A wearable dual-port button antenna that excites pattern-diversity dual-polarized waves is proposed for on-/off-body applications. Its simple structure comprises of two radiators and a common ground plane designed into substrates. The crossed-dipole radiator made by symmetric bowtie dipoles printed on circular-shaped semi-rigid substrate, which covers an ultra-wideband (UWB) application with ci...

The suppression of electromagnetic interferences (EMIs) caused by the out-of-band operation is required for broadband antennas. To achieve this purpose, a compact broadband printed slot antenna with build-in filters for band notching is presented. The filters, including I-shaped and inverse L-shaped narrow slits and an L-shaped conductor strip, whose lengths correspond to half wavelengths, were...