Modern military uses of antennas have presented new challenges to the antenna designer. Only a decade ago, specific band antennas, or tall whips, met the needs of most communications, electronic warfare (EW) and surveillance applications. But with new needs and transceiver technologies, antennas have new challenges: wideband; small; and agile platforms, for software-defined radio (SDR) and mode...

Procedures using Artificial Neural Networks (ANN) are developed for characterizing square microstrip antennas. A Multi-Layer Perceptron (MLP) is used to find out the resonant frequency of the antennas. Same ANN is used to accomplish the task of obtaining different important antenna characteristics like gain, return loss and bandwidth of operation at once. The developed ANN is tested experimenta...

Smart antennas have become an essential paradigm for the enhancement of capacity in cellular communications systems. In 2nd Generation Systems smart antennas were aiming at increasing capacity either by reuse within ceN (Space Division Multiple Access SDMA) or by intercell interference reduction (Spatial Filtering for Interference Reduction SFIR). Later in 3rd Generation UMTS UTRA (Universal Te...

Optical antennas are an emerging concept in physical optics. Similar to radiowave and microwave antennas, their purpose is to convert the energy of free propagating radiation to localized energy, and vice versa. Optical antennas exploit the unique properties of metal nanostructures, which behave as strongly coupled plasmas at optical frequencies. The tutorial provides an account of the historic...

A new set of fractal multiband antennas called mod Sierpinski gaskets is presented.Mod Sierpinski fractal antennas derive from the Pascal triangle and present a log-periodic behavior, which is a consequence of their self-similarity properties.Mod Sierpinski fractal antennas constitute a generalization of the classical Sierpinski antenna.

In this paper, the application of left-handed metamaterials for the realisation of microwave antennas has been considered. Special emphasis is placed on lens antennas based on gradient-index metamaterials, and their advantages and enhanced features in comparison with conventional microwave antennas are highlighted.

In recent years, public concern over possible adverse health impacts from exposure to the radiation emitted by cellular antennas has grown tremendously and shows little sign of abating. Fearing of public protests, theft and vandalism, cellular antennas operators do not publish exact locations of their antennas. Some even try to camouflage their cellular towers in our urban landscape in order to...

receiver antennas is assumed to be large, but not necessarily much larger than the overall number of transmitter antennas jointly using the same time/frequency resource at Mobile Terminals (MT). In this context, we consider several detection techniques and evaluate, in detail, the corresponding detection performances (discussed with the help of selected performance bounds), for a range of value...

In this paper, the large-scale MU-MIMO system is considered where a base station (BS) with extremely large number of antennas (N ) serves relatively less number of users (K). In order to achieve largest sum rate, it is proven that the amount of users must be limited such that the number of antennas at the BS is preponderant over that of the antennas at all the users. In other words, the antenna...