Antenna pattern control techniques for mobile terminals such as adaptive array antenna are expected to improve the characteristic of high-speed radio communications. The drawbacks of adaptive antenna based on DBF (Digital Beam Forming) are the requirement of the same number of RF receivers and A/D (analog-to-digital) converters as the number of array elements, since digital signal processing ha...

Modern microwave and millimeter wave phased array antennas are attractive because of their ability to steer wave beams in space without physically moving the antenna element. A typical phased array antenna may have several thousand elements fed by a phase shifter for every antenna, which can steer the resulting array beam to different directions. Their low loss, low cost and lightweight phase s...

In this paper we propose a novel spatial fading simulator to evaluate the performance of an array antenna and show its spatial stochastic characteristics by computer simulation based on parameters verified by experimental data. We introduce a cavity-excited circular array (CECA) as a fading simulator that can simulate realistic mobile communication environments. To evaluate the antenna array, t...

Code Division Multiple Accesses (CDMA), one of the effective and efficient technologies, is used in 2nd generation (2G), 3rd generation (3G) wireless and becomes one of potential candidates for the physical layer of 4G mobile systems with the aim of improving cell capacity communication. The paper presents the CDMA system with Broadside antenna array is proposed for a multipath fading channel. ...

Reflector antenna optimization schemes using array feeds have been used to recover antenna losses resulting from antenna distortions and aberrations and to generate contour coverage patterns. IIistorically these optimization have been carried out using the antenna far-field scattered patterns. The far-field patterns must be calculated separately for each of the array feed elements. For large or...

An optimal design of a linear antenna array is presented. The antenna array is optimized under the restriction of uniform excitation distribution using a particle swarm optimization based method. The optimization procedure is applied under the requirements for the minimum possible side lobe level and the maximum possible power gain at the desired direction. The method has been applied to collin...

Three working modes, omni-, sector and adaptive modes, for a compact array antenna are introduced. The compact array antenna is an electronically steerable parasitic array radiator (Espar) antenna, which has only a single-port output, and carries out signal combination in space by electromagnetic mutual coupling among array elements. These features of the antenna significantly reduce its cost, ...

A practical normal-mode helical antenna array together with a new method for the compensation of mutual coupling effect is proposed for the efficient adaptive nulling of interferences in a mobile communication environment. The helical antenna array is shown to be able to generate deeper nulls than an equivalent monopole antenna array in the presence of mutual coupling effect. The helical antenn...

A compact size, multiband 2x2 array of circular microstrip antenna has been proposed. The antenna array consists of Genetic Algorithm (GA)optimized, annular slotted circular microstrip antenna elements using probe feed. The spacing of elements has also been optimized using GA in the two directions. The performance of the antenna array has been studied with different shape parameters. The optimi...

In this research, a sub-array preconditioner is applied to improve the convergence of conjugate gradient (CG) iterative solver in the fast multipole method and fast Fourier transform (FMM-FFT) implementation on a large-scale finite periodic array antenna with arbitrary geometry elements. The performance of the sub-array preconditioner is compared with the near-group preconditioner in the array ...