Circular antenna array has gained immense popularity in the field of communications nowadays. It has proved to be a better alternative over other types of antenna array configuration due to its all-azimuth scan capability, and a beam pattern which can be kept invariant. This paper is basically concerned with the thinning of a large multiple concentric circular ring arrays of uniformly excited i...

Low side lobe levels and asymmetrical multiple nulls in specified directions need to be achieved for increasing the efficiency of antenna arrays used in communication systems. Nature inspired algorithms like Invasive Weed Optimization (IWO) algorithm may be applied for synthesis of linear antenna arrays to estimate the element phase excitations for achieving nulls in undesired directions. Sever...

An analysis of MIMO antenna system in the development of LTE (Long Term Evolution) terminal and the compensation of user’s induced loss is presented in this paper. MIMO wireless systems have antenna arrays at both the transmitter and receiver terminals. Multiple input multiple output (MIMO) technology has been regarded as a practical approach to achieve significant increase of wireless channel ...

Coherent wave propagation in disordered media gives rise to many fascinating phenomena as diverse as universal conductance fluctuations in mesoscopic metals and speckle patterns in light scattering. Here, the theory of electromagnetic wave propagation in diffusive media is combined with information theory to show how interference affects the information transmission rate between antenna arrays....

In this work we propose space-multimode (SM-SCP-ULA) space-multimode-polarization stacked circular patch uniform linear antenna arrays (SMP-SCP-ULA) for deployment in size-constrained access points, modems and end-user terminal equipments of IEEE 802.11n MIMO-OFDM WLAN systems at 5.8 GHz. The performance gain of higher-order modal SMP-SCP-ULA in terms of spatio-modal power correlations, ergodic...

This paper presents a significant sidelobe reduction if nonuniform elevational spacing of antenna elements on the sphere is used. Antenna elements are progressively phased with a uniform amplitude excitation. The calculation of the required element position is presented. The achieved sidelobe level reduction with unequally spaced arrays could reach even more than 20dB difference with regard to ...

The design of an active integrated antenna with negative resistance transistor oscillator has been described. Simple but reasonably accurate analysis of oscillation start-up and steady state operating frequency prediction is presented. The active antenna prototype was manufactured and its operating frequency, EIRP and radiation patterns were measured. Two of these antennas were integrated in ac...

Using the sampled data of a desired pattern is a common technique in pattern synthesizing of array factor (AF) of antenna arrays. Based on the obtained data matrix, Least Square Method (LSM) is used to calculate the exciting coefficient of array elements. The most important parameter, which involves the accuracy and complexity of calculation, is the sampling rate of the desired pattern. Classic...

The use of antenna arrays at emission and reception seems to represent a prominent solution for future wireless systems, it improves data rates and enhances the quality of service. The performance of these systems depends mainly on the propagation channel. Therefore, channel’s characterization and modeling are crucial. In this document, we present a MIMO (Multiple Input Multiple Output) channel...

A design problem of non-uniform circular antenna arrays for maximum reduction of both the side lobe level (SLL) and first null beam width (FNBW) is dealt with. This problem is modeled as a simple optimization problem. The method of Firefly algorithm (FFA) is used to determine an optimal set of current excitation weights and antenna inter-element separations that provide radiation pattern with m...