Antenna Design and Optimization

A general analysis of a frequency diverse transmit array antenna with a periodic modulated pattern in range, angle and time is presented. This antenna array system makes a continuous scanning in range and angle without using any phase shifters. The scanning is achieved using the frequency diversity by inserting a smal…

Beamforming is a signal processing technique to steer, shape, and focus an electromagnetic (EM) wave using an array of sensors toward a desired direction. It has been used in many engineering applications, such as radar, sonar, acoustics, astronomy, seismology, medical imaging, and communications. With the advent of m…

• AHMET METE ELBİR

An efficient method based on bees algorithm (BA) for the pattern synthesis of linear antenna arrays with the prescribed nulls is presented.Nulling of the pattern is achieved by controlling only the amplitude of each array element.Numerical examples of Chebyshev pattern with the single, multiple and broad nulls imposed…

• MURAT ONAY

An efficient method based on bees algorithm (BA) for the pattern synthesis of linear antenna arrays with the prescribed nulls is presented.Nulling of the pattern is achieved by controlling only the amplitude of each array element.Numerical examples of Chebyshev pattern with the single, multiple and broad nulls imposed…

The source and receiver plane characteristics of flat topped (FT) beam propagating in turbulent atmosphere are investigated. To this end, source size, beam power and M(2) factor of source plane FT beam are derived. For a turbulent propagation medium, via Huygens Fresnel diffraction integral, the receiver plane intensi…

• ÇAĞLAR ARPALİ

Frequency diverse arrays (FDA) are recently introduced. Not only the phased array and frequency scanning arrays, but also FDA provides electronic beam scanning ability. Moreover, electronic beam scanning is provided without the use of phase shifters or vector modulators. Nevertheless, reported studies on this concept…

A method for calculating the resonant frequency of electrically thin and thick rectangular microstrip antennas, based on the backpropagation multilayered-perceptron network, is presented. The method can be used for a wide range of substrate thicknesses and permittivities, and is useful for the computer-aided design (C…

• ŞEREF SAĞIROĞLU

Analytical formulas are derived for the average irradiance and the degree of polarization of a radially or azimuthally polarized doughnut beam (PDB) propagating in a turbulent atmosphere by adopting a beam coherence-polarization matrix. It is found that the radial or azimuthal polarization structure of a radially or a…

A method for calculating the resonant frequency of electrically thin and thick rectangular microstrip antennas, based on the backpropagation multilayered-perceptron network, is presented. The method can be used for a wide range of substrate thicknesses and permittivities, and is useful for the computer-aided design (C…

In this work, an array thinning procedure is introduced for nonuniform amplitude time-modulated linear arrays (TMLAs). Differential evolution algorithm (DE) is used for both thinning and time modulation (TM) of the given array to suppress the sidelobes and sidebands with fewer elements so as to achieve desired far-fie…

• ERTUĞRUL AKSOY

A useful and flexible method based on the tabu search algorithm for the pattern synthesis of linear antenna arrays with the prescribed nulls is presented. Nulling of the pattern is achieved by controlling the amplitude-only and both the amplitude and phase of each array element. To show the versatility of the present…

This paper presents a bacterial foraging algorithm (BFA) for null steering of linear antenna arrays by controlling only the element amplitudes.The BFA is a new evolutionary computing technique based on the foraging behavior of Escherichia (E.) coli bacteria in human intestine.To show the accuracy and flexibility of th…