Nonplanar trapezoidal tooth log-periodic antennas: Design and electromagnetic modeling

Nonplanar trapezoidal tooth log-periodic (LP) antennas are investigated by combining the wisdom of theoretical design procedures with the power of accurate numerical simulation environments. Once the theoretical design is completed, electromagnetic simulations employing accurate integral equation solvers are utilized to test and correct the original design. A two-element array of trapezoidal tooth LP antennas is designed. The array features beam-steering ability as a novelty, in addition to frequency independence and higher directivity. Beam steering is achieved by optimizing the excitation coefficients of the two LP antennas.


Modeling and synthesis of circular-sectoral arrays of log-periodic antennas using multilevel fast multipole algorithm and genetic algorithms
Ergül, Özgür Salih (American Geophysical Union (AGU), 2007-06-19)
Circular-sectoral arrays of log-periodic (LP) antennas are presented for frequency-independent operation and beam-steering capability. Specifically, nonplanar trapezoidal tooth LP antennas are considered in a circular array configuration, where closely spaced antennas occupy a sector of the circle. Electromagnetic interactions of the array elements, each of which is a complicated LP antenna structure, are rigorously computed with the multilevel fast multipole algorithm (MLFMA). Genetic algorithms (GAs) are ...
Sectorized approach and measurement reduction for mutual coupling calibration of non-omnidirectional antenna arrays
Aksoy, Taylan; Tuncer, Temel Engin (American Geophysical Union (AGU), 2013-03-01)
Mutual coupling calibration is an important problem for antenna arrays. There are different methods proposed for omnidirectional antennas in the literature. However, many practical antennas have non-omnidirectional (NOD) characteristics. Hence, the previous mutual coupling calibration methods cannot be applied directly since the mutual coupling matrix of an NOD antenna array has angular dependency. In this paper, a sectorized approach is proposed with a transformation matrix for mutual coupling calibration ...
Local Primitive Pattern for the Classification of SAR Images
AYTEKİN, orsan; KOÇ, mehmet; Ulusoy, İlkay (Institute of Electrical and Electronics Engineers (IEEE), 2013-04-01)
This paper proposes a new method for the classification of synthetic aperture radar (SAR) images based on a novel feature vector. The method aims at combining the intensity information of pixels with spatial information and structural relationships. Unlike classical approaches which define a static neighborhood via a rectangular moving window of predefined size and relate spatial information for each center pixel to all the pixels within that window, the local primitives (LPs) proposed in this study provide...
Phonon dispersions and elastic constants of disordered Pd-Ni alloys
Kart, SO; Tomak, Mehmet; Cagin, T (Elsevier BV, 2005-01-31)
Phonon frequencies of Pd-Ni alloys are calculated by molecular dynamics (MD) simulation. Lattice dynamical properties computed from Sutton-Chen (SC) and quantum Sutton-Chen (Q-SC) potentials as a function of temperature are compared with each other. We present all interatomic force constants up to the 8th nearest-neighbor shell obtained by using the calculated potential. Elastic constants evaluated by two methods are consistent with each other. The transferability of the potential is also tested. The result...
A new neural network approach to the target tracking problem with smart structure
Caylar, Selcuk; Leblebicioğlu, Mehmet Kemal; Dural, Guelbin (American Geophysical Union (AGU), 2006-10-03)
[1] A modified neural network - based algorithm ( modified neural multiple-source tracking algorithm (MN-MUST)) is proposed for real-time multiple-source tracking problem. The proposed approach reduced the input size of the neural network without any degradation of the accuracy of the system for uncorrelated sources. In addition, a spatial filtering stage that considerably improves the performance of the system is proposed to be inserted. It is observed that the MN-MUST algorithm provides an accurate and ef...
Citation Formats
Ö. S. Ergül, “Nonplanar trapezoidal tooth log-periodic antennas: Design and electromagnetic modeling,” RADIO SCIENCE, pp. 0–0, 2005, Accessed: 00, 2020. [Online]. Available: