Volkan Akan

Bio: Volkan Akan is an academic researcher from Scientific and Technological Research Council of Turkey. The author has contributed to research in topics: Coplanar waveguide & Dipole antenna. The author has an hindex of 6, co-authored 27 publications receiving 87 citations. Previous affiliations of Volkan Akan include Hacettepe University.

A simple formulation for quasistatic solutions of elliptical, cylindrical and asymmetrical coplanar strip lines

Abstract: Simple, analytic CAD-oriented expressions for calculating the quasistatic TEM parameters of asymmetrical coplanar strip lines (ACPS), elliptical coplanar strip lines (ECPS), and cylindrical coplanar strip lines (CCPS) using the conformal mapping method are presented. Derived expressions are accurate and very simple to use in antennas and microwave integrated circuits. Comparisons are also made between the results of this paper and ones available in the literature. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 18–21, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20032

Quasi-static solutions of multilayer elliptical, cylindrical coplanar striplines and multilayer coplanar striplines with finite dielectric dimensions - asymmetrical case

Abstract: In this paper, fast, accurate, and simple analytic closed-form expressions are presented in order to calculate the quasi-TEM parameters of multilayer elliptical coplanar stripline (CPS), multilayer cylindrical CPS, and multilayer CPS, with finite dielectric dimensions by using conformal mapping techniques. The obtained computer-aided-design-oriented expressions are quite accurate and easy to apply in designing microwave integrated circuits and antenna applications. The results have also been compared with the ones of another conformal mapping method available in the literature and also confirmed analytically.

Analytical attenuation calculation of asymmetrical coplanar waveguide with finite‐extent ground planes for coplanar waveguide mode

Abstract: In this study, fast and new analytical formulations have been presented for correct loss calculations in asymmetrical coplanar waveguides (CPW) with finite-extent ground planes for CPW mode. To generalize loss analysis for CPW mode, not only gaps but also finite ground planes are assumed as asymmetric. Moreover, dielectric thickness and ground plane widths are considered as finite for this transmission line. Another important concept presented in this article is that the proposed expressions are easily applicable for CAD platforms. Through the analyses, conformal mapping techniques (CMT) have been employed. The obtained results in this work have been compared with the results of other similar studies (spectral domain method, mode matching, etc.) available in the literature. These comparisons indicate that the expressions developed in this study are found to be more suitable for accurate calculations of loss as well as the characterization of asymmetrical CPW with finite-extent ground planes. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2082–2087, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22709

Quasistatic TEM characteristics of multilayer elliptical and cylindrical coplanar waveguides

Abstract: loss is 1.6 dB within 13.3–13.9 GHz. The maximum return loss is 26.1 dB at 13.5 GHz and the 3-dB fractional bandwidth is 8.1%. 4. CONCLUSION A new type of microstrip bandpass filter using one isoscelestriangle-patch resonator with two transmission zeros has been presented. It has been verified by the simulated and measured results. The two transmission zeros are located at 11.7 and 15.9 GHz with levels of 45.7 and 44.9 dB, respectively. This filter has 8.1% of 3-dB bandwidth and 26.1 return loss at 13.5 GHz. The new filter requires only one patch resonator, instead of the con

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

An Array Antenna for Both Long- and Medium-Range 77 GHz Automotive Radar Applications

Abstract: A novel array antenna with a flat-shoulder shaped radiation pattern is proposed as the transmitting antenna for 77 GHz automotive radar application. When it is used in an automotive radar comprising one transmitter and multiple identical receivers, it can meet the demands of both long-range and medium-range detections without switching the operation mode back and forth between the long-range radar scenario and the medium-range radar scenario. The proposed antenna concept is fully introduced to explain its mechanism. An unconventional array was synthesized to achieve the desired flat-shoulder shaped radiation pattern. Prototype of the proposed array antenna was also designed according to the array synthesis result, which consists of several linear series-fed patch arrays and a substrate-integrated waveguide power and phase distributing network. Fabrication and measurement of the prototype array antenna were completed, showing a good agreement between the measured data and the synthesized as well as the simulation results, thereby validating the design.

Broadband Filtering Power Dividers Using Simple Three-Line Coupled Structures

Abstract: Three-line coupled structure (TLCS) is employed in the design of the filtering power divider (FPD) to achieve a broad fractional bandwidth and good frequency selectivity in this paper. A detailed theoretical analysis of the proposed FPD is presented by using the calculated method of impedance matrix deduction. To validate the design concept, the proposed initial FPD prototype is electromagnetically simulated, whose performance shows good consistency with that of the proposed theoretical calculation. In addition, a simple quasi-lumped impedance transformer is introduced near the input port to further improve the matching status of the FPD. These two above-mentioned FPDs are both designed with center frequencies of 2.42 GHz and 3-dB fractional bandwidths of over 82.6%, the latter one of which is fabricated and tested. Comparisons between the simulated and measured results are presented with good agreement to verify the calculated predictions.

Analysis and Synthesis of Double-Sided Parallel-Strip Transitions

Abstract: Antenna feeders, mixers, and filters made in double-sided parallel-strip technology usually must be adapted to unbalanced lines like the microstrip structure, needing transitions from asymmetric to symmetric waveguides (baluns). In this paper, we propose a new method for the evaluation of a generic tapered balun based on a conformal-mapping technique and an integral equation. This method, along with the use of an optimization technique such as genetic algorithms, allows for quick evaluation of the return losses of any tapered balun and the synthesizing of specific shapes to achieve desired responses in terms of return losses or impedance values.

Quasi-Static Models Based on Artificial Neural Neworks for Calculating the Characteristic Parameters of Multilayer Cylindrical Coplanar Waveguide and Strip Line

Abstract: In this paper, two different neural models are proposed for calculating the quasi-static parameters of multilayer cylindrical coplanar waveguides and strip lines. These models were basically developed by training the artificial neural networks with the numerical results of quasi-static analysis. Neural models were trained with four different learning algorithms to obtain better performance and faster convergence with simpler structure. When the performances of neural models are compared with each other, the best test results are obtained from the multilayered perceptrons trained by the Levenberg- Marquardt algorithm. The results obtained from the neural models are in very good agreements with the theoretical results available in the literature.