Mehmet Duyar

Analyses of elliptical coplanar coupled waveguides and coplanar coupled waveguides with finite ground width

In this paper, the quasi-TEM characteristic parameters of elliptical coplanar coupled waveguides and coupled coplanar waveguide with a finite ground width configuration are presented and analyzed. Computer-aided design (CAD)-oriented fast, simple, and accurate analytic formulas are derived by using conformal mapping techniques, which provide satisfactory accuracy at microwave frequencies and lead to closed-form analytical solutions suitable for CAD software packages. The results for the odd- and even-mode characteristic impedance, effective dielectric constant, and coupling coefficient have been computed by these formulas. Good agreement between the present results and published results is observed. For the planar case, simulations have also been undertaken with Sonnet electromagnetic-circuit solver software. The computed results agree well with those of the simulation ones.

Conductor loss calculation of elliptical, cylindrical coplanar waveguides and coplanar waveguides with finite conductor thickness

In this paper, new and fast analytical formulations have been presented for conductor loss calculations of elliptical (ECPW) and cylindrical coplanar waveguide (CCPW) with finite conductor thickness. These expressions are derived using conformal mapping techniques (CMT) and the validity of them is established by comparing the numerical results in the literature. These comparisons indicate that for the same conductor thickness the conductor losses of elliptical and cylindrical coplanar waveguide are higher than the conductor losses of coplanar waveguide presented in (1). Calculation method developed in this study is an extension of the approximate technique proposed by Ghione (1).

DESIGNS AND ANALYSES OF SOME RF/MICROWAVE PASSIVE ELEMENTS ON CYLINDRICAL CPWS

DESIGNS AND ANALYSES OF SOME RF/MICROWAVEPASSIVE ELEMENTS ON CYLINDRICAL CPWSV. AkanCommunication System GroupTUBITAK Space Technologies Research InstituteODTU KampusuInonu Bulvari, TR-06531, Ankara, TurkiyeM. DuyarRepublic of Turkiye Ministry of Industry and TradeAnkara, TurkiyeE. YazganDepartment of Electrical and Electronics EngineeringHacettepe UniversityTR-06800, Ankara TurkiyeM. BayrakFaculty of EngineeringDepartment of Electrical and Electronics EngineeringSelcuk UniversityKonya, TurkiyeAbstract—In this article, designs and analyses of several CCPW(Cylindrical CPW) discontinuities have been realized as microwavereactive elements. The quasi-TEM characteristic parametersof CCPWs have been obtained by CMT (Conformal MappingTechniques) which provide satisfactory accuracy at microwavefrequencies and lead to closed-form analytical solutions suitablefor CAD software packages. Then these discontinuities have beensimulated in CST Microwave Studio 2006 in order to obtaininductance, capacitance and also input impedance versus frequencyand physical dimensionsof the elements. The results show that CCPW

Analysis of cylindrical conductor-backed coplanar waveguides

CAD-oriented closed-form expressions are presented for calculating the quasistatic parameters of a conductor-backed coplanar () waeguide CBCPW on a cylindrical substrate. The effect of the cura- ture on the quasistatic parameters is also discussed by using the formulas deried by the conformal mapping techniques. Furthermore, comparisons are made between the present results and the results aailable in the literature for CBCPW on a planar substrate and microstrip on a cylindri- cal substrate. 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 144146, 2000.

ANALYSIS OF COPLANAR-COUPLED LINES ON A CYLINDRICAL SUBSTRATE

CAD-oriented closed-form expressions are presented for calculating the quasistatic TEM parameters of coplanar-coupled lines on a cylindrical substrate. The effect of the cur ature on the quasistatic parameters is discussed by using the formulas deri ed by the conformal mapping techniques. Comparisons ha e also been made between the present results and the results a ailable in the literature for coplanar-coupled lines on a planar substrate. The results of this paper are in ery good agreement with the results deri ed by the conformal mapping technique and the spectral-domain method for the planar one. 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 187 190, 2000.

Analysis of a cylindrical coupling structure

Coupled lines perpendicular to their cylindrical ground plane embedded in a cylindrical structure are proposed and analyzed. CAD-oriented analytic formulas for inestigating the quasistatic mode parameters and the coupling properties are deried with the een)odd mode analysis method based on the quasi-TEM approximation. Calcu- lated mode impedances and coupling coefficients are obsered to be sensitie to cylindrical curature, especially for largeralues of the spacing in the ground plane. Calculated results are compared with those obtained for a corresponding planar coupling structure. Q 1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 298)301, 1999.