Cylindrical Coplanar Waveguide Research Articles

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).

QUASI-STATIC MODELS BASED ON ARTIFICIAL NEURAL NEWORKS FOR CALCULATING THE CHARACTERISTIC PARAMETERS OF MULTILAYER CYLINDRICAL COPLANAR WAVEGUIDE AND STRIP LINE

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.

Full-wave analysis for propagation characteristics of cylindrical coplanar waveguides with finite thickness of conductor

A full-wave analysis by the extended spectral-domain approach is successfully applied to solve the cylindrical coplanar-waveguide problem. The analysis incorporates the effects of the edge singularities properly and can afford the efficient and accurate calculation method for the characteristic impedances in addition to the phase constants of cylindrical coplanar waveguides (CCPWs) with zero- and finite-thickness conductor. The numerical results obtained by this method have revealed the effect of conductor thickness on the characteristics of higher order modes, as well as the odd and even dominant modes of CCPWs for the first time.

Coplanar waveguide-fed slot antennas on cylindrical substrates

This paper describes cylindrical coplanar waveguide (CCPW)-fed slot and folded slot antennas encompassing cylindrical substrates. Using a 1.27 cm diameter Teflon substrate, antennas that operate around 7 GHz have been realized with gains of 1.5 dB (slot) and 2.8 dB (folded slot). The antennas have a well-defined pattern null of 8 dB along the side of the CCPW feedline. A 1.6 GHz slot antenna on a 1.27 cm diameter alumina substrate was also fabricated using a novel direct-write technique, and shown to have comparable performance characteristics. The results include measured data and simulated data using a 3D cylindrical finite difference time domain (FDTD) code.

Quasistatic TEM characteristics of multilayer elliptical and cylindrical coplanar waveguides

AbstractSimple analytic CAD‐oriented expressions are presented for calculating the quasistatic TEM parameters of multilayer elliptical coplanar waveguides (ME CPWs) and multilayer cylindrical coplanar waveguides (MC CPWs) by using the conformal mapping method. It is shown that the derived expressions are accurate and very simple for use in related applications. Comparisons have also been made between the results of this paper and those available in the literature. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 317–322, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20290

Improved coplanar waveguide (CPW) bandstop filter with photonic bandgap (PBG) structure

AbstractA new doubly tapered photonic bandgap (DT‐PBG) technique in both planar and cylindrical coplanar waveguide (CCPW) structures is proposed and analyzed. The DT‐PBG structure of a coplanar waveguide (CPW) bandstop filter not only can reduce the passband ripple but can also increase the stopband rejection bandwidth without degrading the upper passband loss. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 274–277, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11036

Dispersion analysis of multilayer cylindrical transmission lines containing magnetized ferrite substrates

Recently, there has been a growing interest in using cylindrical transmission lines that contain magnetized ferrite material in a variety of applications. In this paper, the finite-difference time-domain (FDTD) method (in cylindrical coordinates) and the spectral-domain analysis (SDA) are used to calculate the propagation characteristics of cylindrical transmission lines that contain magnetized ferrite material. The magnetization can be either in the longitudinal or azimuthal directions. Specifically, the cylindrical microstrip line, and the cylindrical coplanar waveguide printed on magnetized ferrite substrate are analyzed. Both the FDTD and SDA results are in very good agreement. In addition, the results are compared to those of planar structures by taking the radius of the substrate to be large enough such that the curvature effect is negligible.

Finite difference time domain analysis of cylindrical coplanar waveguide circuits

There is a growing interest in using cylindrical transmission line structures in microwave applications. In this paper, the finite difference time domain (FDTD) method is used to characterize several three-dimensional cylindrical coplanar waveguide (CCPW) geometries. Specifically, a CCPW series stub and a three-section CCPW filter are studied both theoretically and experimentally. Moreover, CCPW gap is characterized and the FDTD results are compared to those obtained using conformal mapping techniques. Effective absorbing boundary conditions are employed to truncate the FDTD mesh at the end walls and the outer radial boundary.

Two-dimensional finite difference time domain analysis of cylindrical transmission lines

Recently, there has been a growing interest in the use of cylindrical transmission lines in a variety of applications. In this paper, the finite difference time domain (FDTD) method is used to calculate the propagation characteristics of cylindrical transmission lines. An efficient two-dimensional (2D) FDTD algorithm is developed by projecting the three-dimensional FDTD cell in the cylindrical coordinates on to the r−φ plane. An effective absorbing boundary condition is employed to truncate the mesh at its outer radial boundary. In addition to a detailed description of the developed 2D-FDTD algorithm, extensive numerical results are derived for different cylindrical transmission lines and compared with data available in the literature. Specifically, the newly proposed cylindrical coplanar waveguide is studied both theoretically and experimentally.

Quasi-static analysis of asymmetric cylindrical coplanar waveguides with finite-extent ground

Quasi-static characteristics of asymmetric cylindrical coplanar waveguides (CCPWs) with finite-extent ground are analysed using the conformal mapping technique. Closed-form expressions for the effective permittivity and characteristic impedance of inside and outside asymmetric CCPWs with finite ground are derived. Using these expressions, the effect of various parameters on the characteristics of CCPWs is studied.

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 cylindrical transmission lines with the finite-difference time-domain method

In this paper, the finite-difference time-domain (FDTD) method is used to calculate the propagation characteristics of cylindrical transmission lines. An efficient two-dimensional FDTD algorithm is developed by projecting the three-dimensional FDTD cell in the cylindrical coordinates onto the r-/spl phi/ plane. An effective absorbing boundary condition is employed to truncate the mesh at its outer radial boundary. Numerical results are derived for different cylindrical transmission lines and compared to data available in the literature. Specifically, the newly proposed cylindrical coplanar waveguide is studied both theoretically and experimentally.

CAD model of gap in cylindrical coplanar waveguide

Closed-form expressions for the capacitances of the equivalent p-network of a gap in the central strip of a cylindrical coplanar waveguide (CCPW) with asymmetric slot widths are derived using the partial capacitance approach and conformal mapping method (CMM). Good agreement is observed between the CMM results and those obtained using the finite difference time domain technique.

Quasistatic analysis of cylindrical coplanar waveguide with multilayer dielectrics

Quasistatic analysis of cylindrical coplanar waveguide with multilayer dielectrics

Quasistatic analysis of cylindrical coplanar waveguide with multilayer dielectrics

CAD-oriented analytic formulas are given for calculating the quasistatic parameters of the cylindrical CPW with three dielectrics. The effects of the dielectric materials on the quasistatic characteristics are investigated by using conformal mapping techniques. The calculated results are compared with those obtained for a corresponding planar CPW and a cylindrical CPW with a single dielectric. The curvature effects on the quasistatic characteristics are discussed. Moreover, the present expressions can also be extended to the cylindrical CPW with multilayer dielectrics. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 303–314, 1998.

Quasistatic analysis of cylindrical coplanar waveguide with multilayer dielectrics

Quasistatic analysis of cylindrical coplanar waveguide with multilayer dielectrics

Quasistatic solutions of cylindrical coplanar waveguides

Characteristics of cylindrical coplanar waveguides (CPWs) are analyzed with the use of a conformal mapping technique, in which quasistatic solutions of the effective relative permittivity and characteristic impedance of the cylindrical CPW are derived and calculated. Inside and outside cylindrical CPWs are studied, and curvature effects on the characteristics of CPWs are discussed. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14: 347–351, 1997.

Quasistatic solutions of cylindrical coplanar waveguides

Characteristics of cylindrical coplanar waveguides (CPWs) are analyzed with the use of a conformal mapping technique, in which quasistatic solutions of the effective relative permittivity and characteristic impedance of the cylindrical CPW are derived and calculated. Inside and outside cylindrical CPWs are studied, and curvature effects on the characteristics of CPWs are discussed. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14: 347–351, 1997.

Full-wave analysis of the effective relative permittivity of a coplanar waveguide printed inside a cylindrical substrate

The frequency-dependent dispersion characteristics of a coplanar wave-guide printed inside a cylindrical substrate are studied. A full-wave formulation incorporating the derived dyadic Green's function in a moment-method calculation is applied. The theoretical results are calculated and verified by the measurement, and the curvature effects on the dispersion characteristics of an inside cylindrical coplanar waveguide are discussed. © 1996 John Wiley & Sons, Inc.

Dispersion characteristics of cylindrical coplanar waveguides

A full-wave analysis of the coplanar waveguide (CPW) printed on a cylindrical substrate is presented, and the dispersion characteristics of the cylindrical CPW are studied. Numerical results of the effective relative permittivity are calculated using a Galerkin's moment-method calculation. Experiment is also conducted, and the measured data are in good agreement with the theory.