Conductor Backing Research Articles

Characterization of Conductor-Backed Dielectric Substrates Using a Novel Resonance-Based Method

A novel microwave resonance-based method is presented in this paper for complex permittivity characterization of conductor-backed materials. The proposed method constructs a nondestructive technique for extracting complex permittivity proprieties of thin conductor-backed dielectric substrates. The conductor-backed sample is integrated with a planar resonator by employing the conductor backing plane as a grounding surface to the resonance structure. The planar resonator is a finite circular conductive patch hosting a complementary split ring resonator (CSRR). The proposed method exhibits high sensitivity to the conductor-backed material measurements and characterization. Experimental validation of the numerical analysis of the proposed method is provided. Commonly used conductor-backed dielectric substrates with a wide range of relative permittivity values ranging from 2.2 to 10.2 were characterized using the proposed method. Compared to the state of the art material characterization methods using planar resonators, the presented method provides a nondestructive technique for complex permittivity characterization of thin conductor-backed dielectric substrates with high sensitivity to the dielectric properties.

A novel CB ACS-fed dual band antenna with truncated ground plane for 2.4/5 GHz WLAN application

A novel conductor backed asymmetric coplanar strip (CBACS) fed dual band antenna which is suitable for wireless local area network is presented in this paper. The proposed antenna is composed of inverted L-shaped exciting strip, a lateral ground plane and a modified truncated ground plane on the backside with overall dimension of about 25mm×17.5mm×1.6mm. The proposed design comprises monopole patch with asymmetric coplanar ground plane with conductor backing exhibit dual band of response with measured bandwidth of return loss ≤−10dB is 2.30–2.55GHz and 4.06–6.65GHz which cover all the WLAN bands (2.4/5.2/5.8GHz). The parametric studies indicate that operating frequencies and wider bandwidth are determined by the dimension of the ground plane at the top and bottom. The proposed antenna covers IEEE 802.11a/b/HYPERLAN-2/RFID band with good radiation characteristics. The measurement of proposed antenna that has been printed on an FR4 substrate with dielectric constant 4.4 yields good conformity between simulated results. The proposed structure is simulated using the method of moment based electromagnetic solver IE3D version 15.10.

A Planar and Subwavelength Open Guided Wave Structure Based on Spoof Surface Plasmons

A planar and compact open waveguiding structure based on spoof surface plasmon polaritons (SPPs) was demonstrated. For practicality, instead of the well-known wire medium, the uniaxial strip medium (USM) was proposed and used as the effective bulk material with a negative dielectric constant to support the spoof SPP modes. The relevant formulations, including the modal dispersion relations and the formulation for the waves in a multilayer anisotropic structure, are analytically presented in this paper. Interestingly, instead of taming and suppressing the spatial dispersion (SD), which had been done in most past studies, SD was exploited in the proposed structure to enhance the field confinement of the spoof SPP mode by approximately 41%. Moreover, the thickness of the USM slab could be reduced by 50%, using conductor backing and without perturbing the odd mode. This method and SD can help avoid electromagnetic interactions among various components of a multilayer printed circuit board structure and help miniaturize sensors or surface-wave waveguides in the microwave regime. In this study, the subwavelength thickness of the proposed structure was only 0.09 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at 1.34 GHz. Additionally, the propagation loss for such slow-wave structures has seldom been discussed analytically and quantitatively. In this study, through calculations and simulations, low attenuation constants in the spoof SPP propagation direction of the proposed structures were investigated. Finally, an experiment was conducted, and an extraction method for obtaining the required reflection spectrum from the measured S-parameter was developed.

ANN Synthesis Models Trained with Modified GA-LM Algorithm for ACPWs with Conductor Backing and Substrate Overlaying

Accurate synthesis models based on artificial neural networks (ANNs) are proposed to directly obtain the physical dimensions of an asymmetric coplanar waveguide with conductor backing and substrate overlaying (ACPWCBSO). First, the ACPWCBSO is analyzed with the conformal mapping technique (CMT) to obtain the training data. Then, a modified genetic-algorithm-Levenberg-Marquardt (GA-LM) algorithm is adopted to train ANNs. In the algorithm, the maximal relative error (MRE) is used as the fitness function of the chromosomes to guarantee that the MRE is small, while the mean square error is used as the error function in LM training to ensure that the average relative error is small. The MRE of ANNs trained with the modified GA-LM algorithm is less than 8.1%, which is smaller than those trained with the existing GA-LM algorithm and the LM algorithm (greater than 15%). Lastly, the ANN synthesis models are validated by the CMT analysis, electromagnetic simulation, and measurements.

Diffraction by a Double-negative Metamaterial Layer with PEC Backing

This work deals with the difiraction problem originated by a plane wave normally impinging on the edge of a lossy, isotropic and homogeneous double-negative metamaterial layer with a perfect electric conductor backing. The here proposed solution is obtained by using a Physical Optics approximation of the electric and magnetic surface currents in the radiation integral and by performing a uniform asymptotic evaluation of this last. The resulting difiraction coe-cients contain the Geometrical Optics response of the structure and the transition function of the Uniform Theory of Difiraction. The accuracy of the solution is well assessed by comparisons with Comsol Multiphysics r results.

Photothermal wave propagation in media with thermal memory

Generalized expressions of photothermal wave propagation are derived, including the thermal memory effects. The focus is on optically opaque solids. The models of photothermal spectra based on the suggested descriptions are discussed for a semi-infinite sample and two limiting cases of backing—an ideal insulator and an ideal conductor backing. The results are compared with previous models.

Analysis of line to line coupled coplanar waveguides with W-shaped conductor backing using conformal mapping method

A W-shaped microshield coupled parallel coplanar waveguide (CP CPW), which is a new type of CP CPW, is proposed. Closed-form expressions are presented for calculating the quasistatic parameters of this coupled structure by using conformal mapping techniques. The effect of the W-shaped conductor backing on the coupling between CPWs is also discussed. Comparisons are made between the present numerical results and the results available in the microwave literature for CPW V-shaped microshield coupled lines (CWVMCLs) and CP CPWs with a flat conductor backing. In addition, the coupling coefficient of the coupled CPWs is shown to be significantly lower than that of the CWVMCLs in the literature. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 354–359, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce10035

Cad Formulas, Their Inverses and Interrelations for Microstrip, Cpw Lines Without and With a Backing Ground Plane, By Successive Synthetic Asymptotes

This paper derives simple CAD formulas of microstrips, coplanar waveguides (CPW) without and with a backing ground plane. Both analysis and design formulas, in pairs, of the three lines, can be derived from just one technique: the synthetic asymptote. This novel asymptotic technique ensures a maximum error of 4% or less with no limits on the possible parameter values. The technique also shows that a combination of the first two pairs of formulas of the above actually forms the third pair of formulas in a bootstrapping succession. It is possible to get smaller errors than above with formulas including a series of artificial coefficients. This is not done so as to maintain the simplicity of the formulas and to emphasize the insights to the interrelations between the different lines over full ranges of parameter values. Physical insights, such as the microstrip and CPW combining into the CPW with conductor backing, are very helpful in the initial design choices and estimates in an RF circuit. They are lacking at the present time.

Analysis of coupled coplanar waveguides with V-shaped conductor backing using conformal-mapping method

The V-shaped microshield coupled parallel coplanar waveguides, a new type of the coupled parallel coplanar waveguide (CP CPW), is proposed. Closed-form expressions are presented for calculating the quasistatic parameters of this coupled structure by using conformal-mapping techniques. The effect of the V-shaped conductor backing on the coupling between CPWs is also discussed. Comparisons are made between the present numerical results and the spectral-domain method results available in the literature for a conventional CP CPW. In addition, the coupling coefficient of the present coupled CPW is shown to be significantly lower than that of a coupled parallel CPW.

Quasi-TEM analysis of broadside-coupled V-shaped microshield coplanar waveguides

A new type of broadside-coupled CPWs (BC CPWs) is proposed using a V-shaped microshield CPW. Closed-form expressions are presented for calculating the quasistatic parameters of this coupled structure by using conformal mapping techniques. The effect of the V-shaped conductor backing on the quasistatic parameters and the coupling between CPWs are also discussed. Comparisons are made between the present numerical results and the results available in the literature for general BC CPWs. The coupling coefficient of the present BC CPWs is shown to be significantly lower than that of general BC CPWs. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 229–232, 2000.

Effect of upper shielding and conductor backing on quasistatic parameters of asymmetric coplanar waveguides

Effect of upper shielding and conductor backing on quasistatic parameters of asymmetric coplanar waveguides

Effect of upper shielding and conductor backing on quasistatic parameters of asymmetric coplanar waveguides

CAD-oriented analytic formulas are presented for calculating the quasistatic parameters of the conductor-backed asymmetric coplanar waveguide (ACPW), the ACPW with upper shielding, and the conductor-backed ACPW with upper shielding using conformal mapping techniques. The effect of the presence of the upper shielding and the conductor-backing on the quasistatic TEM parameters is discussed. It is also presented that the expressions derived in this work can be used for calculating the quasistatic parameters of various symmetric and asymmetric CPWs. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 394–402, 1999

Analysis of asymmetric coplanar waveguide with conductor backing

This paper presents an analysis of the asymmetric conductor-backed coplanar waveguide by means of conformal mapping techniques. The effective permittivity, characteristic impedance, and electric-field strength are given. The field patterns are also plotted.

Quasistatic analysis of arbitrary coplanar waveguide structures by combination of conformal mapping and finite-difference methods

To evaluate the quasistatic parameters of arbitrary coplanar waveguide (CPW) structures, a new numerical approach based on the combination of the conformal mapping technique and the finite-difference method is presented. The validity and versatility of the proposed method have been demonstrated by application in three kinds of CPWs: 1) with conductor backing, 2) with finite-extent substrate, and 3) with an enclosed shielding box. Compared with the data published in the literature, the numerical results of this method show very good agreement. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 16: 149–154, 1997.

Effect of conductor backing on the line-to-line coupling between parallel coplanar lines

A good estimate of the coupling effect between parallel coplanar waveguide (CPW) lines is important, especially for monolithic microwave integrated circuit (MMIC) applications where unnecessary crosstalk between conductors could be a serious problem. This paper shows how these coupling parameters may be analytically obtained in the presence of the back-face metallization. Closed-form formulas are developed for evaluating the quasi-TEM characteristic parameters based upon the conformal-mapping method (CMM). Very good agreement is observed between the values produced by these formulas and by a spectral-domain method (SDM).

Analysis and application of nonleaky uniplanar structures with conductor backing

Novel conductor-backed uniplanar structures, including the nonleaky CPW and slotline, are analyzed and applied to the active antenna design. Both the spectral domain analysis and finite-difference time-domain techniques are used to simulate these circuits and to justify the numerical results. The measured gain of the novel active antenna is 1.7 dB higher than the conventional CPW antenna due to the unidirectional radiation of conductor-backed circuits. © 1996 John Wiley & Sons, Inc.

Analysis and application of nonleaky uniplanar structures with conductor backing

Analysis and application of nonleaky uniplanar structures with conductor backing

Compact oscillating slot loop antenna with conductorbacking

An oscillating slot loop antenna working at 4.02 GHz is realised with a low cost GaAs MESFET. A conductor backing is used to obtain a unidirectional radiation pattern.

Non-leaky coplanar (NLC) waveguides with conductor backing

In this paper, we present a structure called a non-leaky coplanar (NLC) waveguide with conductor backing. It is a multilayered structure with two possible configurations. The spectral domain approach with a complex root searching procedure is used to investigate leakage phenomena. The simulation results confirm that the leakage in conductor-backed coplanar waveguide (CBCPW) occurs in the form of wave in the parallel plate waveguide with infinite width. The results show that the leakage in the multilayered structure can be removed if the geometrical and material parameters of the structure are chosen appropriately. Experiments were carried out to investigate the transmission of these structures. It was found that the resonance in the transmission of finite-width conductor-backed coplanar waveguide (FW-CBCPW) is caused by the energy leakage from the dominant CPW mode. The resonance is eliminated in the NLC waveguides. These NLC waveguides are feasible and practical in the uniplanar MMIC design due to their planar nature. >

Wideband transition form conductor-backed coplanar waveguide to modified coplanar stripline using multiple substrates

The Letter presents a wideband and low-loss transition from conductor-backed coplanar waveguide to a modified, conductor-backed coplanar strip transmission line. The measured insertion loss is less than 1 dB up to 4.8 GHz and the return loss is greater than 12 dB. To reduce undesired modes two dielectric layers are used between the circuit and the conductor backing.