Modified Wolff Model Research Articles

Multilayer Cavity Model for Microstrip Rectangular and Circular Patch Antenna

We report an improved form of the cavity model called the modified Wolff model (MWM) to compute the resonance frequency, input impedance, bandwidth, efficiency, directivity, and radiation pattern of a multilayer rectangular and circular patch antenna in the lossy iso/anisotropic medium. We compare the MWM against the experimental results obtained from the several sources and also against the computed results of the method-of-moments–based Ensemble. The MWM is revealed as an accurate, fast, and reliable model for computation of all these parameters.

Accurate Determination of Input Parameters of Rectangular Microstrip Patch Antenna on Thick Substrate and Comparision of Several Models

Theoretical models like standard cavity model, multiport cavity model (MCM), MOM-based commercial software, and Ensemble do not provide accurate results on the resonance frequency, input impedance, and bandwidth for the rectangular patch on the thick substrate (h > 0.05 λ g ). This paper reports an improved form of the cavity model called the modified Wolff model (MWM) that computes accurately these parameters of the rectangular patch on the thick substrate up to the substrate thickness 0.229 λ g . We also compare all of these models against the experimental results obtained from the several sources. The MWM comes out as the most accurate model for the computation of input parameters of the rectangular patch both on the thin and thick substrates also having anisotropy.

Determination of dielectric constant and loss‐tangent of substrate sheet using microstrip patch resonator

AbstractThis paper presents a new microstrip rectangular patch resonator based method to determine the dielectric constant and the loss tangent of a dielectric material in sheet form. Using an improved form of the cavity model, called the modified Wolff model (MWM), the present method extracts these two parameters from the measured resonance frequency and Q‐factor. The MWM takes care of all kind of losses in the patch, resulting in accurate determination of the dielectric constant and loss tangent of the substrate. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 175–179, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10549

Analysis of circular microstrip antennas on low‐ and high‐relative‐permittivity substrates

AbstractA simple and accurate cavity model called the modified Wolff model (MWM) is presented to compute the resonance frequency and input impedance of the circular microstrip antenna on the PTFE, alumina, and GaAs substrates. Results of the MWM show better agreement with the experimental results as compared to results of the commercial software; namely, the standard cavity model adopted in the PCAAD, the multiport cavity model (MCM), and the method‐of‐moments– (MOM) based Ensemble. The MWM works with high accuracy on both the thin and thick substrates and from microwave to millimeter‐wave range. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 75–80, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10377

Resonance frequency and bandwidth of rectangular microstrip antenna on thick substrate

We report an improved cavity model called modified Wolff model (MWM) to compute the resonance frequency of a rectangular patch antenna on the thick PTFE substrate (0.037/spl lambda//sub g/-0.229/spl lambda//sub g/). The MWM accounts for the effect of anisotropy and total losses on the resonance frequency, therefore it has a maximum deviation 2% against the experimental results. The previous cavity model, the multiport cavity model, and MOM based commercial software, Ensemble, compute resonance frequency with deviation between 4%-36%. Results on the bandwidth computed by these models have also been compared against the experimental results.

Input impedance of rectangular microstrip patch antenna with iso/anisotropic substrate-superstrate

The modified Wolff model (MWM), which is an improved version of the cavity model, is presented to compute the resonance frequency and input impedance of a rectangular microstrip patch antenna under the isotropic/anisotropic substrate-superstrate configuration. The model has accuracy better than 1.5% for both the resonance frequency and resonant resistance, as compared against the results of the method of moments (MOM) and experimental results.

Input impedance of probe‐fed multilayer rectangular microstrip patch antenna using the modified Wolff model

AbstractThe modified Wolff model (MWM)‐based cavity model is presented for the simple and accurate computation of the input impedance of a probe‐fed multilayer rectangular microstrip patch antenna. Results of the MWM are compared with both the experimental data and data of the MoM, with agreement within 1.5% for resonance frequency and within 0.15 for normalized input impedance. Further results are presented on the input impedance of a suspended rectangular microstrip patch antenna with a two‐layer superstrate. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 237–239, 2001.

Resonance frequency of anisotropicmultilayer rectangular microstrip patch using MWM

The resonance frequency of a multilayer anisotropic microstrip rectangular patch is determined by using the modified Wolff model (MWM formulation) of the cavity model. The model has a deviation of 1-2%, against the results obtained using spectral domain analysis (SDA).

Static capacitance of some multilayered microstrip capacitors

A new unified model, the modified Wolff model (MWM) is presented to determine the lumped capacitance of rectangular, circular, hexagonal and triangular patches on the single layer substrate and under the multilayer condition. Effect of the top shield on the lumped capacitance has also been determined. The MWM is the combination of Wolff-Knoppick model, TTL technique and single layer reduction (SLR) technique, The results of MWM have been compared against the results of SDA, FEM, dual integral method and other forms of the variational methods with accuracy between 0.5-5% for most shapes under various conditions. The present model has accuracy of SDA and other rigorous formulations. No single method has been used in the literature to determine the lumped capacitance of patches of several shapes under the multilayer and shielded condition. The MWM is fast even on the desktop computer. Thus, the model is suitable for a unified CAD for the MMIC applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Resonant frequencies of shielded rectangular and circular microstrip resonators

AbstractResonant frequencies of shielded rectangular and circular microstrip patches have been determined using the modified Wolff model (MWM). The model determines effect of top‐shield, side‐walls, and end‐walls on the resonant frequency. Results of the MWM have been compared to those of SDA and FEM. The MWM has an accuracy of 0.2% compared with experimental results. Numerically, the MWM is fast even on a desktop computer. The model is suitable for CAD applications. © 1995 John Wiley &amp; Sons, Inc.

Resonant frequency of uncovered and covered rectangular microstrip patch using modified Wolff model

A new model, called the modified Wolff model (MWM), is proposed to calculate the resonant frequency of a rectangular open microstrip patch, a patch with a dielectric superstrate and a patch inside a shielded enclosure. The model has also been applied to calculate resonant frequencies of higher-order modes. The dependence of resonant frequency on the various parameters and its accuracy are discussed using the MWM. Results obtained from MWM follow very closely the results from various forms of full-wave analysis, and in almost all cases they are within 0.5% of published experimental results for the fundamental mode and within 1.7% for higher-order modes. The method is computationally fast and efficient even on a desktop computer. The method could be used for other patches like circular, hexagonal and equilateral triangle.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Erratum: Modified Wolff model for determination of resonance frequency of dielectric covered circular microstrip patch antenna

Erratum: Modified Wolff model for determination of resonance frequency of dielectric covered circular microstrip patch antenna

Modified Wolff model for determination of resonance frequency of dielectric covered circular microstrip patch antenna

A new modified Wolff model (MWM) is proposed to calculate the resonance frequency of the circular covered and uncovered patch. For uncovered patches the calculated frequency using the MWM is within 0.5% of the measured value. For covered patch antennas, the MWM determines resonance frequency to within 1% of the results using from SDA.

Modified Wolff model for resonance frequency of covered rectangular microstrip patch antenna

A modified Wolff model is proposed to calculate the resonance frequency of a covered microstrip rectangular patch with the accuracy of spectral domain analysis. In most of the cases the calculated frequency is within 0.6% of the measured value. The modified Wolff model can be used for multilayered substrate and multilayered cover. The original Wolff model determines the resonance frequency of the uncovered microstrip patch.