Single Layer Reduction Research Articles

Computation of static and frequency-dependent line parameters of multilayer CPW using static SDA and single layer reduction method

We reformulate the quasi-static SDA applicable to a lossy multilayer CPW that also incorporates two-layer model of a conductor thickness and the concept of effective permeability due to magnetic field penetration in an imperfect conductor. The present static SDA formulation accounts for the effect of conductor thickness and low frequency dispersion on computation of quasi-static effective relative permittivity and characteristic impedance. The paper also presents the single layer reduction (SLR) formulation and circuit model to compute frequency dependent line parameters of a lossy multilayer CPW. The accuracy of formulation is comparable to that of HFSS and CST, without using complex and time consuming full-wave methods. The results of CST for εeff, Z0, αd, αc of multilayer CPW, in the frequency range 1–100 GHz, deviate from results of HFSS up to 1.26%, 2.78%, 11.75%, and 18.7%, respectively; whereas corresponding deviations of present formulation are up to 1.56%, 2.4%, 3.04%, and 7%. The results of the present formulation and HFSS are also compared against the available experimental results. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:18–29, 2014.

MODELING FOR DISPERSION AND LOSSES OF MULTILAYER ASYMMETRIC CPW ON ISO/ANISOTROPIC SUBSTRATE

In this paper, we reformulate the quasi-static spectral domain analysis (SDA) applicable to a lossy anisotropic multilayer asymmetric coplanar waveguide (ACPW). The SDA formulation also incorporates two-layer model of a conductor thickness and the concept of efiective permeability to account for the low frequency dispersion due to the magnetic fleld penetration in an imperfect conductor. The paper further presents the single layer reduction (SLR) formulation and circuit model to compute frequency dependent line parameters of a lossy anisotropic multilayer ACPW. The accuracy of formulation is comparable to that of the HFSS and CST, without using complex and time consuming full-wave methods. The results of CST for efi , Z0, fid, fic of multilayer ACPW, in the frequency range 1GHz{100GHz, deviate from results of HFSS up to 0.49%, 1.53%, 2.06% and 10.73% respectively; whereas corresponding deviations of the present SDA and SLR combined formulation are up to 1.38%, 2.09%, 3.57% and 8.87%.

Loss Computation of Multilayer Coplanar Waveguide using Single Layer Reduction Method

In this paper, the quasi-static spectral domain approach (SDA) and single layer reduction (SLR) method applicable for multilayer coplanar waveguide (CPW) on isotropic dielectric substrate that incorporates two layer model of conductor thickness is used to compute the impedance, effective dielectric constant, dielectric loss and conductor loss. The transverse transmission line (TTL) technique is used to find the Green’s function for the multilayer CPW in Fourier domain. Dielectric loss of multilayer coplanar waveguide is computed by converting multilayer CPW structure into equivalent single layer CPW using SLR method. Perturbation method is used to compute the conductor loss. The effect of finite conductor thickness is analysed on the impedance, effective dielectric constant, dielectric loss and conductor loss. The present formulation also accounts for low frequency dispersion in computation of quasi-static effective dielectric constant and characteristic impedance.

Biomimetic subwavelength antireflective gratings on GaAs

We have developed a simple and scalable bottom-up approach for fabricating moth-eye antireflective coatings on GaAs substrates. Monolayer, non-close-packed silica colloidal crystals are created on crystalline GaAs wafers by a spin-coating-based single-layer reduction technique. These colloidal monolayers can be used as etching masks during a BCl(3) dry-etch process to generate subwavelength-structured antireflective gratings directly on GaAs substrates. The gratings exhibit excellent broadband antireflective properties, and the specular reflection matches with the theoretical prediction using a rigorous coupled-wave analysis model. These bioinspired antireflection coatings have important technological applications ranging from efficient solar cells to IR detectors.

Analysis and circuit model of a multilayer semiconductor slow-wave microstrip line

An analytical single-layer reduction quasi-static formulation to accurately compute all the line parameters of metal insulator semiconductor (MIS) and Schottky contact multilayer slow-wave microstrip lines is presented. It is valid for a wide range of parameters and its validity is compared with the full-wave spectral domain analysis technique. We also obtain a circuit model, which is able to accurately explain the experimental results, including dispersion at the lower end of the frequency range, for both the MIS and Schottky contact microstrip lines. Useful data to design passive components based on these lines are also presented.

Propagation characteristics of suspended MIS coupled slow‐wave microstrip lines

AbstractThe single‐layer reduction (SLR) formulation is presented to compute the propagation characteristics, that is, the slowing factor (normalized phase constant) and the attenuation constant of the even and odd modes of the suspended MIS coupled slow‐wave microstrip lines. The proposed structure is suitable for the design of a compact high‐directivity coupler. For the standard coupled MIS microstrip line the SLR computes the slowing factor with deviation about 1% and the attenuation constant with 0.005 dB/mm difference against reults of the spectral domain analysis (SDA). The SLR is as accurate as the SDA; however, computationally it is much faster than the SDA. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 403–405, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10476

Propagation characteristics of Schottky contact suspended slow-wave microstrip line

The single-layer reduction (SLR) model computes the normalized phase constant (/spl beta///spl beta//sub 0/), dielectric loss (/spl alpha//sub d/), and conductor loss (/spl alpha//sub c/) for the Schottky contact slow-wave microstrip (SCSM) line with accuracy about 2.0% for /spl beta///spl beta//sub 0/, and within 0.01 dB/mm for the total loss (/spl alpha//sub t/=/spl alpha//sub d/+/spl alpha//sub c/) as compared against the experimental results. The SLR model has been further used to analyze the normal and abnormal characteristics of a proposed Schottky contact suspended slow-wave microstrip (SCSSM) line with 22% increase in /spl beta///spl beta//sub 0/ over the normal SCSM line. The SCSSM line could be useful in the lower range of RF for the development of compact components.

Dielectric loss of multilayer coupled microstrip line using SLR formulation

AbstractThe single‐layer reduction (SLR) formulation is presented to compute the dielectric loss of even–odd modes of a multilayer coupled microstrip line. Results are compared against the results of full‐wave analysis with a maximum deviation of 2% for the wide range of parameters. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 65–67, 2001.

Propagation characteristics of Schottky‐contact slow‐wave microstrip line

AbstractThe present paper computes the normalized phase constant, dielectric loss, and conductor loss of the voltage‐controlled Schottky‐contact microstrip line using the variational method based on the single‐layer reduction (SLR) formulation. Results computed by the SLR formulation show very good agreement with the experimental results, both in the normalized phase constant and total losses with 2.0% and 0.01 dB/mm, respectively. The present formulation can also handle a greater number of dielectric layers. The model is suitable for the CAD of Schottky‐contact microstrip structures. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 341–344, 2001.

Conductor loss of multilayer microstrip line using the single-layer reduction formulation

Conductor loss of multilayer microstrip line using the single-layer reduction formulation

Dielectric loss of multilayer microstrip line

A unified dielectric loss model based upon the single-layer reduction (SLR) formulation is presented for the determination of dielectric loss of a multilayer lossy microstrip line with and without the top shield. The model has accuracy within 0.05 dB/cm or 3% against the field-theoretic results from several sources. The computational efficiency of this model does not depend on the number of dielectric layers, and the model is valid up to the millimeter-wave range. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 368–370, 1998.

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>