The Analysis of Electromagnetic Characteristics of Coplanar Waveguide in Different Models Using Finite-Difference Time-Domain Method

This paper presents the characteristics of coplanar waveguides (CPW) on silicon substrates fabricated through the MCM-D process. The propagation constant and characteristic impedance are measured at frequencies from 0.05 GHz to 10.05 GHz, using a vector analyzer, and with LRRM on-wafer calibration techniques followed with a de-embedding procedure. Two quasi-TEM models are developed to account for the EM affects in the CPW structure: the distributed equivalent elements RLGC were modeled by both closed-form approximation and fully lumped-equivalent circuits. The calculated characteristics show good agreement with the measured ones. The proposed models should be useful for the analysis and design of RFIC on silicon.

To validate the finite element method's suitability for array design on ferrite substrates, measurements were carried out for a z biased ferrite coplanar waveguide (CPW). From the measured S-parameters, propagation constants were extracted over the 1-4 GHz band using 2 different biasing variations. Numerical data for the CPW geometry was also generated using a Finite Element-Boundary Integral (FEBI) analysis. The transverse electric field values in the CPW slots were then used to extract the wavelength of the propagating mode. Using this wavelength, the propagation constant was computed and then compared to experimental measurements.

Correlation of printing faults with the RF characteristics of coplanar waveguides (CPWs) printed on nonwoven textiles

This study presents the accurate characterisation and detailed experimental study of the effect of ground-plane width and suppression of higher-order parasitic modes extending the frequency of operation up to 110 GHz for multilayer conductor-backed coplanar waveguide lines, fabricated in cost-effective thick-film multichip module (MCM) technology. The coplanar waveguides (CPWs) and components have been realised on multiple layers of dielectric onto a ceramic substrate using straightforward and cost-effective photoimageable thick-film process, demonstrating a very low loss of <0.2 dB/mm at 80 GHz for a finite ground CPW and extremely low loss of <0.1 dB at 76 GHz for CPW layer transitions, which are better than many reported results for MCM technologies. Further, the effective dielectric constant (ɛeff) and characteristic impedance (Zch) are extracted from two-port S-parameters measured on a single-line and by conversion to ABCD parameters, to investigate the practical effect of ground-plane width on CPWs on a multilayer ceramic substrate and to facilitate realisation of a cost-effective millimetre-wave MCM.

This paper demonstrates the ink-jet printing of a coplanar waveguide (CPW) transmission line on Kapton™ and Willow Glass substrates for space electronics. A customized Nordson EFD fluid dispensing system with xQR41 Series Microdot™ needle valve was used to print CPW transmission lines using DuPont 5025 conductive paste with feature sizes approximately 200 μm. The printing challenges related to viscosity of ink, deposit size, and fluid inlet pressure were identified and solutions are provided. The characterization of the propagation constant and reflection coefficient of the CPW lines have been carried out using a multiline TRL calibration technique. Additionally, the PNA was calibrated to the probe tips using a GGB Picoprobe Short-Open-Load-Thru (SOLT) calibration standard wafer for measuring the CPW lines over a broader bandwidth (up to 50 GHz). The RF power handling capability and the adhesion tape testing results of the CPW lines are also presented. At 10 W input power, the Kapton bent upwards and the CPW line discolored. Despite all these observed variations, the CPW line operated well.

We present experimental and simulation data of subterahertz attenuation of coplanar waveguides (CPWs) with wide and narrow ground planes. Experimental data are obtained by using a subpicosecond measurement technique based on electrooptic sampling. While time-domain data qualitatively describe the attenuation characteristics, they are converted to the frequency domain by a Fourier transform to give a quantitative interpretation. Simulation data are obtained by full-wave analysis and compared with the experimental results. It is shown that the simulation results consistently agree with experimental results. Furthermore, in the case of CPWs with wide ground planes, both of them are consistent with analytical theory. While CPWs with narrow ground planes have not been analytically studied, our results show that they suffer considerably lower attenuation, which we attribute to a reduced coupling between the CPW mode and substrate modes. The effects of ground-plane width and line dimensions on the attenuation characteristics are discussed in detail.

In this paper the Single Layer Reduction (SLR) technique is presented to compute dispersion characteristics of multilayer coplanar waveguide (CPW) with finite conductor thickness. The effective relative permittivity for the multilayer structure is derived from conformal mapping. Then SLR technique is used to convert multilayer CPW structure to an equivalent single layer structure. The dispersion characteristic of equivalent CPW structure is calculated from the closed form expressions.

This paper describes fabrication, characterization and simulation of low-loss coplanar waveguide (CPW) interconnects on low-resistivity silicon substrate. The fabrication of CPWs is low-temperature (below 250/spl deg/C) and incorporates a spin-on low-k dielectric benzocyclobutene (BCB) and self-aligned electroplating of copper. The performance of CPWs is evaluated by high-frequency characterization and EM simulation. CPWs with different line width (W) and line spacing (S) are investigated and compared. Using a BCB layer as thick as 20 /spl mu/m, CPW fabricated on a low-resistivity silicon substrate exhibits an insertion loss of 3 dB/cm at 30 GHz.

A laterally shielded coplanar waveguide consisting of a coplanar waveguide of finite width placed vertically in a cutoff parallel-plate waveguide is proposed for millimeter-wave applications. Advantages of the waveguide over the conventional coplanar waveguide are weak dispersion and low loss characteristics due to elimination of undesired surface waves and radiation. Simple but accurate analytical formulas for circuit design are derived and semi-empirical formulas for the weakly dispersive characteristics are also examined. Transitions to coaxial line are devised and the propagation constant is measured at millimeter wavelengths.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In this paper, the design of inductively-tuned coil RF MEMS shunt switches, using a novel modeling method, is presented. In this model, both lumped elements and coplanar waveguides (CPW) are used in the electrical equivalent circuit due to the fact that the up-state capacitance is usually very small, and the CPW loss is a main contribution to the up-state insertion loss. The CPW loss is estimated to be less than 0.2 dB at 0-10 GHz in most case. The modeling method allows us to simulate the RF switch more efficiently compare to commercial FEM CAD tools. Using this model, optimized switches with tuning coils operation at S-band are obtained. The isolation of the switches is 23 dB at 4 GHz and 16 dB at 2.4 GHz, respectively. The modeling results are verified by using HFSS simulation.

We investigated the propagation losses and the characteristic impedances Z/sub L/ of coplanar waveguides (CPWs) and microstrip lines (MSLs) on a planar lightwave circuit (PLC)-platform formed on a silica/silicon substrate. The loss of the CPWs was 2.7 dB/cm at 10 GHz on the PLC-platform with 30 /spl mu/m thick silica layer. Thus, a cm-order circuit of this CPW is difficult to fabricate in the 10 Gb/s module. This is because the silicon substrate has a large loss tangent (tan /spl delta/). On the other hand, the loss of the MSLs, where a ground plane shielded the high loss silicon substrate, could be improved to 0.9 dB/cm at 10 GHz with 30 /spl mu/m thick polyimide. These lower loss MSLs on a PLC-platform can be applied to module operation at 10 Gb/s. Furthermore they have the advantage that they are suitable for application to array device circuits or circuits in a module where several devices are integrated because unlike CPWs the ground planes are not divided by signal lines or DC bias lines. The structure of CPWs and MSLs on a PLC-platform with a Z/sub L/ of 50 /spl Omega/ was also studied in detail.

Periodic coplanar waveguides (CPWs) with inductive loading are thoroughly studied by resorting to unit-length transmission parameters, i.e., propagation constant and characteristic impedance, of an equivalent dispersive and/or lossy transmission line. The admittance-type method of moments (MoM) is at first formulated to full-wave modeling of a finite-cell periodic CPW with the two feeding lines and then the short-open-calibration procedure is carried out to deembed the two-port ABCD matrix of the core periodic CPW section. Thus, the above two parameters can be extracted from the MoM simulation to exhibit their guided-wave characteristics, i.e., slow-wave and bandstop behaviors. It is demonstrated for the first time that, within the bandstop or bandgap, the propagation constant must become complex with a nonzero attenuation constant, while the characteristic impedance appears purely imaginary. Three periodic CPW circuits with six finite cells are then characterized on a basis of the transmission-line theorem and the derived S-parameters are validated by Momentum simulation and RF measurement.

In this paper, coplanar waveguide (CPW) method is proposed for identifying the surface wave band-gap of mushroom-like EBG structure. Two lines are cut off from the complete ground plane of the EBG structure and the defected ground plane can be viewed as a coplanar waveguide with characteristic impedance of 50 Ohm. The other layer of the EBG structure is not changed. The surface wave band-gap range can be obtained from the transmission curve of CPW in two cases: EBG inserted and no EBG inserted. Furthermore, the electric field distribution within and beyond the stop-band are studied. And we also investigate the influence of EBG rows on the band-gap. The results extracted from CPW method agrees very weD with that of TEM waveguide model. Compared to the most used experimental method, suspended microstrip line method, the CPW method is a one-layer structure which leads to be low-cost, easy-made and more effective. Both simulated and experimental results verify the effectiveness of the CPW method. Therefore, the CPW method can be applied for identifying the surface wave band-gap of EBG structure much more effectively in engineering applications.

Using the method of lines and the separation of even/odd mode, the dispersion characteristics of broadside-coupled coplanar waveguides (CPW) are analyzed. It is found that the structure has a very weak dispersion in a wide frequency band. The theoretical basis is laid for the application of broadside-coupled CPW in three dimensional microwave integrated circuits, and using the quasi-static TEM approach to analyze and design the circuit in wide frequency band.

The application of an electrooptic sampling technique for the characterization of propagating modes of uniplanar guiding structures on GaAs is described. The characteristics of slotline and even and odd modes of coplanar waveguides (CPW) on semi-insulating GaAs substrate are investigated. The potential distribution over the cross section of each was measured. The guide wavelength for each guide was directly obtained from standing-wave measurements by electrooptic sampling, and the dispersion characteristics of CPW modes and slotline were measured from 15 to 40 GHz. >