coplanar waveguides

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Broadband transitions for membrane-based coplanar waveguides on highly-conductive silicon substrates

Broadband transitions for membrane-based coplanar waveguides on highly-conductive silicon substrates

In (Rohland et al., 2011) we discussed the advantages of on-wafer membrane-based calibration standards in compar- ison to standards built in conventional thin-film technology. By means of Monte Carlo simulations we showed that, for coplanar waveguides used as line standards, an up to tenfold reduction in uncertainty can be achieved for certain electro- magnetic waveguide properties. The calculations were based on an extension to the analytic model of Heinrich (1993), which was presented in (Arz et al., 2011a).

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Adaptive Neuro-Fuzzy Models for Conventional Coplanar Waveguides

Adaptive Neuro-Fuzzy Models for Conventional Coplanar Waveguides

Abstract—In this work a new method based on the adaptive neuro-fuzzy inference system (ANFIS) was successfully introduced to determine the characteristic parameters, effective permittivities and characteristic impedances, of conventional coplanar waveguides. The ANFIS has the advantages of expert knowledge of fuzzy inference system and learning capability of neural networks. A hybrid-learning algorithm, which combines least-square method and backpropagation algorithm, is used to identify the parameters of ANFIS. There are very good agreement between the results of ANFIS models, experimental works, conformal mapping technique, spectral domain approach and a commercial electromagnetic simulator, MMICTL.
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Multilayer Perceptron Neural Analysis of Edge Coupled and Conductor-Backed Edge Coupled Coplanar Waveguides

Multilayer Perceptron Neural Analysis of Edge Coupled and Conductor-Backed Edge Coupled Coplanar Waveguides

Abstract—In recent years, Computer Aided Design (CAD) based on Artificial Neural Networks (ANNs) have been introduced for microwave modeling, simulation and optimization. In this paper, the characteristic parameters of edge coupled and conductor-backed edge coupled Coplanar Waveguides have been determined with the use of ANN model. Eight learning algorithms, Levenberg-Marquart (LM), Bayesian Regularization (BR), Quasi-Newton (QN), Scaled Conjugate Gradient (SCG), Conjugate Gradient of Fletcher-Powell (CGF), Resilient Propagation (RP), Conjugate Gradient back-propagation with Polak-Ribiere (CGP) and Gradient Descent (GD) are used to train the Multi-Layer Perceptron Neural Networks (MLPNNs). The results of neural models presented in this paper are compared with the results of Conformal Mapping Technique (CMT). The neural results are in very good agreement with the CMT results. When the performances of neural models are compared with each other, the best results are obtained from the neural networks trained by LM and BR algorithms.
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High-Frequency Modeling of Coplanar Waveguides Including Surface Roughness

High-Frequency Modeling of Coplanar Waveguides Including Surface Roughness

Abstract. An existing analytical transmission line model to describe propagation properties of coplanar waveguides including dispersion and radiation effects was extended to take into account surface roughness of conductor traces. The influence of parasitics is successively included in the simulation and compared to measurements. The device un- der test (DUT) was fabricated on an Al 2 O 3 wafer. A metal

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Common-Mode Suppression in Broadside Coupled Coplanar Waveguides

Common-Mode Suppression in Broadside Coupled Coplanar Waveguides

Past work to suppress common-mode propagation in microstrip or stripline differential transmission lines has included patterned ground structures [1–5], electromagnetic bandgap structures [6–8], periodic structures [9], and metamaterial inspired structures such as complementary split-ring resonators [5, 10– 13]. Less effort has been directed toward investigating common-mode suppression in differential coplanar waveguides. Table 1 lists transmission line type, filter design, center frequency, and fractional bandwidth for some of the previous work in common-mode filtering along with the results reported here.
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Coplanar Waveguides Incorporating Srrs or CSRRs
: a Comprehensive Study

Coplanar Waveguides Incorporating Srrs or CSRRs : a Comprehensive Study

Abstract—We numerically and experimentally evaluate different designs of coplanar waveguides (CPWs) loaded with split ring resonators (SRRs) and complementary split ring resonators (CSRRs), respectively. In particular, we are interested in their stop-band performance. Starting from structures which consist of two concentric rings, we study devices with only an outer ring, an inner ring or multiple concentric rings. Furthermore, our study shows that introducing slots in the proximity of the SRR or CSRR will modify the stop-band considerably. Single and multiple unit cells for both designs are fabricated and measured. Our results demonstrate the potential of the CSRR/CPW structure for filter applications.
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Accurate Synthesis Formulas Obtained by Using a Differential Evolution Algorithm for Conductor-Backed Coplanar Waveguides

Accurate Synthesis Formulas Obtained by Using a Differential Evolution Algorithm for Conductor-Backed Coplanar Waveguides

Abstract—In this paper, accurate synthesis formulas obtained by using a differential evolution (DE) algorithm for conductor-backed coplanar waveguides (CBCPWs) are presented. The synthesis formulas are useful to microwave engineers for accurately calculating the physical dimensions of CBCPWs. The results of the synthesis formulas are compared with the theoretical and experimental results available in the literature. A full-wave electromagnetic simulator IE3D and experimental results are obtained in this work. The average percentage error of the synthesis formulas obtained by using DE algorithm is computed as 0.67% for 1086 CBCPW samples having different electrical parameters and physical dimensions, as compared with the results of quasi-static analysis.
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Comparison of Adaptive-Network-Based Fuzzy Inference System Models for Analysis of Conductor-Backed Asymmetric Coplanar Waveguides

Comparison of Adaptive-Network-Based Fuzzy Inference System Models for Analysis of Conductor-Backed Asymmetric Coplanar Waveguides

Abstract—A method based on adaptive-network-based fuzzy infer- ence system (ANFIS) is presented for the analysis of conductor- backed asymmetric coplanar waveguides (CPWs). Four optimization algorithms, hybrid learning, simulated annealing, genetic, and least- squares, are used to determine optimally the design parameters of the ANFIS. The results of ANFIS models are compared with the results of conformal mapping technique, a commercial electromagnetic simula- tor IE3D, and the experimental works realized in this study. There is very good agreement among the results of ANFIS models, quasi-static method, IE3D, and experimental works. The proposed ANFIS models are not only valid for conductor-backed asymmetric CPWs but also valid for conductor-backed symmetric CPWs.
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Analytical Investigation of Periodic Coplanar Waveguides

Analytical Investigation of Periodic Coplanar Waveguides

Abstract—This paper presents an analytical formula to evaluate even- and odd-mode characteristics of infinitely parallel coplanar waveguides (CPW) with the same dimensions in each CPW, given name as periodic coplanar waveguides (PCPW). The analysis yields a closed-form expression based on the quasi-TEM assumption and conformal mapping transformation. Calculated results show that both the even- and odd-mode characteristic impedances are in good agreements with the results generated by numerical solvers and available experimental data. The results are important especially for highly demand on miniaturization of circuit design to place multiple CPWs in parallel.
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Design and Modeling of RF MEMS Phase Shifters Using Various Structures of Coplanar Waveguides

Design and Modeling of RF MEMS Phase Shifters Using Various Structures of Coplanar Waveguides

RF MEMS capacitive membrane switches have already demonstrated low loss and low parasitics at frequencies through 40 GHz. A shunt capacitive MEMS switch consists of a thin metal membrane “bridge” suspended over the center conductor of a CPW (Coplanar Waveguide) or micro strip line and fixed at both ends to the ground conductors of the CPW line. When the switch is pulled down to the center conductor, the shunt capacitance increases by a factor of 20-100, presenting an RF short. The MEMS switch has very little DC power consumption (μJ during the switching process), allows for large down-state to up-state capacitance ratios (Cd/Cu = 20-100), has very low inter modulation products, and can be fabricated on almost any substrate.
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Modeling the capacitive behavior of coplanar striplines and coplanar waveguides using simple functions

Modeling the capacitive behavior of coplanar striplines and coplanar waveguides using simple functions

The finite-width conductor-backed coplanar waveguide (FWCBCPW) in an infinite well is a specific geometry found in repeated planar structures with conductor backing. In doing research for modeling the CBICPW, it became apparent that no closed-form expressions were developed for the FWCBCPW due to its unique asymmetry in two dimensions. With the development of the closed-form expressions for the CPS in Chapter 4, similar approximate mappings can be used for the FWCBCPW, although with less precision. The derived expression is compared to simulated data using the MAXWELL™ field solver for a limited range of physical dimensions.
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Coplanar Metamaterial Micro-Resonator

Coplanar Metamaterial Micro-Resonator

The materials and geometric dimensions of the multi-turn spiral (Figure 1) were determined from a study presented earlier by Nemer et al. [5], for an operating frequency in the band [1–2 GHz] (Table 1). Two coplanar waveguides, with and without ground plane [6, 7], are studied (Figure 2). A large slot G L (1300 µm) is necessary to insert the spirals

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The characterisation of acoustic waves in optical
waveguides

The characterisation of acoustic waves in optical waveguides

The role of computerized modelling and simulation tools is important in reducing the time and costs involved in investigating phenomena for the non experimental study. Simulating tools play a part in optimization of the physical parameters, in characterization and in improving efficiency of the device. Much progress has been made in the field of modelling and simulation techniques in photonics. Numerical methods have been studied, new technique developed, and existing techniques have been improved. Nowadays, there are different types of numerical methods available to study acoustic waveguides, for examples the Finite Different Method (FDM) technique [Alford, 1974], or the numerical analysis on elastic waveguides by using mode-matching method [Lawrie, 2009] or an efficient Green’s function [Matsuda, 2007] for acoustic waveguide. In addition, there is also a method for modelling sound propagation in acoustic waveguides by using a Beam propagation numerical method (BPM) [Laude, 2005] and [Mermelstein, 2009].
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FDTD Analysis of Chiral Discontinuities in Waveguides

FDTD Analysis of Chiral Discontinuities in Waveguides

discretizing the rearranged curl equations [12], which is different from literature [13], a leapfrog algorithm for chiral media is achieved. To validate this method, we have calculated the scattering coefficients of waveguides, which are partially filled with chiral or achiral media. By comparing the results of [9] and Ansoft HFSS simulation, the accuracy of this method is demonstrated.

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Characterisation of acoustic waves in optical waveguides

Characterisation of acoustic waves in optical waveguides

Photonics is one of the key enabling technologies (KET) playing an important role in the shaping of tomorrow’s world in many areas such as in communications, energy, sensing, entertainment, and health and safety. Photonic active devices exploit the interaction of lights with other physical effects such as carrier, fields, power density, stress, temperature, or sound. The SBS in optical waveguides is an important nonlinear effect results from the coherent interactions between optical and acoustic modes. However, the analyses of such interactions are not trivial, especially with the increased complexity of modern optical waveguide structures, exemplified in photonic crystal fibres and sub-wavelength waveguides, such as nanowires [Dainese, 2006]. In a way that is similar to the hybrid modes in high-index contrast optical waveguides, the acoustic modes in optical waveguides are also complex. In these cases, a rigorous full vectorial analysis [Rahman, 1984] is required for the accurate characterization of optical wave propagation. In this thesis, a numerical approach based on the versatile FEM has been developed and applied for the analysis of arbitrarily shaped acoustic waveguides and subsequently both weakly and strongly guiding acoustic waveguides have been studied.
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Radiation losses in dielectric optical waveguides

Radiation losses in dielectric optical waveguides

In fig. 4c the most attractive structure for an optical fibre system is shown. Its cross-sectional dimensions are such as to allow only one bound mode to exist. This structure is appropriately known as the monomode step-index fibre and because of this, the modal dispersion present in monomode fibres is due completely to the material dispersion of the core and cladding dielectrics. The main disadvantage of the monomode fibre is its small core size, making handling the fibre and aligning joins in fibres very difficult. The main attraction of these waveguides is the very small impulse response allowing them to carry much more information than multimode waveguides.
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Optical nonlinearity in titanium dioxide waveguides

Optical nonlinearity in titanium dioxide waveguides

The most important component in a setup for measuring FWM is a laser source with intensities that are high enough to generate detectable FWM in the sample waveguides. One powerful laser system available in the Optical Sciences group is the one used for the CARS microscope setup. This system has the added benefit of being tunable across a wide range of wavelengths as well, since it uses an Optical Parametric Oscillator (OPO) for frequency conversion of the light. This system supports wavelengths near 1310 nm. The following OPO settings were found to output a single wavelength peak around 1310 nm: Piezo position: 2135, Crystal temperature: 162 ◦ C. Since the Lyott filter cannot be read out, it was tuned to the position where maximum power output was observed. This resulted in an output beam with a wavelength of 1300 nm
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Development of Mode Conversion Waveguides at KIT

Development of Mode Conversion Waveguides at KIT

Abstract. The development of mode conversion waveguides (launchers) for high power gyrotrons has gone through three stages at KIT. Formerly, harmonically deformed launchers have been used in the series gyrotrons developed for the stellarator W7-X. In 2009, a numerical method for the analysis and synthesis of mirror-line launchers was developed at KIT. Such a launcher with adapted mode-converting mirrors for a 2 MW TE 34,19 -

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Non-coplanar volumetric-modulated arc therapy (VMAT) for craniopharyngiomas reduces radiation doses to the bilateral hippocampus: A planning study comparing dynamic conformal arc therapy, coplanar VMAT, and non-coplanar VMAT

Non-coplanar volumetric-modulated arc therapy (VMAT) for craniopharyngiomas reduces radiation doses to the bilateral hippocampus: A planning study comparing dynamic conformal arc therapy, coplanar VMAT, and non-coplanar VMAT

Each ncVMAT plan consisted of one coplanar arc and two non-coplanar arcs. We employed the RapidArc Sys- tem. The coplanar arc was rotated clockwise with avoid- ances sectors not to irradiate the eyes. The couch positions and arc rotations of the two noncoplanar arcs were the same as those of DCAT. All collimater angles were set to 0°. Optimization was performed to ensure that the coVMAT criteria (see above) were met. As with the DCAT and coVMAT plans, Dmax was set to be below 107 %.

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Photonic crystal waveguides in chalcogenide glasses

Photonic crystal waveguides in chalcogenide glasses

percontinuum spectrum could be achieved by pumping it with 610f s laser pulses at 68W peak power and a wavelength of 1550nm. This can be com- pared with 350nm achieved in a 4.7cm silicon nanowire using 100f s pulses [43]. By comparing the 1W input power of the silicon experiment with the 68W input power of the chalcogenide experiment, it is clear that even though the chalcogenide results are promising, the silicon results are superior. This is due to the fact that the silicon fabrication technology is more mature. The pattern definition and etching for high quality photonic wires requires a higher level of precision than the fabrication of rib-waveguides. Rib waveg- uides benefit from a lower field intensity at the surfaces, hence roughness and imperfections have less impact on the propagation losses. The lower inten- sity is due to the bigger mode in rib-waveguides. This affects the nonlinear response negatively, which has to be compensated for by higher input powers. A step towards higher mode confinement in chalcogenide glasses was the first demonstration of photonic crystals in chalcogenide glasses that were fab- ricated by focused ion beam (FIB) milling [44] in 2005. The first photonic crystals that were fabricated using electron beam lithography and dry etch- ing were fabricated by Yinlan et.al. in 2007 [45], avoiding the parasitic ion implantation of FIB milling. Even though, similar fabrication techniques to
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