Conductor-backed Coplanar Waveguide Research Articles

ACCURATE SYNTHESIS FORMULAS OBTAINED BY USING A DIFFERENTIAL EVOLUTION ALGORITHM FOR CONDUCTOR-BACKED COPLANAR WAVEGUIDES

In this paper, accurate synthesis formulas obtained by using a difierential 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 difierent electrical parameters and physical dimensions, as compared with the results of quasi-static analysis.

COMPARISON OF ADAPTIVE-NETWORK-BASED FUZZY INFERENCE SYSTEM MODELS FOR ANALYSIS OF CONDUCTOR-BACKED ASYMMETRIC COPLANAR WAVEGUIDES

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.

NEURAL MODEL FOR CIRCULAR-SHAPED MICROSHIELD AND CONDUCTOR-BACKED COPLANAR WAVEGUIDE

A Computer Aided Design (CAD) approach based on Artiflcial Neural Networks (ANN's) is successfully introduced to determine the characteristic parameters of Circular-shaped Microshield and Conductor-backed Coplanar Waveguide (CMCB-CPW). ANN's have been promising tools for many applications and recently ANN has been introduced to microwave modeling, simulation and optimization. The Multi Layered Perceptron (MLP) neural network used in this work were trained with Levenberg-Marquart (LM), Bayesian regularization (BR), Quasi-Newton (QN), Scaled Conjugate gradient (SCG), Conjugate gradient of Fletcher-Powell (CGF) and Conjugate Gradient backpropagation with Polak-Ribiere (CGP) learning algorithms. This has facilitated the usage of ANN models. The notable beneflts are simplicity & accurate determination of the characteristic parameters of CMCBCPW's. The greatest advantage is lengthy formulas can be dispensed with.

Design of Trapezoidal Ring Antenna Using Conductor-backed CPW Structure

In this paper, the trapezoidal ring antenna using the conductor-backed CPW is designed and fabricated. The antenna has a broadband characteristic by the coupling efiects through inserted the H-shaped parasitic patch. The conductor-backed CPW shows more sta- ble characteristics than the CPW structure when there is occurred the variation between the feed-line and the ground plane in the front side. The bandwidth of the designed antenna is 2.2GHz»4.6GHz below i10dB.

Open-ended MEMS Probes for Dielectric Spectroscopy of Biological Cells at Radio Frequencies

When an electrical current with a low frequency is applied to a cell, the current passes through the outside of the cell. Thus, impedance measurements at low frequencies cannot be used to determine the pathological change of the cellular organelle taking place inside the cell. However, increasing the frequency of the electrical current makes the capacitive impedance of the cell decrease, allowing the electrical current to ∞ow through the cell. This study presents the design and fabrication of a micro∞uidic device integrated with a coplanar waveguide open-ended MEMS probe for the impedance measurement of the single HeLa cell at radio frequencies. The device includes a PDMS cover with a microchannel and microstructures to capture the single HeLa cell and a conductor-backed CPW fabricated using a silicon chip and two PCB boards. The efiects of the substrate on the characteristic impedance of the CBCPW structure were investigated under three conditions by utilizing a Time-Domain Re∞ectometer (TDR) to obtain the characteristic impedance of the device (46.43›). Finally, impedance measurements using the proposed device and a vector network analyzer (VNA) are demonstrated for sodium chloride solutions with difierent concentrations, DI water, alcohol, PBS, and a single HeLa cell.

Coupling Mechanism in Hybrid SIW–CPW Forward Couplers for Millimeter-Wave Substrate Integrated Circuits

Various publications address the suppression of the undesired mode coupling in laterally bounded conductor-backed coplanar waveguides (CPWs). In this paper, we present an integrated waveguide structure in which this coupling effect of different guided modes is deliberately exploited. Efficient forward coupling at arbitrary levels is achieved between a substrate integrated rectangular waveguide (SIW) and a CPW on its broad wall. Such hybrid integrated couplers combine the SIW's low-loss property with the CPW's flexibility and monolithic microwave integrated circuit compatibility. They are attractive for transitions, six-ports, antenna feeding networks, active antennas, and distributed phase shifters or amplifiers in millimeter-wave applications. The coupling mechanism is studied and a rapid design becomes feasible by use of the provided theory. Two couplers (a 3- and 0-dB version with 4.95- and 9.8-mm-long coupling sections) were designed and fabricated on alumina substrate for operation around 50 GHz. The 3-dB coupler achieves a wide relative bandwidth of 25% at 0.5-dB amplitude imbalance due to the asymmetric coupling structure, whereas the 0-dB coupler (transition) has a 7% relative bandwidth at less than -0.2-dB coupling loss. Results obtained from millimeter-wave probe measurements on realized prototypes agree well with our theory and simulations.

Design of 5 GHz-Band Power Amplifier with On-Chip Matching Circuits Using CPW Impedance (K) Inverters

This Letter employs transmission-line theory for the impedance-matching circuits for a single-chip power amplifier (PA) and verifies for 5GHz-band wireless LAN (IEEE 802.11a) applications. The presented matching circuits are composed of conductor-backed coplanar waveguide (CPW) meander-line resonators and impedance (K) inverters. One of the advantages of the presented circuits is that it can save on-chip space occupied by the matching circuits compared to that using the spiral inductors, thus reducing the cost. The prototype chip, which consists of PA and matching circuits, is designed employing the presented theory and fabricated. A few of the measured results to verify the design theory are presented.

Coupled Twin Slots Fed by Conductor-Backed Coplanar Waveguide

The coupling mechanism of the twin slots fed by the conductor-backed coplanar waveguide is investigated. The goal is to improve the antenna efficiency by using the phase cancellation technique and at the same time keep the structure as simple as possible. The leakage phenomenon is illustrated visually and the effects of the antenna parameters are examined numerically for choosing the appropriate variables. Finally the proposed antenna is fabricated and tested, showing 69.8% of antenna efficiency.

A Novel Calibration Algorithm With Unknown Line-Series-Shunt Standards for Broadband S-Parameter Measurements

This paper presents a novel calibration algorithm using unknown line-series-shunt standards that are suitable for planar transmission line structures for the broadband S-parameter measurements of microwave vector network analyzers. The derivations are based on the eight-term error model with the matched line standard and the lumped assumptions for the series and shunt calibration kits, respectively. With the self-calibration technique, the line propagation constant and the impedance/admittance of the lumped elements are evaluated for further deembedding processes. Simulated and measured results for the conductor-backed coplanar waveguide calibration kit are shown with the additional noise-effect simulation and the two-line thru-reflect-line calibration measurement to validate the proposed approach.

A CAD based Approach on Artificial Neural Networks for Conductor Backed Coplanar Waveguides

In this paper a computer aided design (CAD) approach based on artificial neural networks (ANNs) successfully simulated to determine the characteristics parameters such as effective dielectric constant and characteristic impedances of conductor backed coplanar waveguides (CBCPW). These neural models are trained with Levenberg-Marquardt, Bayesian regularization, gradient descent algorithms. The Levenberg-Marquardt algorithm and Bayesian regularization was found to be the best algorithm among all the three algorithms. As a result, ANN models presented in this work can be used easily, simply and accurately to determine the characteristic parameters of the Conductor Backed Coplanar Waveguides.

Synthesis formulas for conductor‐backed coplanar waveguide

AbstractSimple and accurate formulas are presented for the synthesis of conductor‐backed coplanar waveguide (CPW). These formulas are derived by applying function approximation and curve‐fitting technique to the respective quasi‐static analysis results. The results obtained from these formulas are compared with the results of quasi‐static analysis and experimental works available in the literature. Average percentage error is found to be better than 1% for 1086 conductor‐backed CPW samples having different electrical parameters and geometrical dimensions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1115–1117, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23304

DESIGN AND APPLICATION OF A NOVEL CB-CPW STRUCTURE

On the base of conductor-backed coplanar waveguide (CBCPW) structure, a novel CB-CPW structure is proposed and analyzed, which is realized by using the UC-PBG structure to replace the back conductor of CB-CPW. From 1.3 GHz to 2.8 GHz, The transmission characteristic of the proposed CB-CPW is better than that of CBCPW, and is similar to that of CPW, therefore, this novel CB-CPW not only owns the advantage of CB-CPW, such as good mechanical strength and good heat yield, but also owns the advantage of CPW, such as good transmission characteristic. At last, a dual-band antenna based on this novel CB-CPW is designed and computed, the numerical results validate that this novel CB-CPW is feasible in microwave application.

Ultra-Wideband Bandpass Filters Using Multilayer Slot Coupled Transitions

New Ultra-Wideband (UWB) bandpass filters are proposed and tested. The filters are composed of two microstrip - Conductor-Backed Co-Planar Waveguide (CBCPW) transitions and a multiple-mode resonator, constituted by a line section. The both cases, where the line section is a microstrip or a CBCPW are tested. First, simulated and experimental results for the transition are presented, showing that a wide operating band is obtained. Then, the results for the proposed filters that use this transition structure are presented. Simulated and measured data show that the filters can provide an operating band from 3.1 GHz to 10.6 GHz (–10 dB bandwidth), which is suitable for ultra-wideband systems. The group delay is about 0.3 ns over the most central band and less than 0.45 ns all over the operating band. In addition, using an optimization procedure, a bandwidth of 15 GHz can be achieved with the proposed filter which is more than what was fixed by Federal Communications Commission (FCC) for UWB radio systems. Moreover, a filter constituted by combining the two proposed filters was also designed and fabricated, to improve further the band rejection.

Suppression of Microwave Resonances in Wirebond Transitions Between Conductor-Backed Coplanar Waveguides

Suppression of microwave resonances in wirebond transitions is reported. The transition is made between conductor-backed coplanar waveguides on two different substrates (alumina and silicon), and multiple wirebonds connecting two grounds on each substrate are shown to remove the resonances. It is shown that this additional wirebonding eliminates the nodes which are responsible for the unwanted resonant modes with the frequencies far below the first resonant frequency (19 GHz) of the single substrates. Our work is a unique demonstration of using multiple wirebonds for the removal of resonances.

A Compact and Low-Radiation CPW Probe Pad Using CBCPW-to-Microstrip Transitions for V-Band LTCC Applications

In this paper, a compact and low-radiation coplanar waveguide lines (CPW) probe pad using vialess conductor-backed coplanar waveguide (CBCPW)-to-microstrip transitions is presented for V-band low-temperature cofired ceramic (LTCC) applications. To reduce the radiation loss due to open-end and transition discontinuities, a vialess CBCPW structure with a edge cut back is proposed. The back pad and an optimum transition length suppress the radiation loss of the standard CPW probe pad by 30% and 10%, respectively, compared to a conventional vialess transition. In particular, at 66 GHz, radiation is completely suppressed for the proposed transition and its insertion loss is 0.15 dB at that frequency.

Ultra-wideband microstrip to CB-CPW transition applied to broadband filter

A new ultra-wideband microstrip to conductor backed coplanar waveguide (CB-CPW) transition structure is presented and implemented. Results show good performance in terms of bandwidth, which is about 12 GHz. Using this transition, a new ultra-wideband filter was designed and fabricated. Simulated and measured results show that the filter can cover the band from 3.1 to 10.6 GHz (−10 dB bandwidth).

Ultra-wideband back-to-back CBCPW-to-CBCPW transition

A new ultra-wideband back-to-back conductor-backed coplanar waveguide (CBCPW)-to-CBCPW transition structure is presented and implemented. The design of this transition is based on vertical resonant coupling via a rectangular slot between two stacked CBCPW lines. According to careful design and optimisation, the CBCPW-to-CBCPW transition results show a good performance in terms of bandwidth, which is about 12 GHz.

Design and Verification of On-Chip Impedance-Matching Circuit Using Transmission-Line Theory for 2.4 GHz-Band Wireless Receiver Front-End

SUMMARY Recently, spiral inductors have widely been used instead of resistors in the design of matching circuits to enhance the thermal noise performance of a wireless transceiver. However, such elements usually have low quality factor (Q) and may encounter the self-resonance in microwave-frequency band which permits its use in higher frequencies, and on the other hand, they occupy the large on-chip space. This paper presents a new design theory for the impedance-matching circuits for a single-chip SiGe BiCMOS receiver front-end for 2.4 GHz-band wireless LAN (IEEE 802.11b). The presented matching circuits are composed of conductor-backed coplanar waveguide (CPW) meander-line resonators and impedance (K) inverter. The prototype front-end receiver is designed, fabricated and tested. A few of the measured results to verify the design theory

Miniaturized CBCPW bandpass filter basedon thin film polyimide on lossy silicon

This letter reports a miniaturized conductor-backed coplanar waveguide (CBCPW) bandpass filter (BPF) based on a thin film polyimide layer coated on a lossy silicon. With a 20-μm-thick polyimide interface layer and back metallization, the interaction of electromagnetic fields with the lossy silicon substrate has been isolated, and as a result low-loss and low-dispersive CBCPW line has been obtained. The measured attenuation at 20GHz is below 1.2dB/cm, which is comparable with the CPW fabricated on GaAs. In addition, by using the proposed CBCPW geometry, a miniaturized Ku-band BPF was designed and its measured frequency response demonstrated excellent correlation with the predicted value which validated the performance of the proposed CBCPW geometry used for radio frequency integrated circuit interconnects and filter applications.

A Wideband 77-GHz, 17.5-dBm Fully Integrated Power Amplifier in Silicon

A 77-GHz, +17.5 dBm power amplifier (PA) with fully integrated 50-Omega input and output matching and fabricated in a 0.12-mum SiGe BiCMOS process is presented. The PA achieves a peak power gain of 17 dB and a maximum single-ended output power of 17.5 dBm with 12.8% of power-added efficiency (PAE). It has a 3-dB bandwidth of 15 GHz and draws 165 mA from a 1.8-V supply. Conductor-backed coplanar waveguide (CBCPW) is used as the transmission line structure resulting in large isolation between adjacent lines, enabling integration of the PA in an area of 0.6 mm2. By using a separate image-rejection filter incorporated before the PA, the rejection at IF frequency of 25 GHz is improved by 35 dB, helping to keep the PA design wideband