65纳米硅衬底上低损耗带屏蔽的共面波导传输线建模

共面波导传输线可以用作毫米波频段片上的高品质因子的无源器件。在这篇文章里,采用CMOS 65nm工艺设计和制造了加地线屏蔽和不加地线屏蔽的共面波导传输线。本文提出一个基于物理的模型来描述传输线单位长度的频率相关的电感、电容、电阻和电导参数。从基本的共面波导结构出发,模型里加入了慢波效应和底线屏蔽效应的影响。实验数据表明模型有很高的准确度。     

Theoretical and experimental characterization of coplanar waveguidediscontinuities for filter applications

A full-wave analysis of shielded coplanar waveguide (CPW) two-port discontinuities based on the solution of an appropriate surface integral equation in the space domain is presented. Frequency-dependent scattering parameters for open-end and short-end CPW stubs are computed using this method. The numerically derived results are compared with measurements performed in the frequency range 5-25 GHz and show very good agreement. From the scattering parameters, lumped-element equivalent circuits have been derived to model the discontinuities. The inductors and capacitors of these models have been represented by closed-form equations, as functions of the stub length, to compute the circuit element values for these discontinuities     

Effect of substrate thickness and metallization thickness on dispersion characteristics of CPW

Approximate conformal mapping techniques have been used for analysing the effect of finite substrate thickness on coplanar wave guide (CPW). Calculations for impedance and effective dielectric constant are presented for CPW's with finite substrate thicknesses. Analytical formulation are presented for calculations. Network analytical methods of electromagnetic fields are employed to evaluate the effect of thick metal coating on CPW. Dispersion characteristics of CPW have been plotted for various metallization thicknesses. Effect of thick metal coating on guide wavelength is also plotted. Increase in metallization thickness of CPW causes an increase in wavelength. Due to this fact characteristic impedance and effective dielectric constant decreases.     

Broadband electronically tunable planar active radiating elementsand spatial power combiners using notch antennas

A Gunn device has been integrated with two types of active planar notch antennas. The first types uses a coplanar waveguide (CPW) resonator an a stepped-notched antenna with bias tuning to achieve a bandwidth of 275 MHz centered at 9.33 GHz with a power output of 14.2±1.5 dBm. The second type uses a CPW resonator with a varactor for frequency tuning to achieve a bandwidth of over 1.3 GHz centered at 9.6 GHz with a power output of 14.5±0.8 dBm. This is equivalent to over 14% electronic tuning bandwidth. Both configurations exhibit a very clean and stable output signal. A theoretical circuit model was developed to facilitate the design. The model agrees well with experimental results. Injection-locking experiments on the second configuration show a locking gain of 30 dB with a locking bandwidth of 30 MHz at 10.2 GHz. Power combining experiments of two-varactor-tuned CPW active notch antenna elements in a broadside configuration have achieved well over 70% combining efficiency throughout the wide tuning range. The circuits have advantages of small size, low cost, and excellent performance     

FET-integrated CPW and the application in filter synthesis design method on traveling-wave switch above 100 GHz

A new transmission-line concept, called the field-effect transistor (FET)-integrated coplanar waveguide (CPW), is proposed. This concept treats the passive two-finger FET as CPW and, thus, the scaling rule is more accurate than the previous model, especially in high frequency. The extraction approach of the parameters of the FET-integrated CPW is also included. With this concept, the design procedure of traveling-wave switches can be equivalent to a filter synthesis problem. Based on this design procedure, a single-pole single-throw and a single-pole double-throw traveling-wave switch have been realized and measured using 0.15-/spl mu/m high-linearity AlGaAs/InGaAs/GaAs pseudomorphic high electron-mobility transistors. Finally, the frequency limitation of the traveling-wave switches is also discussed. The results show the FET-integrated CPW is the most efficient way to overcome the frequency limitations of traveling-wave switches, achieving operation frequency to 135 GHz, the highest frequency reported to date.     

Experimental and theoretical investigations of new compact largebandwidth aperture-coupled microstrip antenna

The authors propose an efficient amelioration of the concept of large bandwidth aperture-coupled microstrip antennas by coupling a CPW line-fed slot to a microstrip antenna. The CPW fed aperture-coupled microstrip antenna investigated has a large bandwidth with high gain and low crosspolarisation levels, is compact with only one substrate, and may be easily connected to both passive and active components. A numerical model has been developed and the theoretical results are in good agreement with the experiments     

Characterisation and modelling of mitered coplanar waveguide bends on silicon substrate

Mitered coplanar waveguide (CPW) bends are cascaded to form meandered CPW lines. Test samples are fabricated and characterised. In this article a compact, CAD-oriented semi-empirical equivalent circuit model is presented. The validity of the model is verified by comparing it with the experimental and simulation results. It is demonstrated that a meandered CPW with mitered bends has higher characteristic impedance and lesser loss when compared to straight CPWs.     

Characterization of air-bridges in MM-wave coplanar waveguide usingthe complete mode spectrum of CPW

This paper presents a novel analysis of air-bridges in open CPW, including the effects of finite thickness metallisation, using the complete modal spectrum of the CPW. This is a technique which, in comparison with other methods, allows the common features of CPW circuitry to be extracted and preprocessed without consideration of the particular problem in hand, that is, a suitable basis upon which to build a CAD package for smaller computers. Using this approach, scattering parameters, radiation and substrate leakage patterns of isolated bridges have been derived for both types of fundamental mode incidence and compared, where possible, to those obtained from other methods. Furthermore, pairs of bridges, coupled by both the near and far fields, have been analysed     

Attenuation Characteristics and Sensitivity Analysis for Coplanar Waveguide

The behaviour of attenuation losses in Coplanar waveguides (CPW) is studied for quasi-planar transmission lines with constant characteristic impedance (Z₀) and resistivity, having different geometry's. This behavior helps in making a suitable choice of the type of structure and its dimensional parameters depending upon the application. Minimization of loss for a chosen substrate thickness, conductivity and impedance is analyzed. Dispersion characteristics of CPW have been plotted for various metallization thicknesses. A sensitivity analysis for effective dielectric constant with respect to various dimensional parameters of CPW is presented.     

CPW Circulators with Barium Ferrite Thin Films

A miniaturized circulator using barium ferrite films with a coplanar waveguide(CPW) structure is designed and optimized by high frequency electromagnetic field simulations based on finite element methods.The best circulation performance of the film circulator based on 10 μm thick barium ferrite thin films is obtained with an insertion loss of 0.13 dB and an isolation of 22.89 dB around 36.9 GHz.The microwave characteristics of film circulators with CPW and CPW with ground(CPWG) structures have been compared.The influences of the gap between the ground and the signal line,and the ferromagnetic resonance line width on the microwave properties are also studied.     

Modeling of symmetric composite right/left-handed coplanar waveguides with applications to compact bandpass filters

This study proposes an equivalent-circuit model for the composite right/left-handed (CRLH) coplanar waveguide (CPW) comprising the series interdigital capacitor and shunt meandering short-circuited stub inductor in symmetric configuration. The new technique for extracting the equivalent-circuit elements of the CRLH CPW, which include inductances, capacitances, and resistances to represent the left-handed, right-handed, and lossy characteristics, is developed based on the effective medium concept. The applications to the compact resonators and filters are presented to emphasize the unique features of the CRLH CPW. A novel CRLH CPW resonator with a 0/spl deg/ effective electrical length at resonance is proposed, which gives a 49.1% size reduction when compared with the conventional half-wavelength resonator at 5 GHz. Based on the zeroth-order CRLH CPW resonators, an inductively coupled two-pole bandpass filter with 5.4% 3-dB bandwidth and 2.7-dB insertion loss at 5 GHz is implemented, and it is 51.4% more compact than the conventional structure. A good agreement among the results of the full-wave simulation, equivalent-circuit model, published data, and measurement demonstrates the effectiveness of the proposed modeling technique. To suppress the higher order harmonic spurious passbands, the electromagnetic-bandgap CPW structures are incorporated into the proposed CRLH CPW filter.     

Accurate model for Schottky-contacted coplanar waveguide includingfinite epilayer resistance effects

A new quasistatic model for Schottky-contacted coplanar waveguide (CPW) on a semiconductor substrate is presented. Comparison between experimental measurements for a CPW on a GaAs epilayer and calculations show excellent agreement from 45 MHz to 40 GHz. The new model includes the effect of the finite resistance of the undepleted epilayers under the CPW electrodes     

Novel coplanar waveguide to slotline transition on high resistivity silicon

Two novel coplanar waveguide (CPW) to slotline transitions have been fabricated and tested on high resistivity silicon. The first transition uses an air bridge to couple RF power from the CPW line to the slotline and has the entire circuit on the top side of the wafer. In the second transition, the grounded CPW (GCPW) line and the slotline are on opposite sides of the wafer and are coupled electromagnetically. The measured average insertion loss and return loss per transition are better than 1.5 and 10 dB, respectively, with a bandwidth greater than 30% at C-band frequencies.<>     

一种新型叉指式共面波导的设计与制作

设计制作了一种新型叉指式共面波导传输线并对其性能进行了初步的研究。通过微加工技术加厚的接地线可以减少传输线平行部分之间的相互干扰,仿真和测试表明在5~20GHz范围内其回波损耗有两个极小值,极小值的位置随传输线结构参数的变化而变化。以-20dB为基准,这两个极小值附近的带宽可以达到1.95GHz,相对带宽分别可以达到23.5%和9.97%,相应的插入损耗在0.33dB/cm和0.5dB/cm左右。这种传输线有助于减小器件整体尺寸,在带通滤波器和移相器的设计方面有重要用途。     

One- and two-dimensional coplanar waveguide structures with multiple-frequency-tuned slot resonators

In this letter, a new multiple-frequency-tuned slot resonator is introduced in coplanar waveguide (CPW) technology. Its equivalent circuit model is built up and its frequency characteristics are explained by employing the equivalent circuit parameters and field analysis. Furthermore, one-dimensional (1-D) and 2-D CPW structures with the proposed slot resonator are designed. Measurements show that the proposed CPW structures with compact size exhibit good multiple-stopband behaviours.     

Design of the compact UHF RFID meander-line antenna loaded with CPW elements

In this paper, Coplanar Waveguide (CPW) elements are used to load UHF RFID meander-line antennas. Although, the insertion of these elements allow to design small antennas their gain decrease depending on the CPW structures are connected. In this sense, a new location to print CPW elements in the meander-line antenna is proposed aiming not to deteriorate the gain. A multi-objective optimization algorithm is applied in the meander-line antennas loaded with CPW elements in different positions and a comparison between their performances is done. To validate the computational model of the proposed antenna its input impedance is measured.     

Novel Multifold Finite-Ground-Width CPW Quarter-Wavelength Filters With Attenuation Poles

This paper proposes a novel multifold finite-ground-width coplanar waveguide (CPW) lambda/4 resonator filter that has the capability of realizing attenuation poles by cross coupling of nonadjacent resonators. The newly proposed multifold structures not only greatly shrink the length of a resonator, but also provide a convenient way to implement cross coupling in a filter. The proposed multifold finite-ground-width CPW resonators can have much stronger coupling than that of spiraling and meandering layouts, and any number of folds is possible. Two combline filters are designed and measured with twofold and threefold lambda/4 finite-ground-width CPW resonators. A trisection and a quadruplet generalized Chebyshev filter formed by cross couplings between nonadjacent resonators have been implemented by modifying the layout of the resonator. These filters are smaller in size and have the capability of controlling attenuation poles     

Design and fabrication of a new micromachined interdigital coplanar waveguide

In this paper, a new micromachined interdigital coplanar waveguide (CPW) structure has been developed and its characteristics have been studied as a function of transmission line parameters. In interdigital CPW, the ground conductor is thickened by micromachining techniques which is helpful for reducing the interference between the adjacent center conductors while microwave transmits along it. Within the frequency range from 5 to 20 GHz, the return loss of this structure has two minimal values whose positions change with the structural parameters. The relative bandwidths reached 23.5% and 9.97% at 8.3 and 16.55 GHz while the insertion losses are about 0.33 and 0.5 dB/cm, respectively. The interdigital CPW is useful for designing bandpass filter and phase shifter and minimizing the whole size of microelectromechanical system (MEMS) devices.     

中文题目：考虑共面波导电容的AlGaN/GaN HEMTs小信号建模研究

Given the coplanar waveguide(CPW) effect on AlGaN/GaN high electron mobility transistors at a high frequency, the traditional equivalent circuit model cannot accurately describe the electrical characteristics of the device. The admittance of CPW capacitances is large when the frequency is higher than 40 GHz; its impact on the device cannot be ignored. In this study, a small-signal equivalent circuit model considering CPW capacitance is provided. To verify the model, S-parameters are obtained from the modeling and measurements. A good agreement is observed between the simulation and measurement results, indicating the reliability of the model.     

Low-loss CPW on low-resistivity Si substrates with a micromachinedpolyimide interface layer for RFIC interconnects

The measured and calculated propagation constant of coplanar waveguide (CPW) on low-resistivity silicon (1 Ω·cm) with a micromachined polyimide interface layer is presented in this paper. With this new structure, the attenuation (decibels per centimeter) of narrow CPW lines on low-resistivity silicon is comparable to the attenuation of narrow CPW lines on high-resistivity silicon. To achieve these results, a 20-μm-thick polyimide interface layer is used between the CPW and the Si substrate with the polyimide etched from the CPW slots. Only a single thin-film metal layer is used in this paper, but the technology supports multiple thick metal layers that will further lower the attenuation. These new micromachined CPW lines have a measured effective permittivity of 1.3. Design rules are presented from measured characteristics and finite-element method analysis to estimate the required polyimide thickness for a given CPW geometry