Analysis of Characteristic Impedance and Effective Dielectric Constant of Asymmetrical Coplanar Waveguide with Finite Dimensions

Conformal mapping techniques are used to obtain the closed-form expressions of the characteristic impedance and effective dielectric constant of the asymmetrical coplanar waveguide with finite line dimensions and substrate thickness. These closed-form expressions are generally applicable to design various particular types of coplanar waveguide transmission lines.     

Analysis of Characteristic Impedance and Effective Dielectric Constant of Asymmetrical Coplanar Waveguide with Finite Dimensions

Coplanar waveguide transmission lines have become quite attractive due to its applica-tion to microwave or millimeter-wave integrated circuits and devices.Calculations of char-acteristic impedance and effective dielectric constant of...     

On the modeling of metal strip antennas contiguous with the edge ofelectrically thick finite size dielectric substrates

A solution to the problem of radiation by a narrow metal strip antenna contiguous with the edge of a dielectric substrate is presented where the substrate has parameters such that its electrical thickness is appreciable. Such an antenna may be useful at millimeter wavelengths as an integrated phased array element forming a part of a monolithic microwave integrated circuit (MMIC). A suitable geometry for this application is illustrated and an efficient computational procedure developed. Comparisons with experimental results for the input impedance and far-field radiation patterns show excellent agreement. The influence of the dielectric substrate on the performance of an antenna designed to operate at approximately 60 GHz is discussed. Two examples, the first involving the analysis of a coplanar strip transmission line fed antenna and the second involving impedance matching and control of cross-polarized radiation using a folded strip dipole, are given to illustrate practical applications of the analytical method to design problems     

Analysis of a new configuration of coplanar stripline

A new configuration of coplanar stripline is presented and analyzed. This configuration is derived by augmenting coplanar stripline (CPS) with electrically wide lateral ground planes on either side of the balanced pair of signal lines. The ground planes should replace line-to-line coupling in complex circuits and eliminate the TE₀ parasitic dielectric slab waveguide mode. Also, the spacing from signal lines to ground planes can be adjusted to change the characteristic impedance. Spectral domain analysis is used to calculate the dispersion characteristics of this transmission line. Analytical expressions for quasi-static values of the line are presented. This configuration of CPS should be useful for balanced high-impedance lines in monolithic microwave integrated circuit (MMIC) and high speed digital circuits     

Uniplanar one-dimensional photonic-bandgap structures andresonators

This paper presents uniplanar one-dimensional (1-D) periodical structures, so-called photonic-bandgap (PBG) structures, and defect high-Q resonators for coplanar waveguide, coplanar strip line, and slot line. Proposed uniplanar PBG structures consist of 1-D periodically etched slots along a transmission line or alternating characteristic impedance series with wide band-stop filter characteristics. A stop bandwidth obtained is 2.8 GHz with a stopband rejection of 36.5 dB. This PBG performance can be easily improved if the number of cells or the filling factor is modified in a parametric analysis. Using uniplanar 1-D PBG structures, we demonstrate new high-Q defect resonators with full-wave simulation and measured results. These structures based on defect cavity or Fabry-Perot resonators consist of a center resonant line with two sides of PBG reflectors. They achieve a loaded Q of 247.3 and unloaded Q of 299.1. The proposed circuits should have many applications in monolithic and hybrid microwave integrated circuits     

Picosecond pulse propagation in coplanar waveguide forwarddirectional couplers

The spectral-domain method is used to calculate the frequency-dependent even- and odd-mode effective dielectric constants of symmetric coplanar waveguide forward directional couplers. Comparisons are made with symmetric microstrip forward couplers on the same substrate that have the same line spacing and access port characteristic impedance. Results are shown which indicate that certain coplanar designs will have lower loss and greater bandwidth than the microstrip devices. Picosecond pulse propagation in both structures is studied using the calculated dispersion data     

Characteristic impedance measurements of a coplanar waveguide

A coplanar waveguide which consists of a strip of metallic thin film on the surface of a dielectric slab with two ground electrodes running adjacent and parallel to the strip is easily accessible for shunt connections of semiconductor devices. This letter presents experimental data, and a theoretical equation including correction factors, for an effective relative permittivity concerning characteristic impedance. The measurements have been made by the t.d.r. method.     

Analytical analysis of circular-shaped microshield and conductor-backed coplanar waveguide

In this paper, a new type of circular-shaped microshield and conductor-backed coplanar waveguide is proposed. Analytic closed-form expressions for characteristic impedance and effective dielectric constant for the new line are obtained using conformal mapping method under the assumption of pure-TEM propagation and zero dispersion. The new waveguide proposed by this paper can reduce radiation to much less than the conventional coplanar waveguide and microstrip, and can reduce the current concentration at both the edges of the strip conductor.     

非对称支持宽边耦合共面波导的模式分析

本文用准静态的方法分析了非对称支持宽边耦合共面波导的基本传播模式,给出了C模式和π模式的正确判据,纠正了现有文献中的错误,同时给出了其两线电压比、电流比和C模式和π模式的等效相对介电常数与模式阻抗的正确表达式.在上层介质为空气、下层介质分别为石英或硬铝时,分别计算了其C模式和π模式的等效相对介电常数与模式阻抗随结构参数的变化曲线.这些均为在三维(多层)微波集成电路中非对称支持宽边耦合共面波导电路的分析与设计提供了依据.     

一种新型毫米波集成波导微带转换的分析与设计

提出一种新型集成于单层微带基片的毫米波集成波导微带转换 ,由一圆形微带谐振器、微带共面波导探针组成。利用全波分析软件对该转换器进行了分析计算、优化设计。测试了波导微带转换实物 ,结果表明 ,在Ka波段在 1 GHz频带内 ,该波导微带转换具有较低的插入损耗 ( <0 .4d B)和反射损耗 ( <-1 4d B)。可满足相关毫米波微带集成电路系统的应用要求。     

CAD Models for a Boxed Coplanar Waveguide with Multilayered Substrates and Overlays

By the conformal mapping method, CAD-oriented analytical closed-form expressions for the quasi-TEM parameters for a boxed coplanar waveguide (BCPW) with multilayered substrates and overlays are presented. The parameters include the effective dielectric constant, the characteristic impedance, the wavelength of the guided wave, and the capacitance per unit length. All of the formulas obtained in this paper are simple and accurate enough for microwave circuits' designs and are useful for transmission line theory.     

Full-wave analysis of integrated transmission lines on layered lossy media

Cohn's method of analysis of the slot line on a dielectric substrate is extended to the case of integrated lines on a lossy inhomogeneous substrate. The slow-wave characteristics of the metal-insulator-semiconductor coplanar waveguide for MMIC applications are calculated and found to be in good agreement with the experiments.     

有限尺寸介质基片上的共面波导

有限尺寸介质基片上的共面波导是一种非常接近于工程应用状态的物理模型.本文用共形映射技术分析有限尺寸介质基片上的共面波导,得到了它的单位长度电容、有效介电常数和特性阻抗等基本参数,与介质基片宽度为无限大的理想化模型作了比较,给出了介质基片为多宽可以认为是无限宽的判别公式.     

Low-loss micromachined inverted overlay CPW lines with wideimpedance ranges and inherent airbridge connection capability

A new type of overlay coplanar waveguide (CPW) structure, “inverted overlay CPW (IOCPW)” is developed using micromachining techniques to provide easy means of airbridge connection between the ground planes, as well as to achieve low losses over wide impedance ranges. Measured IOCPW showed less than 1 dB/cm loss at 50 GHz over a wide impedance range from 25 to 80 Ω. It also offered low effective dielectric constant, and insensitivity to the substrate losses. Wide impedance ranges and simple process steps make IOCPW a promising uniplanar transmission line medium for mm-wave monolithic applications     

CMOS 0.13 μm共面波导建模与特性分析

基于TSMC0.13μmCMOS工艺,对深亚微米硅基上的共面波导特性进行了研究。在分析中引入了保角映射等数值方法,给出了有效介电常数εeff、特征阻抗Z、单位电容C等传输线指标随几何参数变化的计算公式。并设计了特征阻抗分别为50Ω和70Ω的共面波导传输线元件库。采用Short-Open-Load-Thru(SOLT)校准测试技术对片上传输线元件库进行测试。在0.1~40GHz范围内,测试结果与数值分析解吻合。这为在硅基上进行RFIC设计提供了一个合理选取传输线结构的方法。     

Behaviour of TFMS and CPW line on SOI substrate versus high temperature for RF applications

Practical application of integrated circuits requires operation over a wide temperature range. In the case of microwave monolithic integrated circuits (MMICs), the quality of the interconnections as well as the passive matching networks in term of losses is predominent. Therefore, there is a need to investigate the performances of transmission line structures on Si-based substrates in a wide temperature range, as a function of frequency. The behaviour of 50 Ω thin film microstrip (TFMS) and coplanar waveguide (CPW) transmission line topologies on both standard and high resistivity silicon-on-insulator (SOI) substrates versus high temperature is presented.     

K-band monolithic InGaP-InGaAs DCFET amplifier using BCB coplanar waveguide technology

A K-band (20 GHz) monolithic amplifier was developed and fabricated by adopting a low-/spl kappa/ benzocyclobutene (BCB) coplanar waveguide (CPW) line and InGaP-InGaAs doped-channel HFETs (DCFETs). This monolithic microwave integrated circuit (MMIC) utilizes a high impedance BCB CPW microstrip line (Z/sub 0/=70 /spl Omega/) for the biasing circuits, and a Z/sub 0/=50 /spl Omega/ line for the RF signal transmission. The low dielectric constant characteristic of the BCB interlayer is beneficial for a common-ground bridge process, which reduces the parasitics. The calculated loss tan/spl delta/ is 0.036 for the BCB at 20 GHz. The one-stage MMIC amplifier achieves an S/sub 21/ of 5 dB at 20 GHz, which is the first demonstration of the K-band InGaP-InGaAs DCFET monolithic circuit.     

Artificial Dielectric Shields forIntegrated Transmission Lines

We present a novel shielding method for on-chip transmission lines built on conductive silicon substrates. The shield consists of an artificial dielectric with a very high in-plane dielectric constant, built from two patterned metal layers isolated by a very thin dielectric film. Inserted below an integrated coplanar transmission line, the artificial dielectric layer blocks the electric field of the line from entering the silicon substrate. Shielded coplanar waveguides fabricated on a conventional silicon wafer show a two- to three-fold loss reduction compared to unshielded lines at frequencies below 30 GHz.     

Behaviour of guided modes in systems of parallelly located transmission lines on dielectric substrates

The dispersion properties of the sets of parallelly located arbitrarily placed coplanar and planar transmission lines on dielectric substrates are analysed by the spectral-domain technique. The developed formulation covers all practically important waveguides for microwave integrated circuits applications.