Showing papers on "Coplanar waveguide published in 1983"

Design and Performance of Coplanar Waveguide Bandpass Filters

Abstract: End-coupled resonator bandpass filters built in coplanar waveguide are investigated. The admittance inverter parameters of the coupling gaps between resonant sections are deduced from experiment, and bandpass filter design rules are developed. This allows easy filter synthesis from "prototype" low-pass designs. Measurements of single section resonator quality factors are used to predict filter insertion losses. Several examples of filters realized in coplanar waveguide are presented. Odd-mode coplanar waveguide filter elements that shortcircuit the even coplanar waveguide mode are investigated. Filter tuning, accomplished by adjusting the height of conducting planes above the resonant filter sections, is demonstrated.

Analysis of Slow-Wave Coplanar Waveguide for Monolithic Integrated Circuits

Abstract: The slow-wave characteristics of an MLS coplanar waveguide are analyzed using two different full-wave methods mode-matching and spectral-domain technique. The theoretical results obtained with them and the experimental values are in good agreement. Several important features of the MIS coplanar waveguide are presented along with some design criteria.

Transmission characteristics of dielectric-coated metallic waveguide for infrared transmission: Slab waveguide model

Abstract: A metallic hollow waveguide with inner dielectric multilayers is proposed for the transmission of infrared light and its basic transmission characteristics are fully analyzed by using a two-dimensional slab waveguide model. The power loss in the waveguide is shown to be extremely reduced by coating dielectric layers properly. Simple loss formulas are also presented which consider absorptions of dielectric materials, and minimum possible losses are theoretically estimated. Finally, relations to bending losses in the waveguide are discussed.

Circuit Duals on Planar Transmission Media

Abstract: Lumped element and multiconductor transmission line configurations in a plane have dual circuit representations, as shown by coplanar and twinstrip transmission lines. Duality relations and circuits having possible applications to MIC and MMIC are given.

Method and device for heating by microwave energy

Abstract: A method of heating objects by microwave energy by supplying microwave energy from a generator to a first waveguide. A second waveguide is located, separated from the first waveguide except for at least one parallel and adjacent coupling distance at a common wall between the waveguides. A coupling of microwave energy distributed in the wave propogation direction of the waveguides takes place at the coupling distance so that microwave energy passes from one waveguide to the other one. The second waveguide is dimensioned, so that action of load (objects being heated) conducts microwave energy in the second waveguide with the same wave phase constant as the first waveguide. Objects to be heated are fed only into and out of said second waveguide. A uniform field is fed-in only into the first waveguide. A uniform field distribution and heating profile is obtained and leakage of microwave energy from the open ended second waveguide is avoided.

Surface-Wave Losses of Coplanar Transmission Lines

Abstract: Coplanar transmission lines lose energy to surface waves when the propagation constant of the surface-wave mode exceeds that of the transmission line. This happens when the substrate thickness is an appreciable fraction of a wavelength. The losses should become important in integrated circuits at near-millimeter wavelengths because it is hard to make the substrate thickness small compared to a wavelength. In this paper we have developed a theory based on reciprocity for predicting these losses. We also utilized the quasi-static approximation method to derive expressions for propagation constants and line impedances. Experimental measurements were made for the surface-wave losses in the two strip line, the two slot line and the three wire line, and the results obtained were consistent with the theory.

Waveguide-microstrip transition arrangement

Abstract: A waveguide-microstrip transition arrangement including, a waveguide section and a microstrip portion, for coupling waveguide modes between the waveguide section and the microstrip portion. The waveguide section has waveguide walls defining waveguide wall surfaces including a short-circuited end wall surface and side wall surfaces. A channel passes through one of the side walls and presents an opening at the associated wall surface. The microstrip portion includes a substrate having opposite sides with a ground plane disposed on one side of the substrate and a microstrip conductor disposed on the other side of the substrate. The substrate passes through the waveguide section, entering the waveguide section at a location where the wall currents of the waveguide section flowing transversely to the substrate are at a miniumum. A portion of the microstrip conductor is disposed on the substrate to pass through the channel into the waveguide section free of contact with the waveguide walls. The substrate has no ground plane in the regions of the interior of the waveguide section and of the plane of separation of the waveguide wall where the substrate is disposed. The ground plane extends into and terminates within the channel.

Slow-Wave Coplanar Waveguide on Periodically Doped Semiconductor Substrate

Abstract: A metal-insulator-semiconductor (MIS) coplanar waveguide with periodically doped substrate is described. An efficient numerical method is introduced in order to obtain the propagation constants and the characteristic impedances of the constituent sections of each period. Using the results, the characteristic of the periodic MIS coplanar waveguide is analyzed by Floquet's theorem. The theoretical study shows reduction of attenuation and enhancement of the slow-wave factor at certain frequencies, compared to the uniform MIS coplanar waveguide. This structure is experimentally simulated and shows good agreement theory.

Numerical Analysis of Shielded Coplanar Waveguides

Abstract: A numerical method is presented to calculate the impedance and the effective dielectric constant for a coplanar waveguide with a ground plane under a thin dielectric. Impedance and effective dielectric constant values are given as a function of geometry for GaAs and alumina substrates. An approximate analytical expression is given to generate the numerical value of the impedance with good accuracy. The results can be used in designing shielded coplanar waveguides. Measurements of a tapered 50-Omega test structure are presented.

Monolithic coplanar waveguide travelling wave transistor amplifier

Abstract: A microwave and millimeter wave amplifier consisting of a field effect travelling wave transistor monolithically integrated into a coplanar waveguide having input, output and matching sections is disclosed. The amplifier consists of a semi-insulating substrate doped on its upper surface to form within an active region of the device a doping layer of predetermined conductivity type, such as an N type layer. At the lateral edges of the active region the N type material is further doped to produce N+ type regions for receiving source electrodes, while a central part of the active region is similarly doped to produce an N+ type region for receiving a drain electrode. A gate line having a bifurcated terminal end extends into the spaces between the drain electrode and the spaced source electrodes and forms junction contacts with the N type layer in the active region. A pair of ground lines extending the length of the substrate are formed as part of the two source electrodes, while the drain electrode is formed as part of a drain line. The gate and ground lines cooperate to form an input and an input matching structure, while the drain and ground lines cooperate to form a coplanar output transmission line. A major feature of the proposed amplifier structure is that all of the circuit elements and transistor elements are placed on the same surface to facilitate fabrication, thereby to obtain low cost and high performance.

Waveguide/microstrip mode transducer

Abstract: A waveguide/microstrip mode transducer operable over a broad frequency range comprises a dielectric substrate (3) extending along an E-plane of a waveguide and having a conductive layer on each major surface, the two layers having three successive pairs of portions. A first pair (10, 11) form a microstrip line, a second pair (12, 13) form a balanced transmission line, and a third pair (14, 15) couple the portions (14, 15) of the balanced line to opposite walls (6, 7) of the waveguide. The microstrip line is coupled to the balanced line in a manner which is independent of frequency over the operating frequency range, rather than by a resonant balun; the strip conductor portion (10) and the ground plane conductor portion (11) of the microstrip line respectively are the same width as, and taper smoothly to the width of, the conductor portions (12, 13) of the balanced line connected thereto, and there are two regions (22, 23) respectively on opposite sides of the balanced line in which there is no conductor on both surfaces of the substrate (3 ) and which exhibit no resonance in the operating frequency range. In order to provide phase velocity matching between the waveguide and the transmission lines on the substrate (3), particularly when the substrate (3) has a high dielectric constant, the substrate (3) has a recess (24) of progressively increasing width along the waveguide.

Analysis of M.I.S. or Schottky Contact Coplanar Lines Using the F.E.M and the S.D.A.

Abstract: The finite element method and the spectral domain approach are used to optimize M.I.S. and Schottky contact coplanar waveguides because the range domain of the slow wave mode depends stronger the geometrical size.

Mode Propagation in Laterally Bounded Conductor-Backed Coplanar Waveguides

Abstract: The propagation characteristics and field distributions in conductor-backed coplanar waveguide are investigated using a full-wave technique. The influence of the lateral boundaries of the structure is illustrated in detail. With respect to the unbounded structure additional modes can propagated even in the low-frequency range.

Slow-wave propagation on MIS periodic coplanar waveguide

Abstract: A metal-insulator-semiconductor periodic coplanar waveguide is described. The propagation constants and the characteristic impedances of each section are calculated by the spectral-domain method, and overall propagation characteristics are estimated by the theory of periodic structure. The line should be useful for monolithic microwave integrated circuits.

New dielectric waveguide structure for millimetre-wave optical control

Abstract: A new dielectric waveguide structure is presented for obtaining large attenuation for millimetre-wave optical control. It is found that the attenuation of the proposed structure is an order of magnitude larger than that of a commonly used rectangular semiconductor waveguide.

Dispersion characteristics of asymmetric coupled slot lines on dielectric substrates

Abstract: A modified coplanar waveguiding structure, an asymmetric coupled slot line, on a dielectric substrate is considered. The dispersion characteristics of asymmetric coupled slot lines and asymmetric coplanar waveguides are found in terms of the numerically efficient spectral domain technique.

Simplified computation of coplanar waveguide with finite conductor thickness

Abstract: The paper presents a simplified method for evaluating the line parameters of a coplanar waveguide. TEM mode of propagation is assumed and Laplace's equation is solved by means of the successive over-relaxation method. The region to be solved is limited to only a quarter of the line cross-sectional area and computation is carried out twice, with and without the substrate present. The results are then superimposed to obtain an approximate solution. Results of this simplified method agree fairly well with those obtained by more elaborate computations, or those by a purely analytical method. Also, measurements are made to confirm the results obtained.

Low impedance coplanar microwave transmission line

Abstract: A small, very low impedance coplanar waveguide microwave transmission line. A composite coplanar waveguide transmission line section composed of a plurality of interleaved fingers (14, 16, 21, 23) is coupled between input and output transmission line sections. Alternate ones of the interleaved fingers are connected to a main conductor (12) of the input and output transmission line sections and to a metal ground plane layer (11). The composite transmission line section may be connected either in cascade with the input and output transmission line sections or in a shunt arrangement. Composite characteristic impedances of less than two ohms are realized.

Slow-Wave Coplanar Waveguide on Periodically Doped Semiconductor Substrate

Abstract: A metal-insulator-semiconductor (MIS) coplanar waveguide with periodically doped substrate is described. Reduction of attenuation and enhancement of the slow-wave factor are observed, compared to the uniform MIS coplanar waveguide. The structure is experimentally simulated and shows good agreement with theory.

Analysis of Multimodes Coplanar Lines for Microwave Integrated Circuits Applications

Abstract: Multimodes coplanar lines with arbitrary cross-section shape are analysed by the spectral domain technique. Two approaches possible in the calculations of the properties of multiconductor printed transmission lines are proposed, discussed and compared to each other. The dispersion characteristics of some new and modified coplanar transmission lines are presented to show the universality of the proposed analytical formulation. This formulation can be also easy extended for the analysis of another coupled waveguiding structures like, for example, uni- or bilateral fin-lines.

A Traveling Wave, Microwave Optical Modulator

Abstract: A Ti-diffused lithium niobate, traveling wave modulator has been fabricated and tested. A Mach-Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4mm interaction length, the modulator has a 3dB bandwidth of 13 GHz and requires only 2 volts to switch at λ = 840 nm. The frequency response is measured directly using an ultra-high speed photodiode, and the test set-up therefore constitutes the highest bandwidth electrooptical transmission system ever reported.