Showing papers on "Coplanar waveguide published in 1988"

Conductor-backed slot line and coplanar waveguide: dangers and full-wave analyses

Abstract: Despite the many attractive features of conductor-backed slotline and coplanar waveguide, there are potential problems that are introduced by the use of conductor backing. These potential problems include leakage of power into surface waves or into the dielectric region between the plates, unexpected crosstalk, significant alteration of the guide wavelength, and unexpected or unwanted coupling to neighboring lines. Two theoretical approaches are presented, one purely numerical and the other in network form and analytical in nature, that agree well with each other and with measurements in a special case. They provide a quantitative description of these potential surprises when the line conductors are either infinite or finite in width. >

Modeling of some coplanar waveguide discontinuities

Abstract: Lumped equivalent-circuit models are presented for several coplanar waveguide discontinuities such as an open circuit, a series gap, and a symmetric step, and their element values as a function of the discontinuity physical dimensions. The model element values are de-embedded from measured S-parameters. The frequency dependence of the effective dielectric constant was measured and compared to computed values. >

Modeling of some coplanar waveguide discontinuities

Abstract: Lumped equivalent circuit models for several coplanar waveguide (CPW) discontinuities such as an open circuit, a series gap in the center conductor, and a symmetric step in the center conductor are presented, and their element value are given as a function of the physical dimensions of the discontinuity. The model element values are de-embedded from measured S-parameters, and the effects of the center conductor width and the substrate thickness on the equivalent circuit element values are obtained. The characteristics of a CPW right-angle bend using a compensation technique are presented. The frequency dependence of the effective dielectric constant is measured and compared to computed values. >

An evanescent-mode tester for ceramic dielectric substrates

Abstract: The TE/sub 01/ mode in a cylindrical waveguide at a frequency below cutoff is used to probe a ceramic dielectric substrate located on the central plane between input and output cooling loops. Maximum transmission occurs at a frequency determined by the waveguide radius, the substrate thickness, and the dielectric constant. The dielectric constant and loss tangent are obtained from the resonant frequency and the absorption bandwidth. The measurement is insensitive to the position of the substrate in the gap between waveguide sections, and no intimate contact is required. >

A coplanar probe to microstrip transition

Abstract: A transition between a coplanar probe and a microstrip transmission line is reported. The transition is significant in that it does not require substrate via holes. A set of microstrip impedance standards was developed for the purpose of de-embedding the transition. The latter is suitable for measuring the S parameters of a number of low-cost monolithic microwave integrated circuits with coplanar probes. >

Coplanar waveguide and slot line on magnetic substrates: analysis and experiment

Abstract: A full-wave analysis is presented for coplanar waveguide (CPW) and slotline phase shifters on magnetic substrates. The analysis is based on a multilayer Green's function which is formulated using a transmission matrix approach. This approach is modified so that its computational efficiency is increased by deriving the transmission matrices for dielectric and ferrite slabs in a closed form. The Green's function is then applied to the full-wave analysis of a slotline and CPW on infinite-width substrates. Several different multilayered configurations are investigated with respect to their nonreciprocal phase-shift properties. Perfectly conducting sidewalls are then added to the analysis and the resulting configuration is used to study the effect of various CPW parameters on differential phase shift. An experimental structure built on the surface of rectangular ferrite toroid is described and its differential phase analysis compared to measurements. Calculated and measured results are in good agreement. >

A broad-band microwave superconducting thin-film transformer

Abstract: The design, construction, and testing of a broadband superconducting transformer based on a Dolph-Chebyshev distribution are described. The transformer is completely compatible with thin-film circuit topologies and allows access to 50- Omega coaxial launchers. The transformer is a taper that utilizes only one side of the substrate and features a coplanar waveguide to microstrip transition without the use of via holes. The taper provides a characteristic impedance transformation from 50 Omega to 2 Omega over a frequency range from 5 to 15 GHz. The taper provides a much larger bandwidth than a linear taper with the same length and impedance transformation. >

Mode conversion due to discontinuities in modified grounded coplanar waveguide

Abstract: Modified grounded coplanar waveguide (CPW) is the same as conventional grounded coplanar waveguide except that the side planes are not of infinite extent. This structure is overmoded, but is still used in monolithic circuits since it does not require via holes. Conversion from the desired CPW mode to an undesirable microstrip-like mode is calculated using a full-wave analysis. The results indicate that mode conversion occurs at discontinuities, but that it is a small effect. In very-high-Q circuits, resonances may occur due to this coupling, but this conversion can be made small for reasonable structural dimensions. >

Confirmation of slow waves in a crosstie overlay coplanar waveguide and its applications to band-reject gratings and reflectors

Abstract: A theoretical and experimental investigation of slow-wave propagation along a crosstie overlay slow-wave coplanar waveguide is discussed. The slow-wave factor observed agrees reasonably well with the theoretical prediction. This structure is used for construction of frequency-selective distributed Bragg reflectors (DBRs) of compact size. The effect of conductor loss is considered. A doubly periodic band-reject grating has been created from the DBRs, and the band-reject phenomenon was observed as predicted. To improve passband characteristics of the grating, a monolithic slow-wave Chebyshev reflector was designed and fabricated. Agreement between theory and preliminary experiment has been found. Based on this theory, a slow-wave reflector was improved characteristics is proposed and examined. Simplicity of the design procedure, lower loss, and better control of the passband ripple size have been achieved. >

Measurements on standing waves in GaAs coplanar waveguide at frequencies up to 20.1 GHz by electro‐optic probing

Abstract: We report the experimental results of the standing waves in GaAs coplanar waveguides at frequencies up to 20.10 GHz with different terminations (open, short, and 50 Ω) by a new electro‐optic probing technique. The effective refractive indices from 4.11 to 20.10 GHz are presented and compared with theoretical values. Dispersion of coplanar waveguide in that frequency range is shown to be negligible.

Integrated millimeter-wave transceiver

Abstract: An integrated millimeter-wave transceiver comprising a substrate on which is provided an annular slot antenna (D) and a balanced mixer (F). Transmitter power is applied to one point of the antenna and the balanced mixer (F) is coupled to a second point of the antenna, the second point being orthogonal to the one point in the plane of the antenna. The coupling of the balanced mixer to the second point is by way of a coplanar waveguide (C). A short circuit (H) in the coplanar waveguide (G) at a quarter wavelength from the mixer prevents an even (asymmetric) mode on the coplanar waveguide from being propagated to the antenna. An IF signal is derived using an RF band stop filter (I).

Monolithically integrated coplanar 75‐GHz silicon impatt oscillator

Abstract: Planar IMPATT diodes have been fabricated for W-band operation on high-resistivity silicon substrates. The active layers are grown by silicon molecular beam epitaxy. The diodes are monolithically integrated in a coplanar disc resonator. Good DC characteristics have been achieved. Oscillations have been detected at a frequency of 76 GHz with a continuous wave output power of about 1 mW.

Miniature circulators for monolithic microwave integrated circuits

Abstract: A miniature circulator which is compatible with integrated circuits is described. The circulator includes a substrate which supports three copolanar waveguide transmission lines which are connected at a common junction. The common junction provides a coupling structure between the coplanar waveguide transmission lines. A ferrite disc having a conductive layer disposed thereover is provided over the intersection of the three coplanar waveguide transmission lines. A magnet is then disposed over the ferrite disc to direct a D.C. magnetic field through the disc. An alternative coupling structure having interwoven, balanced lines disposed on the substrate is also described. An alternative arrangement for the ferrite disc having a hexangular shape, which carries a beam-lead node metalization is also described.

De-embedding coplanar probes with planar distributed standards

Abstract: Two methods to de-embed coplanar probes using offset coplanar waveguide shorts and transmission lines are described. The accuracy of the de-embedded measurements is verified. The S-parameters of lumped standards provided by the manufacturer of the probes are measured and found to be suitable for purposes of calibration up to 26 GHz. >

Accuracy of electro‐optic measurements of coplanar waveguide transmission lines

Abstract: Nonzero backside potentials in microwave and digital GaAs circuits lead to small errors in direct electro‐optic sampling measurements. We present experimental studies of the magnitude of this error signal as a function of center conductor width for 50 Ω coplanar waveguide transmission lines on a 20 mil substrate. Backside voltages 20 dB below the applied frontside signal are found for typical microwave circuit transmission lines. Calculation of this backside signal with finite difference techniques shows excellent agreement with experiment. Analytic estimates of the backside potential also may be derived in terms of the spatially periodic eigenfunctions for Laplace’s equation in the substrate.

Antenna and waveguide mode converter

Abstract: In view of the introduction of cellular radio, there is a requirement for an antenna of simple construction which can be sold in a consumer market. While the invention meets this need it also has application to the problem of providing TM 01 to TE 01 made converters. The invention employs radial conductors printed on a dielectric substrate and aligned with the transverse electric field in a waveguide supporting the TM 01 mode. Circumferential conductors, each coupled to one of the radial conductors, act as monopoles radiating the required field in an antenna where the radial conductors project through apertures in the waveguide. For the mode converter, both radial and circumferential conductors are inside the waveguide, with the radial conductors aligned with the transverse electric field of the TM 01 mode. Arrangements for maximizing the field at the position of the radial and circumferential conductors are described as are means for preventing the propagation of unwanted modes.

A uni-planar MMIC 26-GHz-band receiver

Abstract: A GaAs 26-GHz-band MMIC (monolithic microwave integrated circuit) receiver has been designed, fabricated, and evaluated. All MMICs in the receiver have uniplanar configuration. A coplanar waveguide is mainly used as a microwave transmission line, with air bridges successfully utilized. Total circuit area is sufficiently small so that single-chip integration is possible. Assembled MMICs show stable receiver performance, including a noise figure of 8 dB and conversion gain of 2 dB or more, without any adjustment or external tuning circuits. >

Microstrip resonance isolator

Abstract: A microstrip resonance isolator is provided comprising a dielectric waveguide element which is mounted on the top surface of a length of microstrip transmission line dielectric substrate having an electrically conductive ground plane on the bottom surface of the substrate. The waveguide element has a rectangular rod-shaped central section and two oppositely-inclined ramp-shaped sections at the ends of the central section. The dielectric constant of the waveguide element is substantially more than the dielectric constant of the microstrip transmission substrate. A microstrip conductor is provided on the top surface of the substrate from one end thereof to the other end thereof and passes over the top surface of the dielectric waveguide element. A thin, rectangular substrate of hexagonal, grain-oriented ferrite material is mounted on one side of the waveguide element between the ramp-shaped end sections. The ferrite substrate material is given a predetermined uni-directional magnetic orientation in a direction which is parallel to the plane of the side of the waveguide element on which the ferrite substrate is mounted and is substantially perpendicular to the plane of the microstrip dielectric substrate top surface, so that the ferrite substrate and the dielectric waveguide element cooperate to form a dielectric waveguide resonance isolator and the ends of the microstrip conductor act as the terminals of the microstrip isolator.

Variable printed circuit waveguide filter

Abstract: The position of a printed circuit filter array is mechanically moved from e sidewall to the center of the waveguide to thereby tune the cut-off frequency of the waveguide. An array of printed circuit elements is placed in the E-plane inside a waveguide and serves as a high pass filter. The printed circuit elements make no contact with the guidewalls that are suspended on a dielectric substrate. A sidewall screw tuner is mechanically coupled through the waveguide wall to the dielectric substrate to physically move the dielectric substrate containing the filter elements to selected positions within the waveguide. The substrate may be moved from a position adjacent the waveguide narrow wall wherein no variation of waveguide cut-off frequency occurs to a position at the center of the waveguide wherein the increase in the waveguide cut-off frequency is maximized.

The effects of a dielectric capacitor layer and metallization on the propagation parameters of coplanar waveguide for MMIC

Abstract: The study of coupling phenomena between lines laid on semiconductor substrates in monolithic microwave integrated circuit (MMIC) technologies and the determination of propagation effects on power FETs require the characterization of lines with micron transversal widths. For such lines, the influence of metallization thickness and dielectric cap layer on propagation properties can not be neglected. These effects are characterized for the case of coplanar lines laid on semiconductor substrates. The mathematical development used and the results obtained by a numerical technique are presented. >

Electrooptic sampling measurement of dispersion characteristics of slot line and coplanar waveguide (coupled slot line) even and odd modes

Abstract: The application of an electrooptic sampling technique for the characterization of propagating modes of uniplanar guiding structures on GaAs is described. The characteristics of slotline and even and odd modes of coplanar waveguides (CPW) on semi-insulating GaAs substrate are investigated. The potential distribution over the cross section of each was measured. The guide wavelength for each guide was directly obtained from standing-wave measurements by electrooptic sampling, and the dispersion characteristics of CPW modes and slotline were measured from 15 to 40 GHz. >

Wideband and low return loss coplanar strip feed using intermediate microstrip

Abstract: A wideband and low return loss coplanar strip feed has been achieved using an intermediate microstrip line between coax and coplanar strip lines. The measured and calculated return loss are below 13 dB up to 18 GHz. An extended calculation using TDR data shows the return loss below 10 dB up to 30 GHz. This coplanar strip feed is very practical for feeding wideband electro-optic devices which use coplanar strip as the electrodes.

Package for high frequency integrated circuit

Abstract: PURPOSE: To obtain a high frequency package by providing a conductor layer so as to surround a coplanar waveguide structure on the surface of plural thin insulation sheets and connecting inter-conductor layers, the conductor layer, and a ground layer of a high frequency input output terminal of coplanar guide path structure electrically so as to form a frame. CONSTITUTION: A front and a rear side a thin ceramic green sheet is subject to W paste at a prescribed part to form a conductor layer 9. The layers are eliminated, an opening 12 is formed and a W paste is buried. The W paste is coated to a prescribed part of a wall face of a laminated base 8. Finally, a base 8 is overlapped to the conductor layer on the surface of the ceramic or the metallic base 3 while clipping silver solder and it is roasted at a high temperature. The obtained frame 1 is partitioned electrically into inner and outer portions by conductor layers 9, 10 in continuity with the conductor layer or the metallic base 3 on the surface of the base being a ground layer 7 and the inductance and resistance of peered hole 12 are reduced. The equivalent effect to the metallic frame is obtained except the high frequency input output terminal of the coplanar guide path structure in the frame and the high frequency characteristic is improved. COPYRIGHT: (C)1990,JPO&Japio

Coplanar waveguide isolator with symmetrical structure

Abstract: PURPOSE:To increase the forward/reverse loss ratio and to decrease the insertion loss by coating a radio wave absorbing film onto a slot formed by 1st and 3rd conductor and the 1st and 3rd conductors and locating a 2nd magnetic base onto a coplanar line and the radio wave absorbing film so as to improve the edge guide effect of the coplanar line CONSTITUTION:The coplanar line is made symmetrical by arranging a magnetic base 14 on the base 1 to concentrate the distribution of an electromagnetic field onto the inside of the magnetic base An input signal from a port 7 propagates onto a slot 15 by the edge guide effect and is attenuated by the absorption film 2 and a large reverse loss is obtained On the other hand, since the input signal from a port 8 propagates the slot 16 and is not susceptible to the effect of the absorption film 2, the forward loss is reduced Through the structure above, since the biasing effect of the electromagnetic field is increased, an isolator with a large forward/reverse loss ratio and excellent nonresprocity is realized

Experimental confirmation of slow-waves in a crosstie overlay coplanar waveguide and its application to band-reject gratings

Abstract: Slow-wave propagation along a crosstie overlay slow-wave coplanar waveguide is investigated both theoretically and experimentally. The slow-wave factor observed agrees reasonably well with theoretical prediction. Based on this structure, a doubly-periodic Bragg reflector band-reject grating was fabricated. >

A Coplanar Waveguide Antenna for MMICs

Abstract: The coplanar patch antenna is a recent addition to the range of planar radiators. This paper presents some results for this type of antenna. It has good front to back ratio (15 dB) and low cross polarisation (-20 dB) performances and these have been achieved by exploiting the lens like effects of the high dielectric constant substrate.

Photoconductor Pulse Generators And Sampling Gates For Characterization Of High-Speed Devices And Transmission Lines

Abstract: We describe photoconductive semiconductor devices developed for application in diagnostics of high-speed electronic devices and circuits. Both pulse generation and sampling functions are provided by these ultrafast photoconductors. The photoresponse of different semiconductor materials (GaAs, InP, Si) that have been ion bombarded (Ar, H, He, Ne, 0, Si) was investigated and characterized. Response times as short as 1 picosecond have been observed. High frequency propagation characteristics of microstrip and coplanar waveguide transmission lines have been studied and modelled. Application of this measurement technique to the characterization of a microwave GaAs transistor is presented.

GaAs MMIC slotline/CPW quadrature IF upconverter

Abstract: A GaAs monolithic slotline/coplanar waveguide (SL/CPW) quadrature intermediate-frequency (IF) upconverter integrated circuit (IC) is described. The IC is a single-sideband suppressed carrier upconverter and consists of local oscillator (LO) and RF power splitters, two IF/RF diplexers, and two SL/CPW single balanced mixers. The IC has circuitry on both sides of the chip which required a few additional processing steps to fabricate. With a 7.0-GHz LO, and a 1-MHz to 1000-MHz quadrature IF input signal, the typical upconverter performance was 40-dB LO port-to-RF port isolation, 25-dB carrier suppression, 20-dB sideband suppression, and 14-dB conversion loss in the 6-8-GHz RF output band. >

Computer Oriented Analytic Formulas for the Quasi-TEM Parameters of Broadside-Coupled Coplanar Waveguides with a General Dielectric for MMICS

Abstract: Fast and exact analytic formulas for calcultaing the quasi-static-TEM parameters of a general broadside-coupled coplanar waveguide (GBSC-CPW) are presented. Simplicity, high speed of computation and exactness recommend their use for (M)MIC'S-CAD programs. Numerica1 calculations are presented in order to investigate various electrical properties of the structure. An asymmetrical BSC-CPW as well as the single CPW resulting from connecting the two coupled strips of the GBSC-CPW a the input and the output ports are also discussed. Criteria are obtained to ensure the coplanar behaviour of the structure.

Challenge to 3-D discontinuous dielectric waveguide circuit analysis

Abstract: An accurate theoretical approach for discontinuity problems in dielectric 3-D (rectangular) waveguides of open type is presented. The essential propagation mechanism of a mode on the 3-D structures is used to develop an improved 2-D model for which the radiation as well as the surface-wave transmission characteristics are derived. This approach takes account of the behavior of both surface-wave modes and continuous spectral waves, and is successfully applied in the design of image-guide grating filters. Experimental results are provided that prove the effectiveness of this approach. >