Showing papers in "IEEE Transactions on Microwave Theory and Techniques in 1976"
TL;DR: In this paper, a unified theory is presented for the synthesis of exactly equiripple low-pass prototypes having: a) one simple pole of attenuation at a real frequency; or b) a single pair of real-axis transmission zeros.
Abstract: A new unified theory is presented for the synthesis of exactly equiripple low-pass prototypes having: a) one simple pole of attenuation at a real frequency; or b) a single pair of real-axis transmission zeros (giving linear-phase performance). These types of filters may be regarded as representing the least possible degree of complication over the conventional Chebyshev filter, and are usually realized with one extra cross coupling in the structure. It is demonstrated that this gives much improved skirt selectivity in the case of a finite frequency pole, making it a viable intermediate case between the Chebyshev and elliptic function filters, while in the case of real-frequency zeros, very flat group delay over 50 percent of the passband is achieved with minimal cost in insertion loss and skirt rejection. Approximate and exact synthesis techniques are described, including results for the previously neglected odd-degree case. Experimental results demonstrate agreement with theory.
266 citations
TL;DR: In this paper, a nonlinear analysis of the electron cyclotron maser instability is performed in a frame where both the axial wave number and axial beam velocity vanish.
Abstract: In this paper the linear and nonlinear theory of the electron cyclotron maser instability is considered. The configuration used to study the maser instability consists of relativistic electrons gyrating about and drifting along a uniform magnetic field within a parallel plate waveguide. Relativistic effects associated with the gyrating electrons are responsible for excitation of the transverse electric mode in the waveguide. Linear theory shows that the growth rate maximizes when the axial beam velocity coincides with the axial wave group velocity of the excited electromagnetic wave. This allows us to perform the nonlinear analysis in a frame where both the axial wave number and axial beam velocity vanish. We have found that the maser instability exists only if the perpendicular beam energy exceeds a threshold value. Our analysis also describes the temporal nonlinear evolution of the field amplitude and frequency of a single excited wave. The nonlinear wave dynamics are self-consistently determined from the nonlinear particle orbits through the force and wave equations. The nonlinear analysis shows that there are two possible mechanisms for the saturation of the unstable wave: 1) depletion of the available free energy associated with the rotating particles and 2) phase trapping of the gyrating electrons in the wave. The initial beam parameters determine which of the two mechanisms is responsible for saturation. Competition between the two saturation mechanisms leads to a peaking in the energy conversion efficiency as a function of beam energy. Numerical results of the nonlinear formalism show that energy conversion efficiencies from the particles to the wave can be as high as 60 percent in the beam frame. Furthermore, by appropriately contouring the external magnetic field, among other things, efficiencies as high as 70 percent can be realized.
242 citations
TL;DR: The principle of operation is outlined for Si- and GaAs-MESFET's; the basic device physics, equivalent circuit, high-frequency limitations, and noise behavior are treated.
Abstract: A review of recent and current work on microwave FET's and amplifiers is presented, and an extensive bibliography of recent articles is appended (250 references). First, the various FET structures (MRSFET's, JFET's, and IGFET's) and their performances are reviewed. Second, the principle of operation is outlined for Si- and GaAs-MESFET's; the basic device physics, equivalent circuit, high-frequency limitations, and noise behavior are treated. Third, the design principles and performance of microwave MESFET amplifiers are summarized.
208 citations
TL;DR: It has been shown recently that the cyclotron maser mechanism can explain a wide range of observations on intense relativistic electron beams, including the generation of gigawatt bursts as mentioned in this paper.
Abstract: It has taken nearly twenty years for practical development of the electron cyclotron maser. The initial theoretical notions were put forward by R. Q. Twiss in 1958, but the first clear experimental demonstration did not take place until 1964. Today, in the USSR, these devices are being built which deliver kilowatt-level CW power at submillimeter wavelengths with high efficiency. This paper traces these developments. After the first decade, Western device development became rather somnolent, and the initiative passed to the Soviet scientists. But a healthy resurgence of interest is now growing universally, due to a number of factors including device potential in practical systems. It has been shown recently that the cyclotron maser mechanism can explain a wide range of observations on intense relativistic electron beams, including the generation of gigawatt bursts. Furthermore, theoretical interest is again growing, especially as regards the nonlinear behavior of the interaction.
201 citations
TL;DR: In this paper, a temperature probe consisting of a thermistor and plastic high-resistance leads appears to practically eliminate the problem of field perturbations and direct heating caused by any conventional leads connected to the temperature sensor.
Abstract: Measuring temperature in material being heated by radio-frequency (RF) fields is difficult because of field perturbations and direct heating caused by any conventional leads connected to the temperature sensor. A temperature probe consisting simply of a thermistor and plastic high-resistance leads appears to practically eliminate these problems. The design goals are described, and the performance of an initial test model of this type of probe is discussed.
163 citations
TL;DR: In this article, a new type of dielectric waveguide, which has a number of advantages over other previously available waveguide structures for millimeter-wave integrated circuits, is described.
Abstract: A new type of dielectric waveguide, which has a number of advantages over other previously available waveguide structures for millimeter-wave integrated circuits, is described. Dispersion characteristics and the field distributions in the waveguide are calculated using the concept of effective dielectric constant. Field distributions have been measured in the 80-GHz range in order to check the accuracy of the analytical results. This measurement has been done using a novel experimental technique, which should also be applicable to many other millimeter-wave waveguides and components.
129 citations
TL;DR: In this article, a functional for the curlcurl equation in Cartesian and cylindrical coordinates is derived, which includes the treatment of loss-free anisotropic media.
Abstract: Maxwell's equations can be cast into a basic differential operator equation, the curlcurl equation, which lends itself easily to variational treatment. Various forms of this equation are associated with problems of practical importance. The formulation includes the treatment of loss-free anisotropic media. The boundary conditions associated with electromagnetic-field problems are treated in detail and the uniqueness of the solution is discussed. A functional is derived for the curlcurl equation in Cartesian and cylindrical coordinates.
124 citations
IBM1
TL;DR: In this article, two analytical capacitance formulas were derived using approximate conformal mapping techniques, one gives the capacitance of a finite-thickness metal line over a conducting ground plane, or over a silicon surface.
Abstract: In semiconductor IC technology, capacitance formed by the multilevel interconnection metal lines usually dominate circuit performance. However, for lack of accurate formulas, a numerical method usually has to be used to determine these capacitances. Two analytical capacitance formulas were derived using approximate conformal mapping techniques. One formula gives the capacitance of a finite-thickness metal line over a conducting ground plane, or over a silicon surface. The other formula gives the capacitance of the same metal line, but with an additional conducting metal line over it. The formulas are most accurate for metal lines whose width exceeds the dielectric thickness; accuracy increases with Iinewidth. They are accurate to 1 percent for a metal line whose width is comparable to the dielectric thickness. With these simple formulas, statistical distribution of the metal-line capacitances can be easily determined in a few seconds of computer time.
123 citations
TL;DR: In this paper, an analysis of three-line microstrip-coupler circuits consisting of three parallel lines is presented based on the existence of three mode impedances, and design equations describing the performance of this type of coupler are derived and allow the prediction of its matching and transmission properties.
Abstract: An analysis is presented of microstrip-coupler circuits consisting of three parallel lines. The analysis is based on the existence of three mode impedances. Design equations describing the performance of this type of coupler are derived and allow the prediction of its matching and transmission properties. Numerical results using finite difference methods are presented for a three-line microstrip coupler made on an alumina substrate (k = 9.8). Experimental results for a 10-dB tbree-line coupler with a center frequency of 4 GHz show that its performance can be reasonably well predicted by the developed theory.
118 citations
TL;DR: In this article, the mathematical relations between the dyadic Green's function of the vector potential type and that of the electric type are shown in detail and the mathematical relation between the two types of functions for a rectangular cavity is discussed.
Abstract: Several different but equivalent expressions of the dyadic Green's functions for a rectangular cavity have been derived. The mathematical relations between the dyadic Green's function of the vector potential type and that of the electric type are shown in detail. This work supplements the one by Morse and Feshbach.
117 citations
TL;DR: In this article, a theoretical analysis and experimental verification of the signal properties of the GaAs MESFET mixer is presented, and experimental techniques for evaluating some of the mixer parameters are described.
Abstract: A theoretical analysis and experimental verification of the signal properties of the GaAs MESFET mixer are presented. Experimental techniques for evaluating some of the mixer parameters are described. Experiments performed on GaAs MESFET mixers at X band show that good noise performance and large dynamic range can be achieved with conversion gain. A conversion gain over 6 dB is measured at 7.8 GHz. Noise figures as low as 7.4 dB and output third-order intermodulation intercepts of +18 dBm have heen obtained at 8 GHz with a balanced MESFET mixer.
TL;DR: The segmentation method proposed in this short paper is a method in which the characteristics of a planar circuit are computed by combining those of the segmented elements by a relatively short computer time required.
Abstract: In many practical planar circuitries, the circuit pattern can be divided into several segments which themselves have simpler shapes such as rectangles. The segmentation method proposed in this short paper is a method in which the characteristics of a planar circuit are computed by combining those of the segmented elements. It features a relatively short computer time required. The principle and computer algorithm are described. Finally, as an example, the application of the proposed method to the trial-and-error optimum design of a ladder-type 3-dB hybrid is described.
TL;DR: In this article, a detailed analysis of the slow-wave propagation on Schottky-contact microstrip lines (SCMLs) is presented, including the effect of metallic losses.
Abstract: Schottky-contact microstrip lines (SCML) are a special type of transmission line on the semiconducting substrate: the metallic-strip conductor is specially selected to form a rectifying metal-semiconductor transition while the ground plane exhibits an ohmic metallization. Thus the cross section of SCML is similar to that of a Schottky-barrier diode. The resulting voltage-dependent capacitance per unit length causes the nonlinear behavior of such lines. In this paper a detailed analysis of the, slow-wave propagation on SCML is presented, including the effect of metallic losses. Formulas for the propagation constant and characteristic impedance are derived and an equivalent circuit is presented. Conditions for slow-mode behavior are given, particularly taking into account the influence of imperfect conductors and defining the range of many interesting applications. Experimental results performed on Si-SCML are compared with theory.
TL;DR: In this article, a waveguide-microstrip transition is described for the telecommunication band with a VSWR less than 1.1 and an attenuation less than 0.25 dB.
Abstract: A new waveguide-microstrip transition is described. This design provides wide-band performance (18-26 GHz) and very good reproducibility without the need for variable elements. The circuit is fully integrated on the substrate and the characteristics are much less sensitive to small variations in the dimensions than other known transitions. A narrow-band version has been made for the telecommunication band in particular (17.7-19.7 GHz) with a VSWR less than 1.1 and an attenuation less than 0.25 dB. The design can easily be scaled to other frequencies and is especially useful at frequencies above 10 GHz.
TL;DR: In this paper, a nonuniform discretization of the integral equation on the tangential electromagnetic (EM) field on the boundary surface is proposed as a numerically efficient method to analyze the microstrip-like transmission lines.
Abstract: The nonuniform discretization of the integral equation on the tangential electromagnetic (EM) field on the boundary surface is proposed as a numerically efficient method to analyze the microstrip-like transmission lines. The calculated results of the propagation constant of the microstrip line based on this method are compared with other published analytical results. Various types of planar striplines are treated by the same formulas. The dominant and higher order modes of shielded microstrip line are discussed and compared with the longitudinal-section electric (LSE) and linear synchronous motor (LSM) modes of a two-medium waveguide.
TL;DR: An integrated circuit technique for microwave and millimeter wavelengths which uses refractive-type waveguides and signal processing coupled with planar integration techniques characteristic of microstrip microwave integrated circuits (MIC's) is described in this article.
Abstract: An integrated circuit technique for microwave and millimeter wavelengths which uses refractive-type waveguides and signal processing coupled with planar integration techniques characteristic of microstrip microwave integrated circuits (MIC's) is described. Following a comparison of the optical and millimeter approaches to this circuit technique, a discussion of transmission lines and components for millimeter wavelengths is presented. System applications are also described.
TL;DR: In this article, the dispersion measurements on microstrip lines with characteristic impedances between 10 and 100 Omega were described, covering the frequency range 2-18 GHz, using a single-crystal sapphire cut with a specified crystal orientation as the substrate material.
Abstract: Dispersion measurements on microstrip lines with characteristic impedances between 10 and 100 Omega are described, covering the frequency range 2-18 GHz. Single-crystal sapphire cut with a specified crystal orientation was used as the substrate material. Microstrip effective permittivities were calculated from the resonant frequencies of open-ended straight resonators using a technique which eliminated end-effect. The experimental results are compared with some recent dispersion theories. An empirical dispersion formula is independently developed, and is shown to provide well-fitting curves for all the measured dispersion results.
TL;DR: In this article, a microstrip or stripline four-port structure which allows two signal paths to physically cross over while maintaining high isolation is described, and the structure is shown to work well in the presence of high isolation.
Abstract: A microstrip or stripline four-port structure which allows two signal paths to physically cross over while maintaining high isolation is described in this letter.
TL;DR: In this article, a closed-form characteristic equation was derived from the variational formulation of the wave propagation in an optical fiber, provided that the permittivity in the core is proportional to r/sup alpha, where r is the radial coordinate and 1 < alpha < /spl infin/, and the cladding is uniform.
Abstract: This paper describes first that a simple closed-form characteristic equation can be derived from the variational formulation of the wave propagation in an optical fiber, provided that 1) the permittivity in the core is proportional to r/sup alpha/, where r is the radial coordinate and 1 < alpha < /spl infin/, and 2) the cladding is uniform. The obtained equation is then solved for various permittivity (or refractive-index) profiles. The results obtained are useful both for the understanding of the dispersion characteristics and for the design of inhomogeneous optical fibers. The optimum profile for a multimode fiber is derived and discussed
TL;DR: In this paper, the information given by (10) on page 125 has been incompletely stated and is therefore misleading, and therefore it is therefore unsuitable to be used in this paper.
Abstract: In the above paper, the information given by (10) on page 125 has been incompletely stated and is therefore misleading.
TL;DR: In this paper, the quasi-static characteristics of single microstrip lines on sapphire substrates cut with a specified orientation were investigated and a new permittivity parameter epsilon/sub req/ was introduced, which is a function of the Iinewidth to substrate-height ratio W/h.
Abstract: The well-defined and repeatable electrical properties of single-crystal sapphire make it an attractive substrate material for microstrip, but its dielectric anisotropy constitutes an important design complication. This paper describes investigations into the quasi-static characteristics of single microstrip lines on sapphire substrates cut with a specified orientation. To account for anisotropy, a new permittivity parameter epsilon/sub req/ is introduced, which is a function of the Iinewidth to substrate-height ratio W/h. The variation of epsilon/sub req/ with W/h is derived by finite-difference methods. Universal curves for microstrip on correctly orientated sapphire are presented, showing 1) epsilon/sub req/, 2) the low-frequency limit of effective microstrip permittivity epsilon/sub e0/, and 3) the characteristic impedance of the line Z/sub 0/, all as functions of W/h.
TL;DR: An improved broadband microstrip-to-slot transition has an insertion loss of less than 0.2 dB and is not critical in its dimensions as mentioned in this paper, however, the insertion loss is high in the dimensions of the microstrip.
Abstract: An improved broad-band microstrip-to-slot transition has an insertion loss of less than 0.2 dB and is not critical in its dimensions.
TL;DR: In this article, a moderately high gain alumina dielectric rod antenna that is entirely compatible with insular integrated circuits has been designed and tested for millimeter-wave integrated-circuit applications.
Abstract: The design of dielectric rod antennas for millimeter-wave integrated-circuit applications is described. The experimental investigation was initially performed for sealed models at Ku band and then developed at V band. A moderately high-gain alumina dielectric rod antenna that is entirely compatible with insular integrated circuits has been designed and tested. The antenna has been fabricated and integrated, as one of the system components, into short-range V-band transmitter and receiver moduIes. The measured gain was found to be 15.2 dB. Radiation characteristics are discussed.
TL;DR: In this paper, a hybrid integrated downconverter with a Schottky-barrier diode pair and a stripline conductor pattern has been proposed, which is linearly scaled from an optimized 5-GHz model.
Abstract: Hybrid integrated downconverters which are pumped at half the frequency needed in a conventional downconverter have shown a conversion loss of 3 dB at 50 GHz and 6 dB at 100 GHz with a corresponding single-sideband (SSB) receiver noise figure of 7 dB at 50 GHz and 11 dB at 100 GHz. The circuits are linearly scaled from an optimized 5-GHz model. Each downconverter consists of a stripline conductor pattern, a novel transition from waveguide to stripline, and a Schottky-barrier diode pair. The circuits can be tuned over a useful RF bandwidth of 20 GHz, and they can be readily scaled to other frequency bands.
TL;DR: In this paper, a wide-band microwave balun is described in which the normally balanced line is in the form of a pair of equal-amplitude and antiphase unbalanced lines.
Abstract: A new wide-band microwave balun particularly attractive for microstrip circuitry is described in which the normally balanced line is in the form of a pair of equal-amplitude and antiphase unbalanced lines. This novel method of input-output coupling allows a coplanar arrangement of input and output microstrip lines. Often the balanced and unbalanced line impedances in a balun are unequal, necessitating an impedance-matching network. A first-order reflection coefficient theory that mutually considers the impedance effects of the balun cavity, a compensating stub, and a quarter-wave transformer is used to design wide-band impedance-matched baluns. Curves of VSWR versus bandwidth are presented for several balanced-to-unbalanced line-impedance ratios. Experimental results are given for an octave-band impedance-matched balun with a balanced-to-unbalanced impedance ratio of 2:1. The new wide-band balun is adaptable to a microstrip magic tee. A proposed magic tee that relies on circuit symmetry for operation has multioctave bandwidth potential.
TL;DR: In this paper, the noise power at the IF output of a superheterodyne mixer which is caused by localoscillator noise can be significantly reduced by using the recently developed subharmonically pumped down-converter.
Abstract: The noise power at the IF output of a superheterodyne mixer which is caused by local-oscillator noise can be significantly reduced by using the recently developed subharmonically pumped down-converter. In many cases this reduction is so large that even noisy sources, such as IMPATT oscillators, can be used to pump low-noise mixers without causing significant degradation of noise figure.
TL;DR: Modifications of microwave techniques for in vivo rapid inactivation of brain enzymes offer greater rapidity and homogeneity of inactivation and the microwave-treated brain remains suitable for regional dissection.
Abstract: The paper describes modifications of microwave techniques for in vivo rapid inactivation of brain enzymes. These modified techniques offer greater rapidity and homogeneity of inactivation. The microwave-treated brain remains suitable for regional dissection.
TL;DR: In this paper, a power GaAs MESFET with a high drain-source breakdown voltage in excess of 17 V has been developed, where a selective GaAs epitaxial process is introduced to form "inlaid" n+ source and drain regions that can provide a high source source breakdown voltage and a low ohmic contact resistance.
Abstract: A power GaAs MESFET with a high drain-source breakdown voltage in excess of 17 V has been developed. A selective GaAs epitaxial process is introduced to form "inlaid" n+ source and drain regions that can provide a high drain-source breakdown voltage and a low ohmic-contact resistance. Typical characteristics of the MESFET composed of two-cell units are as follows:
TL;DR: In this article, the inductive component of the equivalent circuit of microstrip step change in width and cross junctions has been evaluated theoretically and a comprehensive set of results is presented, and experimental results for one set of step changes in width obtained using the resonant method compare well with theory.
Abstract: The inductive component of the equivalent circuit of microstrip step change in width and cross junctions has been evaluated theoretically and a comprehensive set of results is presented. Experimental results for one set of step changes in width obtained using the resonant method compare well with theory.
TL;DR: In this article, the authors investigated excess conduction losses and discrepancies between theoretical and measured values of waveguide attenuation and surface resistance, and provided comprehensive experiments to isolate the effects contributing to the discrepancies and excess losses.
Abstract: Excess conduction losses and discrepancies between theoretical and measured values of waveguide attenuation and surface resistance are investigated. The results of comprehensive experiments to isolate the effects contributing to the discrepancies and excess losses are presented.