Showing papers in "IEEE Transactions on Microwave Theory and Techniques in 1974"
IBM1
TL;DR: In this paper, partial element equivalent circuits (PEECs) are derived from an integral equation to establish an electrical description of the physical geometry of the PEECs, which are general in that they include losses.
Abstract: Multiconductor or multiwire arrangements find many applications in electronic systems. Examples are interconnections between digital circuits or integrated microwave circuits. Equivalent circuit models are derived here from an integral equation to establish an electrical description of the physical geometry. The models, which are appropriately called partial element equivalent circuits (PEEC), are general in that they include losses. Models of different complexity can be constructed, to suit the application at hand.
1,166Â citations
TL;DR: In this paper, a tensor integral equation for the electric field inside the body was derived and solved numerically for various biological models, and a theoretical method was developed to determine the electromagnetic field induced inside heterogeneous biological bodies of irregular shapes.
Abstract: A theoretical method has been developed to determine the electromagnetic field induced inside heterogeneous biological bodies of irregular shapes. A tensor integral equation for the electric field inside the body was derived and solved numerically for various biological models.
406Â citations
TL;DR: In this paper, a simple method is described to calculate the capacitances of rectangular and circular microstrip disk capacitors, and the influence of the fringing field on the resonance frequencies of microstrip disks resonators is calculated.
Abstract: A simple method is described to calculate the capacitances of rectangular and circular microstrip disk capacitors. From the edge capacitances of the capacitors the influence of the fringing field on the resonance frequencies of microstrip disk resonators is calculated. A theory to compute the resonance frequencies of microstrip resonators with high accuracy is presented. The resonance frequencies are calculated from a resonator model employing an effective width and length or radius, respectively, filled with a medium of a "dynamic dielectric constant." Theoretical and experimental results are compared and found to be in agreement within 1 percent.
296Â citations
TL;DR: In this paper, the authors have characterized the microwave permeability of partially magnetized materials and showed that the real part of the tensor permeability elements, /spl mu/, /spl kappa/, and/spl mu//sub z/, depends primarily on the parameters /spl gamma/4/spl pi/M/M//spl omega/ and /spl Gamma/ 4/spl π/m/sub s/ /spl omega/.
Abstract: In order to assist the microwave engineer in predicting the performance of partially magnetized devices, we have characterized the microwave permeability of partially magnetized materials. The real part of the tensor permeability elements, /spl mu/, /spl kappa/, and /spl mu//sub z/, depends primarily on the parameters /spl gamma/4/spl pi/M//spl omega/ and /spl gamma/4/spl pi/M/sub s/ / /spl omega/. Empirical formulas have been developed which show the dependence. At frequencies sufficiently below /spl omega/ = /spl pi/4/spl pi/M/sub s/, the loss can be characterized by the value of /spl mu/'' at 4/spl pi/M = 0./spl mu/, /spl kappa/, and /spl mu//sub z/ depend weakly on composition, whereas /spl mu/'' (4/spl pi/M = 0) does depend upon the chemical composition.
214Â citations
TL;DR: In this article, the authors describe the mathematical steps necessary for de-embedding and unterminating with theoretically redundant measurements in order to minimize the effect of experimental errors, where the electrical properties of the intervening structure are known.
Abstract: De-embedding is the process of deducing the impedance of a device under test from measurernents made at a distance, when the electrical properties of the intervening structure are known. Unterminating is the process of deducing the electrical properties of the intervening structure from a series of measurements with known embedded devices. The mathematical steps necessary for de-embedding and unterminating with theoretically redundant measurements in order to minimize the effect of experimental errors.
209Â citations
TL;DR: In this paper, the equivalent circuit of an inductive strip inserted in the middle of a waveguide parallel to the E plane is analyzed theoretically by evaluating the inductive reactance of the equivalent T network which was obtained by the Rayleigh-Ritz variational technique.
Abstract: The equivalent circuit of an inductive strip inserted in the middle of a waveguide parallel to the E plane is analyzed theoretically by evaluating the inductive reactance of the equivalent T network which was obtained by the Rayleigh-Ritz variational technique. A design theory for the bandpass filter of this type is derived from this equivalent circuit. The confirmation between the design theory and the experimental resuIts is also shown.
179Â citations
TL;DR: In this article, an accurate and efficient method was developed for computing the resonant frequencies of microstrip resonators, which was carried out rigorously using the full-wave analysis rather than the quasi-static approximation.
Abstract: An accurate and efficient method was developed for computing the resonant frequencies of microstrip resonators. The formulation of the problem was carried out rigorously using the full-wave analysis rather than the quasi-static approximation. The characteristic equation was derived using Galerkin's method applied in the Fourier transform domain. The accuracy of the method has been proven by comparing the numerical results with the experimental data. Numerical data have been provided for the microstrip resonators with different structural parameters. Finally, the results for microstrip resonators have been used for predicting the end effect at the open end of microstrip structures.
176Â citations
TL;DR: In this article, an analysis of the input impedance and an approximate equivalent circuit for the Y-junction circulator is presented, which shows the relationship between Bosma's equivalent circuit and that of Fay and Comstock.
Abstract: Octave bandwidth operation of Y-junction stripline and microstrip circulators is predicted using Bosma's Green's function analysis. The width of the coupling transmission lines is found to be a significant design parameter. Theoretical and experimental results are presented which show that wide lines and a smaller than usual disk radius can be used to obtain wide-band operation. A microstrip circulator is reported which operates from 7-15 GHz. Also presented are an analysis of the input impedance and an approximate equivalent circuit for the Y-junction circulator which shows the relationship between Bosma's equivalent circuit and that of Fay and Comstock.
162Â citations
TL;DR: Coax-slot and microstrip-slot transitions are discussed in this article, where experimental VSWR and impedance data are presented and compared with values computed using equivalent circuits for these transitions.
Abstract: Coax-slot and microstrip-slot transitions are discussed Experimental VSWR and impedance data are presented and compared with values computed using equivalent circuits for these transitions Thick-film chip terminations are also investigated
160Â citations
TL;DR: In this paper, the boundary value problem associated with the shielded microstripline structure is formulated in terms of a rigorous hybrid-mode representation, and the resulting equations are subsequently transformed, via the application of Galerkin's method in the spectral domain, to yield a characteristic equation for the dispersion properties of shielded microstrip lines.
Abstract: The boundary value problem associated with the shielded microstripline structure is formulated in terms of a rigorous hybrid-mode representation. The resulting equations are subsequently transformed, via the application of Galerkin's method in the spectral domain, to yield a characteristic equation for the dispersion properties of shielded microstrip lines. Among the advantages of the method are its simplicity and rapid convergence. Numerical results are included for several different structural parameters. These are compared with other available data and with some experimental results.
131Â citations
TL;DR: In this article, the relative effectiveness of lithium ferrites, nickel, magnesium, and garnets as elements employed in latching applications at frequencies in the S, C, X, and K/sub u/ bands was discussed.
Abstract: Lithium ferrites are discussed and compared with other spinel microwave ferrites and rare earth-iron garnets. Points of comparison are saturation magnetization, temperature performance, hysteresis loop properties, stress sensitivity, insertion loss, power handling capability, resonance linewidth, and cost. The main points of discussion deal with the relative effectiveness of lithium ferrites, nickel ferrites, magnesium ferrites, and garnets as elements employed in latching applications at frequencies in the S, C, X, and K/sub u/ bands. A section is devoted to the compositional modifications necessary for: 1) adjusting magnetization, spin-wave line width, coercive force, and magnetic anisotropy; 2) the minimization of stress sensitivity and dielectric loss; and 3) the improvement of microstructural characteristics.
TL;DR: In this article, a method of applying the transmission-line matrix method to inhomogeneous waveguide structures is described, which uses open-circuit stubs of variable characteristic impedance at each node in the matrix, thereby providing an analog for a dielectric.
Abstract: A method of applying the transmission-line matrix method to inhomogeneous waveguide structures is described. The technique uses open-circuit stubs of variable characteristic impedance at each node in the matrix, thereby providing an analog for a dielectric. LSE and LSM modes in rectangular waveguides, and problems involving a step of dielectric are solved. Results are given in terms of the cutoff frequency and field pattern for continuous waveguides, and the waveguide input impedance for scattering problems.
TL;DR: By using explicit formulas instead of iterative methods, the computing time for the correction of the scattering parameters of the unknown two-port is significantly reduced and the addition of leakage paths will only have a minor effect on computational complexity while measurement accuracy will increase.
Abstract: Formulas are presented for the direct calculation of the scattering parameters of a linear two-port, when it is measured by an imperfect network analyzer. Depending on the hardware configuration of the test set, the measurement system is represented by one of two flowgraph models. In both models presented, leakage paths are included. The error parameters, i.e., the scattering parameters of the measuring system, are six respective ten complex numbers for each frequency of interest. A calibration procedure, where measurements are made on standards, will determine the error parameters. One of many possible calibration procedures is briefly described. By using explicit formulas instead of iterative methods, the computing time for the correction of the scattering parameters of the unknown two-port is significantly reduced. The addition of leakage paths will only have a minor effect on computational complexity while measurement accuracy will increase.
TL;DR: In this article, the synthesis of narrow-band pass waveguide filters having flat group delay and optimum-amplitude characteristics is described, which utilizes either single- or dual-mode waveguide cavities.
Abstract: The synthesis of narrow-bandpass waveguide filters having flat group delay and optimum-amplitude characteristics is described. The design utilizes either single- or dual-mode waveguide cavities. Experimental results for a 40-MHz-bandwidth filter centered at 4 GHz show excellent agreement with theory.
TL;DR: In this article, the performance of diode phase shifters in L, S, C, and X bands has been evaluated in the presence of a driver and a typical circuit.
Abstract: This paper contains considerations for diode phase shifters used for phased array antenna control. The categories are: 1) areas in which ferrite and diode phase shifters differ, 2) diode phase-shifter circuits, 3) the nature and typical performance of p-i-n diodes, 4) the requirements of a driver and a typical circuit, and 5) measured performance of phase shifters in L, S, C, and X bands.
TL;DR: In this article, the authors proposed very stable CW operation, very high pulsed output, linear polarization, high gain, and many other advantages over discharge excitation over the submillimeter-wave region.
Abstract: Optical pumping of polar molecules by means of infrared lasers is expected to lead to thousands of laser lines throughout the submillimeter-wave region. Already, 282 new laser lines between 34 mu m and 1.814 mm in 18 different molecules have been reported. Very stable CW operation, very high pulsed output, linear polarization, high gain, and many other advantages over discharge excitation are offered.
TL;DR: The most relevant techniques that have either found or should find useful application in analyzing microwave circuit performances in the frequency domain are surveyed and a comparison is made between the direct method and the transpose-matrix method, which is in certain cases similar to the method based on the adjoint circuit.
Abstract: The most relevant techniques that have either found or should find useful application in analyzing microwave circuit performances in the frequency domain are surveyed. The particular needs of the microwave engineer are briefly discussed. Circuit equation formulations in terms of voltages and currents and wave variables are presented and the solution of the set of circuit equations by sparse-matrix techniques is illustrated. Methods based on multiport connection are also reviewed. The techniques for computing the first- and second-order sensitivity are illustrated and a comparison is made between the direct method and the transpose-matrix method, which is in certain cases similar to the method based on the adjoint circuit.
TL;DR: In this paper, a detailed analysis is made of the appropriate form of the radiation condition in cylindrical and toroidal systems, and is applied to the calculation of radiation from curyed dielectric slabs and fibers.
Abstract: The form taken by the radiation condition in the local coordinate system, pertinent to the determination by perturbation methods of the radiation from curved radiating structures, is not the same as it is at very great distances. Specifically, it may contain a term that appears as if it were an incoming or growing wave. A detailed analysis is made of the appropriate form of the condition in cylindrical and toroidal systems, and is applied to the calculation of radiation from curyed dielectric slabs and fibers.
TL;DR: In this paper, the authors presented the development of two microwave integrated circuit (MIC) broadband, high-performance directional couplers with dielectric overlays, and the respective nominal coupling values of these components are 6 and 10 dB with useful bandwidths in excess of 3.4:1.
Abstract: This paper presents the development of two microwave integrated circuit (MIC) broad-band, high-performance directional couplers with dielectric overlays. The respective nominal coupling values of these components are 6 and 10 dB with useful bandwidths in excess of 3.4:1. Thorough descriptions of the design procedure, performance, and fabrication techniques are presented in sufficient detail to permit duplication of these couplers. The computer-aided design method used to develop these couplers is modeled to treat parallel-coupled microstrip lines with a dielectric overlay and is also suitable for developing directional filters and Schiffman phase shifters of similar construction. This and other design methods available for developing dielectric-overlay couplers are reviewed with particular attention given to related technological areas that warrant further investigation.
TL;DR: A comparison of methods for the numerical solution of the hollow waveguide problem is presented in tabular form in this paper, and a table lists waveguide shapes and their cutoff characteristics that have been presented in the literature.
Abstract: A comparison of methods for the numerical solution of the hollow waveguide problem is presented in tabular form. Another table lists waveguide shapes and their cutoff characteristics that have been presented in the literature. These tables and the bibliography afford an aid towards the selection of a method.
TL;DR: In this article, a new system for millimeter-wave integrated circuits is proposed, where high-resistivity silicon is used as a medium for a dielectric waveguide.
Abstract: A new system is proposed for millimeter-wave integrated circuits. It is suggested that high-resistivity silicon be used as a medium for a dielectric waveguide. With the advent of high-resistivity silicon, propagation can occur with relatively low Ioss. Furthermore, since the medium is a semiconductor compatible with active devices, it is proposed that active devices can be constructed directly in the semiconductor dielectric guide or appendaged directly on the surface. The basic approach is similar to that used in integrated optics, except that the medium for millimeter-wave guidance is a semiconductor and the control devices rely on conductivity modulation rather than on electrooptical effects. Some particular devices suggested are oscillator, mechanical and electronic phase shifters, amplitude modulators (switches), and detectors. The first of such devices investigated has been the electronic phase shtiter. Related theory and experiments are reported here. In addition, preliminary results on oscillators imbedded in a dielectric resonator are presented.
TL;DR: In this article, a new design theory is presented based on a sparse capacitance matrix for the array of coupled lines that constitute the filter, as opposed to a sparse-inductance-matrix assumption in previous theories that is much harder to satisfy.
Abstract: Hairpin-line and hybrid hairpin-line/half-wave parallel-coupled-line filters are preferred filters for microstrip and TEM printed-circuit realizations. This class of filters offers small size and, in general, needs no ground connections for resonators. A new design theory is presented that is based on a sparse capacitance matrix for the array of coupled lines that constitute the filter, as opposed to a sparse-inductance-matrix assumption in previous theories that is much harder to satisfy. It is shown that to a good approximation, hairpin-line filters result from frequency-scaling half-wave parallel-coupled-line filters. Because of this; the bandwidth can be accurately predicted. Design procedures are given for Type-A filters, which are useful up to 20-percent bandwidth. A variety of hybrid hairpin-line/half-wave parallel-coupled-line filters is possible, and their design is explained. Numerical results for a number of designs and experimental results for a 5-percent bandwidth filter are included.
TL;DR: In this article, the dispersion relationship describing the propagation of electromagnetic (EM) surface modes supported by a ferrite slab of finite thickness magnetized parallel to the planes of its air-ferrite-air or air ferrite-metal interfaces is investigated.
Abstract: The dispersion relationship describing the propagation of electromagnetic (EM) surface modes supported by a ferrite slab of finite thickness magnetized parallel to the planes of its air-ferrite-air or air-ferrite-metal interfaces is investigated. Surface wave propagation at frequencies greater than the ferrite-metal mode resonance is predicted for thick grounded ferrite slabs thereby clarifying prior results based upon semi-infinite and magnetostatic analyses. The relative energy densities of the electromagnetic surface modes is examined at the air-ferrite interfaces of an ungrounded slab.
TL;DR: In this article, the modal characteristics of quadruple-ridged circular and square waveguides were investigated and the cutoff frequencies for the first few important modes and cutoff frequencies were determined.
Abstract: A theoretical study, backed by experimental verification, was undertaken to determine the modal characteristics of quadruple-ridged circular and square waveguides Field lines for the first few important modes and cutoff frequencies were determined It is shown that for square waveguides quadruple-ridge loading always decreases the TE/sub 10/-TE/sub 11/ bandwidth whereas for circular waveguides only a small amount of additional separation between the first two fundamental modes may be obtained over a limited parameter range Symmetrical excitation will not excite the asymmetrical higher-order modes This feature makes these waveguides acceptable as feeds for wide-band reflector antennas and for similar applications but raises a question mark regarding their use as radiators in wide-band phases arrays
NEC1
TL;DR: In this paper, the operation modes of a waveguide Y circulator with a circular and a triangular ferrite post were investigated both theoretically and experimentally, taking into account the field variation along the ferrite axis.
Abstract: Operation modes of a waveguide Y circulator with a circular and a triangular ferrite post are investigated both theoretically and experimentally. Field analysis is carried out taking into consideration the field variation along the ferrite axis. Frequencies are calculated by assuming TM modes nearly agree with measured frequencies. It is shown that the circulator action occurs at frequencies where two HE modes interfere with each other, besides occurring at HE mode resonance frequencies. Effects of Teflon spacers on circulator performances are investigated in detail.
TL;DR: In this article, a variational method is used to determine the propagation characteristics of an optical fiber consisting of a core with an arbitrary refractive-index distribution and a uniform cladding, and the obtained characteristic equations for the simplest case (uniform core case) are compared with analytic solutions to ensure the validity of the analysis.
Abstract: The variational method is used to determine the propagation characteristics of an optical fiber consisting of a core with an arbitrary refractive-index distribution and a uniform cladding. The problem is first translated into a variational problem; the factional is computed upon the TEM-approximation basis. The variational problem is then solved by using the Rayleigh-Ritz method. The computed propagation characteristics are presented for refractive-index distributions of practical interest. The single-mode condition for a quadratic self-focusing fiber is obtained as v < 3.53 where v denotes the conventionally used normalized frequency; this result agrees with the numerical analysis by Dil and Blok. The obtained characteristic equations for the simplest case (uniform core case) are compared with analytic solutions to ensure the validity of the analysis.
TL;DR: In this paper, a nonlinear large-signal analysis of local current shape and linear small signal analysis for resistive mixers are made for resistivisual mixers, and the conjugate match method is used to find the minimum conversion loss.
Abstract: Nonlinear large-signal analysis of local current shape and linear small-signal analysis of small-signal products are made for resistive mixers. Iteration adapted from Newton's method was used in the nonlinear analysis. The conjugate match method was used in the linear analysis to find the minimum conversion loss. These theories were applied to a new type spurious suppressed mixer and a reliable computer simulation was made.
TL;DR: In this article, the frequency response of uniform transmission lines consisting of a large number of mutually coupled conductors in homogeneous and inhomogeneous media, and illuminated by an electromagnetic (EM) field is investigated.
Abstract: Computationally efficient numerical methods for determining the frequency response of uniform transmission lines consisting of a large number of mutually coupled conductors in homogeneous and inhomogeneous media, and illuminated by an electromagnetic (EM) field are presented.
TL;DR: In this article, the design and performance of an X-band amplifier with GaAs Schottky-gate field effect transistors are described, and the amplifier achieves 20 /spl plusmn/ 1.3-dB gain with a 5.5-dB typical noise figure (6.9 dB maximum) over the frequency range of 8.0-12.0 GHz.
Abstract: The design and performance of an X-band amplifier with GaAs Schottky-gate field-effect transistors are described. The amplifier achieves 20 /spl plusmn/ 1.3-dB gain with a 5.5-dB typical noise figure (6.9 dB maximum) over the frequency range of 8.0-12.0 GHz. The VSWR at the input and output ports does not exceed 2.5:1. The minimum output power for 1-dB gain compression is +13 dBm, and the intercept point for third-order intermodulation products is +26 dBm. The design of practical wide-band coupling networks is discussed. These networks minimize the overall amplifier noise figure and maintain a constant gain in the band.
TL;DR: A procedure based on an analysis algorithm and practical rules is described for the design of waveguide multiplexer, which enables the designer to quickly find a near-optimum solution in a small number of iteration steps.
Abstract: A procedure based on an analysis algorithm and practical rules is described for the design of waveguide multiplexer. Simple rules, which enable the designer to quickly find a near-optimum solution in a small number of iteration steps, are given. An example of a 6-channel communications multiplexer, which utilizes narrow-bandpass elliptic function waveguide filters, is also included.