Showing papers in "IEEE Transactions on Microwave Theory and Techniques in 1973"
TL;DR: In this article, the boundary value problem associated with the open microstrip line structure is formulated in terms of a rigorous, hybird-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 the OML line.
Abstract: The boundary value problem associated with the open microstrip line structure is formulated in terms of a rigorous, hybird-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 the open microstrip line Numerical results are included for several different structural parameters These are compared with other available data and with some experimental measurements
435Â citations
IBM1
TL;DR: In this paper, an integral-equation (IE) computer-solution technique is presented to calculate capacitances for three-dimensional conductors located on parallel planes, which minimizes computer storage requirements while maintaining calculating efficiency computation times.
Abstract: The design and packaging of integrated circuits requires the calculation of capacitances for three-dimensional conductors located on parallel planes. An integral-equation (IE) computer-solution technique is presented, which provides accurate results. The solution technique minimizes computer storage requirements while maintaining calculating efficiency computation times.
377Â citations
TL;DR: In this article, the transmission characteristics of a thick conducting plate perforated with either circular or rectangular holes are presented, and simple explicit formulas for predicting energy leakage through a reflector surface are derived.
Abstract: Transmission characteristics of a thick conducting plate perforated with either circular or rectangular holes are presented. Simple explicit formulas for predicting energy leakage through a reflector surface are derived.
265Â citations
TL;DR: The impulse-response description of interdigital transducers is extended to allow calculation of transducer input admittance and filter frequency response with much less effort than required by earlier equivalent-circuit model approaches.
Abstract: The design of surface acoustic wave bandpass filters which utilize interdigital electrode transducers is reviewed. The impulse-response description of interdigital transducers is extended to allow calculation of transducer input admittance and filter frequency response with much less effort than required by earlier equivalent-circuit model approaches. The application of the impulse model to the straightforward design of VHF and higher frequency bandpass filters is discussed and several examples of high-performance surface-wave bandpass filters are given.
240Â citations
TL;DR: The assumption that the quasi-TEM mode on microstrip is primarily a single longitudinal-section electric (LSE) mode leads to a transmission line model whose dispersion behavior can be analyzed and related to that of microstrip as mentioned in this paper.
Abstract: The assumption that the quasi-TEM mode on microstrip is primarily a single longitudinal-section electric (LSE) mode leads to a transmission line model whose dispersion behavior can be analyzed and related to that of microstrip. Appropriate approximations yield simple, closed-form expressions that allow slide-rule prediction of microstrip dispersion.
238Â citations
TL;DR: In this article, the theory of wave propagation on Iossless multiconductor transmission lines with inhomogeneous dielectrics is developed using matrix analysis, which has the advantage of identifying propagation modes in a way that permits straightforward physical interpretation.
Abstract: The theory of wave propagation on Iossless multiconductor transmission lines with inhomogeneous dielectrics is developed using matrix analysis. The treatment is concise and complete and has the advantage of identifying propagation modes in a way that permits straightforward physical interpretation. The equivalent circuit for the general line is derived and its application to the solution of wave problems with reflections is demonstrated. Special consideration is given to the problem of characteristically terminating a multiconductor line, i.e., terminating without reflections. The realizability of such a characteristic termination network is discussed, and proofs of realizability are given for the important cases of all lines with homogeneous dielectrics and all three-conductor lines, regardless of dielectric inhomogeneities. Symmetric three-conductor lines are discussed to exemplify the general theory, and an application to the problem of mode conversion on symmetric and asymmetric shielded strip lines is given.
183Â citations
TL;DR: In this article, a universal mode chart for the microstrip ring resonator based on a radial waveguide model is presented, where the resonant frequency is related to the width of the ring conductor.
Abstract: A universal mode chart for the microstrip ring resonator, based on a radial waveguide model, is presented. The resonant frequency is related to the width of the ring conductor. Experimental results from 4 to 16 GHz are shown to be in good agreement with the theory.
149Â citations
TL;DR: In this paper, a reflective array compressor (RAC) was developed for the reflection of surface elastic waves at normal and oblique incidence from periodic arrays of grooves and overlayer stripes, which provided guidelines for the choice of the type of reflector, the reflection angle, and the depth of groove.
Abstract: A new type of surface-wave device has been developed which uses the reflection of surface elastic waves to achieve a desired transfer function. A series of experiments on the reflection of surface waves at normal and oblique incidence from periodic arrays of grooves and overlayer stripes provided guidelines for the choice of the type of reflector, the reflection angle, and the depth of grooves. A prototype pulse-compression filter with a time-bandwidth product of 1500 (T=30 /spl mu/S, /spl Delta/f=50 MHz) has been developed. The grooves were etched into LiNbO/sub 3/ by a neutralized argon ion beam in a manner which provided precise depth control and a desired amplitude response. This reflective-array compressor (RAC) has proved to be relatively free of spurious signals and second-order effects and, as a result, large capacities have been obtained. In the prototype device, rms phase errors were 3.5 deg or less and, as a result, the compressed-pulse sidelobe structure was near ideal. A compression ratio of 1500 was demonstrated. The same device, when operated over a wider bandwidth, yielded a compression ratio of about 4000 with only a modest sacrifice in the level of the time sidelobes.
132Â citations
TL;DR: In this article, the properties of acoustic surface waveguides are reviewed, with particular reference to topographic structures in which guiding is achieved by drastic deformation of the substrate surface, and a numerical technique, capable of computing efficiently and with high accuracy the mode spectrum of an anisotropic piezoelectric heterogeneous waveguide of arbitrary cross section, is described.
Abstract: The properties of acoustic surface waveguides are reviewed, with particular reference to topographic structures in which guiding is achieved by drastic deformation of the substrate surface. A numerical technique, capable of computing efficiently and with high accuracy the mode spectrum of an anisotropic piezoelectric heterogeneous waveguide of arbitrary cross section, is described. Characteristics of both the ridge guide and the recently discovered wedge waveguide are discussed in some detail. Techniques for the fabrication of and transduction onto acoustic surface waveguides are discussed, and a preliminary assessment is made of potential linear and nonlinear waveguide applications. A number of experimental devices are described.
124Â citations
TL;DR: In this article, the induced electric fields inside the model exposed to either plane wave or near fields can be described by a combination of quasi-static electric and magnetic induction solutions, and it is shown that for field impedances less than 1200/spl pi/spl Omega/ the magnetically induced energy absorption predominates.
Abstract: The induced fields and the associated power deposition in mail exposed to HF electromagnetic (EM) fields have been investigated theoretically using spherical models. The induced electric fields inside the model exposed to either plane wave or near fields can be described adequately by a combination of quasi-static electric and magnetic induction solutions. It is shown that for field impedances less than 1200/spl pi//spl Omega/ the magnetically induced energy absorption predominates. Therefore, H fields must be measured to obtain any estimate of the hazards due to HF exposure. For a 70-kg model of man exposed to a plane wave field, the theory indicates that the time-average power absorption per unit volume is less than 2.5x10/sup -3/ mW/g for each milliwatt per square centimeter incident at 20 MHz and below. This suggests that the thermal safe-exposure levels for the HF band are many orders of magnitude in excess of the 10-mW/cm/sup 2/ level recommended for the microwave region.
108Â citations
TL;DR: The integral equations governing the electrostatics of the excess charge distribution near microstrip rightangle bends, T junctions, and crossings are formulated and subsequently solved by a projective method as mentioned in this paper.
Abstract: The integral equations governing the electrostatics of the excess charge distribution near microstrip rightangle bends, T junctions, and crossings are formulated and subsequently solved by a projective method. Extensive discontinuity capacitances are presented in graphical form. Where possible, the data are compared to the available experimental results.
TL;DR: In this article, an explicit least-squares criterion is put forward as an alternative to the point-matching method of numerically solving scattering problems, which has been largely ignored in numerical approaches to electromagnetic scattering.
Abstract: An explicit least-squares criterion is put forward as an alternative to the point-matching method of numerically solving scattering problems. While being an established method of functional approximation, it has been largely ignored in numerical approaches to electromagnetic scattering. In contrast to point matching, the least-squares approach has a rigorous proof of convergence. An electric/magnetic weighting factor is found useful in optmizing convergence. Finally, it allows use of perhaps the fastest and most compact matrix inversion algorithm.
TL;DR: In this article, a simple model to describe a nonlinear device or system is proposed which extends the power series expansion, conventionally restricted to amplitude nonlinearities, to include phase non-linearities as well.
Abstract: A simple model to describe a nonlinear device or system is proposed which extends the power series expansion, conventionally restricted to amplitude nonlinearities, to include phase nonlinearities as well. Four different test methods are selected for which the experimentally observed nonlinearity parameters are related to the "gain" and "phase" coefficients of the extended series. A set of simplified relationships is derived where the "1-dB gain compression point" represents gain contributions only while phase nonlinearities are included in the "intercept point," the "third-order intermodulation (IM) coefficients," and the "noise-power-ratio (npr)." For a TWT amplifier in which phase nonlinearities dominate, the third-order IM coefficient was measured. The results are compared with those calculated from single-tone and noise-loading tests using the relationships derived from the model. Agreement to /spl plusmn/ 1 dB is found over a 15-dB power range.
TL;DR: In this paper, the multistrip coupler performs the function of a directional coupler for freely propagating surface acoustic waves on a piezoelectrically active substrate.
Abstract: The multistrip coupler performs the function of a directional coupler for freely propagating surface acoustic waves on a piezoelectrically active substrate. Its operation is analyzed in terms of a transmission line based equivalent circuit. Expressions are obtained for the directionality (transmission and reflection) in terms of the number of coupler strips and the acoustic frequency. Theory and experiment are shown to be in very good agreement. 50-percent metallization is found to give optimum performance; progressive increase in the proportion of the coupler area covered with metal is shown to involve a progressive change from an inline field model to a crossed-field model. Outside a stopband region it is found that a simplified expression for the directionality is valid; this greatly facilitates component design. Design criteria for multistrip components are discussed in terms of substrate and bandwidth requirements. An analysis is included of resistive and capacitative effects on coupling, and problems associated with coupling between dissimilar materials are discussed.
TL;DR: In this article, several new synthesis techniques are described for the design of tapered corrugated waveguide low-pass filters, which can be constructed to work directly from dimensions generated by a computer.
Abstract: Several new synthesis techniques are described for the design of tapered corrugated waveguide low-pass filters. Previous techniques are based on image-parameter methods which are both nonoptimum and difficult to apply to new specifications. The new synthesis methods give filters which can be constructed to work directly from dimensions generated by a computer. The impedance tapering implies that the terminating impedance transformers used in the image-parameter designs may be either eliminated or reduced in length.
TL;DR: The multistrip coupler is a directional coupler which operates on freely propagating surface acoustic waves with broad bandwidth and low loss as mentioned in this paper, and it can perform the function of collinear beamwidth compression.
Abstract: The multistrip coupler is a directional coupler which operates on freely propagating surface acoustic waves with broad bandwidth and low loss. The applications of simple multistrip couplers with straight strips are discussed together with descriptions and properties of a family of multistrip components that can perform particular operations. Stepped couplers can perform the function of collinear beamwidth compression and a surface-wave "magic T" may be constructed. Bent, U-shaped, and J-shaped structures are considered that may redirect or reflect acoustic beams, and results are presented for a multistrip unidirectional transducer. Complex acoustic circuits may be built up using these elements. A beam may be reflected and stepped to the side by one track width, and both directions of a delay line may be used sequentially to double its capacity. The spurious triple transit signal of a delay line is shown to be virtually eliminated at the expense of an extra 3-dB single transit loss.
TL;DR: In this paper, a theoretical and experimental study of the electromagnetic resonances of spheres is presented, in particular the scattering characteristics of spheres inside rectangular waveguides are investigated at and around the resonant frequencies.
Abstract: A theoretical and experimental study of the electromagnetic resonances of spheres is presented. In particular, the scattering characteristics of spheres inside rectangular waveguides are investigated at and around the resonant frequencies. The approach is based on the scattering theory developed by Mie in 1908. Mie's theory is valid for scattering of a plane electromagnetic wave by a homogeneous and isotropic sphere of arbitrary diameter. It encompasses both lossless and lossy spheres. Three continuous functions of frequency are presented. They contain information on the resonant frequencies, the Q-factors, and the output power losses of the sphere. The effect of losses on the resonant behavior was also studied. The theoretical results were compared to experimental data. The agreement between theory and experiment is excellent. An experimental study of the effect of inhomogenities and irregularities of the sphere's material and shape was also made.
TL;DR: In this article, conformal mapping calculations of impedance and effective dielectric constant are presented for coplanar waveguide (CPW) lines with finite-substrate thickness, and experimental data show a departure from the intinite dielectoric approximation as the substrate thickness approaches the guide slot width.
Abstract: Conformal mapping calculations of impedance and effective dielectric constant are presented for coplanar waveguide (CPW) lines with finite-substrate thickness. These calculations and experimental data show a departure from the intinite dielectric approximation as the substrate thickness approaches the guide slot width. The quasi-TEM approximation is retained and calculations of static energy density within the substrate are given. This approximation agrees well with field calculations using a finite-element solution to Laplace's equation.
TL;DR: A new type of signal-processing device which employs the parametric interaction between surface or volume acoustic waves passing in opposite directions through an acoustic delay line is described.
Abstract: A new type of signal-processing device which employs the parametric interaction between surface or volume acoustic waves passing in opposite directions through an acoustic delay line is described. These devices are capable of giving the real-time convolution of two modulated signals, and the time inversion of an arbitrary signal. As one signal acts as the reference for the other, a virtually infinite range of electronically variable signal-processing functions, such as recognition of digital codes, pulse compression of an FM chirp, and the realization of a fast Fourier transform, is possible. Early devices which employed the nonlinearity of the acoustic medium tended to give outputs of the order of 60 dB less than the input signal. Recent developments, in which a semiconductor placed near the piezoelectric medium interacts with the acoustic wave, have yielded results where the loss from input to output is of the order of 30 dB.
TL;DR: In this article, a finite element technique was used to find the necessary harmonic functions and eigenfunctions for the admittance matrix of a planar network with all ports shorted.
Abstract: The port admittance matrix of a planar network is formulated in terms of certain harmonic functions related to the port voltages and the network geometry, together with the natural modes of the network with all ports shorted. The necessary harmonic functions and eigenfunctions are found using a finite element technique, for which general-purpose computer programs already exist. An advantage of the method is that the admittance matrix appears in partial-fraction form with geometric data separated from frequency, leading to inexpensive computations where recalculation at various frequencies is required.
TL;DR: In this paper, it was shown that the apparent position of the short is a small fraction of a wavelength beyond the end of the slot and that the reactance seen at the end is, therefore, inductive.
Abstract: An investigation of the end effect in a shorted-slot line is described. It is shown that the apparent position of the short is a small fraction of a wavelength beyond the end of the slot. The reactance seen at the end of the slot is, therefore, inductive. Experimental curves are presented which show normalized inductive reactance versus frequency for substrates with /spl epsi//sub r/ =12 and /spl epsi//sub r/=20 for several slot widths.
TL;DR: In this article, it was shown that the large-signal S-parameters are relatively independent of power once the device is turned on, making it possible to extend modified small-Signal Sparameter design techniques to largesignal power amplifiers.
Abstract: High-power UHF transistors have been characterized through the use of large-signal S-parameters. These S-parameters have been used successfully to design UHF power amplifiers. Waveform measurements show that due to the Q of the package parasitic, most class C operated UHF power transistors have nearly sinusoidal waveforms at their package terminals. Experimental evidence presented shows that the large-signal S-parameters are relatively independent of power once the device is turned on. These two observations make it possible to extend modified small-signal S-parameter design techniques to large-signal power amplifiers.
TL;DR: In this paper, a technique is described that makes possible the accurate measurement of the dielectric constant of microwave integrated-circuit substrates, where the substrate is metallized on all sides, forming a tiny resonant cavity, and the resonant frequencies are determined either from transmission or reflection.
Abstract: A technique is described that makes possible the accurate measurement of the dielectric constant of microwave integrated-circuit substrates. The substrate is metallized on all sides, hence forming a tiny resonant cavity, and the resonant frequencies are determined either from transmission or reflection. The dielectric constant is then calculated to an accuracy of better than 1 percent.
TL;DR: In this article, a method for calculating the capacitance of a circular disk on a dielectric substrate backed by a ground plane is presented, where Hankel transforms and Galerkin's method are used to derive the expression for capacitance.
Abstract: A method for calculating the capacitance of a circular disk on a dielectric substrate backed by a ground plane is presented. Hankel transforms and Galerkin's method are used to derive the expression for the capacitance. Numerical results are compared with the experimental data and good agreement is reported.
TL;DR: In this paper, a generalized design approach for ladder networks consisting of a cascade of constituent two-port networks connected by short lengths of transmission lines is presented, which enables the general ladder network to be equated to a prototype network at a reference frequency.
Abstract: A generalized design approach is presented for ladder networks consisting of a cascade of constituent two-port networks connected by short lengths of transmission lines. The design is made possible by the derivation of simple equations which define the inverter impedance and associated reference planes of any passive lossless reciprocal two-port. This enables the general ladder network to be equated to a prototype network at a reference frequency. An example is given of the design of a coaxial low-pass filter where fringing capacitances are compensated automatically.
TL;DR: In this paper, a broad-band linear FM dispersive filter with a time-bandwidth (TB) product of 1000 has been proposed, which can achieve a CW insertion loss of less than 35 dB.
Abstract: The development of a low-loss broad-band linear FM dispersive filter having a time-bandwidth (TB) product of 1000 is discussed. Two systems applications for highly dispersive linear FM filters--pulse compression RADAR and a microscan receiver--are discussed with emphasis on filter performance requirements. The principal factors which influence the design of surface-wave filters are reviewed and theoretical design procedures are outlined. The 1000:1 filters, which are implemented on strong-coupling YZ lithium niobate, typically meet the design goal of a 100-MHZ rectangular passband and have a CW insertion loss of less than 35 dB. Measured data are presented for the filter performance in a pulse-compression loop and in a prototype broad-band microscan (compressive) receiver.
TL;DR: In this paper, the inductance of finite-length strips over a ground plane is calculated by the Galerkin method in terms of the quasi-static skin effect equation, and the numerical technique used is discussed and sample results are presented.
Abstract: The inductances of finite-length strips over a ground plane are calculated by the Galerkin method. The formulation is in terms of the quasi-static skin-effect equation. The numerical technique used is discussed and sample results are presented.
TL;DR: In this paper, the authors proposed a temperature reference for high-precision radiometry, which has an accurately known radiometric temperature, a very low reflection coefficient, and whose geometry is well suited to the calibration of horn antennas.
Abstract: The calibration of microwave radiometers is normally achieved by replacing the antenna with a cooled reference termination and then applying corrections for ohmic and reflective losses of the antenna, and for the nonideality of the reference termination. The uncertainty in this correction is the dominating factor in the precision of many high-quality radiometers, and for some applications it is unacceptably large. An alternative is to point the antenna at a target of known temperature. To the extent that this temperature is known and the target is reflectionless and encompasses the full view of the antenna, the calibration is ex'act and no further corrections are required. A target suitable for high-precision radiometry has been developed that has an accurately known radiometric temperature, a very low reflection coefficient, and whose geometry is well suited to the calibration of horn antennas. The essence of the temperature reference is described. A piece of porous microwave absorber having a convoluted surface for a low reflection coefficient is fitted with a cap of nonporous plastic foam whose mating surface is the inverse of that of the absorber. The microwave-absorbing material is then soaked with the chosen cryogen, the nonporous cap forcing the liquid to conform to the shape of said absorbing material. This procedure 1) ensures that the temperature at which the microwaves are absorbed (and therefore thermally emitted) is exactly that of the cryogen, and 2) avoids the reflection that would be produced by the dielectric discontinuity of a plane surface of cryogen.
TL;DR: In this article, a novel design procedure for diplexers built in waveguides below cutoff is presented, where the whole unit is built in a single waveguide, thereby dispensing with the T junction and connecting flanges.
Abstract: A novel design procedure for diplexers built in waveguides below cutoff is presented. The design permits the integral construction of a diplexer--the whole unit is built in a single waveguide, thereby dispensing with the T junction and connecting flanges--if coaxial termination is used at the common junction. The design utilizes foreshortened bandpass filters, and is valid for bandwidths of up to a few percent. Simple expressions on calculating the connecting lengths are arrived at. A satellite telemetry diplexer designed using the derived expressions yields results which are in agreement with computed values.
TL;DR: In this paper, the junction-voltage waveshapes resulting from a 9.375 GHz sinusoidal localoscillator generator voltage are computed for three common equivalent-circuit models of the Shottky-barrier diode.
Abstract: The waveshape of the local-oscillator voltage component that exists across the nonlinear junction of a Shottky-barrier diode is a fundamental determinant of mixer performance. This waveshape significantly differs from that of the total local-oscillator voltage impressed across the diode terminals since it is influenced by parasitic, particularly spreading resistance and contact inductance, which exist in series with the junction. The junction-voltage waveshapes resulting from a 9.375-GHz sinusoidal local-oscillator generator voltage are computed for three common equivalent-circuit models of the diode. In the first model the diode is represented by a nonlinear conductance in series with a fixed spreading resistance. The second model includes the nonlinear capacitance associated with the junction, and the third additionally includes the contact inductance. In each case, the junction-voltage waveshape is significantly nonsinusoidal. It is shown that the contact inductance can induce a peak inverse junction voltage that greatly exceeds the peak voltage impressed across the diode terminals. This parasitic reactance thus can have an important bearing on the burnout properties of the mixer diode.