Showing papers in "Bell System Technical Journal in 1969"
TL;DR: In this paper, a coupled wave analysis of the Bragg diffraction of light by thick hologram gratings is given, analogous to Phariseau's treatment of acoustic gratings and to the dynamical theory of X-ray diffraction.
Abstract: A coupled wave analysis is given of the Bragg diffraction of light by thick hologram gratings, which is analogous to Phariseau's treatment of acoustic gratings and to the “dynamical” theory of X-ray diffraction. The theory remains valid for large diffraction efficiencies where the incident wave is strongly depleted. It is applied to transmission holograms and to reflection holograms. Spatial modulations of both the refractive index and the absorption constant are allowed for. The effects of loss in the grating and of slanted fringes are also considered. Algebraic formulas and their numerical evaluations are given for the diffraction efficiencies and the angular and wavelength sensitivities of the various hologram types.
5,244 citations
TL;DR: In this paper, the authors studied the transmission properties of a guide consisting of a dielectric rod with rectangular cross section, surrounded by several dielectrics of smaller refractive indices.
Abstract: We study the transmission properties of a guide consisting of a dielectric rod with rectangular cross section, surrounded by several dielectrics of smaller refractive indices. This guide is suitable for integrated optical circuitry because of its size, single-mode operation, mechanical stability, simplicity, and precise construction. After making some simplifying assumptions, we solve Maxwell's equations in closed form and find, that, because of total internal reflection, the guide supports two types of hybrid modes which are essentially of the TEM kind polarized at right angles. Their attenuations are comparable to that of a plane wave traveling in the material of which the rod is made. If the refractive indexes are chosen properly, the guide can support only the fundamental modes of each family with any aspect ratio of the guide cross section. By adding thin lossy layers, the guide presents higher loss to one of those modes. As an alternative, the guide can be made to support only one of the modes if part of the surrounding dielectrics is made a low impedance medium. Finally, we determine the coupling between parallel guiding rods of slightly different sizes and dielectrics; at wavelengths around one micron, 3-dB directional couplers, a few hundred microns long, can be achieved with separations of the guides about the same as their widths (a few microns).
1,620 citations
TL;DR: In this article, light transmission through a curved dielectric rod of rectangular cross section embedded in different dielectrics is analyzed in closed-form, though approximate form, in three ranges: (i) small cross section guides such as a thin glass ribbon surrounded by air; making its width 1 percent of the wavelength, most of the power travels outside of the glass; the attenuation coefficient of the guide is two orders of magnitude smaller than that of glass; and the radius of curvature that doubles the straight guide loss is around 10,000Λ.
Abstract: Light transmission through a curved dielectric rod of rectangular cross section embedded in different dielectrics is analyzed in closed, though approximate form. We distinguish three ranges: (i) Small cross section guides such as a thin glass ribbon surrounded by air—Making its width 1 percent of the wavelength, most of the power travels outside of the glass; the attenuation coefficient of the guide is two orders of magnitude smaller than that of glass, and the radius of curvature that doubles the straight guide loss is around 10,000Λ. (ii) Medium cross section guide for integration optics—It is only a few microns on the side and capable of guiding a single mode either in low loss bends with short radii of curvature or in a high Q closed loop useful for filters. Q's of the order of 108 are theoretically achievable in loops with radii ranging from 0.04 to 1 mm, if the percentage refractive index difference between guide and surrounding dielectric lies between 0.1 and 0.01. (iii) Large cross section guides—They are multimode and are used in fiber optics. Conversion to higher order modes are found more significant than radiation loss resulting from curvature.
699 citations
TL;DR: In this article, a miniature form of laser beam circuitry is proposed, where the index of refraction changes of the order of 10−2 or 10−3 in a substrate such as glass allow guided laser beams of width near 10 microns.
Abstract: This paper outlines a proposal for a miniature form of laser beam circuitry. Index of refraction changes of the order of 10−2 or 10−3 in a substrate such as glass allow guided laser beams of width near 10 microns. Photolithographic techniques may permit simultaneous construction of complex circuit patterns. This paper also indicates possible miniature forms for a laser, modulator, and hybrids. If realized, this new art would facilitate isolating the laser circuit assembly from thermal, mechanical, and acoustic ambient changes through small overall size; economy should ultimately result.
600 citations
TL;DR: A model that generates on-off speech patterns representative of those in experimental two-way telephone conversations that yields good fits to all events except “speech before interruption;” when an interruption occurs, a model speaker tends to interrupt the other's talkspurt later than a real speaker does.
Abstract: This paper describes a model that generates on-off speech patterns representative of those in experimental two-way telephone conversations. The model assumes a conversant to occupy one of three speaking or one of three silent states. Transitions among the states arc determined by Poisson processes governed by six parameters (one for each state). The validity of the model is tested by comparing the model computer simulation of 16 conversations with 16 real conversations. Cumulative distribution functions are compared for ten events (such as talkspurts, pauses, mutual silences, and so on) defined on the speech patterns. The model yields good fits to all events except “speech before interruption;” when an interruption occurs, a model speaker tends to interrupt the other's talkspurt later than a real speaker does. Theoretical behavior of the model is also studied. All events consist of concatenations of exponentially distributed “state durations,” even though most events are not themselves exponential. For some purposes, the exponential distribution is a satisfactory empirical fit to talkspurts, but not to pauses. Possible applications of the model include studying people's motivations to talk and fall silent on different circuits, and predicting statistical behavior of voice operated devices on the circuits.
588 citations
TL;DR: In this article, a computer analysis of the propagating modes of a rectangular dielectric waveguide is presented, based on an expansion of the electromagnetic field in terms of a series of circular harmonics multiplied by trigonometric functions.
Abstract: This paper describes a computer analysis of the propagating modes of a rectangular dielectric waveguide. The analysis is based on an expansion of the electromagnetic field in terms of a series of circular harmonics, that is, Bessel and modified Bessel functions multiplied by trigonometric functions. The electric and magnetic fields inside the waveguide core are matched to those outside the core at appropriate points on the boundary to yield equations which are then solved on a computer for the propagation constants and field configurations of the various modes. The paper presents the results of the computations in the form of curves of the propagation constants and as computer generated mode patterns. The propagation curves are presented in a form which makes them refractive-index independent as long as the difference of the index of the core and the surrounding medium is small, the case which applies to integrated optics. In addition to those for small index difference, it also gives results for larger index differences such as might be encountered for microwave applications.
549 citations
TL;DR: In this article, the authors report the impedance and attenuation measurements performed on microstrips, which are useful for the microwave and millimeter wave hybrid integrated circuits required for solid-state radio systems because of their simplicity and planar structure.
Abstract: Microstrips, transmission lines of metallic layers deposited on a dielectric substrate, are very useful for the microwave and millimeter wave hybrid integrated circuits required for solid-state radio systems because of their simplicity and planar structure. To design hybrid integrated circuits with microstrips requires computation or measurement of the impedance, the attenuation, the guide wavelength, and the unloaded Q of the line. These parameters can be obtained from the effective dielectric constant and the characteristic impedance of the corresponding air line. This paper gives the exact design data for all line parameters for the most important cases. We report the impedance and attenuation measurements performed on microstrips. Satisfactory agreement is obtained with theoretical results based on conformal mapping with logarithmic derivatives of theta functions and expressions involving the partial derivatives of the impedance with respect to independent line parameters.
520 citations
TL;DR: In this article, the behavior of oscillators with multiple-resonant circuits is discussed, and the condition for free-running stable oscillations, injection locking phenomena, the stable locking range, and a condition for parasitic oscillations are discussed.
Abstract: This paper discusses the behavior of oscillators with multiple-resonant circuits. It discusses the condition for free-running stable oscillations, the injection locking phenomena, the stable locking range, the noise of free-running and injection-locked oscillators, and a condition for parasitic oscillations in detail, and presents a graphical interpretation of this study for clarity. Finally, this paper shows how broadbanding of oscillators can be achieved with a double-resonant circuit. This provides a systematic guide for the design of broadband frequency deviators and broadband injection-locked oscillators for numerous applications.
485 citations
TL;DR: In this paper, a perturbation theory which is applicable to the scattering losses suffered by guided modes of a dielectric slab waveguide as a consequence of imperfections of the waveguide wall is presented.
Abstract: This paper contains a perturbation theory which is applicable to the scattering losses suffered by guided modes of a dielectric slab waveguide as a consequence of imperfections of the waveguide wall. The development of the theory occupies the bulk of the paper. Numerical results appear in Sections VI and VIII to which a reader less interested in the theory is referred. The theory allows us to conclude that random deviations of the waveguide wall in the order of 1 percent, for guides designed to guide an optical wave of Λ o = 1μ wavelength, can cause scattering losses of 10 percent per centimeter or 0.46 dB per centimeter. A systematic sinusoidal deviation of the waveguide wall can cause total exchange of energy from the lowest order to the first order guided mode in a distance of approximately 1 cm if the amplitude of the sinusoidal deviation from perfect straightness is only 0.5 percent of the thickness of the guide. An rms deviation of one of the waveguide walls of 9A causes a radiation loss of 10 dB per kilometer (index difference 1 percent, guide width 2.5μ).
378 citations
TL;DR: Applications discussed include: enhancement of poles in spectral analysis, high resolution narrow-band frequency analysis, interpolation of band-limited waveforms, and the conversion of a base 2 fast Fourier transform program into an arbitrary radix fast Fouriers transform program.
Abstract: We discuss a computational algorithm for numerically evaluating the z-transform of a sequence of N samples. This algorithm has been named the chirp z-transform algorithm. Using this algorithm one can efficiently evaluate the z-transform at M points in the z-plane which lie on circular or spiral contours beginning at any arbitrary point in the z-plane. The angular spacing of the points is an arbitrary constant; M and N are arbitrary integers. The algorithm is based on the fact that the values of the z-transform on a circular or spiral contour can be expressed as a discrete convolution. Thus one can use well-known high-speed convolution techniques to evaluate the transform efficiently. For M and N moderately large, the computation time is roughly proportional to (N + M) log 2 (N + M) as opposed to being proportional to N · M for direct evaluation of the z-transform at M points. Applications discussed include: enhancement of poles in spectral analysis, high resolution narrow-band frequency analysis, interpolation of band-limited waveforms, and the conversion of a base 2 fast Fourier transform program into an arbitrary radix fast Fourier transform program.
349 citations
TL;DR: The theory of cylindrical magnetic domains provides conditions governing the size and stability of circular magnetic domains in plates of uniaxial magnetic materials together with an estimate of the range of applicability of these conditions as discussed by the authors.
Abstract: The theory of cylindrical magnetic domains provides conditions governing the size and stability of circular cylindrical magnetic domains in plates of uniaxial magnetic materials together with an estimate of the range of applicability of these conditions The results of the theory are directly applicable to the design of cylindrical domain devices Computation to first and second order of the energy variation resulting from general small deviation in the domain shape from an initially circular shape yields the conditions governing domain size and stability The physical origin of the various terms in the energy expansion is examined in detail A graph from which many domain size and stability properties may be obtained summarizes the results of the energy variation calculation The minimum theoretically attainable domain diameter is approximately σ w /πM2 s , where σ w is the wall energy density and M s , is the saturation magnetization For domains to exist, the effective anisotropy field must be greater than 4πM s
TL;DR: The author examines convergence, rate of convergence, and the effect of noisy observations of the received pulses, and he shows that the noisy observations result in a random sequence of tap weight settings whose mean value converges to a suboptimal setting.
Abstract: This paper analyzes an adaptive training algorithm for adjusting the tap weights of a tapped delay line filter to minimize mean-square intersymbol interference for synchronous data transmission. The significant feature of the adjustment procedure is that convergence is guaranteed for all channel response pulses, even for very severe amplitude and phase distortion. The author examines convergence, rate of convergence, and the effect of noisy observations of the received pulses, and he shows that the noisy observations result in a random sequence of tap weight settings whose mean value converges to a suboptimal setting. The mean-square deviation of the tap weights from the suboptimal values is asymptotically bounded with a bound that can be made as small as desired by sufficiently reducing the speed of convergence. The suboptimality arising here results from the use of isolated test pulses for the training signal. However, a training scheme using pseudorandom sequences or the actual data signal does not suffer from the suboptimality effect. Hence, although of possible utility in other pulse shaping applications, the technique presented here appears to be primarily of value in providing a conceptual framework for the closely related but more practical techniques to be examined in the sequel to this paper to be published shortly.
TL;DR: In this paper, it is shown that if the 2's complement adder is modified so that it "saturates" when overflow occurs, then no self-oscillations will be present.
Abstract: The cascade and parallel realizations of an arbitrary digital filter are both formed using second order sections as building blocks This simple recursive filter is commonly implemented using 2's complement arithmetic for the addition operation Overflow can then occur at the adder and the resulting nonlinearity causes self-oscillations in the filter The character of the resulting oscillations for the second order section are here analyzed in some detail A simple necessary and sufficient condition on the feedback tap gains to insure stability, even with the presence of the nonlinearity, is given although for many desired designs this will be too restrictive A second question studied is the effect of modifying the “arithmetic” in order to quench the oscillations In particular it is proven that if the 2's complement adder is modified so that it “saturates” when overflow occurs, then no self-oscillations will be present
TL;DR: An experimental method for encoding television signals which takes advantage of the frame-to-frame correlation to reduce transmission bit rate is described, demonstrated in real-time using the head-and-shoulder view of a person in animated conversation as the picture source.
Abstract: This paper describes an experimental method for encoding television signals which takes advantage of the frame-to-frame correlation to reduce transmission bit rate. The technique encodes only those elements that change between successive frames instead of encoding every element of every frame. We have demonstrated the method in real-time using the head-and-shoulder view of a person in animated conversation as the picture source, such as is likely to be encountered in a visual communication system. An average transmission rate of one bit per picture element gives quality comparable with standard eight-bit PCM transmission.
TL;DR: In this paper, the authors study two models of a system of queues served in cyclic order by a single server, and find expressions for the mean number of units in a queue at the instant it starts service, the mean cycle time, and the Laplace-Stieltjes transform of the cycle time distribution function.
Abstract: We study two models of a system of queues served in cyclic order by a single server. In each model, the ith queue is characterized by general service time distribution function H i (·) and Poisson input with parameter Λ i . In the exhaustive service model, the server continues to serve a particular queue until the server becomes idle and there are no units waiting in that queue; at this time the server advances to and immediately starts service on the next nonempty queue in the cyclic order. The gating model differs from the exhaustive service model in that when the server advances to a nonempty queue, a gate closes behind the waiting units. Only those units waiting in front of the gate are served during this cycle, with the service of subsequent arrivals deferred to the next cycle. We find expressions for the mean number of units in a queue at the instant it starts service, the mean cycle time, and the Laplace-Stieltjes transform of the cycle time distribution function.
TL;DR: In this article, the authors give new expressions for the permitted bending radius with respect to mode conversion, using coupled-wave theory to categorize the wide variety of transmission media possible.
Abstract: The direction-changing capability of electromagnetic waveguides may be limited not only by mode conversion but also by radiation if the transverse field extends indefinitely into a freely propagating region. This paper gives new, more accurate expressions for the permitted bending radius with respect to mode conversion, using coupled-wave theory to categorize the wide variety of transmission media possible. This paper also makes a suggestion for estimating the permitted bending radius when radiation is a limitation. In single-mode “open” waveguides that have transverse fields extending indefinitely into a freely propagating region (such as a dielectric waveguide), the permitted bending radius is limited by radiation effects, whereas in either the open or completely shielded multimode waveguides, the permitted bending radius is usually limited by mode conversion.
TL;DR: In this article, it was shown that if the short-circuit admittance matrix G of the linear portion of the dc model of a transistor network satisfies a certain dominance condition, then the network cannot be bistable.
Abstract: Several results are presented concerning the equation F(x) + Ax = B (with F(·) a “diagonal” nonlinear mapping of real Euclidean n-space Em into itself, and A a real n × n matrix) which plays a central role in the dc analysis of transistor networks. In particular, we give necessary and sufficient conditions on A such that the equation possesses a unique solution x for each real n-vector B and each strictly monotone increasing F(·) that maps Em onto itself. There are several direct circuit-theoretic implications of the results. For example, we show that if the short-circuit admittance matrix G of the linear portion of the dc model of a transistor network satisfies a certain dominance condition, then the network cannot be bistable. Therefore, a fundamental restriction on the G matrix of an interesting class of switching circuits is that it must violate the dominance condition.
TL;DR: The usefulness of the results presented in this paper is that the designer can have at his disposal very simple expressions with which to evaluate the performance of any given Coherent Phase-Shift Keyed system when the received signal is corrupted by both interference and random gaussian noise.
Abstract: In this paper we present a theoretical analysis of the performance of an m-phase coherent phase-shift keyed system in the presence of random gaussian noise and interference. An explicit expression is given for the probability of error of the phase angle of the received signal; we show that this probability of error can be expressed as a converging power series. We show that the coefficients of this series are expressible in terms of well-known and well-tabulated functions, and we give methods of evaluating the character error rates of the systems. We also show that this error rate is minimum when all the interference power is concentrated in a single interferer, and that it attains its maximum [P m ] max when the total interference power is equally distributed amongst the K interferers. The limiting case when K goes to infinity is considered. The cases of K = 1, and m = 2, 4, 8, and 16 are treated in some detail, and the results are given graphically. The usefulness of the results presented in this paper is that the designer can have at his disposal very simple expressions with which to evaluate the performance of any given Coherent Phase-Shift Keyed system when the received signal is corrupted by both interference and random gaussian noise.
TL;DR: In this paper, a planar array of reversed biased silicon photodiodes is used to obtain a low energy scanning electron beam similar to that used in a conventional vidicon.
Abstract: A new electronic camera tube has been developed for Picturephone® visual telephone applications; with minor modifications it should also be suitable for conventional television systems. The image sensing target of the new camera consists of a planar array of reversed biased silicon photodiodes which are accessed by a low energy scanning electron beam similar to that used in a conventional vidicon. This paper presents a description of the operating principles and an analysis of the sensitivity and resolution capabilities of the new silicon diode array camera tube. We also give the detailed experimental results obtained with the tubes. The gamma of a silicon diode array camera tube is unity and its spectral response is virtually uniform over the wavelength range from 0.45 to 0.90 micron with an effective quantum yield greater than 50 percent. For a 13.4 millimeter square target the silicon diode array camera tube's sensitivity is 20 μamp foot-candles of faceplate illumination with normal incandescent illumination or 1.3 μamp per foot-candle with fluorescent illumination; with a center-to-center diode spacing of 15 micron it's modulation transfer function is greater than 60 percent for a spatial frequency of 14 cycles per millimeter. Typical dark currents for a 13.4 millimeter square target are in the range of 5 to 50 nanoamperes.
TL;DR: In this article, the authors report on the realization of low-loss, thin glass films which can be used for circuit fabrication Methods of preparing planar films and waveguides having rectangular cross section are described along with the techniques used in evaluating their optical characteristics.
Abstract: A series of papers which appeared in the September 1969 issue of the Bell System Technical Journal treated the theory of dielectric waveguides and stressed the potential use of such media for optical communication circuits1−4 Here we report on the realization of low-loss, thin glass films which can be used for circuit fabrication Methods of preparing planar films and waveguides having rectangular cross section are described along with the techniques used in evaluating their optical characteristics
TL;DR: It is shown that a class of differential quantizers is equivalent to ordinary quantizers with respect to the design of dither signals and a design method is given for a number of deterministic and random dither waveforms.
Abstract: Dither signals may be added to coarsely quantized picture signals to mask undesirable contours. We show that a class of differential quantizers is equivalent to ordinary quantizers with respect to the design of dither signals. We give a design method for a number of deterministic and random dither waveforms and evaluate their visibility using a simple model of threshold vision.
TL;DR: In this article, the results of the radiation loss theory in terms of the power spectrum of the function describing the thickness of a dielectric slab waveguide were discussed, and it was shown that only those mechanical frequencies near both end points of this mechanical frequency range contribute more to the radiation losses than the region well inside this range.
Abstract: In an earlier paper I described a perturbation theory of the radiation losses of a dielectric slab waveguide. The statistical treatment of the radiation losses was based on the correlation function of the wall distortion. This paper discusses the results of the radiation loss theory in terms of the power spectrum of the function describing the thickness of the slab. We found that only those mechanical frequencies Θ of the power spectrum contribute to the radiation loss that fall into the range β o - k o + k. (β o = propagation constant of guided mode, k = free space propagation constant.) The mechanical frequencies near both end points of this mechanical frequency range contribute more to the radiation loss than the region well inside of this range. We also discuss the far-field radiation pattern caused by a strictly sinusoidal wall distortion.
TL;DR: A new method for computing the parameters which determine the differential equations governing a linear time-invariant system with multiple inputs and outputs, which is easy generalization to the case when the given data is contaminated with noise.
Abstract: This paper presents a new method for computing the parameters which determine the differential equations governing a linear time-invariant system with multiple inputs and outputs. Unlike earlier approaches the method presented does not involve computation of the impulse response. One of the main advantages of this method is its easy generalization to the case when the given data is contaminated with noise.
TL;DR: In this article, the authors showed that the dielectric loss, the filling factor of the microstrip, and the stored field energy in the substrate can be computed from the partial derivative ∂U/∂∊ r where U is the total electric field energy and ∊ r the relative dielectoric constant of the substrate.
Abstract: Dielectric loss is important in integrated microwave and millimeter wave circuits which require small attenuation. Such circuits are usually built with microstrip or suspended microstrip transmission lines. This paper shows that the dielectric loss, the filling factor of the microstrip, and the stored field energy in the dielectric substrate can be computed from the partial derivative ∂U/∂∊ r where U is the total electric field energy and ∊ r the relative dielectric constant of the substrate. It also shows that the effective loss tangent is determined by the partial derivative ∂∊ eff /∂∊ r where ∊ eff is the effective dielectric constant of the microstrip. Useful design formulas for computing the dielectric loss are given for the most important cases.
TL;DR: A single, constant amplitude, in-band, additive interference is included in the analysis of detecting phase shift keyed signals in gaussian noise, applicable to any M-phase system.
Abstract: A single, constant amplitude, in-band, additive interference is included in the analysis of detecting phase shift keyed signals in gaussian noise. For coherent detection we give a method applicable to any M-phase system, and evaluate the symbol error probability for M = 2, 3, and 4. For differential detection we treat the important cases M = 2, 4, 8, and 16, offering comprehensive numerical results for each. The analysis in each case is based on a single sinusoid with random phase adding to the noisy phase shift keyed signal. The results are then interpreted to include an angle modulation impressed on the continuous wave interferer. The receiver consists of an ideal phase discriminator with a perfect slicer. The channel is also assumed ideal in that intersymbol interference is not considered.
TL;DR: In this article, the authors presented the theory of mode conversion and radiation losses of the lowest order circular electric mode in a dielectric rod (fiber) waveguide and its confirmation by a microwave experiment.
Abstract: This paper presents the theory of mode conversion and radiation losses of the lowest order circular electric mode in a dielectric rod (fiber) waveguide and its confirmation by a microwave experiment. The theoretical results were obtained from a theory whose detailed development has been presented in an earlier paper. The microwave experiment was carried out at approximately 50 GHz. The optical fiber with imperfect walls was simulated by a teflon rod of 1 cm diameter and 1 m length with a periodically corrugated wall. Mode conversion was observed in excellent agreement with theory. The observed radiation losses are somewhat less than the prediction of the perturbation theory, but the agreement is quite good. The direction and width of the far-field radiation pattern was observed in agreement with theory.
TL;DR: A pulse code modulation encoder that employs a delta modulator as the analog-to-digital converter that causes delta modulation signals to be converted to a uniformly quantized PCM format is described.
Abstract: This paper describes a pulse code modulation (PCM) encoder that employs a delta modulator as the analog-to-digital converter A tapped binary shift register and an up-down counter cause delta modulation signals to be converted to a uniformly quantized PCM format When tap weights are optimized with respect to a minimum mean square error criterion, the number of shift register stages necessary to obtain a fixed level of output quantizing noise varies inversely with delta modulation sampling rate Because the tap weights may be rounded to a modest number of binary places, the arithmetic operations are simple to implement A significant portion of the delta modulation-to-PCM converter may be time shared among several signals
TL;DR: This paper is a compendium of results based on a simple observation: two information symbols can be appended to certain nonbinary BCH codes without affecting the guaranteed minimum distance of these codes.
Abstract: This paper is a compendium of results based on a simple observation: two information symbols can be appended to certain nonbinary BCH codes without affecting the guaranteed minimum distance of these codes. We give two formulations which achieve this result; the second yields information regarding the weights of coset leaders for the original BCH codes. Single-error-correcting Reed-Solomon codes with the added information symbols yield perfect codes for the Hamming metric. We use these lengthened Reed-Solomon codes as building blocks for perfect single-error-correcting codes in another metric.
TL;DR: In this article, the electrical properties of passive line elements on insulating substrates are discussed and compared with measurements made at 30 GHz with wideband transitions from waveguide to microstrip and the measurements obtained with microstrip IMPATT oscillators and high order varactor multi-pliers.
Abstract: Hybrid integration of microwave and millimeter wave circuits is essential for achieving future communication objectives in radio systems. Hybrid integrated circuits are circuits which are manufactured on a single planar substrate. Passive elements are fabricated by partial metallization of the substrate; active devices are inserted by bonding semiconductor diodes or bulk devices to the metal conductors. We discuss the electrical properties of passive line elements on insulating substrates. We also compare the design formulas given with measurements made at 30 GHz, and present the results obtained at 30 GHz with wideband transitions from waveguide to microstrip and the measurements obtained with microstrip IMPATT oscillators and high order varactor multi-pliers in the same frequency range. There are advantages of scaling for building hybrid integrated circuits which we discuss. Oversize models can be built and tested in a relatively short time and substantial savings in turnaround time, required man-power, and cost can be achieved.
TL;DR: In this paper, the existence and uniqueness of solutions of the dc equations of nonlinear transistor networks is studied. But the results of earlier work concerned with the existence of the uniqueness of the solutions are extended in several directions to deal directly with a more complicated transistor model.
Abstract: This paper extends, in several directions, some of the results of earlier work concerned with the existence and uniqueness of solutions of the dc equations of nonlinear transistor networks. In particular, here we develop techniques which enable us to deal directly with a more complicated transistor model.