Microelectronic realization and circuit properties of a circulator

In the design of sequential relay circuits one often has to consider the circuit as a part of a larger system, and one must take into account the nature of the inputs to the circuit. Frequently, the inputs are two-terminal contact networks with one terminal grounded; such inputs will be called simple. This paper examines the formal design techniques as applied to circuits with simple inputs. It is shown that all relays should be considered as secondary, from the point of view of both races and minimization. Several other shortcomings of the present theory are pointed out. Properties of circuits with simple inputs are examined. It is shown that there are flow tables not realizable without races with simple inputs, and that the presently known secondary assignment methods are not applicable to circuits with simple inputs.

Semiconductor technology has made significant advancements in the telecommunication market in the past few years. There are considerable and increasing demands for higher frequency application, such as for digital cellular phone systems, Personal Handy Phone System (PHS), wireless LAN systems and other mobile communication applications. Therefore, the synthesis of RF signals with low noise loss characteristics becomes important . The market requirements demands that the package or functional substrate also be smaller, has a lower cost and a higher performance. In order to satisfy these market demands, improvements in the size, electrical characteristics, reliability, and cost improvements for high frequency package design technology is necessary. Techniques using equivalent circuits have been popular in the design of high frequency circuits in the past. However, the applicable frequency band is very narrow and limited, particularly in the GHz frequency range. Modeling by equivalent circuits is very complicated, cumbersome, and too difficult to incorporate. Inevitably, the need for adjustment, which requires a large amount of time and labor, is very difficult to efficiently perform the high frequency circuit designs in the GHz range. Using S parameter techniques for high frequency range parameters synthesized in the several tens of giga hertz bands (microwave regions), a method has been developed which can predict the performance characteristics. This method can be applied as a basic design technique.

We have developed a bi-directional neural network as a massively parallel computing architecture for the design of semiconductor devices and circuits. We call this operation reverse modeling since the neural network trained to model a circuit is used in a reverse direction. A feedforward neural network can be used to model the behavior of a system. It can quickly predict the system response of given input parameters. We have extended the applications of neural networks beyond their traditional roles of black box models. Our approach begins with a neural network trained to model the response of the circuit to design parameters. The reverse modeling is then carried out by applying a modified backpropagation learning rule to the trained network. This changes the multi-layer, feedforward neural network from a uni-directional model into a bi-directional model. In the forward direction, the neural network model predicts the circuit property from given design parameters. In the reverse direction, design parameters are synthesized from desired circuit properties. We have demonstrated this reverse modeling approach by designing an RF amplifier. A neural network was trained to model the relations between the matching circuit elements of the amplifier and its output characteristics (output power and power gain). The result model has an average error of 1.7%. The trained model was then used to synthesize matching circuits for 10 sets of desired output characteristics. The neural network synthesized circuits were simulated using LIBRA to verify their performance. The simulated circuit performance was, in average, within 2.6% of the desired characteristics.

Coaxial connectors can be used either to probe the electrical properties of microwave circuits (e.g., microstrip, stripline) or as a permanent interface to the circuit. When used as a permanent interface, connectors can degrade circuit performance unless their electrical properties are characterized and accounted for during circuit design. Although it is more common to characterize microwave devices using scattering parameters (Collin, 1966) S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ij</sub> , we have chosen to utilize impedance parameters since they simplify the derivation of equations presented in this article. The proposed measurement-based method for connector characterization is exact in the sense that its theoretical foundation uses no approximations or assumptions

Retina-inspired neuromorphic edge enhancing and edge detection

Conventional active noise cancelling (ANC) headphones perform well in reducing the low-frequency noise and isolate high-frequency noise by earmuffs passively. These systems often use high-speed digital signal processors (DSPs) to cancel out the disturbing noise at such low frequencies, which result in a high-power dissipation for a commercial ANC headphone. This paper proposes a high-performance feedforward ANC architecture and implements a high-performance low power circuit design accordingly based on the filtered-x least mean square (FxLMS) adaptive algorithm. Experimental results show that the proposed high-performance circuit design can reduce disturbing noise of various frequency bands very well, and outperforms the existing works. After fabricating by using the TSMC 90nm CMOS technology, the proposed design can attenuate 15 dB for the broadband pink noise between 50–1500 Hz when operated at 10 MHz clock frequency at the costs of 84.2 k gates and power consumption of 6.42 mW only.

This paper presents the efforts to introduce integrated circuit (IC) design to Electronics engineering undergraduate students, using the LASI program. The professional Computer-aided Design (CAD) systems for IC design are expensive in terms of hardware, CAD tools and CAD licenses. The next problem connected to their use for educational purposes is the need of training on both the CAD software and the UNIX system. The Windows LASI system is a freeware CAD environment for a full-custom Very Large Scale Integration (VLSI) microelectronic circuits design, intended for educational purposes. The LASI tool is employed for teaching IC design in Electronics engineering undergraduate program at the Department of Electronics, Ruse University, Bulgaria. The paper provides description of the Microelectronics courses, LASI system, technology, and an example design.

IN a preceding paper, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> an attempt was made to present a design point of view, indicating that the criterion for a design method is its direct ability to provide the construction data whereby desired machine specifications are met. The idea was illustrated by a procedure for polyphase motor design, stripped of refinements, and employing a magnetic circuit of fixed contour. Such a condition arises through the use of standard laminations in which designs are made. The questions naturally, arise as to how these laminations are proportioned and what affect the proportions have on performance. It is with such matters that the present paper is concerned, directed chiefly at motors with semiclosed slots of 50 horsepower or less.

In this work, we propose a novel memristor chaotic circuit, which combines current feedback op amp with four basic electronic components, such as capacitance, inductance, resistance and memristor. The dynamic properties of the new circuit are demonstrated, such as system dissipation, equilibrium stability, phase portrait, Lyapunov exponent spectrum, and parameter influence. Numerical simulation results show that the circuit produces a kind of special chaotic attractor and exhibits complicated chaotic behaviour with the evolution of the system parameters. In order to confirm the correctness of the system, a realizing circuit is designed, Pspice simulation results verify the correctness of theoretical analysis.

Transmission spectra from single-layers of high dielectric permittivity (ɛ = 7) glass spheres have been measured, in microwave region, for different angular incidences. The same systems have been calculated by Finite-Difference Time-Domain (FDTD) method. The dispersion diagrams of photonic bands in triangular geometries have been obtained for a number of different compactness cases. The experimental and the calculated photonic band structures show a good agreement in all the compactness values studied. They were also compared with the Mie resonances of the isolated spheres. The results indicate that the characteristics of the Mie resonances appear dominant in the photonic band structure as the compactness of the lattice decreases. Dispersion diagrams present several low dispersion photonic bands, independent of incidence-angle, with high Q-values, that could be useful for future applications of the considered structures like filters or solar cells.

Contribution: This paper demonstrates positive outcomes from reflection-on-action by engineering students, including meaningful insights on their performance, professional and academic practices, and design knowledge as well as promising preliminary exam results. Background: Literature from the engineering education community underlines the benefits of reflection-based upon theories, such as Experiential Learning Theory, and calls for additional use of reflection in engineering education and associated scholarly work. Intended Outcomes: The authors intended for students to obtain meaningful academic and professional insights with implications for their future performance and to perform better on subsequent related exams via reflection. Application Design: Post-quiz and post-design reflective exercises were implemented in two electrical and computer engineering courses, Microelectronic Circuits and Advanced Digital Design, to drive student analysis of differences between their designs or calculations and the “standard solution” using simulation software and question prompts. Reflection-on-action was chosen to enhance students' post-activity understanding and insight, as ultimate learning requires reflection whereby students identify errors and strategies for improvement. Findings: Results demonstrated the value of reflection-on-action using post-activity comparisons and simulation. The students' reflective content and interviews demonstrated substantial professional and academic insights from and appreciation for reflection. On the Microelectronics final exam, a medium effect was associated with the reflection, and for the Digital Design exam, the effect was small to medium. Differences in depth levels of the students' reflections associated with the two types of problems (quiz questions versus design) were evident, suggesting problem type may impact depth.

Introduction to Circuit Analysis and Design

In vibration energy harvesting systems, mechanical damping is reduced to minimum to get large electrical power output. However, small mechanical damping will result in a narrow bandwidth in the frequency domain. This will lead to non-ideal performance when the excitation frequency does not match with the natural frequency. In human body energy harvesting backpack, the human comfort will also have to take into consideration besides harvesting power. In this paper, we proposed an electrical damping tuning method for energy harvesting backpack. The electrical damping will change according to the excitation frequency to achieve high power output at lower frequency. In this way, the frequency bandwidth increases. At resonance and high frequency, the damping will be tuned to control the maximum stroke of the backpack. This will make the wearer feel comfortable while substantial power is harvested. The electrical damping tuning circuit senses the input frequency and tunes the electrical damping accordingly. The circuit design and the control strategy are described in detail. Experiment will be done to validate the design goals.

In this paper, on-wafer de-embedding methods for passive components are evaluated for millimeter wave integrated circuit (MMW IC) design support. An electromagnetic simulation aided de-embedding (EMSAD) technique is proposed. The electromagnetic model is calibrated by matching the open-short de-embedded measurement at relatively lower frequencies. A set of Ground Coplanar Waveguide (GCPW) test structures fabricated on HLMC 40nm RF CMOS process are used for the investigation. The results of the proposed technique are used as reference for de-embedding of passive components at millimeter wave frequencies. As a result, the open-short de-embedding method is found to lose its accuracy above 60GHz in this work.

As the efforts to increase the data rate of single-ended signaling continues, the design of reference voltage generation circuit will likely become more challenging due to the uncorrelated supply-induced noise in particular and external and internal noise in general between signal input and the reference voltage. This is because the receiver of the single-ended interface relies on a reference voltage to reliably discriminate between logic high and low levels at the receiver input. This paper introduces the design of reference voltage generation circuits with the ability to track low and high frequency changes in power supply levels using high order networks. The advantage of the proposed method is demonstrated using measurement and simulation results of a high-speed system based on pseudo open drain signaling running at data rate of 12.8 Gbps.