Computer-aided Design Of Microwave Circuits Research Articles

Multisectional modeling of high-speed electrooptic modulators integrated in a microwave circuit CAD environment

We present a new multisectional model for high-speed electrooptic modulators, fully integrated within the framework of a microwave circuit computer-aided design (CAD) suite (MWOFFICE). Starting from geometrical and layout parameters, the model allows both simple (traveling-wave) and complex (phase reversal, periodically loaded) structures to be assembled, analyzed, and optimized from the standpoint of the electrical and electrooptic response (including chirp effects) both in small-signal (analog) and in large-signal (digital) operation, exploiting standard simulator tools. At no additional effort, parasitic and passive elements (such as optical or electrical delay paths) can be directly included in the modulator schematic, and the effect of transitions and package parasitics can be readily accounted for at a circuit level. Moreover, model integration within a circuit CAD suite enables one to seamlessly perform driver and modulator design and optimization within the same monolithic or hybrid circuit environment. Comparisons with experimental and literature data and design examples are presented to validate the approach and stress its potential in the design of high-speed electrooptic modulators.

Multidimensional Cauchy method and adaptive sampling for an accurate microwave circuit modeling

This paper presents an effective generic approach for computer-aided design of microwave circuits. We extend the one-dimensional Cauchy method for frequency-response interpolation to a multidimensional Cauchy interpolation, with respect to both frequency and physical dimensions. This paper also demonstrates the feasibility of applying adaptive sampling to the multidimensional rational-function expansion. Three examples, including optimization and Monte Carlo analysis, have been given to verify the validity of the proposed approach.

Order-recursive Gaussian elimination (ORGE) and efficient CAD of microwave circuits

Planar circuit elements in millimeter-wave integrated circuits (MMIC's) typically consist of one or more discontinuities (e.g. stubs) connected to a number of transmission lines. In the computer-aided design (CAD) and optimization of such passive elements using the method of moments, it is necessary to iteratively simulate many subproblems involving dimensional changes to various parts of the circuit. On examining the simulation problem closely, it can be seen that there is a considerable overlap of data in various subproblems. In practice, each subproblem is solved independent of others, without taking into account the duplication of data. This leads to an inefficient design technique. In this paper, we present a design technique that effectively exploits the duplication of data by employing a recursive variant of Gaussian elimination, called order-recursive Gaussian elimination (ORGE). The potential utility of ORGE in microwave circuit simulation and CAD is demonstrated by applying it to the design of a microstrip filter.

A unified theory for frequency-domain simulation and sensitivity analysis of linear and nonlinear circuits

The harmonic balance technique from nonlinear simulation is extended to nonlinear adjoint sensitivity analysis. This provides an efficient tool for the otherwise expensive but essential gradient calculations in design optimization. The hierarchical approach widely used for circuit simulation, is generalized to sensitivity analysis and to computing responses in any subnetwork at any level of the hierarchy. Important aspects of frequency-domain circuit computer-aided design (CAD) such as simulation and sensitivity analysis, linear and nonlinear circuits, hierarchical and nonhierarchical approaches, voltage and current excitations, or open- and short-circuit terminations are unified in this general framework. The theory provides a basis for the next generation of microwave CAD software. It takes advantage of mature techniques such as syntax-oriented hierarchical analysis, optimization, and yield-driven design to handle nonlinear as well as linear circuits. The sensitivity analysis approach has been verified by a MESFET mixer example, exhibiting a 90% saving of CPU time over the prevailing perturbation method. >

Microwave engineering and systems applications

SYSTEMS: Microwave Communications Systems Microwave Radar Systems Electronic Warfare Systems MICROWAVE TRANSMISSION, CONTROL, DETECTION, AND GENERATION: Transmission Line Concepts Computational Methods for Transmission Line Problems Computer-Aided Design of Microwave Circuits Planar Transmission Lines and Components Microwave Filter Theory Ferrites Microwave Antennas Linear Passive Applications of Microwave Diodes (Switches, Limiters, and Digital Phase Shifters) Nonlinear and Active Applications of Microwave Diodes (Detectors, Mixers, Harmonic Generators, and Oscillators) Three-Terminal Active Devices Microwave Amplifier and Oscillator Design Monolithic Microwave Integrated Circuits Microwave Tubes MICROWAVE MEASUREMENTS: Practical Microwave Components and Power Measurements Time Domain Management Frequency Domain Measurements MICROWAVE SUBSYSTEMS: Microwave Receiver Front-End Design Transmitters.

Computer-aided design of microwave circuits

computer-aided design of microwave circuits

Book Review: Computer-Aided Design of Microwave Circuits

Book Review: Computer-Aided Design of Microwave Circuits

Efficient Calculation of Exact Group Delay Sensitivities

This paper presents, explicitly, an approach to the exact calculation of group delay and its sensitivities with respect to component parameters based on the adjoint network concept and applicable to linear time-invariant circuits. In general, no more than four analyses are required and the computational effort is only moderately more than is necessary for a single analysis. The results presented are in a form particularly suited to the computer-aided design of microwave circuits and include useful tables of sensitivity expressions.