Abstract — RF circuits exhibit several distinguishing characteristics that make them difficult to simulate

Fast and accurate computation of the steadystate response of large nonlinear networks under periodic and quasi-periodic drive is a key simulation problem for integrated RF designs. In this paper we describe recent work which extends the method of Harmonic Balance to networks containing several million unknowns. A new implementation is described, which includes new methods of preconditioning linear solves and an efficient method of storing derivative information. Then we report simulation and bench measurement results for several large designs, including a complete dual-conversion transmitter chip with extracted layout parasitics. I. Introduction The explosive growth in RF silicon ICs, largely for portable wireless communication, has placed new demands on transistor-level simulation tools: (1) The need to find the steady-state response of a nonlinear network driven by one or more periodic stimuli; In the case of more than one periodic stimulus, the driving periods may not always be har...

Power amplifiers (PAs) are important elements in modern communications systems and they are inherently nonlinear. Nonlinearity generates spectral regrowth in digitally modulated signals and its level is tightly controlled by regulatory bodies. In this paper, we present a closed form expression for the auto-covariance function of the PA output, whose Fourier transform yields the output power spectral density (PSD). The most important feature of our work is that we do not assume the input to be Gaussian. The PSD calculation can be done using common PA descriptions such as the AM/AM and AM/PM characteristics, or, 3rd-order, 5th-order, 7th-order intercept points and the ldB compression point. These analytical results allow us to predict spectral regrowth without running expensive or time-consuming time-domain simulations; they also lead to a variety of optimization possibilities in transmitter design that includes the PAs.

We describe powerful new techniques for the analysis of RF circuits. Next-generation CAD tools based on such techniques should enable RF designers to obtain a more accurate picture of how their circuits will operate. These new simulation capabilities will be essential in order to reduce the number of design iterations needed to produce complex RF ICs. 1 Introduction Design methodology and superior computer-aided design tools are key to success in the integrated circuit (IC) business. They are particularly important in the case of radio-frequency (RF) IC applications, where the digital IC divide-and-conquerdesign style, based on partitioning by functional blocks and abstraction levels, does not apply. The goal of an RF designer is to get a manufacturable design that meets the specifications with minimum cost, under severe time-to-market constraints. Unlike traditional discretecomponent RF design, prototyping is practically impossible, and the validation of a design can only be done b...

The paper presents a novel, unified technique to evaluate, through physics-based modeling, the frequency conversion and noise behavior of semiconductor devices operating in large-signal periodic regime. Starting from the harmonic balance (HB) solution of the spatially discretized physics-based model under (quasi) periodic forced operation, frequency conversion at the device ports in the presence of additional input tones is simulated by application of the small-signal large-signal network approach to the model. Noise analysis under large-signal operation readily follows as a direct extension of classical approaches by application of the frequency conversion principle to the modulated microscopic noise sources and to the propagation of these to the external device terminals through a Green's function technique. An efficient numerical implementation is discussed within the framework of a drift-diffusion model and some examples are finally provided on the conversion and noise behavior of rf Si diodes.

The expansion of the market for portable wireless communication devices has given a tremendous push to the development of a new generation of low-power radio frequency integrated circuit (RFIC) products. In this fast-growing environment where time-to-market constraints force tight schedules, having a good design methodology, innovative computer-aided design (CAD) tools, and a well-integrated design system are key factors to success. In this paper, we describe a design system developed to provide the designer with everything necessary to accurately predict the behavior of RFIC devices, including layout and package parasitic effects. We show how important a well-defined and integrated system is to manufacturing a design that meets specifications at the minimum cost, in the minimum time. A close link between schematic, models, and layout is of paramount importance to ensure the accuracy needed for low-power RF design. We give an overview of the advanced methods and tools currently available for simulation and noise analysis of RF devices. Finally, we show a design example that obtained first-silicon success. Keywords—Design automation, design methodology, design system, device modeling, layout design, layout parasitics, low power, power amplifier, RF integrated circuit design, RF integrated circuit simulation, substrate coupling, substrate noise. I.

This paper describes each of these aspects and provides an overview of associated development work. 1.

OF THE MASTER'S THESIS Author: Janne Roos Name of the thesis: Frequency-domain analysis of nonlinear circuits using Chebyshev polynomials Date: February 22, 1994 Number of pages: 64 Faculty: Electrical Engineering Professorship: Circuit Theory Supervisor: Prof. Martti Valtonen A new frequency-domain method is implemented in APLAC (an ObjectOriented Analog Circuit Simulator and Design Tool). The method can be used for the numerical steady-state analysis of nonlinear circuits. Nonlinear components are described with one-, two-, or three-dimensional Chebyshev expansions, depending on the number of controlling voltages.

LUNSFORD II, PHILIP J. The Frequency Domain Behavioral Modeling and Simulation of Nonlinear Analog Circuits and Systems. (Under the direction of Michael B. Steer.) A new technique for the frequency-domain behavioral modeling and simulation of nonautonomous nonlinear analog subsystems is presented. This technique extracts values of the Volterra nonlinear transfer functions and stores these values in binary files. Using these files, the modeled substem can be simulated for an arbitrary periodic input expressed as a finite sum of sines and cosines. Furthermore, the extraction can be based on any circuit simulator that is capable of steady state simulation. Thus a large system can be divided into smaller subsystems, each of which is characterized by circuit level simulations or lab measurements. The total system can then be simulated using the subsystem characterization stored as tables in binary files.

The recent trend in modern information technology has been towards the increased use of portable and handheld devices such as cellular telephones, personal digital assistants (PDAs), and wireless networks. This trend presents the need for compact and power efficient radio systems. Typically, the most power inefficient device in a radio system is the power amplifier (PA). PA inefficiency requires increased battery reserves to supply the necessary DC bias current, resulting in larger devices. Alternatively, the length of time between battery charges is reduced for a given battery size, reducing mobility.