Bridging the Gap between Physical and Circuit Analysis for Variability-Aware Microwave Design: Modeling Approaches

Abstract

Process-induced variability is a growing concern in the design of analog circuits, and in particular for monolithic microwave integrated circuits (MMICs) targeting the 5G and 6G communication systems. The RF and microwave (MW) technologies developed for the deployment of these communication systems exploit devices whose dimension is now well below 100 nm, featuring an increasing variability due to the fabrication process tolerances and the inherent statistical behavior of matter at the nanoscale. In this scenario, variability analysis must be incorporated into circuit design and optimization, with ad hoc models retaining a direct link to the fabrication process and addressing typical MMIC nonlinear applications like power amplification and frequency mixing. This paper presents a flexible procedure to extract black-box models from accurate physics-based simulations, namely TCAD analysis of the active devices and EM simulations for the passive structures, incorporating the dependence on the most relevant fabrication process parameters. We discuss several approaches to extract these models and compare them to highlight their features, both in terms of accuracy and of ease of extraction. We detail how these models can be implemented into EDA tools typically used for RF and MMIC design, allowing for fast and accurate statistical and yield analysis. We demonstrate the proposed approaches extracting the black-box models for the building blocks of a power amplifier in a GaAs technology for X-band applications.

TCAD Modeling of GaN HEMT Output Admittance Dispersion through Trap Rate Equation Green’s Functions

“…In order to validate the implemented approach, the GF analysis is compared to the Y parameters directly obtained from repeated AC analyses of ( 1)-( 4) with varying trap energy (incremental method, INC). The accuracy is excellent and the saving in simulation time with the GF approach is remarkable (roughly 50% of the INC analysis) [30]. The values of R out at low and high frequency are practically unchanged with varying trap energy, while the frequency at which the transition occurs shifts to lower values with increasing E CT .…”

Analysis of Doherty Power Amplifier Matching Assisted by Physics-Based Device Modelling

“…The device output and transcharacteristics are shown in Figure 1. The MAIN amplifier is a class AB stage with 10% I DSS (V GS = −3 V) and V DS = 8 V, bias conditions that were used in previous works [31] for the design of a single-stage class AB amplifier. The bias point is shown in Figure 1 (red square marks).…”

Power Receiving Unit for High-Power Resonant Wireless Power Transfer

“…The numerical study based on concurrent electronic design automation (EDA) tools such as the OrCAD 17.2-2016 PSpice software makes it difficult to accurately analyze the nonlinear networks. Open-source software, such as YalRF [26] or the commercial software Advanced Design System 2024 Update 1.0 (ADS) [27] from Keysight Technologies Inc. (Santa Rosa, CA, USA), can be used to find the steady-state response of autonomous circuits with periodic and quasiperiodic responses based on the Harmonic Balance method [28]. These software tools are not yet comprehensive for the circuit designer without knowing the parameter-dependent subharmonic frequencies.…”

“…Energies 2023, 16, x FOR PEER REVIEW 18 of 2 (Santa Rosa, CA, USA), can be used to find the steady-state response of autonomous cir cuits with periodic and quasiperiodic responses based on the Harmonic Balance method [28]. These software tools are not yet comprehensive for the circuit designer withou knowing the parameter-dependent subharmonic frequencies.…”