In this paper for the first time, a frequency independent equivalent circuit model is proposed for series stacked inductors having variable width and space (taper) across their turns. The proposed model accounts for the increase in mutual inductance between the stacked spirals due to taper. Also, the proximity effect losses with tapered top and bottom spirals of the series stack is accurately modeled. Finally, the inter-layer capacitance between the stacked spirals which dictates the self-resonant-frequency of the series inductor is calculated across different values of taper. EM simulations and measurements show excellent correlation with model simulations across different layouts with different values of taper thereby demonstrating the scalability of the proposed model. © 2019 IEEE.

Deleep R. Nair

Department of Electrical Engineering

Anjan Chakravorty

Capacitance

Electric inductors

Equivalent circuits

Inductance

Natural frequencies

Mutual inductance

RFIC

SELF RESONANT FREQUENCY

SERIES STACKED

SUBSTRATE CAPACITANCE

Monolithic integrated circuits

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Compact Modeling of Series Stacked Tapered Spiral Inductors

2019 IEEE 19th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, SiRF 2019

This letter presents a technique to accurately predict the proximity effect losses in spiral inductors with variable width and spacing (taper) across the turns. The change in magnetic flux in a spiral turn due to the nearby non-uniformly spaced traces is considered while developing expression that captures proximity effect. A broadband, scalable, and frequency-independent compact model is developed for tapered inductors using the proposed technique. Resistance, inductance, and quality factor plots are shown for spiral inductors with different values of taper. Excellent agreement between model and EM simulated/measured data demonstrates the scalability of the proposed model. The proposed model can be used to accurately predict the high possible with tapered inductors. © 1980-2012 IEEE.

IEEE Electron Device Letters

Compact Modeling of Proximity Effect in High- Q Tapered Spiral Inductors

This brief proposes a technique to increase the performance of spiral inductors through appropriate selection of excitation port, especially in the case of variable width spirals. In this brief, forward excitation refers to applying ac voltage at the outer or upper terminal of the inductor with the inner or lower terminal grounded, while in reverse excitation, the inner or lower terminal is connected to the signal. Performance improvement with reverse excitation is explained using the voltage profile of the spiral. While tapered layout increased the peak-Q from 15.9 to 22.8, reverse excitation increased it further to 26.7. Moreover, reverse excitation also resulted in an increased peak-Q frequency from 5 to 8 GHz and self resonant frequency from 12 to 14.6 GHz in these tapered inductors. On the other hand, a similar approach is shown to be detrimental in the case of series stacked inductors, while symmetric inductors remain unaffected. © 2014 IEEE.

IEEE Transactions on Electron Devices

High-Q characteristics of variable width inductors with reverse excitation

An Analytical Model of Electric Substrate Losses for Planar Spiral Inductors on Silicon

Analytical Formula for Inductance of Metal of Various Widths in Spiral Inductors

International Journal of Numerical Modelling: Electronic Networks, Devices and Fields

An approach for the calculation of magnetic field within square spiral inductors at low frequency

Journal	Data powered by Typeset2019 IEEE 19th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, SiRF 2019
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
Open Access	No