Practical applications of nonlinear measurements

Remley, Kate A.

doi:10.1109/arftg.2009.5278060

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…In contrast to the linear VNA, which measures the magnitude ratio and phase difference between the incident and reflected waves (A 1 and B 1 , respectively) only at the excitation frequency, the NVNA measures the actual A 1 and B 1 waves' magnitudes and phases at the excitation frequency as well as harmonic components to which energy may be transferred due to the device's nonlinear characteristics ( Fig. 4) [18,19]. In this measurement, the excitation frequency f i of the incident wave A 1 was swept from 1 to 15 GHz.…”

Section: B Harmonic Responsementioning

confidence: 99%

Injection Locking at Fractional Frequencies of Magnetic-Tunnel-Junction-Based Read Sensors’ Ferromagnetic Resonance Modes

et al. 2019

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Being nonlinear dynamic systems, magnetic read sensors should respond to an excitation signal of a frequency considerably different from their natural ferromagnetic resonance (FMR) frequencies.Because of the magnetization dynamics' inherent nonlinear nature, the sensors' response should be measured at the DC, excitation frequency, and its multiples (harmonics). In this paper, we present results of such measurements, accomplished using a one-port nonlinear vector network analyzer (NVNA), which show distinct resonances at fractional frequencies of the free layer (FL) FMR mode.Identification of these resonances, resulting from the nonlinear nature of the spin-torque (ST)induced magnetization dynamics, was performed using micromagnetic modeling. In particular, we show that the measured DC response at the above-mentioned fractional frequencies can be explained by a low-order nonlinearity and strong magnetodipolar feedback between magnetic layers adjacent to an MgO barrier. Additionally, we determined that the simulated harmonic response is strongly enhanced by the mutual ST effect between these layers. Finally, we demonstrate that the read sensors' nonlinear magnetization dynamics and, by extension, their harmonic response are highly sensitive to various magnetic and ST parameters. Thus, this study shows that using NVNA measurements in conjunction with micromagnetic modeling can clarify the uncertainty in the definition of these parameters.

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Section: B Harmonic Responsementioning

confidence: 99%

Injection Locking at Fractional Frequencies of Magnetic-Tunnel-Junction-Based Read Sensors’ Ferromagnetic Resonance Modes

et al. 2019

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“…Although only a few papers describe and compare the different measurement setups to measure the nonlinear behavior of systems [28], [30], a lot of papers demonstrate all kinds of applications [28]- [31], which are based on CW measurements performed using the LSNA or the NVNA: power amplifier measurements [32], load-pull measurements [33]- [35].…”

Section: Nonlinear Continuous Wave Measurementsmentioning

confidence: 99%

NVNA versus LSNA: enemies or friends?

Moer¹,

Gomme

2010

IEEE Microwave

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N onlinearities are becoming very hot! After some years of hesitation, the high-frequency measurement world fi nally has acknowledged the need to measure the nonlinear behavior of a device or system correctly. Pushed by the modeling world, which clearly needs good nonlinear measurements to obtain good nonlinear models, some "nonlinear" measurement instruments were developed. Two different approaches to design a measurement instrument that is able to measure the nonlinear time domain waveforms correctly can be followed: a samplerbased methodology or a mixer-based methodology.Wendy Van Moer (wendy.vanmoer@vub.ac.be) and Liesbeth Gommé are with Vrije Universiteit Brussel, , over the years, both of the terms LSNA and NVNA have been used interchangeably to describe these and other similar instruments capable of measuring the vector nonlinear behavior of devices, circuits, and systems. A group of interested users formed the NVNA Users' Forum in 2002 to discuss measurement issues related to this broad class of instrumentation. The group currently meets each year at IMS, EuMW, and the fall ARFTG Microwave Measurement conference. For more information, visit http://www.arftg.org/about_ lsna.html.

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“…However, the VNA and other similar impedance measurement instruments have limitations. For instance, they cannot correctly characterize time-varying or nonlinear devices because the VNA is a virtual 50 Ω environment employing calibrations [1]. Hence, impedance transformation is possible only because the measurement system and the device are linear and time-invariant.…”

Section: Introductionmentioning

confidence: 99%

Time-domain Multitone Impedance Measurement System for Space Applications

Pous

Azpúrua²,

Zhao³

et al. 2022

2022 International Symposium on Electromagnetic Compatibility – EMC Europe

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This paper presents a time-domain methodology to measure the devices' live impedance at the frequency range between 30 Hz and 100 kHz. This measurement is a requirement for some space applications to ensure the stability between DC/DC converters and the onboard power. The methodology is based on a multitone excitation combined with current and voltage measurements performed with an oscilloscope. The experiments show that the measurement system obtains accurate results and offers new capabilities to deal with the drawbacks that traditional frequency-sweep instrumentation implies. The multitone approach injects signals at the entire frequency range simultaneously. Therefore, the measurement system is able to characterize time-varying and the nonlinear devices. The time-domain measurement system has been validated through different test cases achieving excellent results compared with the ones obtained using the reference impedance frequency-sweep approach.

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Practical applications of nonlinear measurements

Cited by 6 publications

References 25 publications

Injection Locking at Fractional Frequencies of Magnetic-Tunnel-Junction-Based Read Sensors’ Ferromagnetic Resonance Modes

Injection Locking at Fractional Frequencies of Magnetic-Tunnel-Junction-Based Read Sensors’ Ferromagnetic Resonance Modes

NVNA versus LSNA: enemies or friends?

Time-domain Multitone Impedance Measurement System for Space Applications

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