Investigation of drain-line loss and the S22 kink effect in capacitively coupled distributed amplifiers

Shohat, J.; Robertson, I.D.; Nightingale, S.J.

doi:10.1109/tmtt.2005.859873

Cited by 13 publications

(4 citation statements)

References 13 publications

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“…Device modelers can exploit the kinks in S 22 and h 21 for extracting equivalent circuit parameters (e.g., the resonance frequency associated with the first kink in h 21 has been used to accomplish the challenging task of determining the intrinsic output capacitance [7,8]). Circuit designers should properly take into account the kink effect in S 22 , especially for the design of broadband output matching networks [14,15]. In addition, circuit designers can benefit from the kinks in h 21 as they enable achieving an increase in the current gain at the resonant frequencies.…”

Section: Introductionmentioning

confidence: 99%

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

et al. 2018

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The aim of this feature article is to provide a deep insight into the origin of the kink effects affecting the output reflection coefficient (S22) and the short-circuit current-gain (h21) of solid-state electronic devices. To gain a clear and comprehensive understanding of how these anomalous phenomena impact device performance, the kink effects in S22 and h21 are thoroughly analyzed over a broad range of bias and temperature conditions. The analysis is accomplished using high-frequency scattering (S-) parameters measured on a gallium-nitride (GaN) high electron-mobility transistor (HEMT). The experiments show that the kink effects might become more or less severe depending on the bias and temperature conditions. By using a GaN HEMT equivalent-circuit model, the experimental results are analyzed and interpreted in terms of the circuit elements to investigate the origin of the kink effects and their dependence on the operating condition. This empirical analysis provides valuable information, simply achievable by conventional instrumentation, that can be used not only by GaN foundries to optimize the technology processes and, as a consequence, device performance, but also by designers that need to face out with the pronounced kink effects of this amazing technology.

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Section: Introductionmentioning

confidence: 99%

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

et al. 2018

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“…Essentially, the kink is due to the transition of the output impedance (

Z_{out}

) from a low‐frequency series RC network to a high‐frequency parallel RC network 13,14 . The true underlying cause of the effect is still a topic for discussion 1–7 .…”

Section: Introductionmentioning

confidence: 99%

Analysis and modeling of the kink effect in S22 based on support vector machine for GaN HEMTs

Zhu

Geng

Cai

et al. 2022

Int J Numerical Modelling

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In this work, the kink effect (KE), typically visible in S22, is analyzed and modeled. Two different modeling techniques: equivalent circuit modeling (ECM) method and machine learning method which based on support vector regression (SVR) technique are presented and compared, when applied to the S22 behavior of a Gallium Nitride (GaN) high electron mobility transistor (HEMT). The device under test (DUT) has a width of 8 Â 125 μm, with a gate feature size of 0.25 μm. The proposed method identifies the effect that the bias voltage and extrinsic elements have on the S22 kink shape. Additionally, compared to ECM, the SVR model attains a superior fitting accuracy across the complete frequency band.

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“…In the last two decades several studies have been addressed to investigate the kink effect (KE) in the scattering parameter S 22 for microwave transistors [1][2][3][4][5][6][7][8][9][10][11][12][13]. This phenomenon is often referred to as 'anomalous dip' and basically its appearance has been attributed to the transition of the output impedance (Z out ) from a low-frequency series RC circuit to a high-frequency parallel RC circuit [1].…”

Section: Introductionmentioning

confidence: 99%

“…It is worth pointing out that, although the reported study is focused on a GaN HEMT, the developed procedure can be straightforwardly applied to other transistor technologies as it is technology independent. The significance of this study lies in the fact that a thorough analysis of the kink phenomena can enable RF circuit designers to take them into account properly, especially for the design of broadband output matching networks [9,21].…”

Section: Introductionmentioning

confidence: 99%

Thermal influence on S₂₂ kink behavior of a 0.15 μm gate length AlGaN/GaN/SiC HEMT for microwave applications

Alim

Rezazadeh

Gaquière

et al. 2019

Semicond. Sci. Technol.

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Thermal influence on S 22 kink behavior has been carried out on a 0.15 μm gate length AlGaN/ GaN/SiC high electron mobility transistor over a wide range of temperature. The size and the shape of the S 22 kink effect (KE) in terms of biasing and temperature have been evaluated. The main finding is that S 22 of the studied device is affected by two kinks: the first one appears at approximately 19 GHz and then the second one appears at about 43 GHz. The impact of the intrinsic circuit parameters on the S 22 kink phenomena is inspected to assess their contribution. In addition, a new procedure is proposed to quantify this type of phenomenon by defining the kink area as the area between the two curves corresponding to S 22 with and without the KE. The relevance of this study emerges from the fact that an exhaustive characterization of these anomalous phenomena can empower RF engineers to effectively take them into account for both modeling and design purposes.

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Investigation of drain-line loss and the S22 kink effect in capacitively coupled distributed amplifiers

Cited by 13 publications

References 13 publications

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

Analysis and modeling of the kink effect in S22 based on support vector machine for GaN HEMTs

Thermal influence on S₂₂ kink behavior of a 0.15 μm gate length AlGaN/GaN/SiC HEMT for microwave applications

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Investigation of drain-line loss and the S22 kink effect in capacitively coupled distributed amplifiers

Cited by 13 publications

References 13 publications

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

Analysis and modeling of the kink effect in S22 based on support vector machine for GaN HEMTs

Thermal influence on S22 kink behavior of a 0.15 μm gate length AlGaN/GaN/SiC HEMT for microwave applications

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Thermal influence on S₂₂ kink behavior of a 0.15 μm gate length AlGaN/GaN/SiC HEMT for microwave applications