Continuous active T-gate travelling-wave transistor

Sebati, N.; Gamand, P.; Varin, C.; Pasqualini, Francois; Meunier, Jean-Christophe

doi:10.1049/el:19890277

Cited by 11 publications

(6 citation statements)

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“…For the flat gate structure used in all of our simulations a > 0, indicating attenuated wave propagation consistent with the results of [3], [4]. Growing waves were calculated in [5]- [7], where "7"' gate structures were used. Note that the "7"' gate dimensions of [7] (a drain-source separation of 140 pm and a drain width of 300 pm) or those of [6] (a drain-source separation of 210 pm and a drain width of 500 pm) that were required to produce growing waves may not be suitable for producing a compact transistor for MMIC applications.…”

Section: A Modelsupporting

confidence: 78%

“…The CMESFET's gain characteristic also exhibits resonance valleys that are typical of travelingwave FETS, whose gate widths are large in comparison to their operating wavelengths as in [5], [6]. We also noted that different gate bias voltages affect the structure of the gain curves, especially at the higher frequencies and the larger gate widths.…”

Section: B Simulationmentioning

confidence: 67%

“…We model the CMESFET as a distributed device and use an analytical technique presented in [3], [4] and used in [5]- [7] to model traveling-wave transistors. The previous analyses of traveling-wave transistors have assumed relatively simple terminations.…”

Section: A Modelmentioning

confidence: 99%

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Design and analysis of a traveling-wave MESFET with enhanced shielding capabilities

Yarbrough

Osofsky

1994

IEEE Trans. Microwave Theory Techn.

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The Concentric MESFET (CMESFET) is a smallsignal, traveling-wave transistor in which a grounded source electrode surrounds and shields the gate and drain electrodes from electromagnetic fields generated by other nearby circuit elements. S-parameters for the transistor are computed to obtain gain curves for several design configurations. For a gate length of 2 pm, maximum gain occurs with a gate width of 3.0 mm. The CMESFET has a calculated bandwidth of 17 GHz for this gate length and a gate width of 300 pm. Coupling capacitances between device electrodes and a nearby transmission line are calculated to demonstrate how the shielding source electrode isolates the device from interference and crosstalk originating in the surrounding circuit. The CMESFET geometry exhibits shielding characteristics better than those of conventional smallsignal FET geometries.

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Section: A Modelsupporting

confidence: 78%

Section: B Simulationmentioning

confidence: 67%

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Design and analysis of a traveling-wave MESFET with enhanced shielding capabilities

Yarbrough

Osofsky

1994

IEEE Trans. Microwave Theory Techn.

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“…These prospective results suggest a new way for solving the difficult problem of metallic losses in travelling wave FET's (TWFET) [17,18]. In fact one can reasonably expect to overcome the small attenuation observed in the passive superconducting structure using the active gain of FET in order to gain a TWFET.…”

Section: Discussionmentioning

confidence: 92%

Analytical Models and Theoretical Analysis of Superconducting Coplanar Lines

Seguinot

Kinowski

Pribetich

et al. 1991

Journal of Electromagnetic Waves and Applications

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Prospective study of the influence of superconducting strips in various coplanar waveguides is proposed using a transmission line model designed in an engineering purpose for CAD programs. This model is tested using a comparison of the results obtained, with the propagation characteristics of superconducting coplanar lines determined with a modified spectral domain approach. For insulating coplanar waveguides the use of YBaCuO instead of classical low temperature NbN superconductor provides lower losses at higher operating temperatures.In superconducting MIS or Schottky contact lines, superconductor losses are negligible as compared to semiconductor losses for transverse dimensions as low as 1 µ. For example, 1 µ gate length FET type structures operated at 77 K exhibit 50 Ω constant characteristic impedance with associated constant slowing factor, and losses lower than 4 dB/mm up to 20 GHz. Similar propagation characteristics can be obtained with different superconductors providing that current transport in superconductor is dominated by the kinetic inductance effect. The influence of temperature is also discussed.

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“…[l3] At this point it became evident that propagation losses along the typically very small gate of a FET were prohibitively large and minimization of this propagation loss is the goal of distributed operation. As a result, a distributed FET with reduced gate loss by low-loss power distribution was realized [14] and the fabrication of large T-gate structures was attempted [15]. The objective of this project is the development of a suitable low-loss FET electrode structure amenable to true traveling-wave operation.…”

Section: Distributed Field-effect Transistors Introductionmentioning

confidence: 99%