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Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the application of the finite-difference time-domain method (fdtd) to the calculation of vlf-lf radiowave propagation in the Earth-ionosphere waveguide. Special techniques have been developed to render the computational time acceptable, namely the use of a moving computational domain and the introduction of an artificial anisotropy in view of reducing the anisotropy of the fdtd scheme. Numerical experiments are provided to illustrate the good agreement of the fdtd method with the waveguide method. Cet article décrit l’application de la méthode des différences finies temporelles au calcul de la propagation des ondes kilométriques et myriamétriques (vlf-lf) dans le guide d’onde Terre-ionosphère. Des techniques particulières sont mises en oeuvre pour rendre le temps de calcul acceptable, à savoir l’utilisation d’un volume de calcul mobile et l’introduction d’une anisotropie artificielle destinée à réduire l’anisotropie du schéma numérique. Des résultats de calcul illustrent le très bon accord de la méthode des différences finies et de la méthode des modes. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper discusses the most recent progress in developing effective physics-based models for devices operating at millimeter-wave frequencies. The model is based on coupling dynamic electromagnetic wave solutions with carrier transport models. The potentials of this modeling approach for both device simulation and the global simulation of millimeter-wave circuits are demonstrated. Results comparing the full-wave model developed with conventional electrostatic models are provided through the simulation of different microwave transistors. The ability of the model to detect traveling wave effects, such as phase mismatch between the input and output electrodes of a conventional transistor, and their effects on the device gain are also provided. Results from the simulation of an air-bridged gate Mesfet, designed to reduce traveling wave effects in high frequency transistors and solve the problem associated with high gate resistance, are illustrated and discussed. Finally, results showing the ability of this technique to model the nonlinearity and the harmonic distortion are provided through the simulation of an amplifier circuit. Cet article discute des plus récents progrès dans les modèles physiques des dispositifs fonctionnant en ondes millimétriques. Le modèle utilise le couplage entre ondes électromagnétiques et les équations dynamiques des porteurs de charge. On montre les potentialités de ce modèle pour la simulation des circuits en ondes millimétriques. Une comparaison entre cette méthode et la méthode classique de l’électrostatique est réalisée par l’intermédiaire de la simulation de différents transistors microondes. L’aptitude du modèle à détecter des effets d’onde progressive, comme la désadaptation de phase entre l’entrée et la sortie d’un transistor ordinaire, et leurs effets sur le gain sont également fournis. Les résultats de la simulation d’une porte Mesfet pontée, conçue pour réduire les effets de propagation et résoudre le problème associé à la forte résistance de porte, sont illustrés et commentés. Enfin, des résultats montrant la capacité du modèle à prendre en compte les non-linéarités ainsi que la distorsion harmonique sont fournis à trovers la simulation d’un circuit amplificateur. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)