Signal-to-Noise Ratio in Heat-Assisted-Recording Media : A Comparison between Simulations and Experiments

We develop a code to extract the signal-to-noise ratio (SNR) arising from the magnetic film in a recording medium. The approach allows us to separate the remanence and transition contributions from the global spatial noise. The results are in excellent agreement with the analysis performed on the same data sets by means of Seagate proprietary software based on ensemble wave-form analysis. We then apply this analytical approach to the results of heat-assisted magnetic recording (HAMR) dynamics simulations by means of the open-source multi-time-scale micromagnetic code mars and compare these with experimental spin-stand measurements of analogous systems. The proposed model could be used as the standard tool to understand the underlying physics of the noise components affecting HAMR operations and how to decrease the noise arising from the medium to improve the writing performance of HAMR

High-speed data transmission using substrate integrated waveguide-type interconnects

Electronic circuits have evolved into multifunctional and highly integrated systems that often require ultra-high-speed and wideband data transmission. Due to the miniaturization trend in CMOS devices, digital processors can now achieve these extreme specifications and enable operation with multi-gigahertz clock frequencies. However, fundamental interconnect limitations prevent from full accomplishment of multi-Gigabit per second data rates. Most importantly, increased conductor and dielectric losses at high frequencies can significantly reduce the channel bandwidth. In addition, crosstalk and electromagnetic interference further deteriorate the link performance, especially in compact routing networks. Therefore, alternative interconnects that enable ultra-high-speed/high-frequency signaling while maintaining signal integrity are needed. This thesis proposes a new method of high-speed data transfer by utilizing waveguide-type interconnects, which offer efficient and confined data transmission due to their low-loss and excellent isolation properties. The electromagnetic bandgap concept is employed for a systematic design of the waveguide sidewalls in order to yield negligible signal leakage in straight and meandered interconnect paths. The performance of the suggested waveguide interconnects is fully investigated from the signal integrity point of view. Due to the three-dimensional nature of the waveguide and its incompatibility with planar structures, a few transition structures are investigated, and important design parameters are identified. Models for transition structures used in 3-D integration, i.e., the via and aperture transitions, are proposed iLes circuits électroniques ont évolué pour devenir des systèmes multifonctionnels hautement intégrés requérant une transmission à très haute vitesse et de large bande. Du à la tendance de miniaturisation des composantes CMOS, les processeurs digitaux peuvent maintenant atteindre ces spécifications extrêmes et permettent par le même fait une opération à plusieurs gigahertz. Cependant, des limitations fondamentales par rapport aux interconnections empêchent une transmission de plusieurs Gigabits par seconde. Plus précisément, la croissance des pertes de conductions et diélectriques aux hautes fréquences peuvent réduire la bande de transmission de façon significative. De plus, la diaphonie et l'interférence électromagnétique contribuent également à détériorer la performance de lien, plus spécialement dans des réseaux de routage compacts. Par conséquent, une alternative aux interconnections standards est nécessaire qui permit une transmission à des fréquences ultra-rapide tout en maintenant l'intégrité des signaux. Cette thèse propose une méthode nouvelle de transmission de données à haute vitesse utilisant des interconnections à guide d'ondes permettant ainsi une transmission de données efficace grâce aux pertes relativement basses et excellentes propriétés d'isolation. Le concept de bande électromagnétique interdite est utilisé pour un design systématique des parois du guide d'ondes afin de procurer une fuite de signal négligeable dans des interconnections droites ou courbées. La performance de l'interconnexion à guide d'ondes suggérée est complètement investiguée du point de vue de l'intégrité du signal. Du fai