The method of differential-Thompson transformation (DTTR) is applied for the first time to the field of electromagnetic scattering. Complex objects and their computational areas are transformed by DTTR to a regular area. By applying the finite-difference-Time-Domain (FDTD) technique, the fieM distribution is solved conveniently. Numerical a mples show good comparison with exact results. 0 ABSTRACT A highly accurate absorbing boundary operation has been devebped to efficiently and accurately truncate the computational domain when using the finite-di~erence-timeime-domain method. Referred to as the compkmentary operators method (COM), this technique consim of averaging the solutions of two indepndent boundary operators that are complementary to each other. Because of its independence of the wave number k,, the boundary operation can significantly reduce arti$cial reflections arising from obliquely incident traveling waves as well as evanescent waves. 0 1995 John Wley & Sons, lnc.

This paper presents the high frequency performance of single-walled carbon nanotube ͑SWNT͒ field-effect transistors, with channel consisting of dense networks of high purity semiconducting SWNTs. Using SWNT samples containing 99% pure semiconducting SWNTs, we achieved operating frequencies above 80 GHz. This record frequency does not require aligned SWNTs, thus demonstrating the remarkable potential of random networks of sorted SWNTs for high frequency electronics.

Flexible electronics mostly relies on organic semiconductors but the limited carrier velocity in polymers and molecular films prevents their use at frequencies above a few megahertz. Conversely, the high potential of graphene for high-frequency electronics on rigid substrates was recently demonstrated. We conducted the first study of solution-based graphene transistors at gigahertz frequencies, and we show that solution-based single-layer graphene ideally combines the required properties to achieve high speed flexible electronics on plastic substrates. Our graphene flexible transistors have current gain cutoff frequencies of 2.2 GHz and power gain cutoff frequencies of 550 MHz. Radio frequency measurements directly performed on bent samples show remarkable mechanical stability of these devices and demonstrate the advantages of solution-based graphene field-effect transistors over other types of flexible transistors based on organic materials.