Dynamical Systems on Hilbert C*-Modules

We investigate the generalized derivations and show that every generalized derivation on a simple Hilbert $C^*$-module either is closable or has a dense range. We also describe dynamical systems on a full Hilbert $C^*$-module ${\mathcal M}$ over a $C^*$-algebra ${\mathcal A}$ as a one-parameter group of unitaries on ${\mathcal M}$ and prove that if $\alpha: \R\to U({\mathcal M})$ is a dynamical system, where $U({\mathcal M})$ denotes the set of all unitary operator on ${\mathcal M}$, then we can correspond a $C^*$-dynamical system $\alpha^{'}$ on ${\mathcal A}$ such that if $\delta$ and $d$ are the infinitesimal generators of $\alpha$ and $\alpha^{'}$ respectively, then $\delta$ is a $d$-derivation.Comment: 7 pages, minor changes, to appear in Bull. Iranian Math. So

A Novel Design of Micromachined Horn Antenna for Millimeter and Sub-millimeter Applications

A novel design of micromachined horn antenna is presented. Horn excited with a quasi-Yagi antenna. In this paper micromachining process of this antenna, and simulation results of a horn structure operate around 330GHz using Agilent High Frequency Structure Simulator (HFSS) software is presented. The results indicate a gain around 10dB, directivity 10.5dB and resonant dipole impedance 48.3Ω for horn antenna. The micromachined horn antenna is a high-efficiency antenna suitable for applications in millimeter-wave imaging systems, remote-sensing, and radio astronomy