this paper proposes a new smart antenna beamforming scheme based on electronically steerable parasitic array radiator (espar). the proposed method is capable of providing better capacity compared to the conventional espar. the termination of each antenna element in this structure comprises a pin diode in addition to a varactor. using pin diode besides the varactor provides more degrees of freed...

Media access protocols that de-emphasize the performance impact of propagation delay, packet processing and switching latency for an optically star-coupled system with pre-allocated WDMA channels are introduced and compared. The channels are pre-allocated to the nodes with this approach, where each node has a home channel that it uses either for all data packet transmission or reception. A home...

Delay-controlled CMOS delay lines have been proved useful in a number of applications, notably the digitization of short time intervals. This paper introduces a new kind of CMOS delay line, in which the delay element is an array of capacitors controlled by a digital signal vector. This choice allows for a robust implementation of the circuitry controlling the delay generation, while the maximum...

We present a tunable microwave scattering device that allows the controlled variation of Fano line shape parameters in transmission through quantum billiards. Transport in this device is nearly fully coherent. By comparison with quantum calculations, employing the modular recursive Green's-function method, the scattering wave function and the degree of residual decoherence can be determined. Th...

We demonstrate a novel method to optically tune the pulse advancement and delay based on stimulated Raman gain in hydrogen. With frequency-chirped pump, generated signal is selectively amplified at leading or trailing edge of pump pulse, depending whether frequency difference between beam blue red detuned from transition, which results peak. Different slow/fast light, where are accompanied with...

Ultra-narrow optical spectral features resulting from highly dispersive light–matter interactions are essential for a broad range of applications such as spectroscopy, slow-light and high-precision sensing. Features approaching sub-megahertz or, equivalently, Q-factors up to one billion beyond, challenging obtain in solid-state systems, ultimately limited by loss. We present novel approach achi...