نتایج جستجو برای: coupler gain
تعداد نتایج: 169610 فیلتر نتایج به سال:
The use of a complex short-period (Bragg) grating which combines matched periodic modulations of refractive index and loss/gain allows asymmetrical mode coupling within a contra-directional waveguide coupler. Such a complex Bragg grating exhibits a different behavior (e.g. in terms of the reflection and transmission spectra) when probed from opposite ends. More specifically, the grating has a s...
BACKGROUND Hypertension contributes to cardiovascular morbidity and mortality. We assessed the safety and efficacy of a central iliac arteriovenous anastomosis to alter the mechanical arterial properties and reduce blood pressure in patients with uncontrolled hypertension. METHODS We enrolled patients in this open-label, multicentre, prospective, randomised, controlled trial between October, ...
We introduce a model of a dual-core optical waveguide with opposite signs of the group-velocity dispersion in the two cores, and a phase-velocity mismatch between them. The coupler is embedded into an active host medium, which provides for the linear coupling of a gain-loss type between the two cores. The same system can be derived, without phenomenological assumptions, by considering the three...
Sensors used for lung sound research are generally designed by the investigators or adapted from devices used in related fields. Their relative characteristics have never been defined. We employed an artificial chest wall with a viscoelastic surface and a white noise signal generator as a stable source of sound to compare the frequency response and pulse waveform reproduction of a selection of ...
BACKGROUND Intima-to-intima microanastomotic vascular remodeling was explored, utilizing a polylactide-caprolactone absorbable vein coupler model (PAVCM), which was designed to simulate a non-absorbable counterpart system with the sole exception of being absorbable. METHODS Six New Zealand white rabbits were used. After transection of the jugular vein, 2 PAVCMs were placed, 1 at each transect...
In this article we describe a new coupling technique which is useful in a variety of perfect sampling algorithms. A multishift coupler generates a random function f() so that for each x ∈ R, f(x) − x is governed by the same fixed probability distribution, such as a normal distribution. We develop the class of layered multishift couplers, which are simple and have several useful properties. For ...
For on-line partial discharge (PD) monitoring of rotating machines, a novel PD sensor is proposed, which can be installed on the power lead inside the terminal box of the machine. The sensor has been designed to have high capacitance, and minimal reflection of measured pulses. As a sensitivity of the PD sensor, transfer impedance Zt has been measured and compared to conventional coupler-type PD...
in recent years, the plasma antenna is a new technology for replacing the metal antennas that have been designed with better performance. in the steady state, the radiation pattern of a plasma antenna will be similar to the case of metallic antennas with the same form, size and performance at the same frequency and power. by sweeping the parameters in the plasma tube, we can change the operatin...
Ahtract -A computer-aided sjnthesis design procedure is given for nonuniform quadrature directional couplers in inhomogeneous media. A wiggly geometry is employed which effective11 slows the odd-mode phase veloci5 to match the even-mode phase velocity. The wiggly geometry results in improved isolation and increased effective dielectric constant. This technique provides a shorter coupler length ...
Modern communication systems need various hybrids to enable digital data transmit via microwave bands. Thus several types of microwave quadrature hybrids have been reported for the realization of balanced circuits, matched attenuators, and phase shifter. The branch line coupler is one of the most popular hybrids for the convenience of design and implementation. But it offers limited bandwidth a...
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