There has been considerable progress in the construction of fundamental bandwidth limits and near optimal design realisations for several classes of passive linear electromagnetic wave devices, most notably for radar absorbent materials, antennas and meta-materials. This article seeks to place balun design on a similar footing, for an important class of baluns; in particular those which are ‘pe...

In this work we present a Schottky diode grid mixer suitable for mixing or detecting quasi-optical signals. The mixer is a planar bow-tie grid structure periodically loaded with diodes. A simple transmission line model is used to predict the reflection coefficient of the grid to a normally incident plane wave. The grid mixer power handling and dynamic range scales as the number of devices in th...

BACKGROUND Systolic blood pressure and pulse pressure are substantially higher in older adults. The relative contributions of increased forward versus reflected pressure wave amplitude or earlier arrival of the reflected wave to elevated pulse pressure remain controversial. METHODS AND RESULTS We measured proximal aortic pressure and flow, forward pressure wave amplitude, global wave reflecti...

The reflection coefficient of longitudinal 25-GHz phonons at a quartz-liquid 4He interface was measured for various phonon intensities. For thoroughly cleaned quartz surfaces a reflection coefficient of I independent of the incident intensity was found. When the sample was covered with a thin hydrocarbon film, however, the reflection coefficient dropped by typically 5-10% when the phonon intens...

This paper introduces an optical measurement system for shock wave characteristics. The system works by mountinga metal plate attached to spring mounts against the shock wavefront. This set is sealed and can plot the shock wave pressure diagram by measuring plate's displacement, radiation and changing the reflection of light during shock wave conflict, and converting these optical data to volta...

In this paper, the reflection and refraction of longitudinal wave from a plane surface separating a micropolar viscoelastic solid half space and a fluid saturated incompressible half space is studied. A longitudinal wave (P-wave) impinges obliquely at the interface. Amplitude ratios for various reflected and transmitted waves have been obtained. Then these amplitude ratios have been computed nu...

True amplitude wave equation migration (WEM) provides the quality image of wave equation migration along with proper weighting of the output for estimation of an angularly dependent reflection coefficient, similar to the output of Kirchhoff inversion. In an earlier paper, Zhang et al. (2003) presented a true amplitude WEM for common-shot data in heterogeneous media. Here we present two addition...

This paper presents a calibration technique for a coaxial sensor using a transmission signal approach. The sensor was fabricated from commercially available RG402/U and RG405/U semi-rigid coaxial cable. The length of the coaxial sensor was correlated with the attenuation and standing wave inside the coaxial line. The functions of multiple reflection amplitude and tolerance length with respect t...

Inductive current profile modification in MST has been successful in reducing fluctuations and transport but is transient and radially non-localized. Current profile control with rf waves offers steady and more precise control. Studies of lower hybrid wave and electron Bernstein wave injection are underway. The lower hybrid antenna has coupled 125 kW to the plasma. Hard x-ray emission with ener...