This paper presents an investigation of a pilot signal influence on directivity of self-phased array under conditions of multipath propagation (either reflections or jamming signals). A suggestion is made that an average reduction in directivity owing to the cutting off (or “dropping out”) of some channels of the array be used as a criterion of this influence. It has been shown that an essentia...

Pulsatile components of blood pressure may arise from forward (ventricular generated) or backward wave travel in the arterial tree. The objective of this study was to determine the relative contributions of forward and backward waves to pulsatility. We used wave intensity and wave separation analysis to determine pulsatile components of blood pressure during inotropic and vasopressor stimulatio...

Abstract We designed and fabricated a microwave transmitting antenna that uses an HTS thick disk as patch with resonant frequency of around 5.0 GHz. The reflection property S 11 , electromagnetic fields, current distributions, far-field several modes in the were analyzed using CST studio suite. compared properties resonance selected TM11 mode, which has smallest resonator size highest directivi...

The aim of this research is to create a microphone array on a rigid sphere that could be used for teleconferences and for recording of music with the aim of five-channel loudspeaker surround sound reproduction. Experiments were undertaken, within a MATLAB environment, by running computer simulations that tested the directivity of a rigid sphere microphone array in both near and far field. The s...

The temporal envelope of plasma density oscillations in the wake of an intense (I ,-, 4 x 10 TM W/cm 2 , Z = 1/an) laser pulse (400 fs) is measured using forward Thomson scattering from a copropagating, frequency doubled probe pulse. The wakefield oscillations in a fully ionized helium plasma (ne=3 x 1019cm -3) are observed to reach maximum amplitude (~ne/ne 0.1) 300 fs after the pump pulse. Th...

For tele-conference systems or voice-controlled systems, the highquality sound capture of distant-talking speech is very important. However, background noise and room reverberations seriously degrade the sound capture quality in real acoustical environments. A microphone array is an ideal candidate for capturing distanttalking speech. With a microphone array, the desired speech signals can be a...

Abstract— This paper describes 2 x 2 triangular microstrip patch antenna using T-junction with quarter wave transformer. By regulating the distance in patch antenna and adjusting feed position, bandwidth can be obtained and by using an array, directivity is enhanced. The requirement of large bandwidth, high directivity, and minimum size leads to the design of 2 x 2 triangular microstrip patch a...

[1] To accurately estimate the seismic energy radiated in an earthquake, it is important to use appropriate corrections for path and source effects. Using slip models obtained by inversion of seismic data, we examine the effect of directivity on estimates of radiated energy and develop a method to correct for this source effect. From our calculations we suggest that the directivity correction f...

We report a high-directivity plasmon-resonant terahertz (THz) emitter (PRE) incorporating a 3D-integrated antenna complex. The emitter structure is based on a high electron mobility transistor having unique doubly interdigitated grating gates as a broadband THz antenna that can convert non-radiative plasmons to radiative electromagnetic waves. Due to the sub-wavelength aperture of practical gra...

This work presents a method to control the perceived distance of an auditory object by changing the directivity pattern of a loudspeaker and consequently the direct-to-reverberant ratio at the listening spot. Control of the directivity pattern is achieved by beamforming using a compact multi-driver loudspeaker unit. A small-sized cubic array consisting of six drivers is assembled, and per drive...