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The unit cells are usually backed by a ground plane, and the incident wave reflects off them towards the direction of the beam, but each cell adds a different phase delay to the reflected signal. A phase distribution of concentric rings is applied to focus the wavefronts from the feeding antenna into a plane wave (to account for the varying ...
In radio communication, multipath is the propagation phenomenon that results in radio signals reaching the receiving antenna by two or more paths. Causes of multipath include atmospheric ducting, ionospheric reflection and refraction, and reflection from water bodies and terrestrial objects such as mountains and buildings.
The sound waves usually reflect off the wall and interfere with other sound waves that are generated later. To prevent sound waves reflecting directly to the receiver, a diffusor is introduced. [16] A diffusor has different depths in it, causing the sound to scatter in random directions evenly.
In astrophysics and planetary science, spectral slope, also called spectral gradient, is a measure of dependence of the reflectance on the wavelength.. In digital signal processing, it is a measure of how quickly the spectrum of an audio sound tails off towards the high frequencies, calculated using a linear regression.
Frequency is a main factor of a good diffused field. Some phenomena linked to frequency of the sound pressure field lead to poor homogeneity of a pressure field. The frequency response of a room is the amplification or reduction of some frequencies. It represents the repartition of pressure with respect to frequency.
In acoustics, acoustic dispersion is the phenomenon of a sound wave separating into its component frequencies as it passes through a material. The phase velocity of the sound wave is viewed as a function of frequency. Hence, separation of component frequencies is measured by the rate of change in phase velocities as the radiated waves pass ...
If the source is passive, i.e. some type of isolated reflector, an iterative technique can be used to focus energy on it. The TRM transmits a plane wave which travels toward the target and is reflected off it. The reflected wave returns to the TRM, where it looks as if the target has emitted a (weak) signal.
It is analogous to an LC resonator of capacitance, C, and inductance, L, and resonant frequency √1/(LC). The speed of sound in the matrix is expressed as c = √ρ/μ with density ρ and shear modulus μ. Although linear elasticity is considered, the problem is mainly defined by shear waves directed at angles to the plane of the cylinders. [14]