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A zone plate is a device used to focus light or other things exhibiting wave character. [1] Unlike lenses or curved mirrors , zone plates use diffraction instead of refraction or reflection . Based on analysis by French physicist Augustin-Jean Fresnel , they are sometimes called Fresnel zone plates in his honor.
Wave. Surface waves in water showing water ripples. In physics, mathematics, engineering, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Periodic waves oscillate repeatedly about an equilibrium (resting) value at some frequency. When the entire waveform moves in one direction ...
Electromagnetic spectrum. The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: radio waves, microwaves, infrared, visible light ...
Melde's experiment is a scientific experiment carried out in 1859 by the German physicist Franz Melde on the standing waves produced in a tense cable originally set oscillating by a tuning fork, later improved with connection to an electric vibrator. This experiment, "a lecture-room standby", [1] attempted to demonstrate that mechanical waves ...
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
Sound is defined as " (a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sensation evoked by the oscillation described in (a)." [2]
An atmospheric wave is a periodic disturbance in the fields of atmospheric variables (like surface pressure or geopotential height, temperature, or wind velocity) which may either propagate (traveling wave) or be stationary (standing wave). Atmospheric waves range in spatial and temporal scale from large-scale planetary waves (Rossby waves) to ...
Substrate-integrated waveguide. The propagating electromagnetic waves are confined within the substrate by the metallic layers on each of the two faces of the substrate and between two rows of metallic vias connecting them. A substrate-integrated waveguide (SIW) (also known as post-wall waveguide or laminated waveguide) is a synthetic ...