Search results
Results from the WOW.Com Content Network
The most commonly used is the center-fed half-wave dipole which is just under a half-wavelength long. The radiation pattern of the half-wave dipole is maximum perpendicular to the conductor, falling to zero in the axial direction, thus implementing an omnidirectional antenna if installed vertically, or (more commonly) a weakly directional ...
The electric field strength at a specific point can be determined from the power delivered to the transmitting antenna, its geometry and radiation resistance. Consider the case of a center-fed half-wave dipole antenna in free space, where the total length L is equal to one half wavelength (λ/2).
Dipole field strength in free space, in telecommunications, is the electric field strength caused by a half wave dipole under ideal conditions. The actual field strength in terrestrial environments is calculated by empirical formulas based on this field strength.
The driven element of the antenna is usually a half-wave dipole, its length half a wavelength of the radio waves used. The parasitic elements are of two types. A "reflector" is slightly longer (around 5%) than a half-wavelength. It serves to reflect the radio waves in the opposite direction.
Dipole gain is the ratio of the power density received from the antenna in the direction of its maximum radiation to the power density , received from a lossless half-wave dipole antenna in the direction of its maximum radiation = , The decibel gain relative to a dipole (dB d) is given by = ( , )
A full-wave loop antenna is slightly more than two half-wavelengths in circumference, which is a bit more than double the size of a halo antenna designed to operate on the same frequency. In contrast, the two semi-circles of a resonant loop, each is a half wavelength long. There is no gap, and each semicircle ends at the semi-circles ...
The coaxial collinear (COCO) antenna uses transposed coaxial sections to produce in-phase half-wavelength radiators. [5] A Franklin array uses short U-shaped half-wavelength sections whose radiation cancels in the far-field to bring each half-wavelength dipole section into equal phase. Another type is the omnidirectional microstrip antenna (OMA ...
Patch antenna gain pattern. A directional antenna or beam antenna is an antenna which radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction is desired, or in receiving antennas receive radio waves from one specific direction only.