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English: Far field radiation pattern of 0.25 wavelength monopole antenna over a perfectly conducting infinite ground plane.The radial axis is relative signal strength (peak electric field magnitude) and the circumferential axis is in degrees.
The biconical antenna has a broad bandwidth because it is an example of a traveling wave structure; the analysis for a theoretical infinite antenna resembles that of a transmission line. For an infinite antenna, the characteristic impedance at the point of connection is a function of the cone angle only and is independent of the frequency.
The far-field pattern of an antenna may be determined experimentally at an antenna range, or alternatively, the near-field pattern may be found using a near-field scanner, and the radiation pattern deduced from it by computation. [1] The far-field radiation pattern can also be calculated from the antenna shape by computer programs such as NEC.
Vertical polarized VHF-UHF biconical antenna 170–1100 MHz with omnidirectional H-plane pattern. Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by ...
This reduces stored energy in the electric field, reducing antenna Q while also reducing losses. The elevation pattern might be distorted with grating lobes. SWR (standing wave ratio) is typically 1.5:1 or less over several octaves of frequency. [4] A discone antenna consists of three main parts: the disc, the cone, and the insulator.
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In telecommunications and antenna design, an image antenna is an electrical mirror-image of an antenna element formed by the radio waves reflecting from a conductive surface called a ground plane, such as the surface of the earth. It is used as a geometrical technique in calculating the radiation pattern of the antenna.
Hence, the monopole antenna has a radiation pattern identical to the top half of the pattern of a similar dipole antenna, and a radiation resistance a bit less than half of a dipole. Since all of the equivalent dipole's radiation is concentrated in a half-space, the antenna has twice the gain (+3 dB) of a similar dipole, neglecting power lost ...