Log-Periodic Antenna


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log-periodic antenna

[′läg ‚pir·ē¦ad·ik an′ten·ə]
(electromagnetism)
A broad-band antenna which consists of a sheet of metal with two wedge-shaped cutouts, each with teeth cut into its radii along circular arcs; characteristics are repeated at a number of frequencies that are equally spaced on a logarithmic scale.

Log-Periodic Antenna

 

a type of a frequency-independent antenna with periodic repetition of the ratios of the characteristic dimensions of the adjoining components. The repetition obeys a logarithmic law in such a way that the ratio between the wavelength of the electromagnetic oscillations being radiated and the characteristic dimensions of the excited part of the antenna remains virtually constant over a wide frequency range.

References in periodicals archive ?
The company also highlighted its latest antenna offering-- the AT700M12G wideband trapezoidal log-periodic antenna (Figure 1), which operates from 700 MHz to 11 GHz.
The University wishes to appoint a design company to develop the mechanical design of a log-periodic antenna sub-system covering 50-650MHz for the low frequency aperture array element of the Square Kilometre Array, SKA, radio telescope.
Chang, "Application of quasi log-periodic antenna for UHF passive RFID tag design featuring constant power transmission coefficient over broadband operation," Journal of Electromagnetic Waves and Applications, Vol.
The lower frequency band uses a biconical antenna while the higher frequency band uses a log-periodic antenna (although the range from 30 to 1000 MHz can also be handled with a single broadband antenna).
The company also will highlight its latest antenna offering--the AT700M12G wideband trapezoidal log-periodic antenna (Figure 2), which operates from 700 MHz to 11 GHz.
And it determines the polarization direction of the log-periodic antenna composed of the treelike fractal dipole is also in y direction.
The measurements were performed with a generator, broadband amplifier, log-periodic antenna and electric field meter, as shown in Figure 8.
The log-periodic part of the AC-220 is 37" long x 22" wide, approximately the same size as the company's Model AL-100, a log-periodic antenna covering 300 MHz to 1 GHz.
The lowest and highest frequency of operation are given by the largest and smallest teeth defined in the log-periodic antenna structure.
The FCC recommends a log-periodic antenna below 960 MHz although other types of measurement antennas such as biconicals may be used.
It describes the theory of thin antennas, the integral equation method, folded antennas of metal wires, multi-folded and multi-level antennas, antennas with concentrated loads, the synthesis of directional radiators, the methods of a complex potential for cylindrical problems and three-dimensional problems, the principle of complementarities, problems of compensation and adjustment, arrays, transparent antennas, ship antennas, log-periodic antennas, and other issues, such as antennas for underground radio communication and observation and magnetic impedance antennas.