Dipoles may be used as standalone antennas themselves, but they are also employed as reflective array, turnstile antenna, log periodic antenna, and phased array.
12.
Until the development of the log periodic antenna in the 1960s it was the only type of antenna that could give adequate fringe reception in areas far from the television transmitter.
13.
The most common types are the Yagi antenna, the log-periodic antenna, and the corner reflector antenna, which are frequently combined and commercially sold as residential TV antennas.
14.
After World War II the rhombic largely fell out of favor for shortwave broadcast and point-to-point communications work, being replaced by log periodic antennas and curtain arrays.
15.
The log-periodic antenna is a more complex design that uses multiple in-line elements similar in appearance to the Yagi-Uda but using transmission lines between the elements to produce the output.
16.
The log-periodic antenna is a modified, folded up, square self-complementary antenna with log-periodic shape, and the original structure before its modification has a typical self-complementary shape.
17.
"' Dwight Isbell "'was a radio engineer, I . E . E . E antennas and propagation fellow, and co-inventor of the Log-periodic antenna while a student at the University of Illinois under Raymond DuHamel.
18.
The most common form of log-periodic antenna is the "'log-periodic dipole array "'or "'LPDA "', The LPDA consists of a number of half-wave dipole driven elements of gradually increasing length, each consisting of a pair of metal rods.
