What are the application of log periodic antenna?

What are the application of log periodic antenna?

Log periodic antenna applications The log periodic antenna is used in many areas wide bandwidth levels are needed along with directivity and gain. There are several areas where the antenna is used: HF communications: Log periodic antenna arrays are often used for diplomatic traffic on the HF bands.

How does log periodic antenna operate?

A log-periodic antenna is an antenna that can operate on a wide frequency band and has the ability to provide directivity and gain. It has radiation and impedance characteristics that are repeated as a logarithmic function of excitation frequency. These antennas are fractal antenna (self-similar antenna) arrays.

What is a log periodic function?

Expression (12), which is known as the Log Periodic Power Law (LPPL), is the fundamental equation that describes the temporal growth of prices before a crash and it has been proposed in different forms in various papers, see e.g. Sornette (2003a) and Lin et al. (2009) and references therein.

What is the bandwidth ratio of log periodic antenna?

The frequency range, in which the log-periodic antennas operate is around 30 MHz to 3GHz which belong to the VHF and UHF bands.

Why is it called log periodic?

Log periodic antenna is so named because its characteristics, could be gain or impedance, shows a periodic variation with log of the input frequency. The principle of operation may be explained by considering a log periodic dipole array. It contains a large number of elements.

What are the advantages of log-periodic antenna?

The Advantages of Log-Periodic Antennas Log periodic antennas have much broader frequency bandwidths than Yagi antennas. One log periodic antenna may work for both HF and UHF frequencies. A log-periodic antenna can be used for EMC measurements when it is necessary to scan a wide band of frequencies.

What is advantage of log-periodic antenna?

The construction and operation of a log-periodic antenna is similar to that of a Yagi-Uda antenna. The main advantage of this antenna is that it exhibits constant characteristics over a desired frequency range of operation. It has the same radiation resistance and therefore the same SWR.

Is Yagi-Uda a log periodic?

They can be thought of as two or three element Yagi antennas connected together, each tuned to a different frequency. This gives Log-periodic antennas the ability to work across a wide range of frequencies, whereas Yagi-Uda antennas are optimized for one particular frequency range.

Why is it called log-periodic?

What are the characteristics of log-periodic antenna?

Being log-periodic, the antenna’s main characteristics (radiation pattern, gain, driving point impedance) are almost constant over its entire frequency range, with the match to a 300 Ω feed line achieving a standing wave ratio of better than 2:1 over that range.

Where can I find information on log periodic antenna design?

George Monser provides some background information into log periodic antenna design in a 1964 (only 5 years since its invention) Electronics magazine article, along with a couple charts that facilitates the design without making a lot of calculations.

When was the first log periodic table created?

However, when Dwight Isbell and Raymond DuHamel of the University of Illinois came up with the log periodic concept in 1958, they did not have the convenience of a computer or even a hand-held calculator. Slide rules and logarithm tables were the order of the day.

How is the end-fed feed of a VHF log‑periodic dipole array routed?

Detail of the end‑fed feed of a VHF log‑periodic dipole array. The feed coax is routed through the inside of the right boom. Only the center conductor of the coaxial cable is connected to the left boom by means of a rivet. The dipole elements are threaded on the outside.