How does a log periodic antenna work?

In general terms, at any given frequency the log-periodic design operates somewhat similar to a three-element Yagi antenna; the dipole element closest to resonant at the operating frequency acts as a driven element, with the two adjacent elements on either side as director and reflector to increase the gain, the …

Why is it called log periodic antenna?

The log periodic antenna or aerial is in many areas to provide a wideband RF antenna solution with gain and directivity over that offered by a dipole. One design named the log periodic antenna is able to provide directivity and gain while being able to operate over a wide bandwidth.

What is log periodic antenna radiation pattern?

The radiation pattern of log periodic antenna is unidirectional and the main lobe is along the axis of the boom [7]. Array of dipole antenna is fed with equal and opposite phase. All dipole elements are fed with successive elements out of phase and radiates in end fire direction.

What is the difference between Yagi and log periodic antenna?

Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas. Conceptually, Log-Periodic Antennas are similar to Yagi Antennas.

Why is a log periodic antenna known as frequency independent antenna?

Explanation: Log periodic antenna is frequency independent. The geometrical structure of the antenna changes according to the wavelength. It is also called as Frequency Independent antenna. Its electrical performance is dependent on logarithmic of frequency only.

Which of the following is an advantage of a log periodic antenna?

Which of the following is an advantage of a log periodic antenna? An advantage of a log periodic antenna is wide bandwidth. In this type of multi-element directional antenna, the lengths of the elements and the spacing among them are both arranged in a log-periodic manner.

What is the gain of the log periodic antenna?

In terms of its specification a typical log periodic antenna might provide between 3 and 6 dB gain over dipole for a bandwidth of 2:1 while retaining an VSWR level of better than 1.3:1.

Why log periodic antenna is frequency independent?

Who invented the log periodic antenna?

Dwight Isbell
Log-periodic antenna/Inventors
As the frequency shifts upward, the active region shifts forward. The upper frequency limit of the antenna is a function of the shortest elements. Log periodic designs vary, but the one most commonly used for EMC work is the Log Periodic Dipole Array (LPDA) invented by D.E. Isbell of the University of Illinois.

What is the abbreviation for log periodic antenna?

t. e. A log-periodic antenna ( LP ), also known as a log-periodic array or log-periodic aerial, is a multi-element, directional antenna designed to operate over a wide band of frequencies. It was invented by John Dunlavy in 1952.

How do you make a log periodic antenna?

Another common construction method is to use two parallel central support booms that also acts as the transmission line, mounting the dipoles on the alternate booms. Other forms of the log-periodic design replace the dipoles with the transmission line itself, forming the log-periodic zig-zag antenna.

What is the difference between Yagi Uda and log periodic antennas?

The Yagi-Uda antenna is mostly used for domestic purpose. However, for commercial purpose and to tune over a range of frequencies, we need to have another antenna known as the Log-periodic antenna. A Log-periodic antenna is that whose impedance is a logarithamically periodic function of frequency.

What is the radiational pattern for uni-directional log-periodic antenna?

For uni-directional Log-periodic antenna, the radiation towards shorter element is of considerable amount, whereas in forward direction, it is small or zero. The radiational pattern for uni-directional log-periodic antenna is given above.