What is the working principle of log periodic dipole antenna array?
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.
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 log-periodic antenna explain the design principle of log-periodic antenna?
The log periodic antenna is constructed by the use of various half-wave dipole elements with a gradual increase in the length. The structural geometry of the log periodic antenna is designed in a way that the electrical properties of the antenna must show periodic repetition with the logarithm of the frequency.
Why log-periodic antenna is frequency independent?
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.
What is the effect of ground on antenna radiation?
Waves radiated from the antenna directly downward reflect vertically from the ground and, in passing the antenna on their upward journey, induce a voltage in it. The magnitude and phase of the current resulting from this induced voltage depends on the height of the antenna above the reflecting surface.
What is the gain of a 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.
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.
What is the frequency range of log periodic antenna?
around 30 MHz to 3GHz
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 are antennas grounded?
Grounding will eliminate static electricity, as well as protect against energy to the mast if the antenna comes in contact with live electrical wires. Outdoor masts should be grounded with Grounding Conductors (see F in diagram) to the building’s Power Service Grounding Electrode System (see E) at a permitted location.
What is grounded antenna?
A ground-plane antenna is a form of dipole antenna designed to work with an unbalanced feed line. A ground-plane antenna is more of less one half of the dipole and mounted above the ground plane. Ease of fabrication and cost makes the ground-plane antenna one of the popular antennas in communication systems.
Is a folded dipole balanced?
Like the basic dipole, the folded dipole antenna is a balanced antenna, and needs to be fed with a balanced feeder. Unbalanced feeders can be used provided that a balun (unbalanced to balanced transformer) is used.