What is the impedance of a 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.

What are the two methods for antenna impedance measurement?

Thus, on the basis of the frequency range, there are two methods of impedance measurement. Basically, for low-frequency applications i.e., below 30 MHz, the bridge method is used for measurement. As against, for high-frequency range i.e., above 1000 MHZ, slotted line measurement is used.

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 are the three regions of log periodic antenna?

There are several type of log-periodic antennas such as the planar, trapezoidal, zig-zag, V-type, slot and the dipole. The mostly used one is log-periodic dipole array, in short, LPDA. The diagram of log-periodic array is given above.

Why is log periodic antenna called so?

This is particularly true of the Yagi beam antenna. One design named the log periodic antenna is able to provide directivity and gain while being able to operate over a wide bandwidth.

Which one of the following is true for log periodic antenna?

Log periodic antenna is frequency dependent. 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.

How do you check antenna impedance with a multimeter?

Antenna impedance is a complex quantity (i.e. real+imaginary). It is typically measured with a Network Analyzer. A multimeter will only give you the real impedance and will only give it at DC. At DC, most actual antennae have zero (ideally) real resistance.

What is the need for antenna measurements?

Antenna measurement techniques refers to the testing of antennas to ensure that the antenna meets specifications or simply to characterize it. Typical parameters of antennas are gain, bandwidth, radiation pattern, beamwidth, polarization, and impedance.

Is a log periodic antenna directional?

A log periodic antenna is a directional antenna developed for use over a wide band of frequencies, built with an array of dipole elements. Log periodic antennas balance directivity, gain and a wide bandwidth, amplifying the strength of a signal.

How good are log-periodic aerials?

A Log Periodic TV aerial has many benefits over traditional wideband TV aerials. For a start, Log Periodic aerials have a flat signal gain characteristic, meaning that they work equally well on all UHF TV channels – making them truly wideband and more likely to give consistent signal strength on all Freeview channels.

Which of the following is best suited to describe the impedance of log periodic antenna?

Impedance is function of logarithmic of frequency in LP so it is called log periodic antenna. 8. Which of the following best suits to describe the impedance of a log periodic antenna? Explanation: Impedance is function of logarithmic of frequency.

What is a log periodic antenna?

A Log-periodic antenna is that whose impedance is a logarithamically periodic function of frequency. The frequency range, in which the log-periodic antennas operate is around 30 MHz to 3GHz which belong to the VHF and UHF bands.

What is the frequency range of log-periodic antennas?

The frequency range, in which the log-periodic antennas operate is around 30 MHz to 3GHz which belong to the VHF and UHF bands. Construction & Working of Log-periodic Antenna The construction and operation of a log-periodic antenna is similar to that of a Yagi-Uda 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 a bi-directional log-periodic antenna?

For bi-directional Log-periodic antenna, the maximum radiation is in broad side, which is normal to the surface of the antenna. The figure given above shows the radiational pattern for a bi-directional log-periodic antenna.