What is a Log Periodic Antenna?
How do LP Antennas Work?
Log Periodic Dipole Array (LPDA) antennas are directional, active broadband antennas that are the ideal solution for interference tracking, site surveying, and most general RF and EMC analysis applications, due to their unique dipole elements positioned along the antenna axis in a triangular shape. With many varieties and names (LP Antenna, LPDA, LP Array Antennas, and Log Periodic Aerial) and minor functionality and design variations amongst each type, these antennas are designed with optimization in specific frequency ranges, and are capable of functioning within the high frequency – extremely high frequency ranges. Aaronia USA offers LP antennas starting as low as 380 MHz, and as high as 35 GHz to cover all potential RFI detection applications.
Left: Aaronia USA Broadband LP Antennas (active and passive)
Right: Aaronia USA EMI-optimized HyperLOG antennas with LP Elements
The common characteristic amongst all types of log periodic antenna is the dipole elements that are mounted closely together and connected parallel to the feedline with alternating phase, at specific intervals following the logarithmic function of the frequency. The length of each dipole element gradually decreases towards the front of the antenna, and each length specifically corresponds to resonance at different frequencies within the antenna’s bandwidth. The electrical function of these active broadband antennas simulates a series of two-element or three-element Yagi antennas, connected together and set to different frequencies.
Basic LPDA Configuration, Image Source: GlenDash.com (click image for link to article)
It is the relationship between these dipole elements’ positioning and graduated length that allows the antennas to function directionally. Directional antennas are the industry standard for interference tracking, as they make transmission source identification as simple as “point-and-shoot” with your antenna and RF analyzer kit. It should be noted, however, that it is not the triangular shape that contributes to the antenna’s broadband capabilities (a common misconception). Unlike Yagi antennas, it is the number of dipole elements that is responsible for the increase in bandwidth.
Where to Buy Log Periodic Antennas
Aaronia USA offers a variety of active and passive broadband antennas, including our full line of RF-optimized and EMI-optimized Log Periodic Directional antennas. For more information on LP antennas, or to determine if an Aaronia USA Log Periodic Antenna is right for your application, call 864-885-0700 or email sales@aaroniausa.com.
We are also proud to offer complete affordable RF and EMF detection kits that include our durable handheld RF and EMC Analyzers, Log Periodic Antennas, Omni-Directional Rubber Rod Antennas, Probes, and PC software for full spectrum analysis. View RF Detection Kits and EMF Detection Kits.
To learn more about Log Periodic Antenans and different antenna types, view sources for this article here:
http://www.radio-electronics.com/info/antennas/log_p/log_periodic.php
http://glendash.com/Dash_of_EMC/Log_Periodic/Log_Periodic.htm
https://en.wikipedia.org/wiki/Log-periodic_antenna
https://en.wikipedia.org/wiki/Self-complementary_antenna
http://www.antenna-theory.com/antennas/wideband/log-periodic-dipole.php
