Content deleted Content added
Tag: references removed |
GreenC bot (talk | contribs) Rescued 1 archive link; Move 9 urls. Wayback Medic 2.5 per WP:URLREQ#ieee.org |
||
(86 intermediate revisions by 47 users not shown) | |||
Line 1:
{{short description|Multi-element, directional antenna useable over a wide band of frequencies}}
[[File:LPDA-Antenna.jpg|thumb|260px|Log-periodic antenna, 400–4000 MHz]]
{{Antennas|expanded=Common Types}}
A '''log-periodic antenna''' ('''LP'''), also known as a '''log-periodic array''' or '''log-periodic aerial''', is
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 element]]s of gradually increasing length, each consisting of a pair of metal rods. The dipoles are mounted close together in a line, connected in parallel to the [[feedline]] with alternating [[phase (waves)|phase]]. Electrically, it simulates a series of two- or three-element [[
LPDA antennas look somewhat similar to
One large application for LPDAs is in rooftop terrestrial [[television antenna]]s, since they must have large bandwidth to cover the wide television bands of roughly 54–88 and 174–216 MHz in the [[Very high frequency|VHF]] and 470–890 MHz in the [[Ultra high frequency|UHF]] while also having high
== Basic concept ==
The LPDA normally consists of a series of [[dipole antenna|half wave dipole]]
Every element in the LPDA
The [[Yagi–Uda antenna|Yagi]] and the LPDA designs look very similar at first glance, as they both consist of a number of dipole elements
In general terms, at any given frequency the log-periodic design operates somewhat similar to a
It should be strictly noted that the log-periodic shape, according to the IEEE definition,<ref>
{{multiple image
| align = center
Line 30 ⟶ 31:
| width1 = 200
| image2 = VHF UHF LP-antenna closeup.JPG
| caption2 = Log
| width2 = 150
| image3 = Log periodic VHF TV antenna 1963.jpg
| caption3 = LP television antenna 1963. Covers 54–88 MHz and 174–218 MHz. Slanted elements were used because on the upper band they operate at the
| width3 = 262
| image4 = Log-periodic monopole antenna.png
| caption4 = Wire
| width4 = 202
}}
== History ==
John Dunlavy invented the log-periodic antenna in 1952 while working for the United States Air Force but was not credited with it due to its "Secret" classification.<ref>{{cite web |website=Stereophile |author=John Atkinson |date=24 August 1996 |title=Loudspeaker designer John Dunlavy: By the Numbers |at=page 4 |url=https://www.stereophile.com/content/loudspeaker-designer-john-dunlavy-numbers-page-4}}</ref> The [[University of Illinois at Urbana–Champaign]] had patented the Isbell and Mayes–Carrel antennas and licensed the design as a package exclusively to JFD Electronics in New York. [[Channel Master]] and [[Blonder Tongue Labs]] ignored the patents and produced a wide range of antennas based on that design. Lawsuits regarding the antenna patent, which the U.I. Foundation lost, evolved into the [[Blonder-Tongue Labs., Inc. v. University of Ill. Foundation|1971 Blonder-Tongue Doctrine]]. This precedent governs patent litigation.<ref>{{Cite web |title=Blonder–Tongue Doctrine Law and Legal Definition |publisher=USLegal, Inc. |website=definitions.uslegal.com |url=https://definitions.uslegal.com/b/blonder-tongue-doctrine/ |url-status=live |access-date=2022-05-04 |archive-url=https://web.archive.org/web/20230325052723/https://definitions.uslegal.com/b/blonder-tongue-doctrine/ |archive-date=Mar 25, 2023 }}</ref>
== Short wave broadcast antennas ==
Line 50:
| header =
| image1 = Moosbrunn drehbare logarithmisch-periodische Antenne (2).JPG
| caption1 = Wire log
| width1 = 288
| image2 = LPA_antenna_suitable_for_short_wave_broadcast.png
| caption2 = Diagram of a zig-zag shortwave LPA antenna
| width2 = 180
}}
The log
== References ==
{{Reflist|30em}}
== Bibliography ==
* {{cite book |title= Antennas|author= John Daniel Kraus |publisher= McGraw-Hill College |year= 1988|edition = Subsequent|page=892 |isbn=978-0-070-35422-7}} $ 15-5: ''The Log-Periodic Antenna'', p. 703-708.
== Notes ==
Line 67 ⟶ 70:
== See also ==
*[[Self-complementary antenna]]
== External links ==
Line 75 ⟶ 77:
*[http://www.members.westnet.com.au/impeh/log%20periodic_A.htm Some thoughts on Log-Periodic Antennas]
*[http://www.com-power.com/log_periodic_antennas.html Com-Power Corporation - Log Periodic Antennas for EMC testing]
*[https://www.allaboutcircuits.com/technical-articles/wi-fi-antennas-part-1-fundamentals/ All About Circuits - The Fundamentals of Wi-Fi Antennas]
*[https://www.electronicspoint.com/forums/threads/antenna.103577/ Electronics Point - Forum / Antenna]
*[https://maker.pro/ Maker Pro]
*[https://eepower.com/ EE Power]
{{Antenna Types}}
|