Editing Phased array (section)

== History ==
[[Image:Braun phased array antenna 1905.png|thumb|[[Ferdinand Braun]]'s 1905 directional antenna, which used the phased array principle, consisting of three monopole antennas in an equilateral triangle. A quarter-wave delay in the feedline of one antenna caused the array to radiate in a beam. The delay could be switched manually into any of the three feeds, rotating the antenna beam by 120°.]]
{{multiple image
| align = right
| direction = horizontal
| header   =
| image1   = PAVE PAWS Radar Clear AFS Alaska.jpg
| caption1 = US [[PAVE PAWS]] [[active electronically scanned array|active phased array]] ballistic missile detection radar in Alaska. Completed in 1979, it was one of the first active phased arrays.
| width1   = 180
| image2   = Cape Cod Air Station - HAER MA-151-A - 384568pu.jpg
| caption2 = Closeup of some of the 2677 crossed dipole antenna elements that make up the plane array. This antenna produced a narrow "pencil" beam only 2.2° wide.
| width2   = 195
| footer   =
}}
[[File:PAVE PAWS&BMEWS.svg|thumb|[[BMEWS]] & [[PAVE PAWS]] radars]]
[[Image:Mammut Hoarding radar illustration.png|thumb|Mammut phased-array radar, [[World War II]]]]

Phased array transmission was originally shown in 1905 by [[Nobel Prize|Nobel]] laureate [[Karl Ferdinand Braun]] who demonstrated enhanced transmission of [[radio]] waves in one direction.<ref>{{cite book |url=https://www.nobelprize.org/prizes/physics/1909/braun/lecture/|chapter=Electrical Oscillations and Wireless Telegraphy|title=Nobel Lectures, Physics 1901-1921|publisher=Elsevier|location=Amsterdam|year=1967|orig-date=Delivered 11 December 1909|last=Braun|first=Karl Ferdinand|access-date=29 July 2023|via=nobelprize.org}} Braun's Nobel Prize lecture. The phased array section is on pages 239–240.</ref><ref>"Die Strassburger Versuche über gerichtete drahtlose Telegraphie" (The Strassburg experiments on directed wireless telegraphy), ''Elektrotechnische und Polytechnische Rundschau'' (Electrical technology and polytechnic review [a weekly]), (1 November 1905). This article is summarized (in German) in:
Adolf Prasch, ed., ''Die Fortschritte auf dem Gebiete der Drahtlosen Telegraphie'' [Progress in the field of wireless telegraphy] (Stuttgart, Germany: Ferdinand Enke, 1906), vol. 4, [https://books.google.com/books?id=ZAAMAAAAYAAJ&pg=RA1-PA184 pages 184–185].</ref> During [[World War II]], Nobel laureate [[Luis Walter Alvarez|Luis Alvarez]] used phased array transmission in a rapidly [[Beam steering|steerable]] [[radar]] system for "[[ground-controlled approach]]", a system to aid in the landing of aircraft. At the same time, the GEMA in Germany built the [[Mammut radar|Mammut]] 1.<ref>http://www.100jahreradar.de/index.html?/gdr_5_deutschefunkmesstechnikim2wk.html {{webarchive|url=https://web.archive.org/web/20070929154159/http://www.100jahreradar.de/index.html?%2Fgdr_5_deutschefunkmesstechnikim2wk.html |date=2007-09-29 }} Mamut1 first early warning PESA Radar</ref> It was later adapted for [[radio astronomy]] leading to [[Nobel Prize for Physics|Nobel Prizes for Physics]] for [[Antony Hewish]] and [[Martin Ryle]] after several large phased arrays were developed at the [[University of Cambridge]] [[Interplanetary Scintillation Array]]. This design is also used for [[radar]], and is generalized in [[interferometry|interferometric]] radio antennas.

In 1966, most phased-array radars use ferrite phase shifters or traveling-wave tubes to dynamically adjust the phase.
The AN/SPS-33 -- installed on the nuclear-powered ships Long Beach and Enterprise around 1961 -- was claimed to be the only operational 3-D phased array in the world in 1966.
The AN/SPG-59 was designed to generate multiple tracking beams from the transmitting array and simultaneously program independent receiving arrays.
The first civilian 3D phased array was built in 1960 at the National Aviation Facilities Experimental Center; but was abandoned in 1961.<ref>
W. J. Evanzia.
[https://www.worldradiohistory.com/Archive-Electronics/60s/66/Electronics-1966-06-27.pdf "Faster, lighter 3-D radars in sight for tactical warfare"].
Electronics.
1966.
p. 81, 83, 87.
</ref>

In 2004, [[California Institute of Technology|Caltech]] researchers demonstrated the first integrated silicon-based phased array receiver at 24&nbsp;GHz with 8 elements.<ref>{{Cite web|url=http://chic.caltech.edu/wp-content/uploads/2013/06/fullyintegrated24ghz.pdf|title=A Fully Integrated 24GHz 8-Path Phased-Array Receiver in Silicon|url-status=live|archive-url=https://web.archive.org/web/20180511100234/http://chic.caltech.edu/wp-content/uploads/2013/06/fullyintegrated24ghz.pdf|archive-date=2018-05-11}}</ref> This was followed by their demonstration of a CMOS 24&nbsp;GHz phased array transmitter in 2005<ref>{{Cite web|url=http://chic.caltech.edu/wp-content/uploads/2013/05/11.7_final.pdf|title=A 24GHz Phased-Array Transmitter in 0.18μm CMOS|url-status=live|archive-url=https://web.archive.org/web/20180511100233/http://chic.caltech.edu/wp-content/uploads/2013/05/11.7_final.pdf|archive-date=2018-05-11}}</ref> and a fully integrated 77&nbsp;GHz phased array transceiver with integrated antennas in 2006<ref>{{Cite web|url=http://chic.caltech.edu/wp-content/uploads/2013/05/Aydin_ISSCC_06.pdf|title=A 77GHz 4-Element Phased Array Receiver with On-Chip Dipole Antennas in Silicon|url-status=live|archive-url=https://web.archive.org/web/20180511100234/http://chic.caltech.edu/wp-content/uploads/2013/05/Aydin_ISSCC_06.pdf|archive-date=2018-05-11}}</ref><ref>{{Cite web|url=http://chic.caltech.edu/wp-content/uploads/2006/02/HajimiriArun_ISSCC_77TX_06.pdf|title=A 77GHz Phased-Array Transmitter with Local LO- Path Phase-Shifting in Silicon|url-status=live|archive-url=https://web.archive.org/web/20150909231447/http://chic.caltech.edu/wp-content/uploads/2006/02/HajimiriArun_ISSCC_77TX_06.pdf|archive-date=2015-09-09}}</ref> by the Caltech team. In 2007, [[DARPA]] researchers announced a 16-element phased-array radar antenna which was also integrated with all the necessary circuits on a single silicon chip and operated at 30–50&nbsp;GHz.<ref>[http://ucsdnews.ucsd.edu/newsrel/science/10-07PhasedArrayChipDK-L.asp World’s Most Complex Silicon Phased Array Chip Developed at UC San Diego] {{webarchive|url=https://web.archive.org/web/20071225084723/http://ucsdnews.ucsd.edu/newsrel/science/10-07PhasedArrayChipDK-L.asp |date=2007-12-25 }} in UCSD News (reviewed 2 November 2007)</ref>

The relative [[amplitude]]s of—and constructive and destructive [[Interference (wave propagation)|interference]] effects among—the signals radiated by the individual antennas determine the effective [[radiation pattern]] of the array. A phased array may be used to point a fixed radiation pattern, or to [[wikt:scan|scan]] rapidly in [[azimuth]] or elevation. Simultaneous electrical scanning in both azimuth and elevation was first demonstrated in a phased array antenna at [[Hughes Aircraft Company]], California in 1957.<ref>See Joseph Spradley, "A Volumetric Electrically Scanned Two-Dimensional Microwave Antenna Array," IRE National Convention Record, Part I{{Snd}} Antennas and Propagation; Microwaves, New York: The Institute of Radio Engineers, 1958, 204–212.</ref>