Talk:Phased array

Untitled

I am doing a project on phased arrays, can anyone give me information? Thanks in advance. - john777

sonogram

What about phased arrays for sonography? --Gbleem 01:37, 22 November 2005 (UTC)

Efficiency

How efficient are phased arrays (especially radars), compared with traditional radar dishes? i.e. how many watts consumes a phased array radar which radiates 1MW, and how much consumes a traditional one? Gorbalad 15:44, 2 December 2005 (UTC)

I fear that you will need to define your parameters more precisely. For instance, a typical antenna must be rotated to focus the main lobe on its target. Phased arrays have no need of such rotation up to +-90degrees. Second, how big/far away/fast is your target? Last, because phased arrays can re-direct radiation by merely shifting phased on relative antennae, they are indispensible for tracking multiple objects.

The short answer would be that a phased array with a minimum of 5 antennae is significantly more efficient than a single, unidirectional antenna. S.N. Hillbrand 14:24, 4 December 2005 (UTC)

thank you, but what i wanted to know was how much of the electrical power you put into a radar is effectively radiated? i.e. i wanted a comparison of the energy efficiency of both types. Gorbalad 22:09, 5 December 2005 (UTC)

Taking into account this clarification, there is no substantive difference between a phased array and a traditional radar. Both are simply antennae and their efficiency is a matter of product design, cabling, materials and the frequency at which you are operating. S.N. Hillbrand 12:28, 6 December 2005 (UTC)

The short-short answer is that all of the RF is radiated in some direction by any antenna system, except that lost due to resistance in the antenna elements, including passive reflective elements. Therefore, a reflective dish actually introduces more loss than a phased array. Do not be misled by the term "destructive interference" -- energy is not destroyed -- it is redirected. Joe Shupienis 05:31, 23 December 2005 (UTC)

SPY-1

I've removed the remarks about controlling 100+ missiles. I'd like to see the citation for that, but I doubt that one exists. I also attempted to clarify missile guidance vs fire control. The paragraph probably needs more work, but I haven't the time to look for references right now. --Dual Freq 01:29, 12 April 2006 (UTC)

I've found a cite (german milatary) that explains the Aegis can track up to 100 targets at a time. I will update the content and add the reference.Logicnazi 08:40, 11 August 2006 (UTC)

That doesn't mean it can control 100+ missiles at a time. It means it can do all that stuff at the same time. NOAA has virtually the same sentence only they say track capacity not capability. This high powered Navy radar is able to perform search, track and missile guidance functions simultaneously with a track capacity of over 100 targets. Everything is a target to a radar, any search radar can probably track 100+ targets depending on how you define "track". Due to physics and timing it is impossible for it to control 100+ missiles in flight. Radar pulses take time to transmit and receive. Searching, detecting new targets, tracking existing tracks and guiding missiles take several pulses per second to do, there isn't enough time to do all that in one second and have 100 missiles in flight. On top of real targets, there are false targets like clutter, jamming, chaff all that stuff takes time for a computer to sort out. Even if it were possible, I believe there are only 4 SPG-62 directors on the ship and they are required for terminal guidance. Certainly 4 directors can't terminally guide 100+ missiles. SPY-1 does mid-course only, of course maybe that could change with technology. See also FAS SPY-1 weaknesses. Dual Freq 14:56, 11 August 2006 (UTC)

Other Types of Energy and Send versus Receive

(1) Phased arrays work with any type of wave energy. (2) The phased array concept works whether you are sending or receiving signals, i.e. even if you are only listening. (3) Search the Internet for "phased array microphone" to read about examples of acoustic receive-only mode. (4) Is 3-D seismic analysis of signals from an array of geophones a phased array application? (5) This is a good article on phased array radar. I'd like to see it expanded to include other wave energy and other applications. This is WAY out of my field (geology) and I don't feel competent to expand it. Rocky143 11:05, 1 December 2006 (UTC)

(4) Seismic analysis that uses continuous waves from a vibrator as source treats its array of geophones as a phased array. Other seismic explorations use an impulse source such as an explosion and here the geophone signals are combined with different delays to get a similar form of steerability. Note that it is not necessary for all the geophones of an array to be present at once: at sea it is common for a boat to tow a string of microphones whose detections of repeated explosions are recorded for combination later as a virtual or "synthetic" wide-area array.84.210.139.189 19:07, 13 January 2007 (UTC)cuddlyable3

No derrivation on diffraction page

This article states "We will begin from the N-slit diffraction pattern derived on the diffraction page." But there is no derrivation on that page - only a statement that a rigours matematical derrivation gives the equation shown. —The preceding unsigned comment was added by 213.78.42.15 (talk) 09:06, 26 April 2007 (UTC). If anyone can derrive the radiation pattern that is valid for arbitrary spacing and works for the near field too (i.e neglect the r squared and r cubed terms of E only at the last minute), I would be interested!

Yeah, the "Mathematical perspective and formulae" section needs to be cleaned up. Beyond referring to a non-existent derivation, there is no definition of symbols, and the small angle sine approximation is used with no justification I can see. If someone knows what's going on here, please edit. 130.216.54.198 (talk) 23:56, 30 March 2008 (UTC)

Math error?

Shouldn't the denominator in the first term be Sin[θ], instead of θ? Bswatson 23:54, 23 July 2007 (UTC)Brad

- Small angle approximation, presumably —Preceding unsigned comment added by 81.187.222.201 (talk) 09:50, 22 October 2007 (UTC)

There should be an explanation of all the variables in the "Mathematical perspective and formulas" section. --Comment added by 64.128.27.82 at 03 August 2012 — Preceding unsigned comment added by 64.128.27.82 (talk) 21:32, 3 August 2012 (UTC)

Was there an earlier attempt at a phased array?

I was reading a Nobel lecture here. Look particularly at pages 239-240 (14-15 in the pdf). I know this was before radar, but doesn't this make it look like Braun in 1905 made the first successful attempt at phased array transmission? Phased array doesn't only refer to radar. Jonnyapple (talk) 19:32, 2 April 2008 (UTC)

Very Large Array

Would it be all right to add "see also: Very Large Array"? --Ancheta Wis (talk) 03:17, 22 April 2008 (UTC)

My vote is yes. I think it is more relevant than many other things already listed there.Mkonca (talk) 22:47, 19 February 2014 (UTC)

Yamaha Sound Projector

Yamaha sells a phased-array home speaker system that creates surround sound by bouncing multiple beams off of the walls. Perhaps this should be mentioned here? Pioneer also had a similar unit, but it cost $40,000, really more of a prototype. --96.255.87.77 (talk) 02:34, 20 September 2009 (UTC)

Indented line What about adding LRAD to the list of "see also" articles? It is a phased array device.

96.229.176.17 (talk) 18:21, 10 October 2011 (UTC)

Airborne Phased Arrays

Phased arrays have been used on aircraft for some time. I think perhaps they warrant a section to explain their history, such as their initial use for ground targetting on aircraft like the B-1 and their later use as high powered, advanced interception radars on aircraft like the Mig-31. It was a significant chapter in the advancement of airborne radar and also a new use for Phased array's which made them much more common so I think its noteable enough to warrant inclusion. Also, before you object and point out that there is an article on Active arrays, I'll point out that I'm talking about traditional Phased Arrays. Active Arrays are fundamentally different and probably warrant their own article, but the earlier Phased Arrays which were included on the aircraft I just named were exactly the same as their land and naval counterparts, except for in scale.--Senor Freebie (talk) 13:29, 4 February 2010 (UTC)

The 2017 Saab Innovation Prize has gone to Dr. Henrik Holter for his invention of a new phased array antenna, which is central to the electronic warfare system of Gripen E.

There are actually very few types of wide band phased array antennas on the market. Henrik‘s main challenge was to reduce cost using modern technology. Henrik estimates that compared with the earlier technology, his system is around 60% cheaper to make.

https://www.saab.com/newsroom/stories/2017/september/advanced-innovation-detected — Preceding unsigned comment added by 2605:B100:327:AD0E:D8EE:B1D3:F993:A412 (talk) 02:32, 13 October 2024 (UTC)

Misleading description?

This article has a confusing and erroneous introduction. The modern meaning of the term "phased array" is an array antenna in which the radiation pattern can be changed electronically by altering the phase of the signals of the individual elements; in other words an antenna whose beam can be "electronically steered" without moving the elements 1, 2, 3, 4, p.xi, 5. It does not include multielement antennas with a fixed radiation pattern, such as the Yagi television antenna; otherwise any antenna with multiple elements would be a "phased array". It also doesn't include antennas in which the phase of the separate elements can be manually adjusted at the antenna to change the pattern, as in most broadcast antennas. The lead paragraph is okay, but the second paragraph of the intro is gobbledygook and erroneously gives a television antenna as an example of a phased array. --Chetvorno^TALK 01:30, 17 April 2013 (UTC)

I agree. The second paragraph can even be removed altogether. I don't think there is a need to explain what an array is. I also agree that if an example is to be given, it will be more appropriate to use a phased array instead of a passive array Mkonca (talk) 22:29, 19 February 2014 (UTC)

I wholeheartedly agree with both of these comments and have therefore taken the liberty to expunge the offending paragraph. If anyone wants to replace it please be sure NOT to confuse passive ie) non-powered arrays with active ie) powered arrays. If you're not aware of the difference you shouldn't be contributing to this article.Spyglasses 19:03, 31 March 2015 (UTC)

The current introduction still does not accord with the definition in antenna literature. A phased array is an array antenna which can be electronically steered, the antenna elements are fed by phase shifters controlled by a computer, which can change the beam direction without moving the antenna [1], [2], [3], [4], [5], [6], [7], [8]. The current introduction says:

"A phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are set in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. The phase relationships among the antennas may be fixed, as is usual in a tower array, or may be adjustable, as for beam steering."

This just defines any Array antenna. We already have plenty of articles covering those. --Chetvorno^TALK 04:06, 4 December 2016 (UTC)

Rewrote introduction to correct. --Chetvorno^TALK 06:52, 6 December 2016 (UTC)

External links modified

Hello fellow Wikipedians,

I have just modified 4 external links on Phased array. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Corrected formatting/usage for http://www.janes.com/defence/naval_forces/news/misc/aegis010425.shtml
• Corrected formatting/usage for http://messenger.jhuapl.edu/the_mission/publications/Wallis_Cheng.2001.pdf
• Added archive https://web.archive.org/web/20051208105830/http://www.ee.ucla.edu/~oecs/comp_pub/intr_opt/Optics23.pdf to http://www.ee.ucla.edu/~oecs/comp_pub/intr_opt/Optics23.pdf
• Added archive https://web.archive.org/web/20090831054307/http://www.alab.t.u-tokyo.ac.jp/~siggraph/09/TouchableHolography/SIGGRAPH09-TH.html to http://www.alab.t.u-tokyo.ac.jp/~siggraph/09/TouchableHolography/SIGGRAPH09-TH.html

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 5 June 2024).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 16:13, 21 May 2017 (UTC)

Addition to external link

I attempted to add an external link for a FOSS tool I made for explaining/visualizing phased array antennas(https://phasedarray.mlago.dev). I believe it could be useful for people that want to better visualize the interaction of the waves, it provides many of the images on the article in an interactive way(you can visualize the wave peaks like in the first image, or the electric field like in the second image, generate, antenna diagrams, etc). I believe it could be helpful, and assumed it was on topic, since it is very similar to another site link, "Software tool to predict the radiation pattern of an antenna array", although mine is more focused on visualization instead of the produced data. The link was removed, apparently automatically by Huggle. @Materialscientist:, is this intended? can we whitelist the link, should I perform any improvement, or further clarification on the website for it to be acceptable? I really do believe people might find this useful(at least I searched a long time for it before setting out to do it). ArthurMLago (talk) 00:25, 10 November 2023 (UTC)

I agree with the removal. Wikipedia isn't a link directory - it isn't a place to provide links to software you have written, even if they are on topic and helpful that is not sufficient for inclusion. MrOllie (talk) 02:35, 10 November 2023 (UTC)