Questions tagged [phased-array]
33 questions
14
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How would a time-difference-of-arrival receiver with two antennas know which side the signal is from?
An easy TDOA design by Byonics was published with the following schematic:
It appears that the antennas are switched at a rate of 640Hz, which allows a 640Hz tone to be heard in the radio when the antennas are not in phase. When the antennas are…
Adam Davis
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Using MIMO in Amateur Radio?
MIMO, Multiple Input, Multiple Output, is used widely in commercial data transmission. 802.11n and LTE devices use it to increase throughput, link reliability, and channel usage without increasing transmission power or using more bandwidth.
While…
Adam Davis
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4 answers
Phasing harness for antenna array
I understand that certain antenna designs (particularly phased arrays) require feeding each radiating element with a certain number of degrees of phase separation in order to achieve a desired radiation pattern or beamwidth.
I found this 2-meter…
Craig
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9
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2 answers
How might one realize a first order, two dimensional RF field antenna for HF?
I just coined the term "field antenna". It is by analogy to the lightfield camera or the soundfield microphone. Essentially, it is an antenna that captures not only the strength of an RF field, but also the direction of it.
Of course, these antennas…
Phil Frost - W8II
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8
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Variable phase antenna
I'm thinking about phased antenna arrays, and am wondering if it's possible to have three fixed position antennas, and vary the length of their individual feedlines to the common point through mechanical means.
The best way to describe what I'm…
Adam Davis
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8
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Phased Array Pattern
I'm working on a passively scanned phased array radar project, as a concept and hopefully design.
One of the things that bugs me is that antenna patterning used. The vast majority of radar arrays I've seen employ a hex grid pattern, with a small…
Oliver
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6
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How to stack circular polarised antennas
I'm interested in stacking a pair of circularly polarized "crosshair" antennas. Do I construct such as both antennas are in phase with one another then match the two signals in phase via the coax line, i.e. equal length, or should I rotate one by…
Ben
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6
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2 answers
Effective Area of Dipole Array
I'm trying to design a low frequency dipole interferometer antenna array. I am realizing how little I know about radio antennae. I'm confused by the concept of effective area $A_e$ and how it applies to arrays. I haven't been able to get a clear…
Spuds
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maximum acheivable range on CB radio by ground wave?
I have 10 watt CB radio system & 0.64 lambda monopole antenna , I think it has a 5 dBi gain .
what is the maximum acheivable range by ground wave in an urban area ?
If I want to increase my range without increase the system’s power , can I make …
abduoman11
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5
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2 answers
Phased array (rx only) with separate complete receivers
Is it possible to have a network of separate (but co-located) 'receivers' (antenna + adc) act as a phased array receiver?
Supposing one can get very precise timestamping on each receiver, couldn't all the receivers be assembled as a phased…
4
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2 answers
Why does beamforming bring more power to the received desired signal?
Consider a normal array model with $N$ element. The output of the array is given by,
$$\mathbf{y}=\mathbf{w}^H\mathbf{x}=\mathbf{w}^H\mathbf{as}$$
where
$\mathbf{a}=[a_1,...,a_N]^T=\in\mathbb{C}^{N\times 1}$ is the manifold of the desired signal (I…
tyrela
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4
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Vertically orienting beams with antenna arrays
Referring to the above picture, can an antenna array mounted on Node A direct beams towards Node B and Node E, without the need for an antenna rotator (or manually orienting the antenna array towards the respective nodes)? In other words, can the…
V-Red
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3
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How to feed an array of dipoles for an end-fire pattern
An array of dipoles can be fed to achieve an end-fire pattern.
If the phase of the current on each element is equal, the array will have maximum radiation broadside to the array. If the phase of the currents is equal to the physical spacing of the…
tomnexus
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3
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Why is the total radiated power of array calculated by sum of square of excitation coefficients different from the result by integral of power pattern
Consider an array with same isotropic antennas, $P_{ele}^n$ is the input power of the nth antenna. As I consider antenna radiation efficiency = 1, the $P_{ele}^n$ is also the radiated power of the nth antenna. If the antenna is matched, this…
tyrela
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2
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How do phased array antennas work when they produce spot beams?
Background
In a lot of literature regarding satellite communications with phased arrays, you'd see this kind of image:
Conceptually, I get the basic concept of how this works - a bunch of small antennas work together to direct a stronger signal to…
0xbad1d3a5
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