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Questions tagged [phased-array]

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Antenna array's relative phase changes at each measurement trail

I am using an Rx antenna array (4 antennas), and a TX transmitter. Without changing my location of both transmitter and receiver as well as modifying my array geometry, I am measuring different phase ...
Xingda Chen's user avatar
0 votes
1 answer
563 views

How to Feed 2 x Co-Phased 4 Element Yagi Antennas?

I am wanting to build 2 x 4 element vertical yagi antennas for 28 MHz and co-phase them and feed with one 50 ohm coaxial transmission line. If i were to use a gamma match for each yagi and tune them ...
Andrew's user avatar
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2 votes
1 answer
630 views

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 ...
0xbad1d3a5's user avatar
3 votes
2 answers
775 views

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 ...
tyrela's user avatar
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1 vote
4 answers
354 views

What cause `multiply` has difference result between `float` and `complex` signal?

Construct 2 similar flow graph in Gnuradio,just different with data type. complex type data has a correct result.But ...
kittygirl's user avatar
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5 votes
2 answers
671 views

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 ...
Touisteur EmporteUneVache's user avatar
4 votes
2 answers
328 views

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\...
tyrela's user avatar
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1 vote
1 answer
326 views

Excitation coefficient of a linear phased array

it's well known that in a linear and equispaced antenna array, the array factor is equal to: The array is then called uniform if $|I_n| = I$ is the same for all elements. The phase terms $\angle I_n$ ...
Kinka-Byo's user avatar
  • 279
2 votes
1 answer
187 views

Total radiation pattern in antenna arrays

let's consider a simple linear uniform spaced array: We know that, from elementary array theory, the total pattern (for instance in terms of E-field) may be evaluated, in case no phase shift is ...
Kinka-Byo's user avatar
  • 279
2 votes
2 answers
272 views

Destructive interference between two close antennas

let's consider this two planar biconical dipoles of total length and width each one 10mm, at a distance D = 25.6mm. They are excited with the discrete ports in the picture, which corresponds in this ...
Kinka-Byo's user avatar
  • 279
2 votes
1 answer
98 views

Phase shifts in antenna arrays

Let's consider a simple antenna array. For instance, this three-elements equispaced dipole array: Each dipole is connected to a signal voltage source. It's well known that it's possible to choose the ...
Kinka-Byo's user avatar
  • 279
1 vote
1 answer
112 views

Dual Rubber Ducky antennas

Can I use 2 identical rubber ducky antennas with a splitter on my CB HT radio to improve range?
user18041's user avatar
1 vote
1 answer
2k views

440MHz collinear dipole array - suitable coax?

friends! Finally found my next antenna project..a collinear dipole array for the 70cm US ham band. The general idea: (image courtesy https://link.springer.com/referenceworkentry/10.1007%2F978-981-...
user avatar
1 vote
3 answers
1k views

Effective area of a phased array

For a $N$-element planar phased array, all the elements are same isotropic antennas. Then, what is the effective area of this array? Is it $$A_e=\frac{\lambda^2}{4\pi}GN$$ where $G$ is the directivity ...
tyrela's user avatar
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1 vote
1 answer
409 views

Double Cross Dipole antenna for 437 MHz don't tune

I'm building a Double Cross Dipole antenna for 437 MHz to be used with a SDR receiver for CW cubesat. The idea is to follow this "classic" paper from Gerald Martes, KD6JDJ. I tuned every single dipole ...
Carlo IU2KQB's user avatar
0 votes
4 answers
574 views

Variable polarization Yagi using two antennas on the same boom, joined together with variable feedpoint phase?

I have been trying for ages to find a way to mount a 10 m vertical Yagi properly, so that the mounting pole doesn't stuff up the impedance and radiation pattern, and have had no luck so far. Apart ...
Andrew's user avatar
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3 votes
1 answer
5k views

how does this collinear antenna work?

I was looking for a cheap and easy to build 2M/70cm vertical. I found this: http://vk2zoi.com/articles/dual-band-high-gain-flower-pot/ Here are the plans to build it: But I don't really understand ...
hjf's user avatar
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0 votes
1 answer
551 views

How should I stack these folded dipoles?

Looking to stack these 8 folded dipoles on my 100ft tower. I can not find any information whatsoever on these. I have 4 consecutive serial numbered boxes. Bluewave Marathon BME139FN1H0 138 - ...
VE6RSO 's user avatar
6 votes
2 answers
361 views

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 ...
Spuds's user avatar
  • 195
2 votes
2 answers
2k views

Bow Tie antennas impedance

I see on the internet that a radio amateur made bowtie antennas for transmitting and receiving on the 2 meter and 10 meter bands. They produced very good SWR bandwidth when fed with 50-$\Omega$ coax. ...
Robert 's user avatar
4 votes
1 answer
52 views

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 ...
V-Red's user avatar
  • 143
1 vote
3 answers
733 views

Total cancellation in corporate feed network for patch antenna

I'm trying to build an array of patch antennas in order to receive a GPS signal. The idea is to build 4 patches and connect them with a corporate feed network. An example of corporate feed is this one....
marcomanzoni's user avatar
1 vote
2 answers
383 views

Does antenna array structure effect overall radiation resistance?

If we consider a basic half wave dipole array does the radiation resistance of array depend on distance between two elements and phase we feed?
Aparna B's user avatar
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3 votes
1 answer
883 views

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 ...
tomnexus's user avatar
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8 votes
1 answer
1k views

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'...
Oliver's user avatar
  • 131
-1 votes
2 answers
440 views

Choosing a type of array antenna

I want to design a steerable beam array antenna which has 15 dBi directivity using uniform fed infinitesimal dipole elements at 1GHz frequency occupying physical aperture. Considering that phases of ...
user4621's user avatar
5 votes
1 answer
3k views

maximum acheivable range on CB radio by ground wave? [duplicate]

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 ...
abduoman11's user avatar
6 votes
1 answer
387 views

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,...
Ben's user avatar
  • 347
14 votes
1 answer
2k views

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 ...
Adam Davis's user avatar
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9 votes
2 answers
2k views

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 ...
Phil Frost - W8II's user avatar
8 votes
1 answer
457 views

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 ...
Adam Davis's user avatar
  • 12.1k
10 votes
3 answers
685 views

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 ...
Adam Davis's user avatar
  • 12.1k
10 votes
4 answers
10k views

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 ...
Craig's user avatar
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