Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [antenna-array]

58 questions
24
votes
1 answer

What is the purpose of the elements of this antenna?

I have a 5GHz 23dBi Wi-Fi panel antenna which has the geometry shown in the images below. I have been quite curious as to the purpose of this bizarre antenna design. The elements have such unique shapes, and each is slightly different, though…
Sam Gallagher
  • 682
  • 3
  • 12
4
votes
3 answers

What is counterpoise?

I was reading about the radio telescope - Murchison Widefield Array (MWA) situated in western Australia. Antennas of this telescope are quite unique and different from usual dish radio telescope. In MWA a four by four regular grid of…
learner
  • 201
  • 1
  • 2
4
votes
0 answers

bearing ambiguity resolve (direction finding) for multiple sources

I am working on wideband direction finding algorithms for passive sensors. I started with Music algorithm. For practical reasons, the spacing can not be maintained lambda/2. For greater antenna spacing, grating lobes appear. I found some…
Sanjoy Basak
  • 41
  • 1
3
votes
1 answer

Why are many radar antenna arrays not rectangular but rather octagonal÷icosagonal?

I've seen that, despite some phased array antennas are rectangular, many of them are not. They are octagonal, decagonal and even more. Why are they built in this way?
Kinka-Byo
  • 3,340
  • 2
  • 19
  • 58
3
votes
2 answers

Which is the cause of "scan losses" in a linear phased antenna array?

in a linear phased array it is possible to move the peak angle ("beam steering") by applying proper phase shift between the excitation currents: The second picture represents the array factor for different beams angle. Last picture taken from…
Kinka-Byo
  • 3,340
  • 2
  • 19
  • 58
2
votes
1 answer

What is difference between resonant and non resonant antennas?

I don't know if it's right place to ask it, but I searched google and books the answer I get seems to be like resonant antenna have small bandwidth and have standing wave instead non resonant antennas have wider bandwidth and travelling waves. What…
SUNITA GUPTA
  • 455
  • 3
  • 19
2
votes
1 answer

Can you create a circularly polarized signal with dipoles that are perpendicular but not crossed?

All of the circularly polarized phased arrays that I can find use elements that are themselves circularly polarized, that is, two perpendicular dipoles that are crossed at their midpoints (the picture on the left). Would something like the pattern…
user201537
  • 91
  • 6
2
votes
3 answers

Distance requirements in antenna arrays?

Antenna array is a broad term and it encompasses at least the following concepts: MIMO or massive MIMO: for spatial multiplexing beamforming: increasing the SNR (at transmitter or receiver) by aligning the signals properly phased array: special…
divB
  • 1,312
  • 14
  • 32
2
votes
0 answers

How to design a 3GHz antenna?

I would like to design a 3GHz high gain antenna. S11 has to be below -10dB and the gain to be above 9dBi - and I want to make it smaller than 8cm. What kind of antenna is better to satisfy the condition? It doesn't matter about the antenna type,…
Churus
  • 21
  • 2
2
votes
1 answer

Aperiodic lattices and beamwidth of reflectarray antenna

This question is about reflectarray antennas. In the paper below, it is mentioned that: "A second useful property of aperiodic arrays is the possibility to reduce the number of elements in one assigned aperture without major impact on the…
Fromage
  • 49
  • 3
2
votes
1 answer

Why does electrical phase vary with element length?

In a reflectarray antenna, each element on the antenna aperture requires a different electrical phase due to different distances from the antenna feed. One way to achieve this phase variation is to vary the size of the elements on the reflectarray.…
Fromage
  • 49
  • 3
1
vote
0 answers

Can we generate a frequency-dependent beams with uniform linear array?

I have some difficulties understand how can we generate frequency-dependent beams using unniform linear array. A paper that discusses this is the following: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9826716. For a carrier frequency…
zdm
  • 111
  • 1
1
vote
2 answers

What is the maximum possible aperture efficiency of an antenna?

The aperture efficiency of an antenna is defined as the ratio of the effective aperture divided by the physical aperture. The typical values are between 0.35 to more then 0.70. Wikipedia What is the maximum realizable aperture efficiency? What drive…
Ed Tate
  • 121
  • 4
1
vote
0 answers

Antenna mutual coupling and estimation of angle of arrival

If I have two RX (receive) antennas at a distance of lambda/2 from each other there is a formula which relates the phase difference to the angle of arrival. The formula is however assuming no mutual coupling between the two antennas . Is there a…
cesar
  • 351
  • 2
  • 9
1
vote
1 answer

Can phased-array (ULA) gain tapering effects be modelled using digital windows?

I am attempting to model the general behaviour of various tapering techniques. It seems applying gain tapering to a ULA has very similar effects to that of applying a digital window to a signal. In fact, some common tapering algorithms also exist in…
brunerm99
  • 61
  • 6
1
2 3 4