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Questions tagged [antenna-array]

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How to find the phase values for the desired steering angle?

The picture attached is self-explanatory. The antenna system system 24 antenna elements with inter antenna element spacing of wavelength/2. There are two types of arrangements. The first one is ...
MGM's user avatar
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Do solid state phased arrays need isolated power supplies?

Non-isolated DC/DC supplies could have higher power density but it seems that high power solid state phased arrays utilize mostly isolated DC/DC converters to power each of their amplifiers. Why are ...
MaxwellEE's user avatar
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What is the behaviour of this antenna array?

I have a subarray-based antenna system as shown here: The four subarrays are arranged vertically. In each subarray there are six antenna elements. Only the bottom three in each subarray have a common ...
MGM's user avatar
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Gain of a signal passed through a N element phased array?

Assuming a isotropic phased array of N elements, the gain would be 10*log10(N) dB which is provided in theory. However, when same signal is passed through all the N elements, the gain is 20 * log10(N) ...
Pacific's user avatar
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Calculating the SLL of an antenna array of 8 elements

I'm given an array of 8 half-wave dipoles separated 0.15m each and I'm told to calculate the SLL in dB (the ratio between main and secondary lobes). The thing is that The only formula that comes ...
Ketterle's user avatar
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Phase Differences and Wave Equation in ULA Antennas with Far-Field Assumption

I am analyzing a signal received by two antennas, where the second antenna is positioned farther than the first in the direction of wave propagation. I am encountering some confusion when it comes to ...
Naetmul's user avatar
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What is a good way to mute antenna while keeping the aperture unchanged?

I have an 2D array of 64 antenna element. Lets say each antenna is connected to one RF chain. with this array total 64 parallel data streams can be transmitted with some pre-processing. When the load ...
MGM's user avatar
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2 votes
2 answers
937 views

Proper way to combine same-frequency PCB antennas

I want to combine 2 identical PCB antennas to increase gain. The antennas are designed to work on 2.4GHz and have 50ohm impedance, linear polarization with Omni-Directional radiation pattern, they are ...
AndreaF's user avatar
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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 ...
Ed Tate's user avatar
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Why does literature call the response of an antenna array the array "manifold" vector?

Van Trees' Optimum Array Processing and other works (e.g. Wikipedia) refer to an antenna array's response (shifts in phase and differences in gain due to the angle of reception) at each element as the ...
gibbss's user avatar
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How can polar plots of radiation fields/array factors be made by hand?

In one of my courses we are expected to plot array factors and other radiation fields by hand. I am comfortable deriving expressions for the array factor by hand but I am struggling when trying to ...
Richard Westmoreland's user avatar
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How well synced do digital channels in a phased array need to be?

In order for a narrowband phased array to be coherent channel to channel, what is the maximum timing jitter that can be tolerated between channels? I assume there can be a constant timing error ...
Gillespie's user avatar
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Antenna: three element array, Balanis problem 6.3

I am trying to solve the below Problem (only question (a)), where I am mainly stuck on figuring out how to read this z/y drawing of the magnitude and phases. The problem has to do with 3 antennas ...
Christianidis Vasilis's user avatar
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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 ...
cesar's user avatar
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What is the frequency measurement range of a NanoVNA?

I have tried to measure a fabricated patch antenna which has theoretically multiband ranging from 1 GHz to 8 GHz, but when I tried to measure it through NanoVNA it barely shows the result from 1 GHz ...
MS-Hossen's user avatar
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Why does an isotropic antenna becomes anisotropic inside a phased array (mutual coupling neglected)?

in this paper the following statement is written: An area A is allotted to each element in the infinite array. This is the maximum area available to each element, and is usually greater than the ...
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Best antenna design with the following requirements?

I'm looking for the best antenna design with the following requirements Small Discrete Wideband (LTE and WiFi) Directional High gain (20-25dBi with relatively high transmission power) Could anyone ...
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Is an antenna array with a tilted (rotated) antenna element always less optimal than a perfectly aligned antenna array?

Suppose I have a traditional linear antenna array. My element factor follows a cosine shape between 0-180 degrees. The relationship between my theoretical total antenna array pattern and the element ...
Xingda Chen's user avatar
3 votes
1 answer
712 views

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's user avatar
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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 ...
brunerm99's user avatar
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2 answers
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Why is the linear phased array pattern a sinc (visual interpretation)?

It has for sure a very obvious answer, but I must admit I find it very difficult to visualize how a linear phased array can focus the beam with a sinc pattern. I'm not talking about the mathematical ...
Kinka-Byo's user avatar
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Symmetric PCB stack-up for phased-array antennas

We all know that a symmetric PCB stack-up is always recommended since it makes manufacturing easier and more reliable. However when designing PCB for antennas application this became quite a difficult ...
Paolo Squadrito's user avatar
1 vote
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What does "degree of freedom" mean in Direction Of Arrival (DOA) estimation?

Recently, I was reading this paper, Nested Arrays: A Novel Approach to Array Processing With Enhanced Degrees of Freedom. In the abstract, it is mentioned: This structure is obtained by ...
Milad A's user avatar
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Finding the side lobe level of an antenna array

I have a circular antenna array with N elements, for which the array factor can be defined as follows: $$AF(\phi)=\sum_{n=1}^N I_n \cdot e^{j \cdot(kr \cdot \cos(\phi-phi_n)+\beta_n}$$ I search a lot, ...
Reza_va's user avatar
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1 answer
301 views

MU-MIMO - do all antennas stream in different frequencies?

I have few questions on how MU-MIMO in WiFi works. Do all antennas stream in different frequencies or stream in same channel but different sub carriers(OFDMA?) Do MIMO antennas always work in OFDM ...
Franc's user avatar
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1 answer
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Derivation of Dolph-Taylor Synthesis

Today, I was trying to deduce by myself the Dolph-Taylor Synthesis. After arriving at the expression: $$AF(\theta) = P_{N-1} \left( \cos \left( \frac{\psi}{2} \right) \right) = T_{N-1} \left(x_o \cos \...
user3141592's user avatar
4 votes
2 answers
5k views

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 ...
Kinka-Byo's user avatar
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-1 votes
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143 views

How reflection occuring in antenna fed by transmission line affects performance?

Transmission line considered is lossless. Basically the configuration is simple. For transmitter side : a non ideal source (can be voltage current or power) feeding a transmission line (TL1) with ...
SUNITA GUPTA's user avatar
1 vote
6 answers
1k views

Why are transmitting antennas generally larger than receiving antennas?

The reasons I can think of are transmitting antenna has to be more directive also larger length will imply larger power and thus will help compensating for losses. But on contrary if receiving antenna ...
SUNITA GUPTA's user avatar
1 vote
1 answer
444 views

Difference between IRS and phased array/reflectarray

just wondering out of curiosity the difference between intelligent reflecting surface (IRS) and more traditional antenna arrays such as phased array and reflectarray? From the surface it looks a whole ...
user3602697's user avatar
1 vote
2 answers
256 views

Combination of different antennas

I was wondering if there was a mathematical way to combine two different types of antenna elements. Let's say that I have an antenna of $$\lambda/2$$ and I want to combine it with an antenna of $$\...
DaDSPGuy's user avatar
1 vote
0 answers
62 views

How can one compare resonant and non resonant antenna based on parameters like Directivity, Radiation resistance, Cross polarisation, Efficiency?

Basically I want to make a choice between two antennas when ample space is given objectively based on parameters 1.Directivity 2.Radiation Resistance 3.Cross Polarization ratio 4.Loss resistance I'll ...
SUNITA GUPTA's user avatar
2 votes
1 answer
2k views

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 ...
SUNITA GUPTA's user avatar
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1 answer
106 views

Design of 5+ channel microphone array

I'm interested in designing a microphone array which will have 5+ inputs which need to be synced, possibly more. I want to sample each input at 20-30khz at 8-10 bit resolution. I would prefer not have ...
FourierFlux's user avatar
2 votes
3 answers
344 views

Do beam-forming devices expect a particular antenna configuration?

Do beam-forming devices expect a particular antenna configuration? For instance, do they expect the antennas to be a certain distance from one another? Or parallel to one another? Etc. Background Info:...
user2800679's user avatar
1 vote
3 answers
164 views

Why do we need array antennas?

If we can increase the directivity of the single element antenna by increasing its electrical size then why do we need array antennas?
hussain ali's user avatar
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0 answers
176 views

How to connect a 4:1 balun to a a log periodic antenna?

I'm following a plan for a home made LTE/4G UHF antenna here: https://www.thingiverse.com/thing:3221812 ...because it looks to be of a very similar to design to a very expensive 4G anntenna I know ...
NickG's user avatar
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1 vote
1 answer
790 views

Dipole array antenna radiation pattern

I have the radiation pattern for a dipole antenna with working frequency of 11 GHz, it looks like figure 1. I wanted to create an array antenna consisting of 2 elements with that same individual ...
DaDSPGuy's user avatar
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1 answer
554 views

Rayleigh distance of array antenna

Far field zone of a single antenna can be determined by using the equation below. $$R>\dfrac{2D^2}{\lambda}$$ Where D is the biggest dimension of the antenna. This equaiton is suitable for single ...
Aldrich Taylor's user avatar
2 votes
1 answer
159 views

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 ...
user201537's user avatar
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1 answer
192 views

Antenna Array - Hundreds of elements forming thousands of beams - How?

How would an antenna array of 100 elements be able to form 5000+ simultaneous beams? Or do I have it wrong, there would only be a maximum 100 beams from the 100 elements at any one time and those ...
Natalie Johnson's user avatar
4 votes
3 answers
220 views

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 ...
learner's user avatar
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1 vote
1 answer
201 views

Why can the polarization of an antenna array be determined by the polarization of its individual elements?

In problems determining the polarization of an antenna array I've looked at, the polarization of the total array is determined by finding the polarization of a single element and then extrapolating ...
Jimmy Vailer's user avatar
1 vote
1 answer
120 views

RFID reader technology

Hopefully this isn't too broad of a question, I will narrow it down the best I can. We need to add RFID tags to feeders on our pick and place machine, to determine that they are loaded into the ...
Kyle Hunter's user avatar
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1 answer
74 views

Satellite array antenna beamforming - basic intuition help

When you see a satellite coverage region on the earth, the array antennas form tens of circles (small coverages) in a large coverage. My question is whether all these small circle coverages exist at ...
Natalie Johnson's user avatar
2 votes
3 answers
5k views

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 ...
divB's user avatar
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Zeros in radiation of Smart Antennas

I have an exercise from a textbook about smart antennas. I think I have the right approach to solve this kind of problem. However, I'm not quite sure if I'm handling it correctly due to the additional ...
Mr.Sh4nnon's user avatar
2 votes
0 answers
74 views

How to design a 3GHz antenna? [closed]

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 ...
Churus's user avatar
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1 answer
119 views

Phased array receiver circular polarization

In a phased array system, what will have to change in a receiver's architecture if it needs to work for both linear and circular polarization? I saw in one article it is said "Supports automatic ...
Rumman Ahmed's user avatar
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1 answer
97 views

Patch antennas: explanation of examples

I am studying patch antennas for mobile communication (technology.) I have found some examples of them but without explanation. Maybe can someone explain to me the difference of examples from this ...
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