Questions tagged [antenna-array]

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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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What does "degree of freedom" mean in Direction Of Arrival (DOA) estimation?

Recently, I was reading this paper. In the abstract, it is mentioned: This structure is obtained by systematically nesting two or more uniform linear arrays and can provide \$O(N^2)\$ degrees of ...
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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,...
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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 ...
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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 \...
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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 ...
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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 ...
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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 ...
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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 ...
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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 $$\...
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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 ...
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1 answer
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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 ...
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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 ...
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3 answers
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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:...
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3 answers
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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2 votes
2 answers
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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 ...
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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 ...
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1 vote
1 answer
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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 ...
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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 ...
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3 answers
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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 ...
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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 ...
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2 votes
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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 ...
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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 ...
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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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Cellular towers in rectangular grid

Not that far from where I live there are 6 towers that appear to be for cellular purposes in a perfect grid. You can see them in the picture I took from google maps. In the center of the road are ...
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Active phased antenna array for Wi-Fi efficiency compared to a directional antenna?

I'm interested in mesh networking of poorly controllable autonomous aerial vehicles (like blimps), so i wonder whether it is viable to use a phased antenna array versus a few traditional directional ...
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Cst phased array feeding

How can I feed my microstrip patch antenna with phase difference? I managed to get more directed beam but now I want to scan an area by changing directivity.
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How are antenna arrays synchronized for direction finding/localisation?

How are antenna arrays synchronized for direction finding/localisation? For example, if the processing unit is located closer to one antenna then another, it will see the signal from the closer ...
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1 vote
1 answer
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Vertically oriented beams using 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 ...
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1 answer
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Transmitting from omni to directional antenna

If an omni-directional antenna (transmitting antenna) transmits to a directional antenna (receiving antenna), how will the SNR be affected compared to when both antennas are omni?
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1 answer
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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 ...
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2 votes
1 answer
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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 ...
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Total Cable/Splitter loss calculation for Gain value compensation

If there is an 8 port splitter attached to cables feeding an array, is the total Cable/Splitter loss = S21 measurement for each port (with terminations on others) OR I have to add the S21 value of ...
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Can i join ground and signal wire in antenna?

Is there need to connect ground and signal wire differently in yagi antenna. I took outer shield(ground) and inner part(signal) of coax cable ( coming from antenna) and twisted them together and then ...
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24 votes
1 answer
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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 ...
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1 vote
1 answer
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How to tell the polarization (horizontal or vertical) of a microstrip linear array antenna just by inspection

I know that a linear array of microstrip patches can be either horizontal or vertical depending on its orientation. Does the feed (input port of the array) determine the direction of polarization?
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