# 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 ...
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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 ...
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164 views

### 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 ...
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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) ...
32 views

### 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 ...
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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 ...
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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 ...
• 103
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 ...
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1 vote
197 views

### 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 ...
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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 ...
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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 ...
97 views

### 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 ...
• 161
899 views

### 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 ...
1 vote
41 views

### 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 ...
109 views

### 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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89 views

### 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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137 views

### 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 ...
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?
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1 vote
84 views

### 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 ...
1 vote
255 views

### 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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157 views

### 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 ...
1 vote
125 views

### 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 ...
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1k views

### 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, ...
1 vote
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 ...
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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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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 ...
• 465
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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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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:...
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1 vote
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?
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 ...
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1 vote
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 ...
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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 ...
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 ...
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 ...
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 ...
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1 vote
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 ...
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1 vote
120 views

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 ...
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 ...
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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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### 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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