Questions tagged [radiation]
While rare, this tag should be used for questions pertaining to using electronic devices (passive or active) in an ionizing radiation environment. This could be space, medical facilities or physics labs. Defense or military related questions are probably classified.
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Does an aggregation of two lambda/2 dipole antennas z-axis oriented radiate towards the mentioned axis?
I'm asked whether by grouping two dipole antennas pointing towards the z-axis, they'll radiate in that direction. I'm aware each dipole alone doesn't do that thus refraction lobes in the z-axis ...
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Antennas Far field radiation pattern
I want to understand this Far field graph of an antenna generated in CST, from the picture:
Is this a good radiation pattern?
If yes, then how?
How to explain the graph?
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Ethernet MLT-3 signall probing
I am getting radiated emission failure in my system, where the emissions were out of limit (~5 dB) for frequencies 125 MHz, 175 MHz, 225 MHz, 275 MHz, 775 MHz, 825 MHz. This sounds like the odd ...
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Is a semi anechoic chamber with absorbers on the floor a fully anechoic chamber?
I have a question about radiation measurements according to EN 300 328. According to the ETSI EN 300 328 V2.2.2 (2019-07) standard, measurements can be performed at one of the following three test ...
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Plotting the radiation pattern of a half-wave dipole antenna with a frequency of 144 MHz in MATLAB
I need to plot the radiation pattern of a half-wave dipole antenna with a frequency of 144 Mhz in MATLAB but I don't know the code, can someone please help me?
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Looking to solve radiated emission test issues (CISPR 11)
We did the radiated emission test as per CISPR 11 with our device similar to tablet and observations were as below
When we tested with an IEC60601-1 certified adapter, many frequencies were going ...
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SBM-20 Geiger-Muller tube constantly on
I have recently purchased an SBM-20 Soviet Geiger-Muller Tube, which I want to use in a Geiger Counter circuit. I powered it with a 12V to 400V DC-DC power supply, connected in series with a 5.6 ...
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MOSFET as a radiation detector
We are making a thesis where we use MOSFETs as an alternative radiation detector.
So to explain it, it works when the MOSFET is irradiated with an external radiation source; its voltage threshold ...
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Is it possible to connect an antenna of the proper length to a CPU and radiate its 4 GHz oscillating current?
Since a 4 GHz CPU has been made to provide that super high frequency, is it possible to connect an antenna of the right length to it and radiate its 4 GHz oscillating current?
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IR LED Safety: Where does this OSRAM App note (AN090) formula come from?
The formula is from OSRAM application note AN090 "Eye safety of IREDs used in lamp applications":
$$ L_{ir} \approx \frac{I_e R(\lambda)}{Z^2} $$
In the app note, they don't give a reference ...
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Radiation tolerance of MCUs
I'm working on a cubesat project intended to operate in low earth orbit. We're considering a few different options for our flight computer, ranging from Raspberry Pi to something like STM32L476. ...
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FCC certification for different products with the same antenna design
I was reading about FCC intentional radiation certification and am confused about a scenario. Let's say I have two products - Product A and product B.
Say I get FCC certification (for the wireless ...
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How is the frequency in the label behind microwave ovens determined? How could one measure the frequency?
It is very common online for people on youtube, forums, and other social media to bring up the following fun home experiment to "measure the speed of light" using chocolate and a microwave ...
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Binomial array directivity and HPBW
Balanis' Antenna Theory Analysis and Design Chapter 6 covers antenna arrays.
Section 6.8.1 discusses the Array Factor and Section 6.8.2, titled Binomial Array, discusses how to determine the array ...
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Will 500 THz frequency glow antenna while radiating?
I read 700 nm wavelength is visible light, for which frequency is 429 THz. If we produce that frequency, whether antenna will be radiating visible light?
Correct me if wrong.
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Half power beamwidth of antenna
I was solving a problem regarding HPBW. From what I understood, HPBW of antenna is the angular separation on the beam where the radiation intensity is half of its maximum value. That means U(radiation ...
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How do PCB trace antennas with pigtail sockets work?
I am trying to understand the general way how wireless devices (cell modem, wifi card, router, other) work that have a socket for an optional external antenna. The main goal is to increase signal ...
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How or why are powerful but low-frequency radio waves, such as from a radio station or cell tower, potentially dangerous? [closed]
Cell towers / base stations and such are limited in the power they are allowed use, even if the wavelengths of radiation used do not adversely affect people or animals.
I have heard (and read) that it ...
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Why are there two different charges on a patch antenna? How are these charge distributions formed?
If we apply an AC signal to a capacitor, we can see only one type of charge on an individual plate. If we apply an AC signal to a patch antenna, there are two different charge distributions on the ...
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Why are patch antennas used instead of planar dipole antennas?
As far as I know, the major advantage of patch antenna over dipole antenna is its directivity. If the planar dipole antenna can achieve the same directivity then why do we use patch antennas? Are ...
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How does selecting a higher permittivity substrate in patch antenna reduce its size?
By selecting a higher permittivity substrate do we reduce the height of the antenna or we reduce the length of the patch antenna? We cannot reduce the length of the antenna as it is dependent on the ...
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IR LED Safety: Subtend Angle and Retinal Exposure Limit
The relevant formulas from OSRAM AN090 "Eye safety of IREDs used in lamp applications" with slight modifications :
$$ Z = (l + w)/2 $$
$$ \alpha = Z/d $$
$$ L_{ir} \approx \frac{I_e R(\...
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261
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Can a LC circuit generate frequencies in the Gigahertz range or higher?
For instance, if you took a bunch of off the shelf capacitors and arranged them in series and a bunch of inductors and arranged them in parallel, could you make the resonant frequency of the LC ...
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Does a DC power supply 24V 6A that functions as a motor for a standing desk produce radiation that might be harmful?
Just curious to know if there's any radiation coming from it that can be harmful if we stay close.
Thanks.
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Microwave Turntable Absorption
Do microwaves turntables absorb some microwave radiation when being used? I heard that they can act as a minimum load on the magnetron. If this is true, can I interchange microwave turntables?
Edit:
...
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How do I find out the dimensions of a rectangular waveguide given the frequency I want to operate it at?
I want to design a horn antenna to detect the 21 cm hydrogen line. I know how to optimize the antenna dimensions by taking into account some functions that approximate the phase errors and ...
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Why have space-grade components such long leads? [duplicate]
What are the reasons why (some) space-grade components are shaped like they are, with their characteristic long flat leads, golden finish, etc.?
Image: DP83561-SP from TI
Are the assembly houses ...
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430
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Antenna radiation plot and negative gain values
In general, how to interpret the negative gain values on antenna radiation diagram plot? I have attached an example.
My guess is that they represent some value relative to some reference value. If so, ...
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How to increase efficiency of antenna without moving antenna far from tree?
I have designed a monopole antenna at 868MHz frequency. Now I would like to attach that antenna to the tree (wood). But, due to Why does placing an antenna far from the wood increase the efficiency of ...
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Why does placing an antenna far from the wood increase the efficiency of the antenna?
I designed a monopole antenna at 868MHz frequency. I placed wood as the surrounding material. I noticed that placing the antenna far from the wood increases the efficiency of the antenna. Can anyone ...
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Is it possible to create a device that can decode the EM waves generated from an electronic machine?
I recently watched a movie in which the hero (a robber) invents a device that can capture and decode the EM waves generated from an Automated Teller Machine (ATM) during its use. The movie claims that ...
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FCC testing for boards with programmable firmware
I'm curious how FCC conformity testing is done on PCBs that contain devices with programmable firmware. Specifically, boards that are designed to allow the end-user to reprogram the firmware (such as ...
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What are up-screened components?
What are up-screened components/devices in the frame of qualification of electronic components?
How is it done?
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Calculating loss due to emission of EM waves (AC)
In AC due to the fact that electrons are accelerated back and forth they emit electromagnetic radiation.
Electromagnetic radiation must depend on the value of AC because more accelerated charges emit ...
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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}$$
I search a lot, ...
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Derivation of Dolph-Taylor Synthesis
Today, I was trying to deduce by myself the Dolph-Taylor Synthesis. After arriving at the expression:
$$AF(\theta) = P_{N-1} \left( \cos \left( \frac{\psi}{2} \right) \right) = T_{N-1} \left(x_o \cos \...
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How to determine radiation at a certain distance from a sunlamp
I have a sunlamp, with four UV bulbs, emitting UVA and UVB. These are parallel-mounted tube bulbs and the total area of the light emitting area is 20 cm × 25 cm = 0.05 m2. Each bulb is 15 W and so ...
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Removing collected charges in a IC CMOS circuit exposed under a 30keV electron beam source
I would like to know if there is any mechanism (for example UV light exposition) to remove charges collected in an IC CMOS circuit that was exposed under a 30keV electron beam source. Presumably, ...
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400Mhz frequence HackRF One
All,
Sorry but I am new to this topic and have no experience with SDR myself.First, I briefly give the hardware that I am using:
HackRF One
Following antenna: https://zsecurity.org/product/atheros-...
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How can someone determine from the surface current distribution the electric field polarization?
How someone can determine by looking at the surface current direction what e-field components to expect? For example only \$E_\theta\$ or only \$E_\phi\$ ?
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With Bluetooth turned off in PC settings, do keyboards and mice still emit radiation? [closed]
Do you know if a wireless mouse emits radiation in wired mode? Using the USB cable, With Bluetooth turned off, but with the switch set to "On"?
And also do you know if a wireless keyboard, ...
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Where are the sensors of the EMF/RF meter on the circuit board?
In the attached photo you can see the PCB of a simple EMF/RF meter.
This meter shows, at the same time, the values of the electric field,
magnetic field, and power density (see small illustration on ...
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What is relation between power deposition and frequency?
1. What is relation between power deposition and frequency in electromagnetic waves?
2. Is it true that even very low power elec.mag.waves can be "dangerous" for long time health if ...
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Maximum Allowed Radiated Continous Wave Power in 61.25GHz ISM Band
I am looking into a possibility for 60GHz energy harvesting for low power sensor nodes and I am little confused about the differences I have found between the US and European regulations related to ...
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How 3mG can be dangerous if the Earth's magnetic field is 500mG? [closed]
All the things I have read says that magnetic fields above 3milligauss is dangerous for people. How this can be true if the Earth has a magnetic field of 500mG?
Do smartphones and gaussmeters measure ...
user268438
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temperamental LED light
I have installed LED tubes in my kitchen ceiling light. They replaced the old fluorescent tubes. I removed the ballast and wired the fixtures according to instructions which essentially connected the ...
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Replacing X-ray or any radiation generating vacuum tubes with solid-state alternatives? [duplicate]
What are the reasons X-ray vacuum tubes could not be replaced by solid state alternatives?
I'm thinking if it is possible to make a compact solid-state X-ray or higher energy photons generator just ...
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Does the bremsstrahlung radiation size depends on the size of the accelerator?
According to this, HERMES III, a 16 terawatt pulsed power accelerator at Sandia National Labs, which fired electron beams with peak energy at 22 MeV and 730 ka current that later converted into ...
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60 GHz radiation
I have always gotten great answers on this site so I thought I'd give this one a shot. In looking into 5G technology, I found that it radiates at 60 GHz, which apparently is in the oxygen absorption ...
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How does being exposed to strong radiations effect nanosatellite electronics equipment?
I'm on paper designing a nanosatellite power system. The satellite would be orbiting in LEO. And I am wondering how and what type of radiation would affect its electronics. The system has a ...
