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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65 views

Where is the RFID antenna hidden on supermarket products? [closed]

Okay. So I read a lot on RFID technology and how it uses a passive antenna design and print them below barcodes. They then use this to detect and 'disable' them for scanning as a customer exits. So ...
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2answers
85 views

Burn hazard of IR LED Array Question

I am performing eye safety calculations on a device and I have hit a roadblock. To perform the calculations I have been following the IEC 62471 "Photobiological safety of lamps and lamp systems&...
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3answers
68 views

Thermal resistance in vacuum

Is it possible to obtain an approximate guess of what the thermal resistance of a device (i.e. a power MOSFET) would be in a vacuum based on the ambient thermal resistance value provided in the ...
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1answer
69 views

Steel cooker is not a Faraday cage? [closed]

I read that steel/iron/metal/conducting cages, with gaps less than the wavelength of electro magnetic waves, shield whatever is inside from that radiation. But when I put my mobile inside a cooker and ...
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0answers
32 views

Plotting the radiation pattern of a dipole antenna using MATLAB

I want to plot the radiation pattern of a half wavelength dipole antenna using MATLAB. But in dB scale, the plot has undesired peaks. The code is shown below: ...
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3answers
52 views

How can I prevent microwave radiation absorption by a camera lens/electronics inside the microwave (behind the shield)?

Let's say I put in an endoscope like camera with the lens at the inside edge of the box and the wire behind metal sheet. Here's a mockup: Possible idea: The lens is behind a holes but the hole is ...
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2answers
92 views

What kind of camera could work inside a microwave?

I want to record video inside a microwave, is it possible? What if it was hid behind a shield or the same galvanized material as the door? The detailed structure may completely ruin visibility tho
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2answers
21 views

Direction of the main beam of an antenna

How can I find direction of the main beam of an antenna if antenna has radiation intensity as following? $$U=[\dfrac{sin(5\pi cos\theta)}{10sin(\pi cos(\theta/2))}]^2$$ Where $$0<\theta<\pi$$ My ...
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0answers
24 views

Side lobe level of an aperture antenna

There is a electric field in the far zone of the rectangular aperture antenna as shown below. Antenna lies along the xy plane. $$E_{\theta}=\dfrac{jke^{-jkr}}{4\pi r}\dfrac{sin(0.5\lambda k sin\theta ...
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1answer
66 views

Practicality of Faraday door [closed]

Building a Faraday bed enclosure..wanted to ask which style of door would you advise in terms of seal - hinge,magnetic,Velcro etc. Measurements of the door is 900*900
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4answers
4k views

Are there any advantages to using rigid RF coaxial cables?

While watching this Signal Path video, I came across this shot: I saw few rigid coaxial cables there and so I started wondering what might their advantages be. I could only find disadvantages: They'...
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1answer
59 views

Can ESP32 radiation cause health hazards?

I am using ESP32 chips for a smart health monitoring device. I will use WiFi 802.11n or Bluetooth BLE/EDR depending on the amount of data to be transferred, so the unit will be mounted on hand, maybe ...
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42 views

Question regarding GM Tubes Calibration Frequency

My friend has has been using GM Tubes for more than a decade now. He has been calibrating them once per year. But the calibration data reveals that his GM Tubes would have remained within allowed ...
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1answer
78 views

What does these heatsinks do?

I think sharing the video will be the easiest way of describing the situation. The transistors are electrically isolated from the heatsinks, I have checked with multimeter. Few days ago, I have ...
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1answer
70 views

How to block / lessen EM-radiation/signal from home Wi-Fi router? [closed]

1) What materials and how can I use to completely block radiation from two antennas of my WiFi router? 2) What materials and how can I lessen by 20-50% radiation/signal from the third router antenna? ...
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2answers
181 views

How much electromagnetic/electric radiation does laptop/computer emit? [closed]

How much electromagnetic or electric radiation does laptop emit? I don't know in what measurement system you have to answer, but at least, I want to get the answer which should be enough "research" ...
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0answers
51 views

Interpretation of data

I hope this question meets the standards of this platform, if not please inform me of how I can improve it. I was trying to design an antenna and I have done so. I am planning on using this antenna ...
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0answers
25 views

Increase in gain of CP micro-strip patch antenna [duplicate]

I have successfully designed my circularly polarized patch antenna shown below. I used the slot method. Which as a bandwidth of 23MHz and a resonance frequency of 915MHz. Though the bandwidth is small ...
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0answers
42 views

Axial ratio of a square microstrip antenna

I am currently designing by CP microstrip antenna using CST. The picture is shown below. However, when I view the axial ratio plot, also shown below it is way above 3dB at 90 degrees. the patch is 31,...
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0answers
20 views

Microstrip square patch design [duplicate]

Circular polarized micro-strip patch antenna This question defers from the previous in that I want to know how to calculate the lengths for A,B and C. I want to know how to calculate the values of A,...
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0answers
23 views

Patch antenna design [duplicate]

Can anyone assist me regarding the design of a circular polarized rectangular patch antenna that is driven at adjacent sides through a power divider? I already calculated the parameters of the width ...
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1answer
172 views

Circular polarized micro-strip patch antenna

Circular/ Elliptical patch antenna design after a bit more research I realized what my mistake was, after a user pointed it out. As such my new post. I have come across a CIRCULAR POLARIZED PATCH ...
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1answer
110 views

Why 'the electric current is “shorted out” by the conductor' in Stutzman-Thiele Antenna Theory and Design?

Page 346, in Stutzman-Thiele Antenna Theory and Design-3d edition, reads 'the electric current is “shorted out” by the conductor' and is thus nullified. Refer to part c of the image below: In this ...
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0answers
87 views

Circular/ Elliptical patch antenna design

I am trying to design a circularly/elliptical polarised antenna like the one in the picture. My frequency is 915MHz, a dielectric constant of 4.4, the thickness of the substrate is 1.6mm, thickness of ...
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1answer
103 views

How does this circular polarized antenna work?

I recently obtained an RHCP antenna, but when I opened it to investigate what's inside of it I found it to be different from the conventional RHCP polarized antenna. I have included pictures in this ...
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1answer
73 views

How to calculate maximum effective radiated power in any direction for Galtronics small cell site

Answer Calculations from PE commissioned by AT&T: the GQ2410-06621 antenna does have 10 total input ports, however, our analysis of the AT&T DAS node includes only the frequencies and power ...
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1answer
102 views

FDTD simulation for beginners using matlab

My previous posts are as follows: 1.Mitigation of dead zones when applying circular polarized antenna 2.Standing waves modes inside a cavity resonator 3.Visual understanding of EM fields within a ...
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1answer
64 views

Multimode cavity resonator

From my previous posts Insight into cavity resonators, Visual understanding of EM fields within a rectangular metal container I have slowly gained a better insight into cavity resonators and thereof. ...
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1answer
45 views

Antenna's resistance: meaning and evaluation

When I studied elementary antenna's theory, I saw that the resistance (for simplicity let's consider only the resistive terms) of an antenna Ra is made of: 1) a parasitic resistance Rl, which causes ...
5
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2answers
350 views

Insight into cavity resonators

Modes of a waveguide As shown in the link above, they show how these modes work for various values of m, n, and p. However, where is the antenna/ source of radiation placed within the cavity? From ...
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3answers
267 views

Visual understanding of EM fields within a rectangular metal container

I have the following scenario setup inside a rectangular metal container. The container size is 12.03m by 2.39m by 1.84m (lxbxh). Additionally, inside the container I have placed 4 antennas equally ...
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1answer
71 views

Mitigation of dead zones when applying circular polarized antenna

I would like to know if I used a circular polarized (RHCP) antenna inside a metal container as show in the configuration below will it reduce the dead zones, as compared to a linear polarized antenna? ...
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1answer
60 views

Detecting radiation - Looking for ideas

I have to detect a small radiation from this tags and I´m looking for some ideas how I can do this with some kind of small electronic circuit (or lecture to read how to do it) - not with a Geiger-...
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1answer
59 views

Long term health effects of a gsm modem [closed]

We all use internet through our mobile phones hence gsm infrastructure. I know the radiation exposure is higher than wifi. That's why I preffer wifi over mobile whereever i can. However I'm currently ...
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0answers
195 views

PIN Photodiode gamma detection amplifier circuit - rectangular wave output

I've been working on a project recently, where I need to build a device which detects gamma radiation and can be used for gamma spectroscopy. I've done some research and found many interesting ways of ...
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2answers
209 views

Am I exposed to high levels of radiation at my job? [closed]

I made this post because I have a safety concern about my job as medical device tester. I was reading the user manual of the equipment I work with and found the next warning: “Per FCC regulations, ...
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3answers
110 views

Non-ionizing radiation [closed]

This is out there - But hear me out. There is a new device on the market that promotes baby sleep by playing white noise. The speaker is directly under the baby’s head while sleeping (separated by ...
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2answers
4k views

Why do radiation hardened IC packages often have long leads?

What purpose do long leads serve?
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0answers
70 views

Radiation Source placement and waveguide parameters for Horn Antenna

I am designing ("arranging", actually) a horn antenna for a 77-81 GHz Radar. My module has a patch antenna which can't be placed inside the waveguide for some reasons. After the patch antenna, we have ...
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3answers
307 views

Physics of Dirty Electricity? [closed]

I've been reading about "dirty electricity" lately and while I know there's much controversy whether it causes adverse health effects this question is not about that subject. I'm simply trying to ...
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2answers
3k views

Microwave starts working when door opens - how dangerous is it?

I've just rented a house that came with an equipped kitchen, and I've found that the microwave has a rather weird behavior - opening the doors seems to trigger it to start working, which the owners ...
1
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1answer
128 views

Reflection of Electric field in open-circuited transmission line

Consider a parallel-wire or parallel-plate or coaxial transmission line, carrying TEM wave, which we model as E,H,V,I, each having a forward(+) and backward(-) wave. In terms of V,I, we define ...
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2answers
139 views

Photodiode Output measurement

I'm using Hamamatshu s8559 photodiode to convert x-rays into it's respective energy. I'm using a 10 bit ADC converter. The problem I'm facing is I have no relationship between the Photo-current ...
14
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6answers
4k views

Can antennas be viewed as light sources?

Clearly antennas are nothing but a device to radiate the electrical energy through electromagnetic waves. Since visible light is also simply a certain range of frequencies, isn't it more easier to ...
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1answer
165 views

Ability of a 100km power transmission line to radiate 50Hz EM waves?

This is about confusion of relating antenna radiation theory to power lines. Assuming a straight 100km or even longer possible power transmisson line with 50Hz frequency. What can be said about the ...
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1answer
194 views

Are headphones with EMF measurement of 10,000 milligauss harmful to me?

I used a EMF detector app on my phone and measured the EMF output on my wired headphones. It measured around 10,000 milligauss on one part of both ear cups. Since wearing these headphones on my head ...
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1answer
629 views

Can a magnet cause a microwave oven to unsafely radiate energy?

I've already successfully warped the colors on a large old CRT Television by setting unshielded speakers on top of it. If I understand correctly, this was due to the deviation of the electro-magnetic (...
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2answers
579 views

Does an electrical outlet radiate EM waves? [closed]

Please consider all cases even with a tiny values. If plug two separated wires to each terminal of electrical outlet, like shown, will it radiate em waves? ...
3
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2answers
705 views

What is the acceptable margin for radiated emission on an European CE device

One of our prototype (IOT gateway) has completed the emission test (EMC) but we have a margin on two particular frequencies, just wondering what is the acceptable margin for CE device in Europe ? I ...
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1answer
235 views

Calculate radiation power of an antenna in respect to a given antenna radiation pattern and a given angle

I work on a program that simulates the wave propagation of high frequency electromagnetic waves (2.4 or 5 GHz Bands) in 3D. I use a ray launching approach, where the emitted rays approximate the ...