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.
178 questions
-1 votes
1 answer
94 views
Long differential pair into balanced antenna
If I understand correctly, a differential PCB trace pair feeding a balanced antenna will not radiate much. Of course, there will be no ground plane above or below the diff pair. So then the antenna's ...
- 1,158
1 vote
2 answers
273 views
Why ist the parallel RGB LCD interface radiating on my PCB?
My PCB is working perfectly but it failed EMC test. It is a STM32H7A3 controller with a 4.6" TFT LCD 800x320px through an 40 pins FFC cable with 24 bit parallel RGB interface. It is radiating at ...
- 11
0 votes
0 answers
60 views
TRP radiation pattern from 2D slices
I have 2D radiation patterns of power measurements on the XY, YZ and XZ planes. The output is a *.csv file; in the first colunm we have the rotation angle from 0 to ...
- 39
7 votes
3 answers
1k views
Can a microwave antenna detect single microwave photons?
In a lecture about satellite sounding our professor explained how microwave radiance is measured typically on satellites: There is an antenna behind a parabolic mirror and the received signal is ...
- 834
3 votes
1 answer
144 views
Why doesn't common mode current on an isolated PCB cause EMI problems?
I was reading "Signal and power integrity simplified third edition" by Eric Bogatin and on chapter 11.16 the author states that connecting an external cable to a PCB that contains an ...
- 511
1 vote
1 answer
114 views
Am I misinterpreting data from a UV sensor?
I have a UV sensor that gives me both the power in watts per square meter and the UV radiation index. The manufacturer gives me an example of a reading and its interpretation as shown in the following ...
- 680
0 votes
1 answer
73 views
Paradox: E field created by two antennas vs E field created by one antenna with twice the power
I have stumbled into what seems to be a paradox. Consider a perfect antenna with perfect radiation efficiency and an isotropic radiation pattern. It is fed with a power P. If you consider the E field ...
- 549
1 vote
0 answers
129 views
Does anyone know the history of the SBM-20 Geiger Tube?
I know they were manufactured by the Soviets, but anything more than that I'm unsure of. I really want to know who originally designed the tube and what companies manufactured it and where it was ...
- 21
0 votes
0 answers
95 views
SRAM not writing properly after radiation exposure
I have an SRAM memory device GM76C88AL with this datasheet. The RAM was exposed to a radioactive beta source (~2MeV) for some time (about 2 hours). The source was just right above it (placed on it), ...
- 1,207
0 votes
1 answer
178 views
Harmonics of Ethernet (100MBps) MLT-3 signals [closed]
I have EMC Issue (Radiation) as attached..where at some frequencies the emission levels are exceeding the limits.. I use 36V power and Ethernet (MLT3) for communication. These failing frequencies are ...
- 137
4 votes
2 answers
456 views
Can I test the EM shielding of a material with a spectrum analyzer?
I am a hobbyist and I am intersted in testing some materials for their ability of reflectance/absorbance/transmittance for microwave radiation and I want to know if a spectrum analyzer is suitable ...
- 95
1 vote
1 answer
102 views
Is it possible to slow down the rise time when using the DRV8412 for PWM?
I am using a DRV8412 to drive a 36 V DC motor with 100 kHz PWM. I see a radiation issue due to sharp 100 kHz PWM to the motor. When I probe the motor current, I see current ringing at each transition ...
- 137
0 votes
2 answers
287 views
Testing antenna without anechoic chamber or RF foam absorber
I have to test an inset-fed microstrip antenna operating at 2.4 GHz. My objective is to measure S11 and the radiation pattern. The problem is I cannot count on an anechoic chamber or microwave ...
2 votes
3 answers
307 views
Why are signals reflected from an antennas dish as opposed to being absorbed?
I am trying to learn in the area of electromagnetic noise ect. I see online that a Faraday cage can work without been contected to ground (like the ones found on radio PCBs.) It sort of makes sense to ...
- 721
0 votes
0 answers
101 views
NE555 pulse extender for PIN photodiode radiation detector is it fast enough? And more
I've designed a circuit using a PIN photodiode for a radiation detector aimed at identifying radium in an old watch. However, I'm uncertain about its effectiveness, particularly regarding the speed of ...
- 3