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Incident Mobile Radiation measurement

时间:04-04 整理:3721RD 点击:
Experts,

Greetings from sunny India. Need some help on my research study.

I'm working on a research project to measure incident radiation coming from 100s of mobile phones around us in public areas. In other words, if in a closed public space like a shopping mall, how much radiation is emitted by people around me (averaged based on numbers) and how much is incident on my body.

I have electronics and telecommunications background and I have been thinking of some very simple ideas (simplicity works best for me) to measure the incident radiation coming from mobile phones. Since there are 3 mobile communications bands viz: 900 MHz (2G), 1800 MHz (2G DSC) and 2100 MHz (3G WCDMA), I thought if we could have 3 antennae with 3 band-pass filters for the above 3 bands, pass on the output to a high frequency op-amp, measure the outputs of the 3 op-amps and compute the incident radiations based on this output and some numerical methods.

I know it is easier said than done.
1. Output of the antenna would be in micro volts. To amplify this output to millivolts level while cancelling out noise would be a challenge. A multi-staged instrumentation amplifier could be possible, but for those high frequencies?
2. Band pass output from the antenna could be achievable, but different phones would be transmitting at different frequencies, but within the bandpass range. I wonder if that will affect the output.
3. Even if we are able to amplify the AC voltage to milli volt level, how to handle it from there on at those high frequencies? ADC? Direct uC interface?
4. Sensitivity of other peripheral components for circuit stability etc.

Anybody done something similar or can provide any inputs on how to approach the problem(s)? How best to handle? What design approach to adopt?

Inputs would be greatly appreciated.

Regards,
Deepak

I'm picturing a case where we have photons coming from two different phones, at an identical frequency but out of phase. I do not believe the photons eradicate each other. Your body is hit by photons from both phones. Your radio tuner may read zero signal, in terms of electrical detection. I cannot say if that's misleading, because we don't really know what photons are.

To be thorough in the way you gather information, you ought to build two tuners. The first one is narrowband, detecting one individual frequency at any moment. The other tuner is wideband as you describe picking up general intensity for a band of frequencies simultaneously.

Watch readings on the first (narrowband) tuner while a phone transmits on its frequency. Compare with readings from the second (wideband) tuner. Try dialing around the frequencies, in hopes you'll have times when several phones are transmitting. That way you can find out to what degree their waveforms cancel, or whether they reinforce.

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