resisitivity human body frequence

Colleagues,

I?m trying to estimate the skin depth of the human body at 13.5MHz (one of the RFID frequencies). To do this I need to know the resistivity of the body or the tissue. I couldn?t find this number on the web. Does anyone know this number? The closest thing I could was resistivity of the seawater, which is 0.2 Ohm-meters. Is the resistivity of the human tissue much different from that of the seawater? Is it frequency-dependednt?

Cheers,
Nick

Hi,
I Dont have the exact value but the body conductivity vary with blod circulation
regards

I just realized that the medical saline has 0.9% salt and seawater has 3.5% salt. That could make a big difference in conductivity. The temperature difference between the normal conditions (25C) and the body temperature (37C) can make a big difference in conductivity too. Does anyone know of a table or a formula or a program that allows to find the conductivity of a salt solution of a given concentration at a given temperature?

Cheers,
Nick

Try this converter:

"Water Quality Monitoring: Conductivity to Salinity Conversion"
http://www.fivecreeks.org/monitor/sal.html

or if you prefer to do calculations by yourself, use formulas from:
http://oceanworld.tamu.edu/resources...apter06_01.htm

Regards,
IanP

No worky. I need the other way around: salinity to conductivity.

Thanks for the formulae!

Hi Kender

of course: the dielectric properties of human tissue are depending on the frequency!
Take a look here: http://www.fcc.gov/fcc-bin/dielec.sh
You can type in your frequency (13.5 MHz?) and get the values for different types of human tissue; e.g. skin dry: sigma=0.237/eps=286.3

hope this helps
best: Ricy

But how to calculate the total complex value of the skin for example, Epslon and sigma how to add them to get the total dielectric value or the real value i mean.

Regards

what are dielectric properties at low frequencys?