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Question about PIN diode and Insertion Loss

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Thepretender76

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insertion loss diode

Hello

I am doing a power limiter with shunted PIN diode. If we consider PIN diode with different intrinsic region thickness, is there more insertion loss with a thiner I region Pin diode or not ? Why ? Is it because of the jonction capacitance ?

Thanks for your response

Added after 3 hours 42 minutes:

any idea ?

Please
 

pin diode insertion loss

Quote from the net:
“Increasing the dimensions of the intrinsic region (and its stored charge) allows the diode to look like a resistor at lower frequencies. It adversely affects the time needed to turn off the diode and its shunt capacitance. PIN diodes will be tailored for a particular use.”
 

Well, yes, to some extent, a limiter diode with a thin I region will be lossier. That is because you can not dope a diode abruptly from P to N material. It varies from being all P on one side of the I region, to all N on the other side of the I region. So for much of the middle of the I region, is is low resistivity (lossy) silicon. A thicker I region allows the middle of the I region to more approximate a lossless insulator.
 
biff44 said:
Well, yes, to some extent, a limiter diode with a thin I region will be lossier. That is because you can not dope a diode abruptly from P to N material. It varies from being all P on one side of the I region, to all N on the other side of the I region. So for much of the middle of the I region, is is low resistivity (lossy) silicon. A thicker I region allows the middle of the I region to more approximate a lossless insulator.
Click to expand...

Thanks for your response because I read that a pin diode with a thiner I region has a lower capacitance and so a pin diode with a thick I region will be lossier than a thin one. That's why I didn't what to think... Can yo explain me ? May be we have to separate PIN diode for limiter and PIN diode for general application.
Thanks in advance for your response
 

Thepretender76 said:
biff44 said:
Well, yes, to some extent, a limiter diode with a thin I region will be lossier. That is because you can not dope a diode abruptly from P to N material. It varies from being all P on one side of the I region, to all N on the other side of the I region. So for much of the middle of the I region, is is low resistivity (lossy) silicon. A thicker I region allows the middle of the I region to more approximate a lossless insulator.
Click to expand...

Thanks for your response because I read that a pin diode with a thiner I region has a lower capacitance and so a pin diode with a thick I region will be lossier than a thin one. That's why I didn't what to think... Can yo explain me ? May be we have to separate PIN diode for limiter and PIN diode for general application.
Thanks in advance for your response
Click to expand...

I do not know if that is true at all. If you have a diode of a given cross sectional area, the one with the thicker I region is, of course, going to have a smaller capacitance. Think of two round movable metal plates. Less capacitance when they are separated more.
 

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