RMS RF Detector Design

Over what frequency range?, over what input level range?. Normal way is to use a linear detector and follow it with a log amp.
Frank

thanks for your reply
the frequency is about 60 GHz and power (typical value) 0.20mW

Maybe you need a schottky detector diode.
http://www.cernex.com/cernex_products.html
Check the detector. And as foresaid, add a log amp after it.

thank you for your answers,
i will follow your instructions