Powermeter: how it works

Hi all,

I'm newbie in RF. I'd like to now how a powermeter works. What are the principles on which this measurements tool relies on? Any documents or articles..?
Thanks for your explanations.
RFbegin

It converts RF energu to heat. I think

Agilent Application Notes is useful

http://www.home.agilent.com/cgi-bin/...OUNTRY_CODE=US

Generally ,at microwave frequency square of volt or square of current will be measured to donate power

http://www.microwaves101.com/encyclo...asurements.cfm