Wideband meter suggestions
A transistor/ fet can have its bias adjusted to a
level so it responds to a very low threshold signal from an antenna. Then amplifies it. This is a step better than the diode detector idea.
The link below has a gallery of wideband rf detector circuits. An internet search turned up myriad more. I received a simple field strength detector with a kit I purchased, which broadcast mic audio to a nearby fm radio.
http://www.hobbyprojects.com/F/Field...th_Meters.html
I suppose mosfets are ideal fets for the task. I also assume the least Cgs & Cgd fets are optimal. Pretty much I should use an RF mosfet or are jfets more suited for this task? Since jfets don't have much of a threshold voltage.
What's the intended power range? Do you expect true power reading for multi-frequency and modulated input?
Usual solutions are thermal and square law diode detectors.
Why not use an integrated detector. Examples: ADL5920, ADL5910, ADL5903 or LTC5587