rf feild detector

hi
im need a very sensitivity rf feild detector as bug detector
work range 500mhz to 2.5ghz
thank

I suggest a wire antenna followed by several cascadable amplifier modules and then a diode detector and then an op amp stage and then an analog meter or a comparator.

You may have a look at Mobile detector circuit in the given link. It detects Rf in the frequency range from 700Mhz-2Ghz. Cheers
http://electroschematics.com/381/mob...phone-detector

Depending on the existing RF enviroment (e.g. presence of mobile phones, wireless LAN and other wireless operated
equipment), a non-selective wideband detector may be more or less useless for the said task. In this case, you won't come
far without a portable spectrum analyzer, e.g. a TTI PSA2701.