Depending on your exact application, perhaps you could simply use a suitably-wide bandwidth oscilloscope and trigger it at the appropriate point in time. Then you read the voltage amplitude off the screen and calculate the power being delivered to your load.
This method has several limitations and might not be applicable.
jimkirk beat me to the post about Analog Devices. AD has a variety of these RF detectors that are useful for RF detection - some with a very wide dynamic range. Check their site for application notes as well - as I remember, some of them deal with the pulse response of various part numbers.
Linear Tech in this nich market is playing catch-up. They have come out with somewhat similar devices. LT is trying to beat AD in the type of detector that is used to power control RF amplifers in wireless apps. Maxim is now comming out with these too.
The LT5504 with it's downconversion I had not seen. I don't know of any other downconverting type like this.
I found also LT5534 50Mhz-3Ghz RF level measurement Transient Response 38ns Single 2.7V to 5.25V Supply Low Supply Current: 7mA and 60dB
Cost 9€ at RS, it consumption is very few and it is very easy to use. I will see analogs also, thanks.
I would like use a loop antenna to measure with because broadband range. I would use a half loop wire to calibrate it. Do anybody know the volts/meter (aprox) relation with inducted voltage and wire size?
I have seen that I could use also to measure magnetic flux
