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Hi Mick,
At those frequencies the energy is very radiant. Everything has to be made according to RF rules and treated as transmission lines. Else the signal doesn't follow the signal path as planned. Any change in impedance reflects or splits the signal. Read Ivor Catt on this even though he explains it using digital signals. If attaching a current buffer everything has to match. I haven't worked on such high frequencies. If trying this at least know the theory behind it or have the measuring instruments for this frequency range.
This site (http://nov79.com/amr/cont.htm http://nov79.com/amr/cont.htm) shows how to make a simple current amplifier by using matched bipolar transistors. The upper frequency is only limited by the upper frequency of the transistors. This can be 40MHz for an audio amplifier. This may cause oscillations at the max frequency if not done the correct way.
What about a small 3W broadband power amplifier module:
https://www.ebay.com/itm/1-1000MHz-3W-RF-Broadband-Power-Amplifier-Module-Radio-Transmission-FM-VHF-/183031453375 https://www.ebay.com/itm/1-1000MHz-3W-RF-Broadband-Power-Amplifier-Module-Radio-Transmission-FM-VHF-/183031453375
It only goes to 1GHz.
Google search for 'broadband power amplifier module':
https://www.google.dk/search?source=hp&ei=c8G4Wuv0LIXbwALZxJTQDw&q=broadband+power+amplifier+module&oq=broadband+power+ampli&gs_l=psy-ab.3.2.0l2j0i22i30k1l8.1878.9748.0.22828.21.20.0.1.1.0.104.1822.18j2.20.0....0...1c.1.64.psy-ab..0.21.1820...46j0i46k1j0i10k1.0.jIuIG0_77XA https://www.google.dk/search?source=hp&ei=c8G4Wuv0LIXbwALZxJTQDw&q=broadband+power+amplifier+module&oq=broadband+power+ampli&gs_l=psy-ab.3.2.0l2j0i22i30k1l8.1878.9748.0.22828.21.20.0.1.1.0.104.1822.18j2.20.0....0...1c.1.64.psy-ab..0.21.1820...46j0i46k1j0i10k1.0.jIuIG0_77XA
Or search 'rf power amplifier module'
Regards
Ole
---In [email protected], <mkjekyll@...> wrote :
Ole,
What would be the negative issues trying to attach a FET current buffer
to an LNA in order to make a few watt wideband RF amplifier?
As I am an audio guy I am paralleling this to an audio amp seems simple
a voltage gain stage and then a current gain or buffer stage.
There are plenty of cheap LNA's that are very wideband like this
https://www.ebay.com/itm/New-1MHz-2GHz-64dB-Gain-LNA-RF-Broadband-Low-Noise-Amplifier-Module-HF-VHF-UHF/232103825103?hash=item360a774ecf:g:iCQAAOSwgu9ZZEBg https://www.ebay.com/itm/New-1MHz-2GHz-64dB-Gain-LNA-RF-Broadband-Low-Noise-Amplifier-Module-HF-VHF-UHF/232103825103?hash=item360a774ecf:g:iCQAAOSwgu9ZZEBg