Variable RF Capacitor needed - 0.01 pf

[ahsaan]

Hello
I need to buy a variable RF capacitor for my antenna (2.4GHz). It should have a value of 0.01 pf to 1pf or above. I have found in the range starting from 1.5pf and above. Do you know where I can get capacitor starting from 0.01pf? Pl help

 

[betwixt]

I doubt you will find one commercially made. The capacitance of the structure alone will be more than 0.01pF - before the capacitor plates are even fitted.

The simplest and cheapest solution is to use two short insulated wires and twist them. Copper 'coil' wire is suitable and reasonably temperature stable. The tighter you twist the wires, the higher capacitance you will get.

Brian.

 

[karesz]

Hali Ahsaan,
Or you can solder a "mini-plate" over the one potential (hopfely GND) and vary distance, or length of "mini-plate" , from it to tho other potential...
Calculta pls, how short these "mini-plate" is to realize i.e. for 0.05 or even 0.5pF
K.