square law RF detector - choice of diodes in commercial design

[Barry Lennox]

Below is the reverse engineered schematic of the famous BOONTON RF
MILLIVOLTMETER probe (also Ballantine labs). The unmarked diodes
*must* have a square law characteristic like germanium in order to
work down to a mere 50uV, but yet the thing works up into the GHz
region and has a mere 1.5pF input capacitance, indicating that they
are NOT a 1N34A.

You might want to look at the diodes from M Pulse, They have some zero
bias Schottky diodes with Ct around 0.1 to 0.25 pF. I have not used
these ones, but have used their SRDs with good results.

www.mpulsemw.com

Also Vol 15 of the MIT Radlab series "Crystal Rectifiers" has 432
pages of amazing stuff on diodes.

Barry Lennox