The peak forward voltage on the datasheets is 1.1.This device can handle reverse voltages within the range of 500 with a peak RMS value of 500 .Maintaining the forward voltage of a system above 1.1(V) is recommended.
S500 Features
the forward peak voltage is 1.1 the peak RMS reverse voltage range of 500
S500 Applications
There are a lot of Diotec Semiconductor AG S500 applications of RF diodes.