The datasheets state that the peak forward voltage is 1.In this device, the reverse voltage range can reach a maximum of 280, which makes it highly efficient.
GBU8G-E3 Features
the forward peak voltage is 1 the peak RMS reverse voltage range of 280
GBU8G-E3 Applications
There are a lot of Vishay GBU8G-E3 applications of RF diodes.