In the datasheets, 1.1 is stated as the peak forward voltage.A continuous forward current of 1.5 is the maximum consumption of this device.RF diode is necessary to operate the device at a DC reverse voltage below 50.
1N5391 R0 Features
the forward peak voltage is 1.1
1N5391 R0 Applications
There are a lot of Taiwan Semiconductor 1N5391 R0 applications of RF diodes.