IN3LBQ on the Hühnerspiel (Amthorspitze) - photo by IN3OTD

Two BAR64 PIN diodes in parallel

I have seen a suggestion from W8JI to connect two PIN diodes in parallel for the RF but in series for the DC, with the anode and cathode reversed in one diode (so actually in "anti-parallel") to futher reduce the distortion.

PIN diodes test fixture schematic 2xBAR64 measurement setup

Small-signal loss vs bias

S-parameters measured at -20 dBm

Forward biased

Diode forward biased with currents from 1 mA to 100 mA.

2xBAR64 loss vs bias current

Reverse biased

Diode reverse biased with voltages from 0 V to 20 V.

2xBAR64 isolation vs bias voltage

Harmonics level vs power

At 1.8 MHz

2xBAR64 fundamental at 1.8 MHz 2xBAR64 H2 at 1.8 MHz 2xBAR64 H3 at 1.8 MHz 2xBAR64 H4 at 1.8 MHz 2xBAR64 H5 at 1.8 MHz

Intermodulation distortion vs power

At 1.8 MHz

2xBAR64 IM3 at 1.8 MHz 2xBAR64 IM5 at 1.8 MHz 2xBAR64 IM7 at 1.8 MHz