A PIN diode circuit comprising a RF input coupled to a first junction point via a first DC blocking circuit and a constant voltage source coupled to the first junction point via a first DC feeding circuit, the constant voltage source configured to DC bias the first junction point. The PIN diode circuit further comprises a first PIN diode with an anode coupled to the first junction point and a cathode coupled to an anode of a second PIN diode via a second DC blocking circuit. The cathode of the second PIN diode is configured to be coupled to ground potential. The PIN diode circuit further comprises an adjustable voltage source coupled to a second junction point via a second DC feeding circuit. The second junction point is coupled to the cathode of the first PIN diode via a first resistor and is further coupled to the anode of the second PIN diode via a second resistor.