DC bias device for high power, low intermodulation RF-systems

A DC bias device for a radio-frequency transmission system of high power and low intermodulation, the transmission system including an RF source of an RF signal with a central frequency corresponding to .lambda., a receiver for receiving the RF signal from the RF source on a coaxial line, and a DC source, direct current being fed by the DC source to the receiver, the device comprising:

• a first coaxial branch connecting to the RF source and comprising an open-circuit stub having a first free head and a normalized characteristic admittance, and
• a second coaxial branch connection from the DC source to the receiver and comprising a short-circuit stub having a second free head and a normalized characteristic impedance;
• wherein
• the normalized characteristic impedance of the short-circuit stub of the second coaxial branch is substantially equal to the normalized characteristic admittance of the open-circuit stub, and wherein
• the free heads of the two stubs are disposed proximate one another and are separated from each other by a finite distance of less than .lambda./20.