Phase Combiners

Phase Combiners

A popular method of increasing amplifier power and security is to combine the power of two or more amplifiers. This can be achieved using one or more 3 dB Power Couplers (Hybrids), or Magic Tees.

When using a 4 port Hybrid for combining power from 2 amplifiers, each of the 2 output ports typically receives half the power from each amplifier input, and the signals from each amplifier are out of phase by 90 degrees. By adding a phase shifter, the input signals can be adjusted so that both amplifiers are in phase. This results in one output port where the signals are out of phase, and thus terminated, and one output port where both signals are in phase, transmitting full power from both amplifiers.

When using Magic Tees, a similar result can be achieved with two in-phase input signals. The out-of-phase port is terminated, and full power from both inputs signals is combined and transmitted through the 4th port.

The phase difference also provides a measure of cancellation of returned energy, providing a better match to the amplifiers. Another benefit is that they reduce the amplitudes of second order distortion products by 3 dB compared to individual amplifiers. For the same power output of one amplifier, a phase combined system can have a 6 dB lower distortion.

Phase combiners require that the combined input frequencies be the same. This is in contrast to a power combiner, in which any frequencies within the waveguide size may be combined.


  • WR-22 to WR-650
  • Excellent phase and amplitude matching
  • Superior VSWR, insertion loss and isolation
  • Robust construction for high power applications