A power combiner system for use in a single-mode waveguide includes an input waveguide, an output waveguide, at least one power amplifier module that includes a plurality of amplifiers, and at least one input dipole antenna extending into the input waveguide. Each input dipole antenna includes two input dipole antenna arms, and each input dipole antenna arm is coupled to an input of a corresponding one of the plurality of amplifiers. The system further includes at least one output dipole antenna extending into the output waveguide. Each output dipole antenna includes two output dipole antenna arms, and each output dipole antenna arm is coupled to an output of a corresponding one of the plurality of amplifiers. Each power amplifier module is disposed in a plane that runs parallel with the direction of propagation.