A single input resonant mode combiner for combining/dividing power and including a wave device for supporting electromagnetic waves, the wave device comprising a conductive plate with a first input, a second input and an output connected to the conductive plate at positions such that electromagnetic waves may be provided to the first and second inputs so as to set up first and second respective standing waves across the conductive plate which both have anti-nodes substantially at the position of the output, wherein first and second amplifiers are connected to the wave device by respective individual inputs only.
