Traveling-wave microwave power combiner

This paper discusses the design and characteristics of power combining and power dividing-combining by means of traveling-wave power divider/combiners using waveguides. First, the perfect power combining condition is given when the divider/combiner is used as a single power combiner. From the numerical analysis based on the equivalent circuit, it is shown that a highly efficient power combining is possible over a very broad frequency range. It is shown also that the degradation of the combining efficiency with respect to the deviation of the input amplitudes and phases from the designed values is small. For a power dividing-combining system using two identical power divider/combiners, it is shown that a broadband characteristic can be obtained, the bandwidth increases with a number of branches, and the performance degradation by failure of one of the devices in the unit amplifiers can be kept minimum by appropriate choices of the device location. Further, the four- and six-way power dividing-combining experiment has been carried out at X-band. The validity of the theory was confirmed. In the six-way power dividing-combining, a broadband characteristic was realized as evidenced by the bandwidth of 2.87 GHz with a combining efficiency of more than -0.5 dB and of 3.90 GHz with a return loss of less than -20 dB.