Axially symmetric Fabry-Perot power combiner with active devices mounted on both the mirrors

We investigate an axially symmetrical Fabry-Perot power combiner with many more active devices operating in axially symmetric TEM/sub 01n/ mode, which has an excellent feature of uniform device-field coupling required for high power combining efficiency. By numerical calculation using the boundary element method, it was shown that high combining efficiency can be obtained when a circular groove of larger radius is installed on either the plane mirror or the concave mirror. In experiments at X-band, almost perfect power combining of twenty or twenty-four Gunn diode oscillators mounted on both of the mirrors was achieved.