Power combining by a Fabry-Perot resonator with active devices mounted on both the mirrors

A power combining technique using a Fabry-Perot resonator with many more ac tive devices is investigated. The Fabry-Perot power combiner consists of tw o mirrors with a circular groove mounted with the active devices. The power combiner has an axially symmetrical structure and operates at an axially s ymmetrical TEM01n mode so that uniform device-field coupling required for p erfect power combining can be realized. By numerical calculation using the boundary element method, it was shown that high combining efficiency can be obtained when the active devices are mounted in the circular groove of lar ger radius on either of the two mirrors. In experiments at X-band, power co mbining efficiency over 90% was obtained for the case of twelve devices on either of the mirrors and the output powers of the twenty or twenty-four de vices on both the mirrors were almost perfectly combined.