| 摘要 |
A magnetron includes a cathode 1, coaxially disposed within anode 2, having end regions 10 and 11 which are electron emissive during operation and a central region 12 which is substantially non-emissive. Such an arrangement has been found to give improved performance. The non-emissive region preferably occupies less than one third of the total axial extent of the cathode. In various other cathode configurations disclosed, Figs. 2-7 (not shown), a plurality of symmetrically disposed non-emissive regions may be provided, or the cathode surface may be grooved with some of the grooves filled with emissive material, the remaining grooves being left empty or filled with non-emissive material. <IMAGE> |
