Beam-Cavity Interaction Circuit at W-Band

We describe the design, fabrication and bench-study of a mm-wave cavity employed as a relativistic klystron output structure. The OFE copper cavity was prepared by electrodischarge machining and diffusion bonding, cleaned, and tuned to 91.4 GHz. Measured cavity characteristics are presented and compared with theory, including quality factor, Q, coupling parameter ß, scattering matrix S11, and axial electric field profile Ez . This work provides the basis for understanding of the cavity as a transfer structure. Submitted to IEEE Transcations on Microwave Theory and Techniques Work supported by the Department of Energy contract DE-AC03-76SF00515