A Design Of Input Coupler For Rf-Cavity

INTRODUCTION Characteristics of a newly designed input coupler are presented. The coupler was designed for a 500 Mhz damped cavity [1] to be installed in the high-brilliant VUV and soft X-ray synchrotron radiation ring planned at ISSP [2] and in the Photon Factory (PF) storage ring with a high brilliant configuration [3]. The design study of the coupler has been done mainly using the computer code, High Frequency Structure Simulator (HFSS, HP85180A), which can calculate the S-parameters of high frequency structures. II. CHECK OF APPLICABILITY OF HFSS At first, we compared the results of HFSS with experimental results in order to examine how HFSS realizes the rf characteristics of the structure such as input coupler. We simulated the microwave transmission in a cold model of coupler for 714 Mhz cavity to be installed in ATF (Accelerator Test Facility) at KEK [4]. The model coupler was fabricated by TOSHIBA Corp. Figure 1 shows the frequency dependence of VSW