The dumb bell resonant cavity characteristics for W-band sheet beam klystron (SBK) are analyzed with one-, three-, and five-gap coupled cavity models by three dimensional high frequency simulation software(CST-MSW). The dependence of the cold parameters on the configurations of the cavity was analyzed. For the particle in cell (PIC) simulation analysis, the optimized cavity frequency combination of eight-cavity WSBK circuit was obtained using 2-D software SBK2D, which runs with high speed, thereby allowing an efficient investigation of input parameters. To unify the electronic-beam wave interaction system's hot parameter design, the calculated results are examined by PIC simulation (MAGIC-3D), and show good agreement with CST, thereby confirming the design method mentioned above. These results provide key parameters and a good foundation for developing higher performance on RF structure of sheet beam klystron in the future.