Fig. 1. Model for calculating s₁₁ of a single cavity composed of 12 periods of SDRWSWS and calculated results (a) a period of SDRWSWS, (b)model for calculating s₁₁, (c) calculated s₁₁;(d)the calculated results E_zc of the z component of electric field intensity at the z-axis and the fitness E_zs

Fig. 2. Dispersion curve of even period resonant cavity and 19 kV electron beam line

Fig. 3. Affects on even period EIO of beam voltage (a)PIC model for a single cavity EIO based on 12 periods of even SDRWSWS, (b)normalized output voltage under a 19 kV，300 mA beam, (c) FFT of normalized output voltage under a 19 kV，300mA beam, (d)curve of frequencies vs beam voltage, (e) curve of powers vs beam voltage and electron efficiencies vs beam voltage, (f) normalized output voltage under a 21 kV，300 mA beam

Fig. 4. Affects on even period EIO of beam current (a) curve of frequencies vs beam current, (b) curve of powers vs beam current and electron efficiencies vs beam voltage

Fig. 5. Compared performances of even period EIO and uneven period EIO (a)Frequencies of even period EIO and uneven period EIO under varied beam voltage, (b) powers of even period EIO and uneven period EIO under varied beam voltage, (c) electron efficiencies of even period EIO and uneven period EIO under varied beam voltage, (d)Frequencies of even period EIO and uneven period EIO under varied beam current, (e) powers of even period EIO and uneven period EIO under varied beam current, (f) electron efficiencies of even period EIO and uneven period EIO under varied beam current

Fig. 6. Calculated results of the even period cavity compared with of the uneven period cavity (a) calculated s₁₁ of the even period cavity compared with calculated s₁₁ of the uneven period cavity, (b) calculated result E_zc of E_z in the even period cavity compared with calculated result E_zc-uneven of E_z in the uneven period cavity

Fig. 7. The calculated results E_zc of the z component of electric field intensity at the z-axis and the fitness E_zs (i ) (a)comparison between E_zc and E_zs (1) within periods 1～4, (b)comparison between E_zc and E_zs (2) within periods 5～6, (c)comparison between E_zc and E_zs (3) within periods7～12

Fig. 8. Calculated power vs time of even period EIO compared with of uneven period EIO under a 300 mA，18.7 kV beam

Table 1. Structural parameters of SDRWSWS

Table 2. Calculated frequencies according to the minimums of s₁₁ of even period resonant cavity

Table 3. calculated frequencies according to the minimums of s₁₁ of uneven period resonant cavity