Table 1: Comparison of natural frequencies and loss factors obtained herein with those of [19] ( mm,  mm,  mm,  mm,  kV/mm, .

Mode Natural frequency  (Hz) Loss factor Present Ref. Present Ref. 1 10.011 10.005 0.00393 0.00395 2 40.091 40.051 0.00507 0.00512 3 89.125 89.028 0.00459 0.00461 4 152.926 152.702 0.00336 0.00339 5 236.396 235.761 0.00244 0.00250