Optimization of electrode shape for stripline beam position monitors

ビーム電極形状の最適化

菖蒲田 義博   ; Chin, Y. H.*

Shobuda, Yoshihiro; Chin, Y. H.*

The exponentially tapered beam position monitor (BPM) has been proposed by Linnecar to produce a flat and wide-band frequency response for beam position signals. However, it still has a large ringing fluctuation on the amplitude of the transfer function. This paper aims at improving the overall characteristics of the transfer function. With the help from the window function theory, we investigate the correlation between the shape of the electrode and the resulting transfer function. Finally, we propose a polynomial shape for the electrode that provides a much flatter response function. Three-dimensional results using the CST STUDIO are also presented to demonstrate the validity of the polynomial shape even in more realistic conditions.