The present invention relates to a ceramic filter comprising clay and a process for preparing the same. A current switch comprising of the composite switching devices including a switch stage implemented in a InP-HBT technology and a cascode stage implemented in a GaN FET technology. The process can be either land based or sea based. One or more second parameters are calculated in a calculation involving pairs of HBi and HBBi-n, where n is second predetermined integer different from m.