contact is made to metal regions 121a and 121b at contact points 119 c shaped sliding contacts 301a and 301b further include extensions 303 for engaging a ceramic bar 305 other materials may be substituted for ceramic bar 305 provided they are compatible with microwave applications the construction techniques employed and the requirement of mechanical stability ceramic bar 305 mechanically couples the two c shaped sliding contacts 301 together in opposed parallel facing relation so as to keep them engaged with edges 105a and 105b of substrate 101 furthermore ceramic bar 305 maintains proper mechanical alignment between c shaped sliding contact 301 during manual adjustment of their position in order to enhance the mechanical stability of this arrangement an adhesive or glue suitable for attaching ceramic to metal may be applied between adjacent surfaces of arms 303 and ceramic bar 305 any other means for securing c shaped sliding contact 301 to ceramic bar 305 such as swaging may be used in order to maximize the range of physical adjustability ceramic bar 305 includes a notch 307 which permits clearance for c shaped end terminals 123 and c shaped center terminals 125 ceramic bar 305 could also be simply raised.