d e K l e r k Westinghouse R e s e a r c h L a b o r a t o r i e s P i t t s b u r g h , P e n n s y l v a n i a 15235ABSTRACT: Unique f a b r i c a t i o n t e c h n i q u e s have been used t o make p l a n a r , two p o r t d e l a y l i n e s on h i g h r e s i s t i v i t y s i l i c o n w i t h a s i n g l e d e p o s i t e d ZnO t r a n s d u c e r s i t e .f a b r i c a t e d on t h e s i l i c o n s u b s t r a t e conduct t h e microwave s i g n a l t o and from t h e i n p u t and o u t p u t t r a n s d u c e r sThe r e s u l t i n g V.S.W.R. of e i t h e r p o r t i s less t h a n 3 t o 1 o v e r a f r e q u e n c y r a n g e of 2.5 t o 5.5 G H z . For planep a r a l l e l r e f l e c t i n g s u r f a c e s (bottom s u r f a c e of t h e s u b s t r a t e ) i n p u t and o u t p u t t r a n s d u c e r s must be s e p a r a t e d by n o t more t h a n s e v e r a l m i The b u l k a c o u s t i c wave is r e f l e c t e d t h a n 45-dB f o r -a 200 nanosecond d e l a y ;ill b e r e p o r t e d . I n t r o d u c t i o n Microwave d e l a y l i n e s are c r i t i c a l l y i m p o r t a n t components t h a t a r e n e c e s s a r y f o r r a d a r s y s t e m s and ECM ( E l e c t r o n i c Countermeasure) u n i t s t h a t a r e c a r r i e d on m i l i t a r y a i r c r a f t . F u n c t i o n a l l y , t h e s e d e v i c e s d e l a y a r a d a r s i g n a l f o r a s p e c i f i c t i m e p e r i o d ( e . g . 0 . 1 microsecond) as p a r t of t h e s i g n a l p r o c e s s i n g r e q u i r e d . For most present-day equipment, t h e d e l a y l i n e s are made from e i t h e r c o i l e d l e n g t h s of c o a x i a l c a b l e o r waveguides; f o r b o t h t y p e s , t h e s i z e and w e i g h t r e q u i r e d a r e c o n s i d e r e d t o b e a s i g n i f i c a n t p e n a l t y f o r a i r b o r n e a p p l i c a t i o n s . I n t r o d u c t i o n of an a c o u s t i c d e l a y l i n e a s a s u b s t i t u t e f o r t h e e l e c t r omagnetic l i n e s now i n use c o u l d r e s u l t i n a r e d u c t i o n i n s i z e from a b o u t 70 c u b i c i n c h e s t o less t h a n 1 c u b i c i n c h and r e d u c t i o n i n weight by a f a c t o r of 50. a d e q u a t e t r i p l e t r a n s i t a t t e n u a t i o n (about 25 dB below f i r s t t r a n s i t ) . A s d e s c r i b e d i n Ref. 1, d e f r a c t i o n l o s s h a s an i n v e r s e f r e q u e n c y s q u a r e d dependence and t h e r e f o r e may b e made t o compensate f o r t h e f r e q u e n c y dependence of t h e p r o p a g a t i o n l o s s t o g i v e a f l a t frequency r e s p o n s e o v e r t h e r e q u i r e d band. There may be t h e f u r t h e r a d v a n t a g e of working w i t h s i l i c o n i n t h a t f u t u r e microwave i n t e g r a t e d c i r c u i t s may b e n e f i t from a n a b i l i t y t o f a b r i c a t e d e l a y l i n e s on t h e subs t r a t e . O t h e r s u b s t r a t e m a t e o u t p u t t r a n s d u c e r s l o c a t e d a t t n e c e n t e r of t h e s u b s t r ...
