Nonlithi saw resonator osillator
Abstract
Thi s t h e s i g - ' l B c o n c e r n e d wi t h a n o v e l SAW o s c i l l a b a r
c a l l e d m o n o l i t h i c 3AW r e s o n a t o r o s c i H a t o ’K SSn'which, t he
Trequency c o n t r o l l i n g c omponent i s s jSA^- res;anator and
t h e g a i n e l e me n t i s a m o n o l i t h i c ?t hi n' f i l m InSb SAW
s m p l l f i e r l o c a t e d i n s i d e - t h e r e s o n a t o r c a v i t y / T h e o r e t i c a l
and e x p e r i m e n t a l f e a s i b i l i t y s t i i d i e s o f the m o n o l i t h i c SAW
r e s o n a t o r o s c i l l a t o r a r e c a r r i e d o n t . The f a b r i c a t i o n o f the
m o n o l i t h i c SAW r e s o n a t T o ' ^ a ^ t ' i l l a t o r i s o s u c c e s s f u l e f f o r t
d i r e c t e d t 'f ^ s ^ .^ ^ ^ a ji s ^ n g t he i n t e g r a t i o n o f a c o u s t i c and
s e m i c o n d u c t o r f u n c t i o n s ' o n t he same . s u b s t r a t e . . T h i s d o v i c e
i ^ - >,ompletely i n t e g r a t e d u n i t ' ( a t p r e s e n t SA'..' o s c l l l n t . j r s
use e x t e r n a l o r s e p a r a t e d medium SAW a m p l i f i e r s ' ! .
The g ai n r e qui r ement o f the f e e d b a c k a m p l i f i e r s i n
the c a s e o f 5AW r e s o n a t o r o s c i l l a t o r s ( t h e f e e d bacU
a m p l i f i e r csn t - i t h e r be on e x t e r n a l o r a SAW o m p l i f i e r )
was worked out from energy c o n s i d c r D t l o n s i n terms o f n
and t he e f f e c t i v e l e n g t h o f t he r e a o n a t o r c a v i t y . In the
c a s e o f SAW r e s o n a t o r s with Q 1 a COO, i t war. f ound t h a t
t he g a i n r e q u i r e m e n t «as s.-nall ( # 1 d a ) . S i n c e m o n o l i t h i c
SAW a m p l i f i e r s u s r e c a p a b l e o f y i e l d i n g u s e f u l g a i n , i t whs
i n f e r r e d t h a t t he l o s s e s i n t he r e s o n a t o r c.'^vity c o u l d be
made up f o r by means o f a m o n o l i t h i c 3AVi a m p l i f i e r ^
A h i g h Q-SAW r e s o n a t o r havi ng £i l a r g e c a v i t y and a
m o n o l i t h i c SAW a m p l i f i e r ( S i O / I n S b / S l O ^ s l r u b t u w l o c a t e d
i n s i d e t he r i s s o n a t o r c a v i t y ) « s r e d e s i g n e d snd f a b f i c s t e d
on a YZ l i t h i u m n i o b a t e s u b s t r a t s c
The SAW r e s o n a t o r wos f a b r i c a t e d usi ng c o n v e n t i o n s !
shadow p r i n t i n g t e c h n i q u e s ; The s a l i e n t f e a t u r e s o f the. SAW
r e s o n a t o r were high f undamental f r e q u e n c y o f o p e r a t i o n
15B MHz) 2 nd a l a r g e s e p a r a t i o n between the g r a t i n g s . in
o t h e r wordsp the SAW r e s o n a t o r was de s i g ne d t o hove a hi gh q
and ade quat e s e p a r a t i o n between the g r a t i n g s as- wel l p so t h a t
t h e m o n o l i t h i c SAW a m p l i f i e r l o c a t e d i n s i d e t h e SAW r e s o n a t o r
c a v i t y c o u l d p r o v i d e the r e q u i s i t e g ai n f o r the s u s t a i n e d
o s c i l l a t i o n s t o s e t i n .
The m o n o l i t h i c SAW a m p l i f i e r was f a b r i c a t e d by r e s i s t a n c e
and f l a s h e v a p o r a t i o n methods* The m o n o l i t h i c SAW resonsbi^or
o s c i l l a t o r was o p e r a t e d i n pul sed mode t o a v o i d b e s t
d i s s i p a t i o n problems*
Of the t en m o n c l i t h i c SAW r e s o n a t o r o s c i l.-.a uora
fBbric^-nted, e i g h t y i e l d e d o s c i l l a t i o n s a t r - o 15S MHz.
A n a l y t i c a l e x p r e s s i o n s f o r t'ne v a r i s t i c n o f f r e q u e n c y o f
o s c i l l a t i o n s with, r e s p e c t t o s i g n a l t o n n i s e r a t i o and d r i f t
f i e l d have been d e r i v e d *

