The Parallel-Plate Transmission Line for Lightning Electromagnetic Effects Testing of Electronics Systems

Abstract

L ig h tn in g e le c tro m a g n e tic e f f e c t s t e s t i n g o f d i g i t a l e l e c t r o n ic s has shown t h a t c i r c u i t p r o t e c t io n can p rev en t s e r io u s u p se t in f l i g h t c o n t ro l sy s tem s . An u n p ro te c te d system can be ex trem ely s e n s i t i v e to induced t r a n s i e n t v o l ta g e s r e s u l t i n g i n p o s s ib le memory dump and unprogram­ med lo o p in g . The in c re a se d u se o f lo w le v e l c i r c u i t r y and th e t r e n d to more com posites in a i r c r a f t s t r u c t u r e s w ith a t te n d e n t re d u c t io n i n s h ie ld in g has shown a need f o r a sim ple means o f t r a n s i e n t t e s t i n g com plete d i g i t a l system s b e fo re new p ro to ty p e a e ro sp ace v e h ic le s a r e a v a i l a b l e fo r in v e h ic i e t e s t s . The p a r a l l e l p l a t e tr a n s m is s io n l i n e m eets t h i s need by p ro v id in g a r e l a t i v e l y un ifo rm and p re ­ d i c t a b l e t r a n s i e n t e le c tro m a g n e tic f i e l d in a volume s u i t ­ a b le fo r exposing a com ple te f l i g h t c o n t r o l system . The tr a n s m is s io n l i n e , used a s a lu m p ed -constan t e lec trom ag ­ n e t i c f i e l d g e n e ra t io n f a c i l i t y , can be design ed and c a l ­ ib r a te d r e l a t i v e l y e a s i l y u s in g an e l e c t r o l y t i c ta n k and s im ple f i e l d p ro b e s . A th r e e p l a t e l i n e was d esig ned and f a b r ic a te d to t e s t a d i g i t a l f l i g h t c o n t r o l system . T e s ts d is c lo s e d th a t th e f l i g h t c o n t r o l system w ith s to o d ty p i ­ c a l i n t e r n a l f i e l d s e x i s t i n g in a i r c r a f t exposed to sev ­ e re l i g h tn in g s t r i k e s . The t e s t e i l l u s t r a t e d th e im port­ ance o f c lo s e sp ac in g o f c a b le s over th e ground p la n e in b o th th e t e s t f a c i l i t y and th e new ae ro sp ace v e h ic le .