A Test System for Evaluating New Developments in RF Absorbing Materials for Radiated EMI Measurements

Abstract

S e r i o u s measurement problems a r e e n c o u n t e r e d when r a ­ d i a t e d EMI measurements a r e c o n d u c t e d w i t h i n s h i e l d e d rooms. T h is p a p e r d e s c r i b e s a t e s t sy s te m t o e v a l u a t e t h e u s e f u l n e s s o f newly d e v e lo p e d RF a b s o r b e r m a t e r ­ i a l s and room d e s i g n s t o improve t h e a c c u r a c y o f t h e v a r i o u s r a d i a t e d EMI measurement p r o c e d u r e s used w i t h ­ i n s h i e l d e d rooms. P r e l i m i n a r y d a t a i s g i ve n on t h e f i e l d d i s t r i b u t i o n s t h a t a r e found when c o n d u c t i n g t h e MIL-STD-461/462 and P a r t 15 F .C.C . /C ISP R t e s t p r o c e ­ d u r e s w i t h i n s h i e l d e d rooms w i t h and w i t h o u t two ty p e s o f RF a b s o r b e r on t h e i n t e r i o r s u r f a c e s o f t h e t e s t e n c l o s u r e .