High Frequency Dielectrics and Their Applications

Abstract

D i e l e c t r i c r e s o n a t o r ce ramics have ga ined an i m p o r t a n t p o s i t i o n a s a key e lement f o r microwave components. m a t e r i a l s commonly used i n d i e l e c t r i c r e s o n a t o r ce ramics a r e i n t r o d u c e d h e r e . T h e i r d i e l e c t r i c c o n s t a n t s K a r e 2 1 , 25 , 30, 38, and 90 , and t h e i r Q v a l u e s ( Q D = l / t a n 6 ) a r e 5,000, 2 0 , 0 0 0 , 10,000, 5,000, and 500 a t 10 GHz. The p e c u l i a r i t i e s such as h i g h K , h igh Q and good t empera tu re s t a b i l i t y must be cons ide red c a r e f u l l y when choos ing of m a t e r i a l . The 6 a p p l i c a t i o n s cons ide red h e r e a r e 1 ) c o a x i a l type a n t e n n a bandpass f i l t e r s f o r c e l l u l a r mobi le r a d i o s , 2 )mono l i th i c t ype an tenna bandpass f i l t e r s of c e l l u l a r hand-held r a d i o s , 3 , 4 ) m i c r o s t r i p l i n e f i l t e r s and d i e l e c t r i c l o c a l o s c i l l a t o r s of SHF-TV c o n v e r t e r s , 5 )channe l dropping f i l t e r s of c e l l u l a r base s t a t i o n s and 6)nar row band f i l t e r s of mar ine s a t e l l i t e communicaticns equipme-it . The d i e l e c t r i c c h a r a c t e r i s t i c s o f 5 b a s i c