Relation between spacing and receiving efficiency of finite rectenna array

Abstract

I n t h e rectenna a r r a y used f o r r e c t i f ic a t i o n of t h e microwaves received on t h e ground i n t h e s o l a r power s a t e l l i t e system, i t i s required t h a t t h e rectenna elements have a high dc power conversion e f f i c i e n c y and t h a t t h e element spacing i s optimized so t h a t t h e a r r i v i n g microwave power i s received e f f i c i e n t l y and t h e number of e l ements can be reduced.I n t h i s paper, a microwave r e c t i f i e r is f a b r i c a t e d i n an i n t egrated form w i t h a m i c r o s t r i p l i n e on a t e flon s u b s t r a t e . A c i r c u l a r m i c r o s t r i p patch antenna i s used. A high r e c t i f i c a t i o n e f f iciency, 66.7 percent i s obtained a t a microwave input of 750 mW and 75.7 percent f o r input of 500 mW. With t h i s rectenna element, a 7 x 7 l a t t i c e a r r a y i s formed and t h e v a r i a t i o n of t h e r e c e i v i n g e f f i c i e n c y ( t h e r a t i o of t h e power converted t o d c t o t h e i n p u t microwave power) i s measured by varying t h e element spacing. On t h e o t h e r hand, t h e r e c e i v i n g e f f i c i e n c y i s c a l c u l a t e d f o r a given element spacing of t h i s rectenna a r r a y from t h e c i rc u i t equation of t h e antenna system by der i v i n g t h e mutual coupling between t h e elem e n t s . The r e l a t i o n s h i p between t h e element spacing of a f i n i t e a r r a y and t h e r e c e i v i n g e f f i c i e n c y i s obtained both experimentally and t h e o r e t i c a l l y . This computation method i s extended t o t h e c a s e w i t h many elements so t h a t t h e change of t h e r e c e i v i n g e f f iciency i s i n v e s t i g a t e d . 1. I n t r o d u c t i o n The s o l a r power s a t e l l i t e (SPS) i s a system i n which s o l a r power generation i s c a r r i e d out on a spsce s t a t i o n and i t s power i s t r a n s m i t t e d t o t h e ground a f t e r being 88 converted t o a microwave a t 2.45 GHz. The rectenna a r r a y i s used t o r e c e i v e t h i s microwave on t h e ground and t o convert t o t h e dc power. The rectenna (receiving and r e c t i f i e r antenna) i s a device c o n s i s t i n g of an antenna t o r e c e i v e t h e microwave and a r e c t i f i e r c i r c u i t t o convert t h e received microwave t o dc power. The rectenna a r r a y i s required t o have a c a p a b i l i t y t o c o l l e c t t h e i n c i d e n t microwave power without l o s s (capture e f f i c i e n c y ) and t h e one t o convert t h e received microwave t o t h e dc power without l o s s (transmission e f f i c i e n c y from t h e antenna t o t h e r e c t i f i e r and r e c t i f i c a t i o n e f f i c i e n c y ) . Since t h e microwave from t h e space illuminates an a r e a of about 100 km2, the number of rectenna elements is enormous. For t h e c o s t reduction, t h e element spacing must be made a s l a r g e a s p o s s i b l e t o reduce t h e number. The purpose of t h i s research i s t o f a b r...

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