Hoʻouna a loaʻa paha ka ʻike i nā antennas ma o ka hoʻolaha ʻana i ka ikehu electromagnetic. No laila, ʻo ka ikehu a me ka mana nā ʻano koʻikoʻi e pili ana i kēia mau nalu electromagnetic, a he mea nui e kūkākūkā iā lākou. Aia kahi nalu electromagnetic i kahi kahua uila a me kahi kahua magnetic.
I kēlā me kēia manawa, hiki ke wehewehe ʻia ka nalu e kēia mau vectors ʻelua. Hōʻike ke kiʻi ma lalo nei i nā ʻāpana uila a me ke kahua magnetic o kahi nalu electromagnetic.
I loko o kahi nalu electromagnetic, kū pololei ke kahua uila i ke kuhikuhi o ka hoʻolaha ʻana, a kū pololei pū ke kahua magnetic i ke kuhikuhi o ka hoʻolaha ʻana, ʻoiai kū pololei nā kahua uila a me nā kahua magnetic kekahi i kekahi.
ʻO Poynting Vector
Hōʻike ka vector Poynting i ka ikehu o kahi nalu electromagnetic i kēlā me kēia manawa i kēlā me kēia wahi i kēlā me kēia manawa. Ua loaʻa mua ia e John Henry Poynting i ka makahiki 1884 a ua kapa ʻia ma muli ona.
Wehewehena: Hāʻawi ka vector Poynting i ka wikiwiki o ka hoʻoili ikehu no kēlā me kēia ʻāpana.
ʻOkoʻa: Hāʻawi ʻia ka ikehu i lawe ʻia e kahi nalu i kēlā me kēia anakahi manawa no kēlā me kēia anakahi wahi e ka vector Poynting.
Ua hōʻike ʻia ka vector Poynting eS.
ʻĀpana
ʻO ke anakahi SI o ka vector Poynting he watts no ka mika kuea (W/m²).
Hōʻike Makemakika
ʻO ka vector Poynting koke, ka mea e wehewehe ana i ka mana e pili ana me kahi nalu electromagnetic, ua wehewehe ʻia penei:
ma heaEʻo ia ka vector ikaika o ke kahua uila aHʻo ia ka vector ikaika o ke kahua magnetic.
Ka Hoʻokumu ʻana o ka Poynting Vector
I mea e hoʻomaopopo maikaʻi ai i ka vector Poynting, e hana kākou i kāna hōʻike ʻana i kēlā me kēia ʻanuʻu.
E noʻonoʻo i kahi nalu electromagnetic e hele pololei ana i kahi ʻāpana A e orthogonal ana i ke kuhikuhi o ka hoʻolaha ʻana (i lawe ʻia ma ke ʻano he axis X). I loko o kahi manawa liʻiliʻi loa dt, hele ka nalu i kahi mamao dx:
ma heaSʻo ia ka vector Poynting. Hāʻawi ka hoʻohālikelike ma luna nei i ka ikehu no kēlā me kēia manawa no kēlā me kēia wahi i kēlā me kēia manawa - ʻo ia ke ʻano kino o ka vector Poynting.
No ka ʻike hou aku e pili ana i nā antennas, e kipa i ka pūnaewele:
Ka manawa hoʻouna: Mei-15-2026
