kiʻi 1
1. Ka pono o ke kukuna
ʻO kekahi ʻano maʻamau no ka loiloi ʻana i ka maikaʻi o ka hoʻouna ʻana a me ka loaʻa ʻana o nā antennas ʻo ia ka beam efficiency. No ka antenna me ka lobe nui ma ke kuhikuhi z-axis e like me ka mea i hōʻike ʻia ma ke Kiʻi 1, ua wehewehe ʻia ka beam efficiency (BE) penei:
ʻO ia ka lakio o ka mana i hoʻouna ʻia a i loaʻa paha i loko o ke kihi cone θ1 i ka mana holoʻokoʻa i hoʻouna ʻia a i loaʻa paha e ka antenna. Hiki ke kākau ʻia ke ʻano ma luna penei:
Inā koho ʻia ke kihi e ʻike ʻia ai ka helu zero mua a i ʻole ka waiwai liʻiliʻi loa ʻo θ1, hōʻike ka beam efficiency i ka lakio o ka mana ma ka lobe nui i ka mana holoʻokoʻa. I nā noi e like me ka metrology, astronomy, a me ka radar, pono ka antenna i kahi beam efficiency kiʻekiʻe loa. ʻO ka maʻamau, ʻoi aku ma mua o 90% ka mea e pono ai, a pono e liʻiliʻi ka mana i loaʻa e ka lobe ʻaoʻao.
2. Pākuʻi
Ua wehewehe ʻia ka bandwidth o kahi antenna ʻo ia hoʻi "ka laulā alapine (frequency) ma luna o ia mea e kū ai ka hana o kekahi mau ʻano o ka antenna i nā kūlana kikoʻī". Hiki ke noʻonoʻo ʻia ka bandwidth ma ke ʻano he laulā alapine (frequency) ma nā ʻaoʻao ʻelua o ke alapine waena (e pili ana i ke alapine resonant) kahi e kū ai nā ʻano antenna (e like me ka impedance input, directional pattern, beamwidth, polarization, sidelobe level, gain, beam pointing, radiation efficiency) i loko o ka laulā i ʻae ʻia ma hope o ka hoʻohālikelike ʻana i ka waiwai o ke alapine waena.
No nā antennas broadband, hōʻike pinepine ʻia ka bandwidth ma ke ʻano he ratio o nā alapine kiʻekiʻe a me nā alapine haʻahaʻa no ka hana i ʻae ʻia. No ka laʻana, ʻo ka bandwidth o 10:1 ʻo ia hoʻi, ʻo ke alapine kiʻekiʻe he 10 manawa o ke alapine haʻahaʻa.
No nā antennas narrowband, ua hōʻike ʻia ka bandwidth ma ke ʻano he pakeneka o ka ʻokoʻa alapine i ka waiwai kikowaena. No ka laʻana, ʻo ka bandwidth 5% ʻo ia hoʻi ka laulā alapine i ʻae ʻia he 5% o ke alapine kikowaena.
Ma muli o ke ʻano o nā ʻano o ka antenna (input impedance, directional pattern, gain, polarization, etc.) e loli me ke alapine (frequency), ʻaʻole kū hoʻokahi nā ʻano bandwidth. ʻO ka maʻamau, ʻokoʻa nā loli i ke ʻano kuhikuhi a me ka input impedance. No laila, pono ka bandwidth directional pattern a me ka impedance bandwidth e hoʻokūpaʻa i kēia ʻokoʻa. Pili ka bandwidth directional pattern i ka loaʻa, ka pae sidelobe, ka beamwidth, ka polarization a me ke kuhikuhi beam, ʻoiai pili ka input impedance a me ka pono o ka radiation i ka impedance bandwidth. ʻŌlelo pinepine ʻia ka Bandwidth ma ke ʻano o ka beamwidth, nā pae sidelobe, a me nā ʻano pattern.
Manaʻo ke kūkākūkā ma luna nei ʻaʻole e loli nā ana o ka pūnaewele hoʻopili (transformer, counterpoise, etc.) a/a i ʻole antenna i kekahi ʻano e like me ka loli ʻana o ke alapine. Inā hiki ke hoʻoponopono pono ʻia nā ana koʻikoʻi o ka antenna a/a i ʻole ka pūnaewele hoʻopili i ka loli ʻana o ke alapine, hiki ke hoʻonui ʻia ka bandwidth o kahi antenna narrowband. ʻOiai ʻaʻole kēia he hana maʻalahi ma ke ʻano laulā, aia nā noi kahi e hiki ai ke hoʻokō. ʻO ka laʻana maʻamau ka antenna lekiō i loko o kahi lekiō kaʻa, kahi maʻamau he lōʻihi hiki ke hoʻololi ʻia e hiki ke hoʻohana ʻia e hoʻoponopono i ka antenna no ka hoʻokipa maikaʻi ʻana.
No ka ʻike hou aku e pili ana i nā antennas, e kipa i ka pūnaewele:
Ka manawa hoʻouna: Iulai-12-2024
