ʻO kahi ʻāpana kūpono e helu ana i ka mana loaʻa o kahi antenna ʻo ia kawahi kūponoa i ʻolepuka kūpono.E noʻonoʻo ʻoe ua kū ka nalu mokulele me ka polarization like me ka antenna loaʻa ma luna o ka antenna.E manaʻo hou aʻe e holo ana ka nalu i ka antenna ma ke kuhikuhi o ka antenna o ka radiation kiʻekiʻe (ke kuhikuhi e loaʻa ai ka mana nui loa).
A laila kapuka kūponoʻO ka ʻāpana e wehewehe ana i ka nui o ka mana i hopu ʻia mai ka nalu mokulele i hāʻawi ʻia.E ʻaepka mānoanoa mana o ka nalu mokulele (i W/m^2).InaP_thōʻike i ka mana (ma Watts) ma nā ʻāpana antennas i loaʻa i ka mea hoʻokipa antenna, a laila:
No laila, hōʻike wale ka wahi kūpono i ka nui o ka mana i hopu ʻia mai ka nalu mokulele a hāʻawi ʻia e ka antenna.ʻO kēia wahi ke kumu i nā poho i loko o ka antenna (ohmic poho, dielectric poho, etc.).
Hāʻawi ʻia kahi pilina maʻamau no ka aperture kūpono e pili ana i ka loaʻa ʻana o ka antenna peak (G) o kekahi antenna e:
Hiki ke ana ʻia ka aperture kūpono a i ʻole ka wahi kūpono ma nā antenna maoli ma ka hoʻohālikelike ʻana me kahi antenna i ʻike ʻia me kahi aperture kūpono i hāʻawi ʻia, a i ʻole ma ka helu ʻana me ka hoʻohana ʻana i ka waiwai i ana ʻia a me ka hoʻohālikelike o luna.
He manaʻo kūpono no ka helu ʻana i ka mana i loaʻa mai ka nalu mokulele.No ka ʻike ʻana i kēia i ka hana, e hele i ka ʻāpana aʻe ma ka palapala hoʻouna Friis.
ʻO ka Friis Transmission Equation
Ma kēia ʻaoʻao, hoʻolauna mākou i kekahi o nā hoʻohālikelike koʻikoʻi loa i ka ʻenehana antenna, ʻo kaFriis Transmission Equation.Hoʻohana ʻia ka Friis Transmission Equation e helu i ka mana i loaʻa mai hoʻokahi antenna (me ka loaʻaG1), ke lawe ʻia mai kahi antenna ʻē aʻe (me ka loaʻaG2), hoʻokaʻawale ʻia e kahi mamaoR, a me ka hana ma ke alapinefa i ʻole lambda lōʻihi nalu.Pono kēia ʻaoʻao e heluhelu i ʻelua mau manawa a pono e hoʻomaopopo piha ʻia.
Hoʻomaka ʻana o ka Friis Transmission Formula
No ka hoʻomaka ʻana i ka loaʻa ʻana o ka Friis Equation, e noʻonoʻo i ʻelua antenna ma kahi ākea (ʻaʻohe mea keakea kokoke) i hoʻokaʻawale ʻia e kahi mamao.R:
Manaʻo ʻia ʻo （ ）Watts o ka mana holoʻokoʻa e hāʻawi ʻia i ka antenna transmit.No ka manawa, e noʻonoʻo ʻoe he omnidirectional ka antenna transmit, ʻaʻole nalowale, a aia ka antenna loaʻa ma kahi mamao loa o ka antena transmit.A laila ka nui o ka manap(ma Watts no ka mika square) o ka hanana nalu mokulele ma ka antenna loaʻa i kahi mamaoRHāʻawi ʻia mai ka antenna transmit e:
Kiʻi 1. Hoʻouna (Tx) a loaʻa (Rx) nā Antenna i hoʻokaʻawale ʻia eR.
Inā loaʻa i ka antenna transmit ka loaʻa ʻana o ka antenna i ke kuhikuhi o ka antenna loaʻa i hāʻawi ʻia e （ ） , a laila lilo ka hoʻohālikelike mana ma luna:
ʻO ke kumu o ka loaʻa ʻana o ka manawa i ke kuhikuhi a me ka nalowale o kahi antena maoli.E noʻonoʻo i kēia manawa ua loaʻa i ka antenna loaʻa kahi puka kūpono i hāʻawi ʻia e（ ）.A laila hāʻawi ʻia ka mana i loaʻa i kēia antenna ( ) e:
No ka mea hiki ke hōʻike ʻia ka aperture kūpono no kekahi antenna e like me:
Hiki ke kākau ʻia ka mana i loaʻa e like me:
Ka hoohalike1
ʻIke ʻia kēia ʻo ka Friis Transmission Formula.Hoʻopili ia i ka nalowale o ke ala ākea, ka loaʻa ʻana o ka antenna a me ka lōʻihi o ka nalu i nā mana i loaʻa a hoʻouna.ʻO kēia kekahi o nā hoʻohālikelike koʻikoʻi i ka ʻenehana antenna, a pono e hoʻomanaʻo ʻia (a me ka derivation ma luna).
Hāʻawi ʻia kekahi ʻano pono o ka Friis Transmission Equation ma ka Equation [2].No ka mea pili ka nalu a me ka alapine f e ka wikiwiki o ka māmā c (e ʻike i ka hoʻomaka ʻana i ka ʻaoʻao alapine), loaʻa iā mākou ka Friis Transmission Formula ma ke ʻano o ke alapine:
Ka hoohalike2
Hōʻike ka hoʻohālikelike [2] i ka nalowale o ka mana ma nā alapine kiʻekiʻe.He hopena kumu kēia o ka Friis Transmission Equation.ʻO ia ke kumu no nā antenna me nā loaʻa i ʻōlelo ʻia, ʻoi aku ka kiʻekiʻe o ka hoʻoili ʻana o ka ikehu ma nā alapine haʻahaʻa.ʻO ka ʻokoʻa ma waena o ka mana i loaʻa a me ka mana i hoʻouna ʻia i ʻike ʻia ʻo ke ala poho.Ua ʻōlelo ʻia ma kahi ʻano ʻē aʻe, ʻōlelo ʻo Friis Transmission Equation e ʻoi aku ka kiʻekiʻe o ke ala ala no nā alapine kiʻekiʻe.ʻAʻole hiki ke hoʻonui ʻia ke koʻikoʻi o kēia hopena mai ka Friis Transmission Formula.ʻO ia ke kumu e hana mau ai nā kelepona paʻalima ma lalo o 2 GHz.Hiki ke loaʻa i nā alapine alapine hou aku i nā alapine kiʻekiʻe, akā ʻaʻole hiki i ka nalowale ala pili ke hiki ke hoʻokipa maikaʻi.Ma ke ʻano he hopena hou o Friss Transmission Equation, manaʻo paha e nīnau ʻia ʻoe e pili ana i nā antenna 60 GHz.Me ka ʻike ʻana he kiʻekiʻe loa kēia alapine, ʻōlelo paha ʻoe e kiʻekiʻe loa ka poho o ke ala no ke kamaʻilio lōʻihi - a pololei ʻoe.Ma nā alapine kiʻekiʻe loa (60 GHz i kekahi manawa i kapa ʻia ʻo ka mm (milimeter wave) ʻāpana), kiʻekiʻe loa ka poho o ke ala, no laila hiki ke kamaʻilio kiko-a-kahi.Hana ʻia kēia i ka manawa o ka mea hoʻokipa a me ka transmitter i loko o ka lumi hoʻokahi, a kū pono kekahi i kekahi.Ma ke ʻano he corrollary hou o Friis Transmission Formula, ke manaʻo nei ʻoe e hauʻoli nā mea kelepona kelepona i ka hui LTE (4G) hou, e hana ana ma 700MHz?ʻO ka pane ʻae: he haʻahaʻa haʻahaʻa kēia ma mua o ka hana maʻamau o nā antenna, akā mai ka Equation [2], ʻike mākou e haʻahaʻa loa ke alahele.No laila, hiki iā lākou ke "uhi hou i ka ʻāina" me kēia alapine alapine, a ua kapa ʻia kahi luna hoʻokele Verizon Wireless i kēia "kiʻekiʻe kiʻekiʻe spectrum", pololei no kēia kumu.Manaʻo ʻaoʻao: Ma ka ʻaoʻao ʻē aʻe, pono nā mea hana kelepona e hoʻokomo i kahi antenna me ka lōʻihi o ka nalu nui i loko o kahi hāmeʻa paʻa (ke alapine haʻahaʻa = ka lōʻihi o ka nalu nui), no laila ua paʻakikī iki ka hana a ka mea hoʻolālā antenna!
ʻO ka mea hope loa, inā ʻaʻole i hoʻohālikelike ʻia nā antennas, hiki ke hoʻonui ʻia ka mana i loaʻa i luna e ka Polarization Loss Factor (PLF) e helu pono i kēia mismatch.Hiki ke hoʻololi ʻia ka hoohalike [2] ma luna e hana i ka Friis Transmission Formula maʻamau, e komo pū ana me ka polarization mismatch:
Ka hoohalike3
Ka manawa hoʻouna: Jan-08-2024
