ʻO kahi palena pono e helu ana i ka mana loaʻa o kahi antenna ʻo ia kawahi kūponoa i ʻolepuka kūpono. Manaʻo ʻia he nalu mokulele me ka polarization like me ka antenna loaʻa e pili ana i ka antenna. E manaʻo hou e hele ana ka nalu i ka antenna ma ke kuhikuhi o ka antenna o ka radiation kiʻekiʻe loa (ke kuhikuhi mai kahi e loaʻa ai ka mana nui loa).

A laila, ʻo kapuka kūponowehewehe ke ʻano hoʻohālikelike i ka nui o ka mana i hopu ʻia mai kahi nalu mokulele i hāʻawi ʻia. E ʻaepʻo ia ka nui o ka mana o ka nalu mokulele (ma W/m^2). InāP_thōʻike i ka mana (ma Watts) ma nā kikowaena antennas i loaʻa i ka mea loaʻa o ka antenna, a laila:

No laila, hōʻike wale ka ʻāpana kūpono i ka nui o ka mana i hopu ʻia mai ka nalu mokulele a hāʻawi ʻia e ka antenna. Hoʻopili kēia ʻāpana i nā pohō intrinsic i ka antenna (nā pohō ohmic, nā pohō dielectric, a me nā mea ʻē aʻe).

ʻO kahi pilina laulā no ka puka kūpono e pili ana i ka loaʻa ʻana o ka antenna kiʻekiʻe (G) o kekahi antenna i hāʻawi ʻia e:

Hiki ke ana ʻia ka puka kūpono a i ʻole ka ʻāpana kūpono ma nā antennas maoli ma ka hoʻohālikelike ʻana me kahi antenna i ʻike ʻia me kahi puka kūpono i hāʻawi ʻia, a i ʻole ma ka helu ʻana me ka hoʻohana ʻana i ka loaʻa i ana ʻia a me ka hoʻohālikelike ma luna.

He manaʻo pono ka puka kūpono no ka helu ʻana i ka mana i loaʻa mai kahi nalu mokulele. No ka ʻike ʻana i kēia ma ka hana, e hele i ka ʻāpana aʻe ma ke ʻano hoʻoili Friis.

ʻO ka Friis Transmission Equation

Ma kēia ʻaoʻao, ke hoʻolauna nei mākou i kekahi o nā hoʻohālikelike koʻikoʻi loa i ke kumumanaʻo antenna, ʻo kaKa Hoʻohālikelike Hoʻoili FriisHoʻohana ʻia ka Friis Transmission Equation e helu i ka mana i loaʻa mai hoʻokahi antenna (me ka loaʻaG1), i ka wā i hoʻouna ʻia mai kahi antenna ʻē aʻe (me ka loaʻaG2), i hoʻokaʻawale ʻia e kahi mamaoR, a me ka hana ʻana ma ke alapine (frequency)fa i ʻole ka wavelength lambda. He mea kūpono ke heluhelu ʻia kēia ʻaoʻao i kekahi mau manawa a pono e hoʻomaopopo piha ʻia.

Ka Hoʻomaka ʻana o Friis Transmission Formula

No ka hoʻomaka ʻana i ka loaʻa ʻana o ka Friis Equation, e noʻonoʻo i ʻelua mau antennas i kahi ākea (ʻaʻohe mea keakea kokoke) i hoʻokaʻawale ʻia e kahi mamao.R:

Manaʻo ʻia ua hāʻawi ʻia nā Watts o ka mana holoʻokoʻa i ka antenna hoʻouna. No kēia manawa, manaʻo ʻia he omnidirectional ka antenna hoʻouna, ʻaʻohe pohō, a aia ka antenna loaʻa ma ke kahua mamao o ka antenna hoʻouna. A laila ka nui o ka manap(ma Watts no ka mika kuea) o ka nalu mokulele e kū mai ana ma ka antenna loaʻa i kahi mamaoRmai ka antenna hoʻouna i hāʻawi ʻia e:

Kiʻi 1. Nā Antenna Hoʻouna (Tx) a me Loaʻa (Rx) i hoʻokaʻawale ʻia eR.

Inā loaʻa i ka antenna hoʻouna kahi loaʻa antenna ma ke kuhikuhi o ka antenna loaʻa i hāʻawi ʻia e （）, a laila lilo ka hoʻohālikelike density mana ma luna:

ʻO nā kumu o ka huaʻōlelo loaʻa i ke kuhikuhi a me nā pohō o kahi antenna maoli. Manaʻo i kēia manawa he puka kūpono ka antenna loaʻa i hāʻawi ʻia e（）A laila hāʻawi ʻia ka mana i loaʻa e kēia antenna () e:

ʻOiai hiki ke hōʻike ʻia ka puka kūpono no kekahi antenna penei:

Hiki ke kākau ʻia ka mana i loaʻa ma ka hopena penei:

Kaulike 1

Ua ʻike ʻia kēia ʻo ke ʻano hoʻoili Friis. Hoʻopili ia i ka nalowale o ke ala ākea manuahi, nā loaʻa antenna a me ka nalu i nā mana i loaʻa a me ka hoʻouna. ʻO kēia kekahi o nā kaulike kumu i ke kumumanaʻo antenna, a pono e hoʻomanaʻo ʻia (a me ka derivation ma luna).

ʻO kekahi ʻano pono o ka Friis Transmission Equation i hāʻawi ʻia ma ka Equation [2]. ʻOiai ʻo ka wavelength a me ke alapine f e pili ana i ka wikiwiki o ka mālamalama c (e ʻike i ka intro i ka ʻaoʻao alapine), loaʻa iā mākou ka Friis Transmission Formula ma ke ʻano o ke alapine:

Kaulike 2

Hōʻike ka Equation [2] ua nalowale ka mana hou aʻe ma nā alapine kiʻekiʻe. He hopena koʻikoʻi kēia o ka Friis Transmission Equation. ʻO ke ʻano kēia no nā antenna me nā loaʻa i kuhikuhi ʻia, ʻoi aku ka kiʻekiʻe o ka hoʻoili ikehu ma nā alapine haʻahaʻa. ʻO ka ʻokoʻa ma waena o ka mana i loaʻa a me ka mana i hoʻouna ʻia ua ʻike ʻia ʻo ka pohō ala. Ua ʻōlelo ʻia ma ke ʻano ʻokoʻa, ʻōlelo ʻo Friis Transmission Equation ʻoi aku ka kiʻekiʻe o ka pohō 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 ai nā kelepona paʻalima ma lalo o 2 GHz. Loaʻa paha nā alapine hou aʻe i loaʻa ma nā alapine kiʻekiʻe, akā ʻaʻole hiki i ka pohō ala pili ke hoʻokipa maikaʻi. Ma ke ʻano he hopena hou aʻe o Friss Transmission Equation, manaʻo ʻia ua nīnau ʻia ʻoe e pili ana i nā antenna 60 GHz. Ke hoʻomaopopo nei he kiʻekiʻe loa kēia alapine, hiki iā ʻoe ke ʻōlelo e kiʻekiʻe loa ka pohō ala no ke kamaʻilio lōʻihi - a pololei loa ʻoe. Ma nā alapine kiʻekiʻe loa (ʻo 60 GHz i kekahi manawa i kapa ʻia ʻo ka mm (millimeter wave) region), kiʻekiʻe loa ka pohō ala, no laila hiki ke kamaʻilio wale nō ma waena o nā kiko. Hana ʻia kēia i ka wā e noho ai ka mea hoʻokipa a me ka mea hoʻouna i loko o ka lumi hoʻokahi, a e kū pono ana kekahi i kekahi. Ma ke ʻano he hopena hou aʻe o Friis Transmission Formula, manaʻo ʻoe ua hauʻoli nā mea lawelawe kelepona paʻalima e pili ana i ka hui LTE (4G) hou, e hana ana ma 700MHz? ʻAe ka pane: he alapine haʻahaʻa kēia ma mua o ka hana maʻamau a nā antennas, akā mai ka Equation [2], ʻike mākou e emi ana ka nalowale o ke ala. No laila, hiki iā lākou ke "uhi i ka ʻāina hou aʻe" me kēia alapine spectrum, a ua kapa ʻia kēia e kahi luna hoʻomalu o Verizon Wireless i kēia "spectrum kiʻekiʻe", no kēia kumu. ʻŌlelo Aʻo: Ma ka ʻaoʻao ʻē aʻe, pono nā mea hana kelepona e hoʻokomo i kahi antenna me kahi nalu nui aʻe i loko o kahi hāmeʻa compact (alapine haʻahaʻa = nalu nui aʻe), no laila ua paʻakikī iki ka hana a ka mea hoʻolālā antenna!

ʻO ka mea hope loa, inā ʻaʻole i kūlike ka polarization o nā antennas, hiki ke hoʻonui ʻia ka mana i loaʻa ma luna e ka Polarization Loss Factor (PLF) e helu pono ai no kēia mismatch. Hiki ke hoʻololi ʻia ka Equation [2] ma luna e hana i kahi Friis Transmission Formula generalized, nona ka polarization mismatch: