ʻO ka polarization kekahi o nā ʻano kumu o nā antennas. Pono mua mākou e hoʻomaopopo i ka polarization o nā nalu mokulele. A laila hiki iā mākou ke kūkākūkā i nā ʻano nui o ka polarization antenna.
ka polarization linear
E hoʻomaka mākou e hoʻomaopopo i ka polarization o kahi nalu electromagnetic mokulele.
He nui nā ʻano o ka nalu electromagnetic planar (EM). ʻO ka mea mua, ʻo ia ka hele ʻana o ka mana i hoʻokahi ala (ʻaʻohe loli o ke kahua i ʻelua mau ala orthogonal). ʻO ka lua, ua kū pololei ke kahua uila a me ke kahua magnetic kekahi i kekahi a kū pololei kekahi i kekahi. Ua kū pololei nā kahua uila a me nā kahua magnetic i ke ala o ka hoʻolaha ʻana o ka nalu mokulele. Ma ke ʻano he laʻana, e noʻonoʻo i kahi kahua uila alapine hoʻokahi (kahua E) i hāʻawi ʻia e ka hoohalike (1). Ke hele nei ke kahua electromagnetic ma ke ala +z. Kuhikuhi ʻia ke kahua uila ma ke ala +x. Aia ke kahua magnetic ma ke ala +y.
Ma ka hoʻohālikelike (1), e nānā i ka hōʻailona: . He vector unit kēia (he vector o ka lōʻihi), e ʻōlelo ana aia ke kiko kahua uila ma ke kuhikuhi x. Ua hōʻike ʻia ka nalu mokulele ma ke Kiʻi 1.
kiʻi 1. Hōʻike kiʻi o ke kahua uila e hele ana ma ke kuhikuhi +z.
ʻO ka polarization ke ʻano o ka trace a me ka propagation (contour) o kahi kahua uila. Ma ke ʻano he laʻana, e noʻonoʻo i ka hoʻohālikelike kahua uila nalu mokulele (1). E nānā mākou i ke kūlana kahi o ke kahua uila (X,Y,Z) = (0,0,0) ma ke ʻano he hana o ka manawa. Ua hoʻolālā ʻia ka amplitude o kēia kahua ma ke Kiʻi 2, i kekahi mau manawa i ka manawa. Ke oscillating nei ke kahua ma ke alapine "F".
kiʻi 2. E nānā i ke kahua uila (X, Y, Z) = (0,0,0) i nā manawa like ʻole.
ʻIke ʻia ke kahua uila ma ke kumu, e hoʻoluliluli ana i mua a i mua i ka amplitude. Aia mau ke kahua uila ma ka axis x i hōʻike ʻia. ʻOiai ua mālama ʻia ke kahua uila ma kahi laina hoʻokahi, hiki ke ʻōlelo ʻia kēia kahua he polarized linearly. Eia kekahi, inā kūlike ka axis X me ka honua, ua wehewehe ʻia kēia kahua he polarized horizontally. Inā kuhikuhi ʻia ke kahua ma ka axis Y, hiki ke ʻōlelo ʻia ka nalu he polarized vertically.
ʻAʻole pono e kuhikuhi ʻia nā nalu polarized linear ma kahi axis ʻākea a kū paha. No ka laʻana, ʻo kahi nalu kahua uila me kahi palena e waiho ana ma kahi laina e like me ka mea i hōʻike ʻia ma ke Kiʻi 3 e polarized linearly hoʻi.
kiʻi 3. ʻO ka amplitude o ke kahua uila o kahi nalu polarized linearly nona ke alahele he kihi.
Hiki ke wehewehe ʻia ke kahua uila ma ke Kiʻi 3 e ka hoohalike (2). I kēia manawa aia kahi ʻāpana x a me y o ke kahua uila. Ua like ka nui o nā ʻāpana ʻelua.
ʻO kahi mea e hoʻomaopopo ai e pili ana i ka hoʻohālikelike (2) ʻo ia ka xy-component a me nā kahua uila i ka lua o ka pae. ʻO ke ʻano kēia he like ka amplitude o nā ʻāpana ʻelua i nā manawa āpau.
ka polarization pōʻai
I kēia manawa, e manaʻo ʻia ua hāʻawi ʻia ke kahua uila o kahi nalu mokulele e ka hoohalike (3):
I kēia hihia, ʻo nā mea X- a me Y he 90 degere ma waho o ka pae. Inā ʻike ʻia ke kahua e like me (X, Y, Z) = (0,0,0) e like me ma mua, e ʻike ʻia ke kahua uila e kūʻē i ka piʻo manawa e like me ka mea i hōʻike ʻia ma lalo nei ma ke Kiʻi 4.
Kiʻi 4. Ka ikaika o ke kahua uila (X, Y, Z) = (0,0,0) kikowaena EQ. (3).
Hoʻohuli ke kahua uila ma ke Kiʻi 4 i loko o kahi pōʻai. Ua wehewehe ʻia kēia ʻano kahua he nalu polarized circular. No ka polarization circular, pono e hoʻokō ʻia nā pae hoʻohālikelike:
- Kūlana no ka polarization pōʻai
- Pono ke kahua uila i ʻelua mau ʻāpana orthogonal (perpendicular).
- Pono nā ʻāpana orthogonal o ke kahua uila i nā amplitudes like.
- Pono nā ʻāpana quadrature e 90 degere ma waho o ka pae.
Inā e hele ana ma ka pale Wave Figure 4, ua ʻōlelo ʻia ka wili ʻana o ke kahua he counterclockwise a me ka circularly polarized ʻākau (RHCP). Inā e wili ʻia ke kahua ma ke kuhikuhi ʻākau, e lilo ke kahua i left-handed circular polarization (LHCP).
ʻO ka polarization elliptical
Inā loaʻa i ke kahua uila ʻelua mau ʻāpana perpendicular, 90 degere ma waho o ka pae akā like ka nui, e elliptically polarized ke kahua. Ke noʻonoʻo nei i ke kahua uila o kahi nalu mokulele e hele ana ma ke kuhikuhi +z, i wehewehe ʻia e ka Equation (4):
Ua hāʻawi ʻia ka locus o ke kiko kahi e manaʻo ai ka piko o ka vector kahua uila ma ke Kiʻi 5.
Kiʻi 5. Kahua uila o ka nalu polarization elliptical. (4).
ʻO ke kahua ma ke Kiʻi 5, e hele ana ma ke kuhikuhi ʻākau, he elliptical ʻākau ia inā e hele ana i waho o ka pale. Inā wili ka vector kahua uila i ke kuhikuhi ʻē aʻe, e polarized elliptical ka kahua hema.
Eia kekahi, pili ka polarization elliptical i kona eccentricity. ʻO ka lakio o ka eccentricity i ka amplitude o nā axes nui a me nā axes liʻiliʻi. No ka laʻana, ʻo ka eccentricity nalu mai ka hoohalike (4) he 1/0.3= 3.33. Ua wehewehe hou ʻia nā nalu polarized elliptically e ke kuhikuhi o ke axis nui. Loaʻa i ka hoohalike nalu (4) kahi axis i haku nui ʻia me ka axis-x. E hoʻomaopopo he hiki i ke axis nui ke noho ma kekahi kihi mokulele. ʻAʻole pono ke kihi e kūpono i ka axis X, Y a i ʻole Z. ʻO ka mea hope loa, he mea nui e hoʻomaopopo he mau hihia kūikawā o ka polarization elliptical nā polarization pōʻai a me ka linear. 1.0 eccentric he nalu polarized pōʻai ka nalu elliptical. Nā nalu polarized elliptically me ka eccentricity palena ʻole. Nā nalu polarized linear.
Ka polarization antenna
I kēia manawa ua ʻike mākou i nā kahua electromagnetic nalu polarized, ua wehewehe maʻalahi ʻia ka polarization o kahi antenna.
ʻO ka Polarization Antenna He loiloi kahua mamao antenna, ka polarization o ke kahua i hoʻopili ʻia. No laila, ua helu pinepine ʻia nā antennas ma ke ʻano he "linearly polarized" a i ʻole "right-handed circularly polarized antennas".
He mea nui kēia manaʻo maʻalahi no ke kamaʻilio ʻana o ka antenna. ʻO ka mea mua, ʻaʻole e kamaʻilio kahi antenna polarized horizontally me kahi antenna polarized vertically. Ma muli o ke kumumanaʻo reciprocity, hoʻouna a loaʻa ka antenna ma ke ʻano like. No laila, hoʻouna a loaʻa nā antenna polarized vertically i nā kahua polarized vertically. No laila, inā ʻoe e hoʻāʻo e hoʻouna i kahi antenna polarized horizontally polarized, ʻaʻohe loaʻa.
Ma ke ʻano laulā, no ʻelua mau antenna polarized linearly i hoʻohuli ʻia e pili ana kekahi i kekahi ma kahi kihi ( ), e wehewehe ʻia ka pohō mana ma muli o kēia mismatch polarization e ka polarization loss factor (PLF):
No laila, inā like ka polarization o nā antenna ʻelua, ʻo ke kihi ma waena o kā lākou mau kahua electron radiating he zero a ʻaʻohe pohō mana ma muli o ka polarization mismatch. Inā hoʻokahi antenna i polarized vertically a ʻo kekahi i polarized horizontally, ʻo ke kihi he 90 degere, a ʻaʻohe mana e hoʻoili ʻia.
HOʻOMANAʻO: ʻO ka hoʻoneʻe ʻana i ke kelepona ma luna o kou poʻo i nā kihi like ʻole e wehewehe ana i ke kumu e hiki ai ke hoʻonui ʻia ka loaʻa ʻana i kekahi manawa. ʻO ka maʻamau, ua linearly polarized nā antennas kelepona paʻalima, no laila hiki i ka hoʻohuli ʻana i ke kelepona ke hoʻohālikelike pinepine i ka polarization o ke kelepona, a pēlā e hoʻomaikaʻi ai i ka loaʻa ʻana.
ʻO ka polarization pōʻai kahi ʻano makemake ʻia o nā antennas he nui. Ua polarized pōʻai nā antennas ʻelua a ʻaʻole e ʻeha i ka nalowale o ka hōʻailona ma muli o ka mismatch polarization. ʻO nā antennas i hoʻohana ʻia i nā ʻōnaehana GPS ua polarized pōʻai ʻākau.
I kēia manawa, e manaʻo e loaʻa ana i kahi antenna polarized linearly nā nalu polarized circular. Ma ke ʻano like, e manaʻo e hoʻāʻo ana kahi antenna polarized circular e loaʻa nā nalu polarized linearly. He aha ka hopena o ka polarization loss factor?
E hoʻomanaʻo he ʻelua mau nalu polarized linearly orthogonal ka polarization circular, 90 degere ma waho o ka pae. No laila, e loaʻa wale i kahi antenna polarized linearly (LP) ka ʻāpana pae nalu polarized circularly (CP). No laila, e loaʻa i ka antenna LP kahi pohō mismatch polarization o 0.5 (-3dB). He ʻoiaʻiʻo kēia me ka nānā ʻole i ke kihi i hoʻohuli ʻia ai ka antenna LP. no laila:
ʻO ka polarization loss factor i kekahi manawa i kapa ʻia ʻo ka polarization efficiency, antenna mismatch factor, a i ʻole antenna reception factor. Pili kēia mau inoa a pau i ka manaʻo hoʻokahi.
Ka manawa hoʻouna: Dec-22-2023
