Polarization bụ otu n'ime njirimara ndị bụ isi nke antenna. Anyị kwesịrị ibu ụzọ ghọta polarization nke ebili mmiri ụgbọelu. Anyị nwekwara ike ịtụle ụdị polarization nke antenna ndị bụ isi.
Njikọta ahịrị
Anyị ga-amalite ịghọta polarization nke ikuku electromagnetic ụgbọelu.
Ebili eletriki planar (EM) nwere ọtụtụ ihe e ji mara ya. Nke mbụ bụ na ike na-aga n'otu ụzọ (ọ dịghị mgbanwe ubi na ntụziaka orthogonal abụọ). Nke abụọ, ubi eletriki na ubi magnetik na-adabere n'otu akụkụ ma na-adabere n'otu akụkụ. Ubi eletriki na magnetik na-adabere n'akụkụ nke mgbasa ebili ikuku ụgbọelu. Dịka ọmụmaatụ, tụlee ubi eletriki otu ugboro (ọhịa E) nke e nyere site na nha nhata (1). Ubi eletriki na-agagharị na ntụziaka +z. Ubi eletriki na-eduzi na ntụziaka +x. Ubi magnetik dị na ntụziaka +y.
Na nhazi (1), lee ihe e dere n'elu ya: . Nke a bụ vektọ nkeji (vektọ ogologo), nke na-ekwu na isi ihe dị n'ọhịa eletriki dị na ntụziaka x. E gosipụtara ebili mmiri ụgbọelu na Foto 1.
eserese nke 1. Ngosipụta eserese nke mpaghara eletriki na-agagharị na +z.
Polarization bụ akara na ọdịdị mgbasa (contour) nke ubi eletriki. Dịka ọmụmaatụ, tụlee nha nha ọkụ eletrik (1). Anyị ga-ahụ ọnọdụ ebe ọkụ eletrik dị (X,Y,Z) = (0,0,0) dịka ọrụ oge. A na-ese onyinyo oke nke ubi a na Foto 2, n'ọtụtụ oge n'oge. Ubi ahụ na-agbagharị na ugboro "F".
Foto nke 2. Lee ebe ọkụ eletrik (X, Y, Z) = (0,0,0) n'oge dị iche iche.
A na-ahụ ebe ọkụ eletrik ahụ si malite, na-agbagharị azụ na azụ n'obosara. Ebe ọkụ eletrik ahụ na-adị mgbe niile n'akụkụ ebe ọkụ eletrik ahụ a na-egosi. Ebe ọ bụ na a na-edozi ebe ọkụ eletrik ahụ n'otu ahịrị, a pụrụ ikwu na ebe ọkụ eletrik a nwere oghere kwụ ọtọ. Na mgbakwunye, ọ bụrụ na ebe ọkụ eletrik ahụ dị n'akụkụ ala, a na-akọwakwa ebe ọkụ eletrik a dị ka ebe ọkụ eletrik ahụ kwụ ọtọ. Ọ bụrụ na ebe ọkụ eletrik ahụ dị n'akụkụ ebe ọkụ eletrik ahụ, a pụrụ ikwu na ebili mmiri ahụ nwere oghere kwụ ọtọ.
E kwesịghị ka e duzie ebili mmiri ndị nwere oghere n'ahịrị kwụ ọtọ ma ọ bụ kwụ ọtọ. Dịka ọmụmaatụ, ebili mmiri eletrik nwere ihe mgbochi dị n'ahịrị dịka egosiri na eserese nke 3 ga-abụkwa nke nwere oghere n'ahịrị kwụ ọtọ.
onyonyo nke 3. Oke ike eletrik nke ebili mmiri nke nwere oke polarized nke ụzọ ya bụ akụkụ.
Enwere ike ịkọwa ubi eletriki dị na eserese nke 3 site na nhazi (2). Ugbu a, enwere akụkụ x na y nke ubi eletriki. Akụkụ abụọ ahụ hà nhata n'ogo.
Otu ihe ị ga-eburu n'uche gbasara nha nhata (2) bụ oghere xy-component na eletrọniki n'ọkwa nke abụọ. Nke a pụtara na ihe abụọ ahụ nwere otu mgbasawanye oge niile.
okirikiri polarization
Ugbu a, were ya na e nyere ọkụ eletrik nke ebili mmiri ụgbọelu site na nha anya (3):
N'okwu a, ihe ndị dị na X na Y dị ogo 90 site na usoro ahụ. Ọ bụrụ na a hụ ubi ahụ dịka (X, Y, Z) = (0,0,0) ọzọ dịka ọ dị na mbụ, oghere eletrik megide usoro oge ga-apụta dịka egosiri n'okpuru na Foto 4.
Foto nke 4. Ike ubi eletriki (X, Y, Z) = (0,0,0) ngalaba EQ. (3).
Ọgba eletriki dị na Foto nke 4 na-agbagharị n'okirikiri. A kọwara ụdị ubi a dị ka ebili mmiri gbara okirikiri. Maka polarisation gburugburu, a ga-emezurịrị ihe ndị a:
- Ọkọlọtọ maka polarization gburugburu
- Ọgba eletriki ahụ ga-enwerịrị ihe abụọ dị n'otu (perpendicular).
- Akụkụ orthogonal nke ubi eletriki ga-enwerịrị nha nhata.
- Akụkụ quadrature ahụ aghaghị ịdị ogo 90 site na ọkwa ahụ.
Ọ bụrụ na ị na-agagharị na ihuenyo Wave Fig 4, a na-ekwu na ntụgharị ubi ahụ bụ nke megidere elekere na nke aka nri nwere polarized gburugburu (RHCP). Ọ bụrụ na a na-atụgharị ubi ahụ n'ụzọ elekere, ubi ahụ ga-abụ polarization okirikiri aka ekpe (LHCP).
Mgbawa elliptical
Ọ bụrụ na ọkụ eletrik nwere ihe abụọ dị n'akụkụ abụọ, ogo 90 site na usoro mana nha nhata, ubi ahụ ga-abụ nke nwere elliptical polarized. N'ịtụle ọkụ eletrik nke ebili mmiri ụgbọelu na-agagharị na ntụziaka +z, nke Equation (4) kọwara:
E nyere ebe isi ihe dị na vektọ ubi eletrik ga-eche na ọ dị na Foto nke 5.
Foto nke 5. Ọdụ eletriki nke ebili mmiri polarization nke ngwa ngwa. (4).
Ọgba ahụ dị na Foto nke 5, nke na-aga n'akụkụ aka nri, ga-abụ elliptical ma ọ bụrụ na ọ na-apụ na ihuenyo ahụ. Ọ bụrụ na vektọ ọkụ eletrik na-agbagharị n'akụkụ nke ọzọ, ọgba ahụ ga-abụ nke aka ekpe nke nwere elliptical.
Ọzọkwa, polarization elliptical na-ezo aka na eccentricity ya. Oke nke eccentricity na oke nke isi na obere axes. Dịka ọmụmaatụ, eccentricity ebili mmiri site na nha (4) bụ 1/0.3= 3.33. A na-akọwakwa ebili mmiri ndị nwere elliptical site na ntụziaka nke isi axis. Equity ebili mmiri (4) nwere axis nke mejupụtara x-axis. Rịba ama na isi axis nwere ike ịdị n'akụkụ ọ bụla nke plane. Achọghị akụkụ ya ka ọ dabara na axis X, Y ma ọ bụ Z. N'ikpeazụ, ọ dị mkpa ịmara na ma polarization gburugburu na nke linear bụ ikpe pụrụ iche nke polarization elliptical. 1.0 eccentric elliptical polarized ebili mmiri bụ ebili gburugburu polarized. Ebili mmiri ndị nwere elliptical polarized nwere eccentricity na-enweghị njedebe. Ebili mmiri ndị nwere linear polarized.
Mgbasa nke antenna
Ugbu a anyị maara maka oghere elektrọnik nke a na-agbanwe agbanwe, a na-akọwapụta polarization nke antenna.
Nhazigharị Antenna Nnyocha nke antenna dị anya, nke bụ njikọta nke oghere redioaktivu sitere na ya. Ya mere, a na-edekarị antenna dị ka "usoro polarized" ma ọ bụ "antena okirikiri polarized nke aka nri".
Echiche dị mfe a dị mkpa maka nkwukọrịta antenna. Nke mbụ, antenna nke nwere polarized kwụ ọtọ agaghị ekwurịta okwu na antenna nke nwere polarized kwụ ọtọ. N'ihi usoro reciprocity, antenna ahụ na-eziga ma na-anata n'otu ụzọ ahụ. Ya mere, antenna ndị nwere polarized kwụ ọtọ na-eziga ma na-anata ubi polarized kwụ ọtọ. Ya mere, ọ bụrụ na ị gbalịa ibuga antenna nke nwere polarized kwụ ọtọ, agaghị enwe nnabata.
N'okwu izugbe, maka antenna abụọ nwere oghere n'usoro nke na-agbagharị n'akụkụ ibe ha site n'akụkụ (), a ga-akọwa mfu ike sitere na enweghị nkwekọ polarization a site na ihe na-ebelata polarization (PLF):
Ya mere, ọ bụrụ na antenna abụọ nwere otu polarization, akụkụ dị n'etiti ubi elektrọn ha na-egbukepụ egbukepụ bụ efu, ọ dịghịkwa mfu ike n'ihi enweghị nkwekọ polarization. Ọ bụrụ na otu antenna kwụ ọtọ ma nke ọzọ kwụ ọtọ, akụkụ ya bụ ogo 90, a gaghịkwa ebufe ike ọ bụla.
RỤBA AMA: Ịkwaga ekwentị n'elu isi gị gaa n'akụkụ dị iche iche na-akọwa ihe kpatara enwere ike iji mụbaa nnabata mgbe ụfọdụ. Antenna ekwentị mkpanaka na-abụkarị nke nwere polarized n'ahịrị, yabụ ịtụgharị ekwentị ahụ nwere ike ijikọ polarization nke ekwentị ahụ, si otú a na-eme ka nnabata dịkwuo mma.
Mgbawa okirikiri bụ ihe a na-achọsi ike maka ọtụtụ antenna. Antenna abụọ ahụ nwere mgbawa okirikiri ma ha anaghị enwe mfu mgbaàmà n'ihi enweghị ike ịhazi polarization. Antenna eji na sistemụ GPS nwere mgbawa gburugburu aka nri.
Ugbua, were ya na antenna nke nwere polarized n'ahịrị na-enweta ebili mmiri nke nwere polarized gburugburu. N'otu aka ahụ, were ya na antenna nke nwere polarized gburugburu na-anwa ịnweta ebili mmiri nke nwere polarized n'ahịrị. Gịnị bụ ihe na-akpata mfu polarization?
Cheta na polarization gburugburu bụ n'ezie ebili mmiri abụọ nke nwere polarized n'usoro, nke dị ogo 90 site na usoro. Ya mere, antenna nwere polarized n'usoro (LP) ga-enweta naanị akụkụ nkewa ebili gburugburu (CP). Ya mere, antenna LP ga-enwe mfu polarization nke 0.5 (-3dB). Nke a bụ eziokwu n'agbanyeghị akụkụ ọ bụla a na-atụgharị antenna LP. Ya mere:
A na-akpọ ihe na-ebelata polarization loss factor mgbe ụfọdụ dị ka polarization efficiency, antenna mismatch factor, ma ọ bụ antenna reception factor. Aha ndị a niile na-ezo aka n'otu echiche ahụ.
Oge ozi: Disemba-22-2023
