I-Directivity yiparameter ye-antenna esisiseko. Le yindlela yokulinganisa indlela ipateni yemitha ye-antenna ebhekisa kwicala eliyiyo. I-antenna ekhupha ngokulinganayo kuzo zonke iindlela iya kuba ne-directivity elingana no-1. (Oku kufana ne-zero decibels -0 dB).
Umsebenzi wee-spherical coordinates ungabhalwa njengepatheni yemitha eqhelekileyo:
[Isilinganiselo 1]
Ipateni yemitha eqhelekileyo inomfanekiso ofanayo nowepatheni yemitha yokuqala. Ipateni yemitha eqhelekileyo incitshiswa ngobukhulu kangangokuba ixabiso eliphezulu lepatheni yemitha lilingana no-1. (Eyona inkulu yi-equation [1] ka-"F"). Ngokwezibalo, ifomula yesikhokelo (uhlobo "D") ibhalwa ngolu hlobo:
Oku kunokubonakala ngathi yi-equation eyinkimbinkimbi yecala. Nangona kunjalo, iipateni zemitha yeemolekyuli zibaluleke kakhulu. I-denominator imele amandla aqhelekileyo ajikeleziswa kuzo zonke iindlela. I-equation ke ngoko yindlela yokulinganisa amandla aphezulu ajikelezisiweyo ahlulwe ngomyinge. Oku kunika i-antenna directionactivity.
Iparadigm yesikhokelo
Njengomzekelo, cinga ngee-equation ezimbini ezilandelayo zepateni yemitha yee-antenna ezimbini.
I-antenna 1
I-antenna 2
Ezi pateni zemitha zidwetshwe kuMfanekiso 1. Nceda uqaphele ukuba imo yemitha ixhomekeke kuphela kwi-polar angle theta(θ)Ipatheni yemitha ayingomsebenzi we-azimuth. (Ipatheni yemitha ye-azimuthal ayitshintshi). Ipatheni yemitha ye-antenna yokuqala ayibhekiseli ngqo, kunomzekelo wemitha ye-antenna yesibini. Ke ngoko, silindele ukuba i-directivity ibe phantsi kwi-antenna yokuqala.
umfanekiso 1. Umzobo wepateni yokukhanya kwe-antenna. Ngaba ikwicala eliphezulu?
Sisebenzisa ifomyula [1], singabala ukuba i-antenna inesikhokelo esiphezulu. Ukujonga ukuqonda kwakho, cinga ngoMfanekiso 1 kunye nokuba yintoni indlela esiya ngayo. Emva koko misela ukuba yeyiphi i-antenna enesikhokelo esiphezulu ngaphandle kokusebenzisa naziphi na izibalo.
Iziphumo zokubala ngokwemiyalelo, sebenzisa ifomula [1]:
Ubalo lwe-antenna 1 oluya kwicala, 1.273 (1.05 dB).
Ubalo lwe-antenna 2 oluya kwicala, 2.707 (4.32 dB).
Ukwanda kokuqondisa kuthetha i-antenna egxile ngakumbi okanye ebhekisa kwicala. Oku kuthetha ukuba i-antenna efumana ii-2 inamandla okubhekisa kwicala aphindwe kayi-2.707 kune-antenna ebhekisa kwicala ngalinye. I-antenna 1 iya kufumana amandla aphindwe kayi-1.273 kunamandla e-antenna ebhekisa kwicala ngalinye. Ii-antenna ezibhekisa kwicala ngalinye zisetyenziswa njengesalathiso esiqhelekileyo nangona kungekho zi-antenna ze-isotropic ezikhoyo.
Ii-antenna zeselfowuni kufuneka zibe ne-directivity ephantsi kuba imiqondiso inokuvela nakweyiphi na indlela. Ngokwahlukileyo koko, i-satellite dish ine-directivity ephezulu. I-satellite dish ifumana imiqondiso evela kwicala elimiselweyo. Umzekelo, ukuba ufumana i-satellite TV dish, inkampani iya kukuxelela apho umele uyikhombe khona kwaye i-dish iya kufumana i-signal oyifunayo.
Siza kuphetha ngoluhlu lweentlobo zee-antenna kunye nesikhokelo sazo. Oku kuza kukunika umbono wokuba yeyiphi indlela eqhelekileyo yokubhekisa kwicala.
Uhlobo lwe-antenna Ulwalathiso oluqhelekileyo Ulwalathiso oluqhelekileyo [decibel] (dB)
I-antenna emfutshane ye-dipole 1.5 1.76
I-antenna ye-dipole ye-half-wave 1.64 2.15
Ipetshi (i-antenna ye-microstrip) 3.2-6.3 5-8
I-antenna yephondo 10-100 10-20
I-antenna yesitya 10-10,000 10-40
Njengoko idatha engentla ibonisa ukuba ulawulo lwe-antenna luyahluka kakhulu. Ke ngoko, kubalulekile ukuqonda ulawulo xa ukhetha i-antenna efanelekileyo kwisicelo sakho esithile. Ukuba ufuna ukuthumela okanye ukufumana amandla avela kwiindlela ezininzi kwicala elinye, kuya kufuneka uyile i-antenna ene-directivity ephantsi. Imizekelo yezicelo zee-antenna ze-directivity ephantsi ibandakanya iirediyo zemoto, iifowuni, kunye nokufikelela kwi-intanethi engenazingcingo zekhompyutha. Ngokwahlukileyo koko, ukuba wenza i-remote sensing okanye udluliselo lwamandla olujoliswe kuyo, kuya kufuneka i-antenna ejolise kakhulu. Ii-antenna ezijolise kakhulu ziya kwandisa ukudluliselwa kwamandla ukusuka kwicala olifunayo kwaye zinciphise imiqondiso evela kwiindlela ezingafunekiyo.
Masithi sifuna i-antenna ekwaziyo ukulawula izinto kancinci. Sikwenza njani oku?
Umgaqo jikelele wethiyori ye-antenna kukuba udinga i-antenna encinci yombane ukuze uvelise i-directivity ephantsi. Oko kukuthi, ukuba usebenzisa i-antenna enobukhulu obupheleleyo be-0.25 - 0.5 wavelength, uya kuyinciphisa i-directivity. Ii-antenna ze-half-wave dipole okanye ii-antenna ze-half-wavelength slot zihlala zine-directivity engaphantsi kwe-3 dB. Oku kuphantsi njenge-directionality onokuyifumana xa usenza.
Ekugqibeleni, asinakwenza ii-antenna zibe ncinci kunekota yobude be-wavelength ngaphandle kokunciphisa ukusebenza kakuhle kwe-antenna kunye ne-bandwidth ye-antenna. Ukusebenza kakuhle kwe-antenna kunye ne-bandwidth ye-antenna kuya kuxoxwa ngazo kwizahluko ezizayo.
Kwi-antenna ene-directibility ephezulu, siya kufuna ii-antenna ezinobukhulu obahlukeneyo be-wavelength. Ezifana nee-antenna ze-satellite dish kunye nee-antenna ze-horn zine-directibility ephezulu. Oku kungenxa yokuba zinobude obuninzi be-wavelengths.
kutheni kunjalo? Ekugqibeleni, isizathu sinxulumene neempawu zenguquko yeFourier. Xa uthatha inguqu yeFourier ye-short pulse, ufumana i-spectrum ebanzi. Olu faniso alukho ekumiseleni ipateni yemitha ye-antenna. Ipateni yemitha inokucingwa njengotshintsho lweFourier lokusasazwa kombane okanye i-voltage ecaleni kwe-antenna. Ke ngoko, ii-antenna ezincinci zinepateni zemitha ebanzi (kunye ne-directivity ephantsi). Ii-antenna ezine-voltage enkulu efanayo okanye ukusasazwa kombane Iipateni ezikhokelela ngqo kakhulu (kunye ne-directivity ephezulu).
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Ixesha lokuthumela: Novemba-07-2023
