umfanekiso 1
1. Ukusebenza kakuhle kwemitha
Enye ipharamitha eqhelekileyo yokuvavanya umgangatho wee-antenna zokudlulisa nezokwamkela kukusebenza kakuhle kwemitha. Kwi-antenna ene-lobe ephambili kwicala le-z-axis njengoko kubonisiwe kuMfanekiso 1, ukusebenza kakuhle kwemitha (BE) kuchazwa ngolu hlobo:
Lumlinganiselo wamandla adluliselweyo okanye afunyenweyo ngaphakathi kwe-engile yekhowuni θ1 kumandla apheleleyo adluliselweyo okanye afunyenwe yi-antenna. Le fomyula ingasentla ingabhalwa ngolu hlobo:
Ukuba i-engile apho inqaku lokuqala le-zero okanye ixabiso elincinci livela khona likhethwe njenge-θ1, ukusebenza kakuhle kwe-beam kubonisa umlinganiselo wamandla kwi-main lobe kumandla apheleleyo. Kwizicelo ezifana ne-metrology, i-astronomy, kunye ne-radar, i-antenna kufuneka ibe nokusebenza kakuhle kwe-beam okuphezulu kakhulu. Ngokwesiqhelo kufuneka ngaphezulu kwe-90%, kwaye amandla afunyenwe yi-side lobe kufuneka abe mancinci kangangoko.
2. Ibhendiwidth
I-bandwidth ye-antenna ichazwa "njengoluhlu lwefrikhwensi apho ukusebenza kweempawu ezithile ze-antenna kuhlangabezana nemigangatho ethile". I-bandwidth ingathathwa njengoluhlu lwefrikhwensi kumacala omabini efrikhwensi esembindini (ngokubanzi ibhekisa kwifrikhwensi ye-resonant) apho iimpawu ze-antenna (ezifana ne-input impedance, i-directional pattern, i-beamwidth, i-polarization, i-sidelobe level, i-gain, i-beam pointing, i-radiation efficiency) zingaphakathi koluhlu olwamkelekileyo emva kokuthelekisa ixabiso lefrikhwensi esembindini.
． Kwii-antenna ze-broadband, i-bandwidth idla ngokubonakaliswa njengomlinganiselo weefrikhwensi eziphezulu nezisezantsi zokusebenza okwamkelekileyo. Umzekelo, i-bandwidth ye-10:1 ithetha ukuba ifrikhwensi ephezulu iphindwe kalishumi kunefrikhwensi esezantsi.
． Kwii-antennas ze-narrowband, i-bandwidth ichazwa njengepesenti yomahluko we-frequency kwixabiso le-center. Umzekelo, i-bandwidth ye-5% ithetha ukuba uluhlu lwe-frequency olwamkelekileyo yi-5% ye-center frequency.
Ngenxa yokuba iimpawu ze-antenna (i-input impedance, i-directional pattern, i-gain, i-polarization, njl.njl.) ziyahluka ngokwexesha, iimpawu ze-bandwidth azifani. Ngokwesiqhelo utshintsho kwi-directional pattern kunye ne-input impedance zahlukile. Ke ngoko, i-directional pattern bandwidth kunye ne-impedance bandwidth ziyafuneka ukugxininisa lo mahluko. I-directional pattern bandwidth inxulumene ne-gain, i-sidelobe level, i-beadwidth, i-polarization kunye ne-beam direction, ngelixa i-input impedance kunye nokusebenza kakuhle kwe-radiation zinxulumene ne-impedance bandwidth. I-bandwidth idla ngokuchazwa ngokwe-beadwidth, amanqanaba e-sidelobe, kunye neempawu ze-pattern.
Le ngxoxo ingentla icinga ukuba ubukhulu benethiwekhi yokudibanisa (i-transformer, i-counterpoise, njl.njl.) kunye/okanye i-antenna ayitshintshi nangayiphi na indlela njengoko i-frequency itshintsha. Ukuba ubukhulu obubalulekileyo be-antenna kunye/okanye inethiwekhi yokudibanisa inokulungiswa ngokufanelekileyo njengoko i-frequency itshintsha, i-bandwidth ye-antenna ye-narrowband inokwandiswa. Nangona oku kungengomsebenzi ulula ngokubanzi, kukho izicelo apho kunokwenzeka khona. Umzekelo oqhelekileyo yi-antenna yerediyo kwirediyo yemoto, edla ngokuba nobude obuhlengahlengiswayo obunokusetyenziswa ukulungisa i-antenna ukuze yamkelwe ngcono.
Ukuze ufunde okungakumbi ngee-antenna, nceda undwendwele:
Ixesha lokuthumela: Julayi-12-2024
