Iindaba - I-Helical Antenna: Ukhetho Olufanelekileyo lwe-Broadband Circular Polarization

AI-Antenna ejikelezayongumzekelo oqhelekileyo we-antenna yocingo, ebonakaliswa yisakhiwo sayo esimile okwe-spiral. Yi-antenna ye-broadband efanelekileyo kwiibhendi ze-VHF kunye ne-UHF.

I-antenna ejikelezayo isebenza kuluhlu lweefrikhwensi olumalunga ne-30 MHz ukuya kwi-3 GHz, ikakhulu igubungela iibhendi ze-VHF kunye ne-UHF.

Imigaqo Yokwakha Nokusebenza Ye-Spiral Antenna

I-Spiral Antenna yenziwa ngokubhijela i-conductor kwimo ye-spiral kwaye iyidibanise nomhlaba nge-feedline. Ngesakhiwo esilula, ngokwemvelo ivelisa amaza ajikelezileyo ajikelezayo kwaye isetyenziswa kakhulu kunxibelelwano lwangaphandle komhlaba olufana neenkqubo ze-satellite relay.

Umfanekiso ongasentla ubonisa inkqubo ye-Spiral Antenna esetyenziselwa unxibelelwano lwesathelayithi. Ezi antenna zihlala zifuna indawo enkulu yokufakela ngaphandle.

I-Spiral Antenna yenziwe yi-coil yocingo lobhedu oluqinileyo okanye ityhubhu eyenziwe yaba yi-helix, esebenza kunye neplani yomhlaba yesinyithi esithe tyaba. Isiphelo esinye se-helix siqhagamshelwe kwi-coaxial cable esembindini, ngelixa i-coaxial yangaphandle iqhagamshelwe kwiplani yomhlaba.

Umfanekiso ongentla ubonisa ulwakhiwo lwe-Spiral Antenna, kunye nombono oneenkcukacha zezinto ezikuyo.

Iimpawu zemitha ye-Spiral Antenna zimiselwa ikakhulu bububanzi be-helix, isithuba esiphakathi kokujika (iphitshi), kunye ne-angle yephitshi.

I-angle yepitch ichazwa njenge-angle ephakathi kwe-tangent kwi-helix kunye ne-plane eqhelekileyo kwi-axis ye-helix, kwaye inikwe ngu:

Apho:

•U-D bububanzi be-helix

•S yipitch (isithuba esiphakathi ukuya embindini phakathi kokujika okukufutshane)

•α yi-engile yepitch

Indlela Yokusebenza

Ii-Antennas ezijikelezayo zisebenza ngeendlela ezimbini eziphambili:

•Imo Eqhelekileyo (ekwaziwa ngokuba yimo yemitha ethe nkqo)

•Imo ye-Axial (ekwaziwa ngokuba yimo yokuphela komlilo okanye imo yokukhanya kwemitha)

Imo nganye ichazwe ngokweenkcukacha ngezantsi.

Kwimo yeradiyo eqhelekileyo, intsimi erhabaxa imile okwe-axis ye-helix, kwaye igagasi elirhabaxa lijikeleziswa nge-polarized. Le mo ifumaneka xa ubukhulu be-helix buncinci xa kuthelekiswa nobude be-wavelength. Kule meko, iimpawu zeradiyo ze-antenna ye-helical zinokuthathwa njengomxube we-antenna emfutshane ye-dipole kunye ne-antenna ye-loop.

Umfanekiso ongentla ubonisa ipatheni yokukhanya kwe-Spiral Antenna esebenza kwimo eqhelekileyo.

Le ndlela imiselwa bububanzi be-helix D kunye nesithuba esiphakathi kokujika kwe-S. Iingxaki zale ndlela yokusebenza ziquka ukusebenza kakuhle kwemitha ephantsi kunye ne-bandwidth encinci; ngoko ke, ayisetyenziswa rhoqo kwiindlela ezisebenzayo.

Imo ye-Axial

Kwimo yemitha ye-axial, intsimi efumana imisebe ibonisa iimpawu zokuphela komlilo ecaleni kwe-helix axis, kwaye igagasi elifumana imisebe lijikeleza okanye liphantse libe yi-polarized. Le mo ifumaneka xa umjikelezo we-helix unyuswa ukuya kumyalelo we-wavelength enye (λ) kwaye isithuba phakathi kokujika simalunga ne-λ/4. Phantsi kwezi meko, ipateni yemitha ibanzi ecaleni kwe-axis eneempawu zecala, kwaye ii-lobes ezisecaleni zivela kwii-engile ezichasene ne-axis.

Umfanekiso ongentla ubonisa ipatheni yemitha ye-Spiral Antenna esebenza kwimo ye-axial.

Xa i-antenna yenzelwe amaza ajikelezileyo ajikelezileyo (RHCP) ngasekunene, ayizukufumana amaza ajikelezileyo ajikelezileyo (LHCP) ngasekhohlo, kwaye ngokuchaseneyo. Le ndlela yokusebenza kulula ukuyisebenzisa kwaye isetyenziswa kakhulu kwizicelo ezisebenzayo.

Iingenelo eziphambili ze-Spiral Antenna zezi zilandelayo:

• Isakhiwo esilula kwaye kulula ukuyila

•Isikhokelo esiphezulu

•I-bandwidth ebanzi

•Iyakwazi ukupolarization ejikelezayo

•Ifanelekile kwiibhendi ze-HF kunye ne-VHF

Izicelo eziphambili ze-Spiral Antenna zezi zilandelayo:

•Ii-antenna ezijikelezileyo okanye ii-array zazo zisetyenziselwa ukuhanjiswa kunye nokwamkelwa kwesignali ye-VHF

•Isetyenziswa kakhulu kwiinkqubo zonxibelelwano zesathelayithi kunye ne-deep-space probe

•Isetyenziswa kwiikhonkco ze-telemetry phakathi kwee-missile ze-ballistic, ii-satellites, kunye nezikhululo zomhlaba

•Isetyenziselwa ukuseka unxibelelwano phakathi kweNyanga noMhlaba

•Ikwadlala indima ebalulekileyo kwizicelo ze-radio astronomy