Iyo inobatsira parameter kuverenga simba rekugamuchira re antenna ndiyonzvimbo inoshandakanaburi rinoshanda.Fungidzira kuti mafungu endege ine polarization yakafanana neyekugamuchira antenna inoitika pane antenna.Uyezve fungidzira kuti wave iri kufamba yakananga kune antenna munzira yeantenna yeradio yakawanda (iyo nzira yaizogashirwa simba rakawanda).
Zvadaro theburi rinoshandaparameter inotsanangura kuti ingani simba rinotorwa kubva kune yakapihwa ndege wave.Regaipiva uwandu hwesimba hwemafungu endege (muW/m^2).KanaP_tinomiririra simba (muWatts) pamateminari anowanikwa kune anogamuchira antenna, ipapo:
Nekudaro, iyo nzvimbo inoshanda inongomiririra kuti ingani simba rinotorwa kubva kune ndege wave uye nekuunzwa neantenna.Iyi nharaunda inokonzeresa mukurasikirwa kwemukati kune antenna (ohmic kurasikirwa, kurasikirwa kwedielectric, nezvimwewo).
Hukama hwakajairwa hweiyo antenna inoshanda maererano neiyo peak antenna kuwana (G) yechero antenna inopihwa ne:
Inoshanda aperture kana nzvimbo inoshanda inogona kuyerwa pamaantenna chaiwo nekuenzanisa neantenna inozivikanwa ine yakapihwa inoshanda aperture, kana nekuverenga uchishandisa yakayerwa kuwana uye iyo iri pamusoro equation.
Aperture inoshanda ichava pfungwa inobatsira pakuverenga simba rakagamuchirwa kubva kune ndege wave.Kuti uone izvi zvichiitika, enda kune chikamu chinotevera pane iyo Friis transmission formula.
Iyo Friis Transmission Equation
Papeji rino, tinosuma imwe yeanonyanya kukosha equation mune antenna dzidziso, iyoFriis Transmission Equation.Iyo Friis Transmission Equation inoshandiswa kuverenga simba rakagamuchirwa kubva kune imwe antenna (nekuwanaG1), kana ichifambiswa kubva kune imwe antenna (nekuwanaG2), vakaparadzaniswa nechinhambweR, uye kushanda nenguva yakawandafkana wavelength lambda.Iri peji rakakodzera kuverenga kakati uye rinofanirwa kunzwisiswa zvizere.
Kutorwa kweFriis Transmission Formula
Kuti utange kutorwa kweiyo Friis Equation, funga ma antenna maviri munzvimbo yemahara (hapana zvipingamupinyi padyo) akapatsanurwa nechinhambwe.R:
Fungidzira kuti (）Watts esimba rose anounzwa kune inotapurirana antenna.Parizvino, fungidzira kuti iyo antenna yekufambisa ndeye omnidirectional, haina kurasikirwa, uye kuti iyo inogashira antenna iri kumunda uri kure weanotumira antenna.Zvadaro simba densityp(muWatts per square metre) yechiitiko yendege wave pane inogashira antenna chinhambweRkubva kune transmit antenna inopiwa ne:
Mufananidzo 1. Tumira (Tx) uye Gamuchira (Rx) Antennas akaparadzaniswa neR.
Kana iyo antenna yekufambisa iine antenna kuwana munzira yekugamuchira antenna yakapihwa na ( ） , ipapo simba density equation pamusoro inova:
Iyo yekuwana temu zvinhu mukutungamira uye kurasikirwa kweiyo antenna chaiyo.Fungidzira ikozvino kuti antenna yekugamuchira ine aperture inoshanda yakapihwa na(）.Ipapo simba rinogamuchirwa neiyi antenna ( ) rinopihwa ne:
Sezvo iyo inobudirira aperture yechero antenna inogona zvakare kuratidzwa se:
Simba rakagamuchirwa rinogona kunyorwa se:
Equation1
Izvi zvinozivikanwa seFriis Transmission Formula.Inoenderana nekurasikirwa kwenzvimbo yemahara nzira, antenna inowaniswa uye wavelength kune yakagamuchirwa uye kutumira masimba.Iyi ndiyo imwe yeakakosha equations mune antenna dzidziso, uye inofanirwa kuyeukwa (pamwe nekutorwa kuri pamusoro).
Imwe nzira inobatsira yeFriis Transmission Equation inopiwa muEquation [2].Sezvo wavelength uye frequency f zvine hukama nekumhanya kwechiedza c (ona sumo kune frequency peji), isu tine Friis Transmission Formula maererano ne frequency:
Equation2
Equation [2] inoratidza kuti simba rakawanda rinorasika pama frequency epamusoro.Ichi ndicho mhedzisiro yakakosha yeFriis Transmission Equation.Izvi zvinoreva kuti kune antenna ane akatsanangurwa mabhenefiti, iyo simba rekufambisa ichave yakakwirira pane yakaderera frequency.Musiyano uripo pakati pesimba rinogamuchirwa uye simba rinofambiswa unozivikanwa sekurasikirwa kwenzira.Akataura neimwe nzira, Friis Transmission Equation inotaura kuti kurasikirwa kwenzira kwakakwira kune yakakwira ma frequency.Kukosha kwemhedzisiro iyi kubva kuFriis Transmission Formula haigone kuwedzeredzwa.Ichi ndicho chikonzero nharembozha dzinowanzo shanda pane isingasviki 2 GHz.Panogona kuve neakawanda frequency spectrum inowanikwa kune yakakwirira frequency, asi yakabatana nzira yekurasikirwa haigone kugonesa kugamuchirwa kwemhando.Sezvimwe mhedzisiro yeFriss Transmission Equation, ngatiti iwe wabvunzwa nezve 60 GHz antennas.Uchiona kuti iyi frequency yakakwira zvakanyanya, unogona kutaura kuti kurasikirwa kwenzira kuchave kwakanyanyisa kutaurirana kwenguva refu - uye wakanyatso kurongeka.Pama frequency akanyanya (60 GHz dzimwe nguva inodaidzwa kuti mm (millimeter wave) dunhu), kurasikirwa kwenzira kwakakwira zvakanyanya, saka kutaurirana chete kunogoneka.Izvi zvinoitika kana anogamuchira uye anotumira ari mukamuri imwechete, uye akatarisana.Seimwezve tsinhiro yeFriis Transmission Formula, unofunga here kuti vashandisi venharembozha vari kufara nebhendi idzva reLTE (4G), rinoshanda pa700MHz?Mhinduro ndeyokuti hongu: iyi inguva yakaderera pane antenna inowanzoshanda pairi, asi kubva kuEquation [2], tinoona kuti kurasikirwa kwenzira kuchave kwakaderera zvakare.Nekudaro, ivo vanogona "kuvhara yakawanda pasi" neiyi frequency spectrum, uye Verizon Wireless Executive ichangobva kudana iyi "yemhando yepamusoro spectrum", chaizvo nechikonzero ichi.Padivi Chiziviso: Kune rimwe divi, vagadziri venharembozha vanozofanirwa kukwana antenna ine yakakura wavelength mune compact mudziyo (yakaderera frequency = yakakura wavelength), saka basa remugadziri weantenna rakawedzera kunetsa!
Chekupedzisira, kana ma antenna asina kufananidzwa, iro riri pamusoro rakagamuchirwa simba rinogona kuwanzwa nePolarization Loss Factor (PLF) kuti rizvidavirire pakusawirirana uku.Equation [2] pamusoro inogona kuchinjwa kuti ibudise yakajairika Friis Transmission Formula, iyo inosanganisira polarization mismatch:
Equation3
Nguva yekutumira: Jan-08-2024
