Iparameter eluncedo ebala amandla okufumana i-eriyali yiindawo esebenzayookanyeindawo yokuvula esebenzayo.Cinga ukuba iliza lenqwelomoya elinepolarization efanayo nelokufumana i-eriyali liyenzeka kwi-eriyali.Ngokubhekele phaya cinga ukuba iliza lihamba lisingise kwi-eriyali kwicala le-eriyali yemitha ephezulu (icala apho awona mandla maninzi aya kufunyanwa khona).
Emva koko iindawo yokuvula esebenzayoiparameter ichaza ukuba mangakanani amandla abanjwayo kwindiza enikiweyo.Vumelapyiba yingxinano yamandla yendiza yamaza (kwi-W/m^2).UkubaP_timele amandla (kwiiWatts) kwiitheminali ze-eriyali ezifumanekayo kumamkeli we-eriyali, emva koko:
Ke, indawo esebenzayo imela ngokulula ukuba angakanani amandla athatyathwa kwiza lenqwelomoya kwaye ahanjiswe yi-eriyali.Le ndawo ibangela ilahleko yangaphakathi kwi-antenna (ilahleko ze-ohmic, ilahleko ze-dielectric, njl.).
Unxulumano oluphangaleleyo lwendawo yokuvula esebenzayo ngokumalunga nencopho yenzuzo ye-eriyali (G) yayo nayiphi na i-eriyali inikwa ngu:
Indawo yokuvula esebenzayo okanye indawo esebenzayo inokulinganiswa kwii-eriyali zokwenyani ngokuthelekisa ne-eriyali eyaziwayo enendawo esebenzayo enikiweyo, okanye ngokubala kusetyenziswa inzuzo elinganisiweyo kunye nale nxaki ingentla.
Indawo yokuvula esebenzayo iya kuba yingcamango eluncedo ekubaleni amandla afunyenweyo asuka kumaza endiza.Ukubona oku kusebenza, yiya kwicandelo elilandelayo kwifomula yothumelo lweFris.
iFris Transmission Equation
Kweli phepha, sazisa enye yezona equations zisisiseko kwithiyori ye-eriyali, iFriis Transmission Equation.I-Friis Transmission Equation isetyenziselwa ukubala amandla afunyenwe kwi-eriyali enye (ngenzuzoG1), xa ikhutshwa kwenye i-eriyali (ngenzuzoG2), yahlulwe ngumgamaR, kwaye isebenza rhoqofokanye i-wavelength lambda.Eli phepha lifanelekile ukuba lifundwe izihlandlo ezimbalwa kwaye kufuneka liqondwe ngokupheleleyo.
Ukukhutshwa kweFormula yoThumelo lweFriis
Ukuqala ukuvela kweFris Equation, qwalasela ii-eriyali ezimbini kwindawo ekhululekileyo (akukho zithintelo kufutshane) ezahlulwe ngumgama.R:
Cinga ukuba (() iiWatts zamandla ewonke zihanjiswa kwi-eriyali yothumelo.Okwangoku, cinga ukuba i-eriyali yokuhambisa i-omnidirectional, ayilahleki, kwaye i-eriyali yokufumana ikwindawo ekude yokuhambisa i-eriyali.Emva koko ukuxinana kwamandlap(kwi-Watts ngemitha yesikwere) sesiganeko samaza endiza kwi-eriyali yokufumana umgamaRukusuka kwi-eriyali yokuhambisa inikwa ngu:
Umzobo 1. Dlulisa (Tx) kunye no-Receive (Rx) Ii-Antenna ezihlulwe nguR.
Ukuba i-eriyali yothumelo inenzuzo ye-eriyali kwicala le-eriyali yokufumana enikwe ngu () , ngoko ke i-equation yoxinaniso lwamandla ingentla iba:
Iimeko zexesha lenzuzo kwindlela eya kwicala kunye nelahleko ye-eriyali yokwenyani.Cinga ngoku ukuba i-eriyali yokufumana inendawo yokungena esebenzayo enikwe ngu(().Emva koko amandla afunyenwe yile eriyali ( ) inikwa ngu:
Kuba indawo yokuvula esebenzayo yayo nayiphi na i-eriyali inokubonakaliswa ngolu hlobo:
Amandla afunyenweyo anesiphumo angabhalwa ngolu hlobo:
Inxaki1
Oku kwaziwa ngokuba yiFriis Transmission Formula.Inxulumanisa ilahleko yesithuba esikhululekileyo, iinzuzo ze-eriyali kunye nobude bewavevele kumandla afunyenweyo kunye nokuhambisa.Le yenye yee-equations ezisisiseko kwithiyori ye-eriyali, kwaye kufuneka ikhunjulwe (kunye nokuvela ngasentla).
Olunye uhlobo oluluncedo lwe-Friis Transmission Equation inikwe kwi-Equation [2].Kuba ubude be-waveleng kunye nefrikhwensi f zinxulunyaniswa nesantya sokukhanya c (jonga intshayelelo ukuya kwiphepha lefrikhwensi), sineFormula yoThutho lweFriis malunga nokuphindaphindwa:
Inxaki2
I-equation [2] ibonisa ukuba amandla amaninzi alahlekile kwi-frequencies ephezulu.Esi sisiphumo esisisiseko seFris Transmission Equation.Oku kuthetha ukuba kwii-eriyali ezineenzuzo ezichaziweyo, ukuhanjiswa kwamandla kuya kuba phezulu kumaza asezantsi.Umahluko phakathi kwamandla afunyenweyo kunye namandla agqithisiweyo waziwa njengokulahleka kwendlela.Yatsho ngendlela eyahlukileyo, iFriis Transmission Equation ithi ilahleko yendlela iphezulu kumaza aphezulu.Ukubaluleka kwesi siphumo esivela kwi-Friis Transmission Formula ayinakubaxa.Kungenxa yoko le nto iifowuni eziphathwayo zisebenza ngokubanzi ngaphantsi kwe-2 GHz.Kusenokubakho i-spectrum engakumbi efumanekayo kumaza aphezulu, kodwa ilahleko yendlela enxulumeneyo ayizukwenza ulwamkelo lomgangatho.Njengesiphumo esongezelelweyo seFriss Transmission Equation, masithi ubuzwa malunga nee-eriyali ezingama-60 GHz.Ukuqaphela ukuba le frequency iphezulu kakhulu, ungatsho ukuba ilahleko yendlela iya kuba phezulu kakhulu kunxibelelwano olude-kwaye uchanekile ngokupheleleyo.Kwii-frequencies eziphezulu kakhulu (i-60 GHz ngamanye amaxesha ibizwa ngokuba yi-mm (millimeter wave) ummandla), ukulahleka kwendlela kuphezulu kakhulu, ngoko ke unxibelelwano lwe-point-to-point lunokwenzeka.Oku kwenzeka xa umamkeli kunye nomthumeli bekwigumbi elinye, kwaye bejongene.Njengomnye ulandelelwano lweFriis Transmission Formula, ucinga ukuba abaqhubi beefowuni eziphathwayo bonwabile malunga nebhendi entsha ye-LTE (4G), esebenza kwi-700MHz?Impendulo nguewe: oku kuphindaphindwa okungaphantsi kunee-eriyali ngokwesiko ezisebenza kuyo, kodwa ukusuka kwi-Equation [2], siqaphela ukuba ukulahleka kwendlela kuya kuba sezantsi ngokunjalo.Ke, banokuthi "bagqume umhlaba omninzi" ngolu hlobo lwefrikhwensi, kunye neVerizon Wireless Executive isandula ukubiza le "spectrum ephezulu", kanye ngesi sizathu.Inqaku elisecaleni: Kwelinye icala, abavelisi beeselfowuni kuya kufuneka bafake i-eriyali enobude obukhudlwana kwisixhobo esibambeneyo (i-frequency esezantsi = i-wavelength enkulu), ukuze umsebenzi womyili we-eriyali ube nzima ngakumbi!
Ekugqibeleni, ukuba ii-antenna azihambelani ne-polarization, amandla afunyenwe ngasentla angaphinda aphindwe nge-Polarization Loss Factor (PLF) ukuze aphendule ngokufanelekileyo oku kungafani.Inxaki [2] apha ngasentla ingatshintshwa ukuze ivelise iFormula yoThutho lweFriis ngokubanzi, equka ukungahambelani kwepolarization:
Inxaki3
Ixesha lokuposa: Jan-08-2024
