Ipharamitha eluncedo ebala amandla okwamkela e-antenna yiindawo esebenzayookanyeukuvuleka okusebenzayoMasithi igagasi lendiza eline-polarisation efanayo ne-antenna efumanayo liyenzeka kwi-antenna. Kwakhona cinga ukuba igagasi liya kwi-antenna kwicala le-antenna apho i-radiation ephezulu (icala apho amandla amaninzi aya kufunyanwa khona).

Emva kokoukuvuleka okusebenzayoipharamitha ichaza ukuba angakanani amandla abanjwa kwi-plane wave ethile.pyi-power density ye-plane wave (kwi-W/m^2). UkubaP_timele amandla (kwiiWatts) kwiiterminal ze-antenna ezifumanekayo kwi-receiver ye-antenna, emva koko:

Ngoko ke, indawo esebenzayo imele nje ukuba ingakanani amandla abanjwa kwi-plane wave aze ahanjiswe yi-antenna. Le ndawo ibangela ilahleko ezingaphakathi kwi-antenna (ilahleko ze-ohmic, ilahleko ze-dielectric, njl.njl.).

Ulwalamano oluqhelekileyo lwe-aperture esebenzayo ngokwe-peak antenna gain (G) yayo nayiphi na i-antenna lunikwa ngu:

Indawo esebenzayo yokuvula okanye indawo esebenzayo inokulinganiswa kwii-antenna zokwenyani ngokuthelekisa ne-antenna eyaziwayo enokuvula okusebenzayo, okanye ngokubala kusetyenziswa i-gain elinganisiweyo kunye ne-equation engentla.

Ukuvula okusebenzayo kuya kuba yingcamango eluncedo yokubala amandla afunyenweyo avela kwi-plane wave. Ukuze ubone oku kusebenza, yiya kwicandelo elilandelayo kwifomula yokudluliselwa kweFriis.

I-Fris Transmission Equation

Kweli phepha, sizazisa enye yezona zibalo zibalulekileyo kwithiyori ye-antenna,I-Friis Transmission EquationI-Friis Transmission Equation isetyenziselwa ukubala amandla afunyenwe kwi-antenna enye (ngokufumana amandlaG1), xa idluliselwa kwenye i-antenna (nge-gainG2), yahlulwe ngumgamaR, kwaye isebenza rhoqofokanye ubude bexesha i-lambda. Eli phepha lifanelekile ukufundwa izihlandlo ezimbalwa kwaye kufuneka liqondwe ngokupheleleyo.

Ukukhutshwa kweFormula yoThumelo lweFriis

Ukuqala ukufumana i-Friis Equation, cinga ngee-antenna ezimbini ezikwindawo ekhululekileyo (akukho zithintelo zikufutshane) ezahlulwe ngumgama.R:

Masithi iiWatts zamandla apheleleyo zithunyelwa kwi-antenna yokudlulisa. Okwangoku, cinga ukuba i-antenna yokudlulisa ayijikelezi, ayinalahleko, kwaye i-antenna yokwamkela ikwindawo ekude ye-antenna yokudlulisa. Emva koko uxinano lwamandlap(ngeeWatts ngemitha yesikwere) yesiganeko segagasi lendiza kwi-antenna yokufumana umgamaRI-antenna yokudlulisa inikwe ngu:

Umfanekiso 1. Ii-Antennas zokudlulisa (Tx) kunye ne-Receive (Rx) ezahlulwe yiR.

Ukuba i-antenna yokudlulisa ifumana i-antenna kwicala le-antenna efumanayo enikwe yi（）, ngoko ke i-equation yoxinano lwamandla engentla iba:

I-gain term ibangela ukuba i-antenna yokwenyani ibe kwicala eliya kulo kunye nokulahleka kwayo. Masithi ngoku i-antenna yokwamkela inomngxuma osebenzayo onikwe yi()Emva koko amandla afunyenwe yile antenna ( ) anikwa ngu:

Ekubeni i-aperture esebenzayo kuyo nayiphi na i-antenna inokubonakaliswa ngolu hlobo:

Amandla afunyenweyo angabhalwa ngolu hlobo:

Isilinganiselo1

Oku kwaziwa ngokuba yiFriis Transmission Formula. Inxulumanisa ukulahleka kwendlela yesithuba esikhululekileyo, ukuzuza kwe-antenna kunye nobude be-wavelength namandla afunyenweyo nadluliselwayo. Le yenye yezibalo ezisisiseko kwithiyori ye-antenna, kwaye kufuneka ikhunjulwe (kunye nesiphumo esingentla).

Olunye uhlobo oluluncedo lweFriis Transmission Equation lunikwe kwi-Equation [2]. Ekubeni ubude be-wavelength kunye ne-frequency f zihambelana nesantya sokukhanya c (jonga intshayelelo kwiphepha le-frequency), sineFriis Transmission Formula ngokwe-frequency:

Isilinganiselo2

I-Equation [2] ibonisa ukuba amandla amaninzi alahleka kwiifrequencies eziphezulu. Esi sisiphumo esisisiseko seFriis Transmission Equation. Oku kuthetha ukuba kwii-antenna ezineenzuzo ezithile, ukudluliselwa kwamandla kuya kuba phezulu kwiifrequencies ezisezantsi. Umahluko phakathi kwamandla afunyenweyo kunye namandla adluliselweyo waziwa ngokuba yi-path loss. Kuthiwa ngendlela eyahlukileyo, iFriis Transmission Equation ithi ilahleko yendlela iphezulu kwiifrequencies eziphezulu. Ukubaluleka kwesi siphumo esivela kwiFriis Transmission Formula akunakugxininiswa kakhulu. Yingakho iifowuni eziphathwayo zihlala zisebenza ngaphantsi kwe-2 GHz. Kunokubakho i-frequency spectrum engaphezulu ekhoyo kwiifrequencies eziphezulu, kodwa ilahleko yendlela ehambelana nayo ayiyi kuvumela ukwamkelwa komgangatho. Njengesiphumo esongezelelweyo seFriss Transmission Equation, masithi ubuzwa malunga nee-antenna ze-60 GHz. Uqaphela ukuba le frequency iphezulu kakhulu, ungatsho ukuba ilahleko yendlela iya kuba phezulu kakhulu kunxibelelwano olude - kwaye uchanekile ngokupheleleyo. Kwiifrequencies eziphezulu kakhulu (i-60 GHz ngamanye amaxesha ibizwa ngokuba yi-mm (millimeter wave region) region), ilahleko yendlela iphezulu kakhulu, ngoko ke kuphela unxibelelwano lwe-point-to-point olunokwenzeka. Oku kwenzeka xa umamkeli kunye nomthumeli bekwigumbi elinye, kwaye bejongene. Njengomnye umzekelo weFriis Transmission Formula, ngaba ucinga ukuba abaqhubi beefowuni eziphathwayo bayavuya ngebhendi entsha ye-LTE (4G), esebenza kwi-700MHz? Impendulo ngu-ewe: le yi-frequency ephantsi kunee-antennas ezisebenza kuzo ngokwesiko, kodwa kwi-Equation [2], siphawula ukuba ukulahleka kwendlela kuya kuba phantsi. Ngenxa yoko, banoku "gubungela umhlaba omninzi" ngale frequency spectrum, kwaye umphathi weVerizon Wireless kutshanje ubize le "spectrum esemgangathweni ophezulu", ngenxa yesi sizathu. Inqaku Elisecaleni: Kwelinye icala, abenzi beefowuni eziphathwayo kuya kufuneka bafake i-antenna enobude obukhulu kwisixhobo esincinci (ubude obuphantsi = ubude obukhulu), ngoko ke umsebenzi womyili we-antenna waba nzima ngakumbi!

Okokugqibela, ukuba ii-antenna azifaniswanga ne-polarization, amandla afunyenweyo angentla anokuphindwa-phindwa yi-Polarization Loss Factor (PLF) ukuze kujongwe ngokufanelekileyo oku kungafani. I-Equation [2] engentla inokutshintshwa ukuvelisa i-generalized Friis Transmission Formula, equka ukungafani kwe-polarization: