Ipharamitha ewusizo ebala amandla okwamukela othi yiindawo ephumelelayonomaukuvuleka okusebenzayo. Cabanga ukuthi igagasi lendiza eline-polarization efana ne-antenna eyamukelwe liyenzeka othini. Futhi cabanga ukuthi igagasi lihamba libheke othini ophikweni lwe-antenna lwemisebe ephezulu (indlela okuzotholwa kuyo amandla amaningi).

Bese kuthi iukuvuleka okusebenzayoipharamitha ichaza ukuthi mangakanani amandla athathwe kugagasi lendiza elinikeziwe. Vumelapkube ukuminyana kwamandla wegagasi lendiza (ku-W/m^2). UmaP_timele amandla (ku-Watts) kumatheminali ezinti atholakalayo kumamukeli wothi, bese:

Ngakho-ke, indawo esebenzayo imane imele ukuthi mangakanani amandla athathwe kugagasi lendiza futhi alethwe uthi. Le ndawo ifaka phakathi ukulahlekelwa okungaphakathi kwe-antenna (ukulahlekelwa kwe-ohmic, ukulahlekelwa kwe-dielectric, njll.).

Ubudlelwano obujwayelekile bokuvula okusebenzayo ngokuya ngenzuzo ephezulu ye-antenna (G) yanoma yiluphi uthi bunikezwa ngu:

Indawo evulekayo noma indawo esebenzayo ingalinganiswa kuzimpondo zangempela ngokuqhathanisa nothi oluyaziwayo olunembobo esebenzayo enikeziwe, noma ngokubala kusetshenziswa inzuzo elinganiselwe kanye nesibalo esingenhla.

Ukuvula okusebenzayo kuzoba umqondo owusizo wokubala amandla atholiwe avela kugagasi lendiza. Ukuze ubone lokhu kusebenza, hamba esigabeni esilandelayo sefomula yokudlulisa iFris.

I-Fris Transmission Equation

Kuleli khasi, sethula enye yezibalo eziyisisekelo kuthiyori ye-antenna, iI-Fris Transmission Equation. I-Friis Transmission Equation isetshenziselwa ukubala amandla atholwe ku-antenna eyodwa (ngenzuzoG1), uma idluliswa isuka kolunye uthi (ngenzuzoG2), ihlukaniswe ibanganaR, futhi isebenza njalofnoma i-wavelength lambda. Leli khasi lifanele ukufunda izikhathi ezimbalwa futhi kufanele liqondwe ngokugcwele.

Ukutholwa kwe-Friis Transmission Formula

Ukuze uqale ukutholwa kwe-Friis Equation, cabangela izimpondo ezimbili esikhaleni esikhululekile (azikho izithiyo eduze) ezihlukaniswe ibanga.R:

Cabanga ukuthi (）Ama-Watts aphelele alethwa othini lokudlulisela. Okwamanje, cabanga ukuthi i-antenna yokudlulisa i-omnidirectional, ayilahleki, nokuthi uthi olutholayo lusesigabeni esikude se-antenna yokudlulisa. Bese kuba ukuminyana amandlap(ngama-Watts ngemitha-skwele ngayinye) wesigameko segagasi lendiza ku-antenna ebangeniRkusuka ku-antenna yokudlulisa inikezwa ngu:

Umfanekiso 1. Dlulisa (Tx) kanye no-Receive (Rx) Izimpondo ezihlukanisweR.

Uma i-antenna yokudlulisa inenzuzo ye-antenna ibheke othini lokwamukela olunikezwe ngu () , khona-ke isibalo sokuminyana kwamandla ngenhla siba:

Izinto zetemu lenzuzo ekuqondeni nasekulahlekelweni kwe-antenna yangempela. Cabanga manje ukuthi i-antenna eyamukelayo inembobo esebenzayo enikezwe ngu(）. Khona-ke amandla atholwe yile antenna ( ) anikezwa ngu:

Njengoba ukuvuleka okusebenzayo kwanoma iyiphi i-antenna kungabuye ivezwe ngokuthi:

Amandla atholiwe angumphumela angabhalwa kanje:

Izibalo1

Lokhu kwaziwa ngokuthi yiFriis Transmission Formula. Ihlobene nokulahleka kwendlela yamahhala yesikhala, izinzuzo ze-antenna kanye nobude begagasi namandla atholiwe kanye nokudlulisa. Lokhu kungenye yezibalo eziyisisekelo kuthiyori ye-antenna, futhi kufanele kukhunjulwe (kanye nokutholwa okungenhla).

Olunye uhlobo oluwusizo lwe-Friis Transmission Equation lunikezwe ku-Equation [2]. Njengoba ubude begagasi kanye nemvamisa f kuhlobene nesivinini sokukhanya c (bona isingeniso ekhasini lefrikhwensi), sineFormula Yokudluliswa kweFris ngokuya ngemvamisa:

Izibalo2

Isibalo [2] sibonisa ukuthi amandla amaningi alahleka kumafrikhwensi aphezulu. Lona umphumela obalulekile we-Friis Transmission Equation. Lokhu kusho ukuthi kuma-antenna anezinzuzo ezithile, ukudluliswa kwamandla kuzoba okuphezulu kakhulu kumaza aphansi. Umehluko phakathi kwamandla atholiwe namandla adlulisiwe waziwa njengokulahleka kwendlela. Isho ngendlela ehlukile, i-Friis Transmission Equation ithi ukulahleka kwendlela kuphezulu kumafrikhwensi aphezulu. Ukubaluleka kwalo mphumela ovela ku-Friis Transmission Formula ngeke kugcizelelwe. Yingakho omakhalekhukhwini ngokuvamile besebenza ngaphansi kuka-2 GHz. Kungase kube khona i-spectrum eyengeziwe etholakala kumafrikhwensi aphezulu, kodwa ukulahlekelwa kwendlela ehambisanayo ngeke kuvumele ukwamukela ikhwalithi. Njengomphumela owengeziwe we-Friss Transmission Equation, ake sithi ubuzwa ngama-antenna angu-60 GHz. Ngokuqaphela ukuthi le mvamisa iphezulu kakhulu, ungase usho ukuthi ukulahleka kwendlela kuzoba kukhulu kakhulu ekuxhumaneni kwebanga elide - futhi uqinisile. Kumafrikhwensi aphezulu kakhulu (i-60 GHz kwesinye isikhathi ibizwa ngokuthi isifunda se-mm (millimeter wave), ukulahleka kwendlela kuphezulu kakhulu, ngakho-ke ukuxhumana kwephoyinti kuya kwephuzu kuphela kungenzeka. Lokhu kwenzeka lapho umamukeli nesidlulisi besegumbini elilodwa, futhi bebhekene. Njengokunye okuhambisana ne-Friis Transmission Formula, ingabe ucabanga ukuthi opharetha bomakhalekhukhwini bajabule ngebhendi entsha ye-LTE (4G), esebenza ku-700MHz? Impendulo ithi yebo: lena imvamisa ephansi kunezimpondo ezisebenza kuso ngokwesiko, kodwa ukusuka ku-Equation [2], siphawula ukuthi ukulahleka kwendlela kuzoba phansi nakho. Ngakho-ke, bangakwazi "ukumboza umhlabathi owengeziwe" ngalesi sibonisi se-frequency, futhi isikhulu se-Verizon Wireless muva nje sibize lesi "spectrum sekhwalithi ephezulu", ngenxa yalesi sizathu. Inothi Eliseceleni: Ngakolunye uhlangothi, abakhi bamaselula kuzofanela bafake i-antenna enobude beza obukhudlwana edivayisini ehlangene (imvamisa ephansi = ubude begagasi obukhulu), ukuze umsebenzi womklami wezinti ube nzima nakakhulu!

Okokugcina, uma ama-antenna engafaniswa ne-polarization, amandla atholiwe angenhla angaphindaphindwa nge-Polarization Loss Factor (PLF) ukuze aphendule ngokufanelekile ngalokhu kungafani. I-equation [2] ngenhla ingashintshwa ukuze kukhiqizwe Ifomula Yokudluliswa Kwe-Friis ejwayelekile, ehlanganisa ukungafani kwe-polarization: