
apperchar (aantina)

vaidyuthakaanthikathilum aantina sidhaanthathilum, oru aantinayude appercharine nirvachichirikkunnathu "aantinaykku sameepamo allengil athil nirmmikkaan soukaryapradamaaya oru uparithalamaan" ennaanu.
baahya pooyintukalile feeldukal anakkukoottunnathinulla feeld moolyangalekkurichulla anumanangal. vikiranathinte pradhana bhagam kadannupokunna paramavadhi vikiranathinte dishayilekku lambamaayi aantinaykku sameepamulla oru samathala uparithalathinte bhagamaayaanu apperchar palappozhum edukkunnathu."
phalapradamaaya pradesham.
oru aantinayude phalapradamaaya vistheernnam nirvachichirikkunnathu "oru nischitha dishayil, oru sweekarikkunna aantinayude terminalukalil labhyamaya powerinte anupatham aaa dishayil ninnulla aantinayile oru playin taranga sambhavathinte power fluxes saandrata, tharamgam dhruveekaranam aantinayumaayi poruthappedunnu."eee nirvachanathil prathyeka shradhikkendathu, phalapradamaaya eriyayum power fluxes densityum oru playin tharamgatthinte insident aamgilinte pravarthanangalaanu ennathaanu. oru prathyeka dishayil ninnulla oru playin tharamgam, athaayath asimat, elevation angle ennivaykku oru "power fluxes density" formula 2 undennu karuthuka; ithu oru chathurashra meettarinte playin tharamgatthinte dishayilekku saadhaarana yoonit eriyayiloode kadannupokunna pavarinte alavaanu.
nirvachanam anusarichu, oru aantina athinte outtputtu terminalukalumaayi bandhippichirikkunna transmission linelake formula 3 whats vitharanam cheiyukayaanenkil, power density formulayude ekeekritha feeld prathi chathurashra meterinu 4 whats vazhi vikiranam cheyyumbol, aaa playin tharamgatthinte dishayilekkulla aantinayude phalapradamaaya eriya formula 5 nalkunnu
aantina amgeekaricha power formula _ 3 (aantina terminalukalile power) aantinayude radiation karyakshamatha formula _ 9 oru aantinaykku labhikkuna power formula _ 8 nekkaal kuravaanu. formula _ 8 ennathu vaidyuthakaanthika oorjja formula _ 11-nte oorjja saandrathaykku thulyamaanu, ivide formula _ 12 ennathu array apperturinu normal yoonit vektaraanu, physical apperchar eriya formula _ 13 kondu gunikkunnu. incoming vikiranathinu aantinayude athe dhruveekaranamundenn anumaanikkappedunnu. athinaal,
oppam
oru aantinayudeyo apperturinteyo phalapradamaaya pradesham oru "sweekarikkunna" aantinaye adisthaanamaakkiyullathaanu. ennirunnaalum, parasparabandham kaaranam, sweekarikkunnathilum kaimaarunnathilum oru aantinayude dayaraktivitti samaanamaan, athinaal vyathyastha dishakalilekku (radiation paatten) oru aantina kaimaattam cheiyunna shakthiyum phalapradamaaya eriya formula _ 16 nuu aanupaathikamaanu. oru dishayum vyakthamaakkaathappol, formula _ 16 athinte paramavadhi moolyathe soochippikkunnuvennu manassilakkunnu.
phalapradamaaya neelam.
mikka aantina designukalum oru bhauthika mekhalayaal nirvachikkappedunnilla, pakshe vayarukaloo nerttha vadikaloo adangiyirikkunnu; appol phalapradamaaya apperturinu aantinayude valuppavumaayo vistheernnavumaayo vyakthamaaya bandhamilla. atharam aantinakalude bhauthika neelavumaayi kooduthal bandhamullah aantina prathikaranatthinte oru ithara alavu phalapradamaaya neelam formulayanu meettaril alakkunnathu, ithu sweekarikkunna aantinaye ingane nirvachikkunnu
evide
phalapradamaaya neelam ethratholam neelamulluvo, athinte terminalukalil volteju kooduthalaayi drishyamaakum. ennirunnaalum, aaa volteju soochippikkunna yadhaartha shakti aantinayude pheed pooyint impedencine aasrayichirikkunnu, athinaal ithu aantina nettavumaayi nerittu bandhappedutthaan kazhiyilla, ithu "labhicha shakthiyude alavaanu (ennaal voltejo vaidyuthadhaarayo nerittu vyakthamakkunnilla). udaaharanathinu, oru haff-wave dvidhruvathinu oru cheria dvidhruvathekkaal valare dairkhyameriya phalapradamaaya neelamundu. ennirunnaalum, hraswa dvidhruvathinte phalapradamaaya vistheernnam haff-wave aantinaykku thulyamaanu, kaaranam (anuyojyamaaya), anuyojyamaaya impedence-matching network nalkiyaal, aaa tharamgathil ninnu eathaandu athra vaidyuthi sweekarikkaan kazhiyum. thannirikkunna aantina pheed pooyint impedensinu, oru aantinayude geyin allengil formula _ 22 formula _ 18-nte "square" anusarichu vardhikkunnu, angane vyathyastha taranga dishakalumaayi thaarathamyappeduthumbol oru aantinayude phalapradamaaya neelam aaa dishakalile geyininte "square root" pinthudarunnu. ennaal oru aantinayude bhauthika valuppam maattunnath anivaryamaayum impedencine mattunnathinaal (palappozhum oru valia ghadakam), phalapradamaaya neelam oru aantinayude ettavum uyarnna dayaraktivitti vivarikkunnathin upayogapradamaaya oru yogyathayalla, mathramalla saidhaanthika praadhaanyavum kooduthalaanu.
apperchar karyakshamatha.
pothuve, oru aantinayude apperchar athinte bhauthika valuppathil ninnu nerittu oohikkaan kazhiyilla. ennirunnaalum, parabolic vibhavangal, hoonn aantinakal thudangiya "apperchar aantinakal" ennu vilikkappedunnavaykku, atharam vikiranathinu atharyamaaya oru valia (tharamgadairkhyavumaayi thaarathamyappeduthumbol) physical eriya formula _ 24 undu, ithu pradhaanamaayum oru playin tharamgathil ninnu oru nizhal idukayum angane yadhaartha beam ninnu oru power formula _ 25 neekkam cheyyukayum cheiyunnu. prathala tharamgathil ninnu neekkam cheytha aaa oorjjam yadhaarthathil aantinaykku (vaidyuthashakthiyaayi parivartthanam cheytha) sweekarikkaam, prathifalippikkukayo chitharikkidakkukayo agiranam cheiyukayo (thaapamaayi parivartthanam cheytha) cheyyaam. eee saahacharyathil "phalapradamaaya apperchar" formula _ 16 ellaayppozhum aantinayude physical apperchar formula _ 24-nte vistheernnathekkaal kuravo (allengil thulyamo) kuravo aayirikkum, kaaranam athu yadhaarthathil vaidyuthashakthiyaayi labhicha aaa tharamgatthinte bhagam maathramaan. oru apperchar aantinayude "apperchar karyakshamatha" formula _ 28 eee rund mekhalakaludeyum anupaathamaayi nirvachikkappedunnu
0 num 1 num edayilulla alavillaatha oru paaraameteraanu aperture karyakshamatha, athu bhauthika apparcharine murichukadakkunna ellah radio tharamgashakthiyum upayogichu aantina ethratholam aduthuvarunnuvennu alakkunnu. apperchar karyakshamatha 100% aayirunnengil, athinte bhauthika appercharil veezhunna ellah tharamgatthinteyum shakthiyum athinte outtputtu terminalukalil gadippichirikkunna lodilekku vitharanam cheiyunna vaidyuthashakthiyaayi parivartthanam cheyyappedum, athinaal eee rund mekhalakalum thulyamayirikkum formula _ 30. ennaal oru parabolic dishinte pheed vazhi ekeekrithamallaatha prakasham, athupole mattu chitharal allengil nashtam samvidaanangal kaaranam, ithu praayogikamaayi kaivarikkanavilla. oru parabolic aantinayude vilayum kaattinte bharavum "physical" apperchar valuppathinanusarichu vardhikkunnathinaal, apperchar karyakshamatha paramavadhi vardhippikkunnathiloode iva kuraykkunnathinu (oru nirddishta aantina nettam kaivarikkunna samayat) sakthamaaya prachodanam undakam. saadhaarana apperchar aantinakalude apperchar karyakshamatha 0.35 muthal 0.70 vare vyathyaasappedunnu.
oraal oru aantinayude "karyakshamatha" yekkurichu samsaarikkumbol, mikkappozhum ardhamaakkunnathu "radiation karyakshamatha" aanu, ithu ellah aantinakalkkum (apperchar aantinakal mathramalla) baadhakamaaya oru alavukolaanu, koodaathe nashtam moolamulla nettatthil kuravundaakunnathinu maathram kaaranamaakunnu. apperchar aantinakalkk purathu, mikka aantinakalilum nerttha vayarukaloo vadikaloo adangiyirikkunnu, oru cheria physical cross-sekshanal eriya (saadhaaranayaayi formula _ 5 nekkaal valare cheruth), athinaayi "apperchar karyakshamatha" nirvachikkappettitla.
appercher nettavum.
oru aantinayude "dayaraktivitti", radio tharamgangale oru dishayil mungananayode nayikkaano allengil oru nischitha dishayil ninnu mungananayode sweekarikkaano ulla kazhivu, "aantina geyin" ennu vilikkunna oru paaraameettar formula _ 32 aanu prakadippikkunnathu. oru nischitha dishayilulla tharamgangalil ninnu aaa aantinaykku labhikkuna power formula 33-nte anupaathavum oru anuyojyamaaya isotropic aantinaykku labhikkuna power formula 34-num, athaayath ellah dishakalil ninnum thulyamaayi power sweekarikkunna oru saangalppika aantinayude anupaathavumaan ithu. (oru nischitha aavruthiyilulla aantinakalkk) nettavum eee aantinakalude apparcharukalude anupaathathinu thulyamaanennu kaanaan kazhiyum
thaazhe kaanichirikkunnathupole, eee nirvachanam anusarichu yoonitti gaine ulla nashtappedaattha isotropic aantinayude apperchar
ivide soothravaakyam _ 37 ennathu radio tharamgangalude tharamgadairkhyamaanu. angane
athinaal valia phalapradamaaya apparcharukalulla aantinakal thaarathamyena cheria koneeya beam veethiyulla uyarnna nettamulla aantinakal (allengil "beam aantinakal") aayi kanakkaakkappedunnu. aantinakal sweekarikkunnathinaal, mattu dishakalil ninnu varunna tharamgangale apekshichu (ithu edapedal aayi kanakkakkum) avaa mungananayulla dishayil ninnu varunna radio tharamgangalodu kooduthal sensitiivu aanu. aantinakal kaimarunnathinal, avayude shakthiyude bhooribhaagavum mattu dishakalude chelavil oru prathyeka dishayilekku vikiranam cheyyappedunnu. aantina nettavum phalapradamaaya appercher dishayude pravarthanangalaanenkilum, oru dishayum vyakthamaakkaathappol, iva avayude paramavadhi moolyangale soochippikkunnuvennu manassilakkunnu, athaayath, aantinayude uddeshicha upayogathinte dishayilaanu (aantinayude pradhana loob allengil borisaitt ennum ariyappedunnu).
fris transmission formula.
oru reseaving aantinaykku labhikkuna traansmitting aantinayilekku vitharanam cheiyunna pavarinte bhagam aantinakalude apparcharukalude uthppannathin aanupaathikavum aantinakalum tharamgadairkhyavum thammilulla dooratthinte square moolyangalkku vipareeta anupaathathilumaanu. fries transmission formulayude oru roopathilaanu ithu nalkiyirikkunnath
evide
thermodynamic parigananakalil ninnu aantina appercharinte vyulppannam.
mukalilulla nettatthinte nirvachanatthinte adisthaanamaaya oru isotropic aantinayude apperchar thermodynamicsumaayulla sthirathayude adisthaanathil uruthirinjedukkaam. r" enna driving pooyint impedensulla oru anuyojyamaaya isotropic aantina "a" thaapanila "t" yill thermodynamic santhulithaavasthayil oru clossed sisttam ca-yill irikkunnuvennu karuthuka. aantina terminalukale nammal oru second clossed sisttam sii. aarr.-nullil, thaapanila "tii" yill "aarr" resistansulla oru resistarumaayi bandhippikkunnu. athinidayil chila freekwansi gadakangal maathram kadannupokunna ekapaksheeyamaaya nashtappedaattha electronic filter "efnn" cherkkaam.
oro arayum taapa santhulithaavasthayilaanu, athinaal thaapanila "tii" kaaranam black body vikiranam kondu nirayunnu. aaa thaapanila kaaranam, rasisttar oru ooppan surcuted volteju upayogichu jonson-nikvist shabdam srishtikkum, athinte sharashari-square spectral saandrata nalkunnu
ivide formula _ 50 ennathu freekwansi "f"-nuu baadhakamaaya oru kwaandam-mechanical gadakamaanu; saadhaarana thapanilayilum electronic freekwansi formula _ 51-lum, ennaal pothuve ithu nalkunnu
oru vaidyutha srothassaaya "r" oru poruthappedunna lodilekku (athaayath, "r" enna impedensulla onnu, caaile aantina pole) rms ooppan surcuted volteju "v" rms aanu, athu nalkunna oorjjathinte alavu
filter "fν" kadannupokunna aavruthikalil sharashari-chathura shabda voltejinte spectral saandrathaykkaayi melpparanja samavaakyam samyojippichukondu sharashari-chathura volteju soothravaakyam _ 54 kandethanakum. laalithyathinaayi, central freekwansi "f" 1 nuu chuttumulla bandwidth "b" 1 nte oru idungiya baand filteraayi namukk "fν" pariganikkaam, eee saahacharyathil integral inipparayunna reethiyil lalithamaakkunnu
resistaril ninnulla jonson shabdam moolamulla eee shakti aantinaykku labhikkunnu, athu clossed systethilekku vikiranam cheiyunnu.
athe aantina, thaapanila "tii" yude black body vikiranathil kulikkumbol, plaankinte niyamam nalkunna oru spectral prakasham (yoonit soolid aamgilil yoonit freakwensick yoonit eriyaykku power) labhikkunnu
mukalil nirvachichirikkunna _ 50 enna notteshan formula upayogikkuka.
ennirunnaalum, aaa vikiranam dhruveekarikkappedaathaana, athesamayam aantina oru dhruveekaranathodu maathrame sensitiivu aakunnulloo, athu 2 enna ghadakam kuraykkunnu. aantina amgeekaricha black body vikiranathil ninnulla motham shakti kandethunnathinu, aaa alavu ellah khara konukalilum aantinayude "eiii. eph. eph" ennu anumaanikkappedunna cross-sekshanal eriyayude "eiii" thavana ellah freekwansikalilum "eph" aayi samyojippikkanam
nammal oru isotropic radiator anumaanichathinaal, "a" "eiii. eph. eph konukalil ninnu swathanthramaanu, athinaal khara konukalilulla samyojanam nissaaramaan, ithu 4π enna ghadakam avatharippikkunnu. veendum namukk oru idungiya baand electronic filter function "fν"-nte lalithamaaya cases edukkaam, athu bandwidth "b" 1-nte power freekwansi "f" 1-nuu chuttum maathrame kadannupookoo.
ivide formula _ 61 ennathu "f" 1 "enna aavruthiyumaayi bandhapetta swatantra-bahirakasha tharamgadairkhyamaanu.
oro samvidaanavum ore thapanilayil thermodynamic santhulithaavasthayilaayathinal, arakalkkidayil motham vaidyuthi kaimaattam undaakillenn njangal prathekshikkunnu. allengil thermodynamicsinte randaamathe niyamam lamghichu oru arra choodaakukayum mattonn thanukkukayum cheyyum. athinaal, rund dishakalileyum vaidyuthi ozhukunnathu thulyamaayirikkanam
isotropic aantina thadassappeduthunna cross-sekshanal eriyayaaya "eiii" ephinaayi namukk pariharikkaam
athinaal oru saangalppika isotropic aantinaykku, sweekarikkunna aantinayude phalapradamaaya cross-sekshan λ2/4π vistheernnamullathaayirikkanna thermodynamics aavashyappedunnu. integral ovar freekwansi kooduthal pothuvaayirikkan anuvadikkukayaanenkil eee phalam kooduthal saamaanyavalkkarikkaanaakum. λ = "c"/"f" upayogichu athe aantinayude "a" iii. eph. eph athe formula anusarichu aavruthiyanusarichu vyathyaasappedanamennu nammal kandethunnu. koodaathe, "isotropic allatha" (athaayath eathenkilum yadhaartha aantina) oru aantinaykku soolid aamgilinekkaal integral saamaanyavalkkarikkam. vaidyuthakaanthika vikiranam varunna koonn melpparanja integralil "a" ephylake maathrame praveshikkunnulloo ennathinaal, phalapradamaaya cross sekshante "sharashari" enna phalatthil nammal athicherunnu, ellah konukalilum tharamgadairkhyathil λ enna "efdi" yum nalkanam
 = \frac {\lambda ^ 2} {4\paai}.</kanakk>
melpparanjava mathiyaya thelivaanenkilum, aantinayude impedence resistarinu thulyamaaya "r" aayirikkunna avasthayum elakkividaan kazhiyumennu namukk sradhikkaam. thathwathil, anuyojyamaaya (nashtappedaattha) poruthappedunna shringhala cherkkunnathiloode eathu aantina impedence (poornnamaayum prathipravarthanarahithamaaya) resisttar "r" maayi poruthappedutthaam. aaa shringhala nashtappedaatthathinaal, aantinayilum resistarinte terminalukalilum kaanunna voltage vaidyuthadhaarayum vyathyasthamaanenkilum "p" a, "p" r "ennee sakthikal appozhum ethir dishakalilekku ozhukum. iru dishakalileyum oorjjapravaahathinte spectral saandrata ippozhum formula 65 nalkum, vaasthavathil ithu oru vaidyuthakaanthika modumaayi bandhapetta valare taapa-shabda power spectral saandrathayaanu, athu swatantra-sthalathaayaalum vaidyuthamaayi kaimaattam cheyyappettaalum. resistarumaayi orotta kanakshan maathrame ulloo ennathinaal, resisttar thanne orotta modine prathinidheekarikkunnu. orotta vaidyutha kanakshanulla oru aantinayum, athinte sharashari phalapradamaaya cross sekshan formula _ 66 anusarichu vaidyuthakaanthikakshethrathu oru modilekk jodiyaakkunnu.

