I. Chiyambi
Ma Fractals ndi zinthu zamasamu zomwe zimawonetsa zinthu zofanana pamiyeso yosiyanasiyana. Izi zikutanthauza kuti pamene mutsegula / kunja pa mawonekedwe a fractal, gawo lililonse limawoneka lofanana kwambiri ndi lonse; ndiko kuti, mawonekedwe a geometric ofanana kapena zomanga zimabwerezedwa pamilingo yosiyana yakukulitsa (onani zitsanzo za fractal mu Chithunzi 1). Ma fractals ambiri amakhala ndi mawonekedwe ovuta, atsatanetsatane, komanso ovuta kwambiri.
chithunzi 1
Lingaliro la fractals linayambitsidwa ndi katswiri wa masamu Benoit B. Mandelbrot m'ma 1970, ngakhale kuti chiyambi cha fractal geometry chimachokera ku ntchito yakale ya masamu ambiri, monga Cantor (1870), von Koch (1904), Sierpinski (1915) ), Julia (1918), Fatou (1926), ndi Richardson (1953).
Benoit B. Mandelbrot adaphunzira za ubale wapakati pa fractals ndi chilengedwe poyambitsa mitundu yatsopano ya ma fractals kuti afanizire zinthu zovuta kwambiri, monga mitengo, mapiri, ndi magombe. Anapanga mawu oti "fractal" kuchokera ku adjective yachilatini "fractus", kutanthauza "wosweka" kapena "wosweka", mwachitsanzo wopangidwa ndi zidutswa zosweka kapena zosawerengeka, kufotokoza mawonekedwe osakhazikika komanso ogawanika a geometric omwe sangathe kugawidwa ndi chikhalidwe cha Euclidean geometry. Komanso, iye anayamba masamu zitsanzo ndi ma aligorivimu popanga ndi kuphunzira fractals, zomwe zinachititsa kuti pakhale wotchuka Mandelbrot akonzedwa, amene mwina wotchuka kwambiri ndi zowoneka chidwi fractal mawonekedwe ndi dongosolo zovuta kubwerezabwereza (onani Chithunzi 1d).
Ntchito ya Mandelbrot sinakhudze masamu okha, komanso imagwira ntchito m'magawo osiyanasiyana monga physics, zithunzi zamakompyuta, biology, economics, ndi luso. M'malo mwake, chifukwa cha kuthekera kwawo kuwonetsa ndikuyimira zovuta komanso zofananira, ma fractals ali ndi ntchito zambiri zatsopano m'magawo osiyanasiyana. Mwachitsanzo, amagwiritsidwa ntchito kwambiri m'malo otsatirawa, omwe ndi zitsanzo zochepa chabe za momwe amagwiritsidwira ntchito kwambiri:
1. Zithunzi zamakompyuta ndi makanema ojambula pamanja, kutulutsa malo enieni komanso owoneka bwino achilengedwe, mitengo, mitambo, ndi mawonekedwe;
2. Ukadaulo wopondereza wa data kuti uchepetse kukula kwa mafayilo a digito;
3. Kukonza zithunzi ndi zizindikiro, kuchotsa zinthu kuchokera pazithunzi, kuzindikira mawonekedwe, ndikupereka njira zogwirira ntchito zopondereza zithunzi ndi kumanganso;
4. Biology, kufotokoza kukula kwa zomera ndi dongosolo la neurons mu ubongo;
5. Chiphunzitso cha antenna ndi metamatadium, kupanga tinyanga tating'onoting'ono / ma multi-band ndi ma metasurfaces atsopano.
Pakadali pano, fractal geometry ikupitilizabe kupeza ntchito zatsopano komanso zatsopano m'njira zosiyanasiyana zasayansi, zaluso komanso zaukadaulo.
Muukadaulo wamagetsi amagetsi (EM), mawonekedwe a fractal ndiwothandiza kwambiri pamapulogalamu omwe amafunikira miniaturization, kuchokera ku tinyanga kupita ku ma metamatadium ndi ma frequency selective surface (FSS). Kugwiritsa ntchito fractal geometry mu tinyanga wamba kumatha kukulitsa kutalika kwa magetsi, potero kumachepetsa kukula konse kwa mawonekedwe a resonant. Kuphatikiza apo, mawonekedwe ofananirako a mawonekedwe a fractal amawapangitsa kukhala abwino kuzindikira ma multi-band kapena ma Broadband resonant. Kuthekera kwachilengedwe kwa ma fractals kumakhala kokongola kwambiri popanga zowunikira, tinyanga tating'onoting'ono, zolowetsa metamaterial ndi ma metasurfaces pazogwiritsa ntchito zosiyanasiyana. M'malo mwake, kugwiritsa ntchito zinthu zazing'ono kwambiri kumatha kubweretsa zabwino zingapo, monga kuchepetsa kulumikizana kapena kutha kugwira ntchito ndi mindandanda yokhala ndi malo ang'onoang'ono, potero kuwonetsetsa kuti sikanthu ikugwira bwino ntchito komanso milingo yayikulu yokhazikika pamakona.
Pazifukwa zomwe tazitchula pamwambapa, ma fractal antennas ndi metasurfaces akuyimira magawo awiri ochita kafukufuku okhudza ma elekitiroma omwe akopa chidwi kwambiri m'zaka zaposachedwa. Malingaliro onsewa amapereka njira zapadera zosinthira ndi kuwongolera mafunde amagetsi, okhala ndi mitundu ingapo yogwiritsira ntchito mawayilesi opanda zingwe, makina a radar ndi zomverera. Makhalidwe awo ofananira amawalola kukhala ang'onoang'ono kukula ndikusunga mayankho abwino kwambiri amagetsi. Kuphatikizikaku kumakhala kopindulitsa makamaka pamapulogalamu omwe ali ndi malo, monga zida zam'manja, ma tag a RFID, ndi makina apamlengalenga.
Kugwiritsiridwa ntchito kwa fractal antennas ndi metasurfaces kungathe kupititsa patsogolo kwambiri mauthenga opanda zingwe, kujambula, ndi makina a radar, chifukwa amathandizira zipangizo zogwirira ntchito, zogwira ntchito kwambiri ndi ntchito zowonjezereka. Kuphatikiza apo, fractal geometry ikugwiritsidwa ntchito kwambiri popanga masensa a microwave kuti azindikire zakuthupi, chifukwa cha kuthekera kwake kogwira ntchito m'magulu angapo afupipafupi komanso kuthekera kwake kocheperako. Kafukufuku wopitilira m'magawowa akupitilizabe kufufuza mapangidwe atsopano, zida, ndi njira zopangira kuti akwaniritse zomwe angathe.
Pepalali likufuna kuunikanso momwe kafufuzidwe ndi kagwiritsidwe ntchito ka fractal antennas ndi metasurfaces ndikufanizira tinyanga tating'ono tating'ono tating'ono tating'onoting'ono ndi ma metasurfaces, ndikuwunikira zabwino ndi zolephera zawo. Pomaliza, kuwunika kwatsatanetsatane kwa zowunikira zatsopano ndi mayunitsi a metamaterial kumaperekedwa, ndipo zovuta ndi zomwe zidzachitike m'tsogolo mwazinthu zamagetsi zamagetsi zimakambidwa.
2. FractalMlongotiZinthu
Lingaliro lazonse za ma fractals zitha kugwiritsidwa ntchito kupanga zinthu zachilendo za mlongoti zomwe zimapereka magwiridwe antchito bwino kuposa tinyanga wamba. Ma antenna a Fractal amatha kukhala ophatikizika kukula komanso kukhala ndi magulu angapo komanso/kapena burodibandi.
Kapangidwe ka tinyanga ta fractal kumaphatikizapo kubwereza mawonekedwe apadera a geometric pamasikelo osiyanasiyana mkati mwa kapangidwe ka tinyanga. Chitsanzo chofananirachi chimatithandiza kuonjezera kutalika kwa mlongoti mkati mwa malo ochepa a thupi. Kuphatikiza apo, ma radiator a fractal amatha kukwaniritsa magulu angapo chifukwa magawo osiyanasiyana a tinyanga amafanana pamiyeso yosiyanasiyana. Chifukwa chake, zinthu za fractal antenna zimatha kukhala zophatikizika komanso zamitundu yambiri, zomwe zimapereka kufalikira kwafupipafupi kuposa tinyanga wamba.
Lingaliro la fractal antennas limatha kutsatiridwa mpaka kumapeto kwa zaka za m'ma 1980. Mu 1986, Kim ndi Jaggard adawonetsa kugwiritsa ntchito kudzifananitsa kwapang'onopang'ono mu kaphatikizidwe ka antenna.
Mu 1988, wasayansi Nathan Cohen adapanga mlongoti woyamba padziko lapansi. Ananenanso kuti pophatikiza ma geometry ofananira nawo mumpangidwe wa tinyanga, magwiridwe ake ndi luso laling'ono litha kuwongolera. Mu 1995, Cohen adayambitsa nawo Fractal Antenna Systems Inc., yomwe idayamba kupereka mayankho oyamba padziko lonse lapansi a fractal-based antenna.
Pakatikati mwa zaka za m'ma 1990, Puente et al. adawonetsa kuthekera kwamagulu angapo a fractals pogwiritsa ntchito Sierpinski's monopole ndi dipole.
Chiyambireni ntchito ya Cohen ndi Puente, ubwino wobadwa nawo wa fractal antennas wakopa chidwi chachikulu kuchokera kwa ofufuza ndi mainjiniya okhudzana ndi matelefoni, zomwe zidapangitsa kuti afufuzenso ndikukula kwaukadaulo wa fractal antenna.
Masiku ano, ma fractal antennas amagwiritsidwa ntchito kwambiri pamakina olumikizirana opanda zingwe, kuphatikiza mafoni am'manja, ma routers a Wi-Fi, ndi mauthenga a satana. M'malo mwake, tinyanga tating'onoting'ono tating'onoting'ono, tambirimbiri, komanso zogwira mtima kwambiri, zomwe zimawapangitsa kukhala oyenera pazida zosiyanasiyana zopanda zingwe ndi maukonde.
Ziwerengero zotsatirazi zikuwonetsa tinyanga tating'onoting'ono totengera mawonekedwe odziwika bwino a fractal, omwe ndi zitsanzo zochepa chabe za masinthidwe osiyanasiyana omwe amakambidwa m'mabuku.
Mwachindunji, Chithunzi 2a chikuwonetsa Sierpinski monopole yomwe ikufunsidwa ku Puente, yomwe imatha kupereka ntchito zamagulu ambiri. Makona atatu a Sierpinski amapangidwa pochotsa makona atatu opindika pakati pa makona atatu, monga momwe tawonetsera pa Chithunzi 1b ndi Chithunzi 2a. Izi zimasiya makona atatu ofanana pamapangidwewo, mbali iliyonse ili ndi kutalika kwa theka la makona atatu oyambira (onani Chithunzi 1b). Momwemonso kuchotsa ndondomeko akhoza kubwerezedwa kwa makona atatu otsala. Choncho, chilichonse mwa zigawo zake zazikulu zitatu ndi zofanana ndendende ndi chinthu chonsecho, koma mowirikiza kawiri, ndi zina zotero. Chifukwa cha kufanana kwapadera kumeneku, Sierpinski ikhoza kupereka magulu angapo afupipafupi chifukwa magawo osiyanasiyana a mlongoti amafanana pamiyeso yosiyana. Monga tawonetsera pa Chithunzi 2, Sierpinski monopole yomwe ikufunsidwa imagwira ntchito m'magulu asanu. Zitha kuwoneka kuti iliyonse mwa ma sub-gaskets asanu (zozungulira zozungulira) mu Chithunzi 2a ndi mawonekedwe a scaled a dongosolo lonse, motero amapereka magulu asanu ogwiritsira ntchito maulendo osiyanasiyana, monga momwe akuwonetsedwera mu coefficient yowonetsera yolowera mu Chithunzi 2b. Chiwerengerochi chikuwonetsanso magawo okhudzana ndi gulu lililonse la ma frequency, kuphatikiza kuchuluka kwa fn (1 ≤ n ≤ 5) pamtengo wochepera wa kutayika kobwereza koyerekeza (Lr), bandwidth wachibale (Bwidth), ndi kuchuluka kwafupipafupi pakati magulu awiri oyandikana nawo pafupipafupi (δ = fn +1/fn). Chithunzi 2b chikuwonetsa kuti magulu a Sierpinski monopoles amakhala motalikirana nthawi ndi nthawi ndi gawo la 2 (δ ≅ 2), lomwe limafanana ndi makulitsidwe omwewo omwe amapezeka m'mapangidwe ofanana mumpangidwe wa fractal.
chithunzi 2
Chithunzi 3a chikuwonetsa tinyanga tating'ono tawaya tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'onoting'ono totengera Koch fractal curve. Mlongoti uwu ukuperekedwa kuti uwonetse momwe angagwiritsire ntchito bwino mawonekedwe odzaza malo a mawonekedwe a fractal kupanga tinyanga tating'ono. M'malo mwake, kuchepetsa kukula kwa tinyanga ndiye cholinga chachikulu cha mapulogalamu ambiri, makamaka okhudzana ndi ma terminals am'manja. Koch monopole imapangidwa pogwiritsa ntchito njira yomanga ya fractal yomwe ikuwonetsedwa mu Chithunzi 3a. Kubwereza koyamba K0 ndi monopole yowongoka. Kubwereza kotsatira K1 kumapezedwa pogwiritsa ntchito kusintha kofanana kwa K0, kuphatikizapo kukweza ndi gawo limodzi mwa magawo atatu ndi kuzungulira ndi 0°, 60°, -60°, ndi 0°, motsatana. Njirayi imabwerezedwa mobwerezabwereza kuti mupeze zinthu zotsatila Ki (2 ≤ i ≤ 5). Chithunzi 3a chikuwonetsa kubwereza kwachisanu kwa Koch monopole (ie, K5) ndi kutalika kwa h kofanana ndi 6 cm, koma kutalika kwake kumaperekedwa ndi ndondomeko l = h · (4/3) 5 = 25.3 cm. Tinyanga zisanu zofananira ndi zobwereza zisanu zoyambirira za curve ya Koch zazindikirika (onani Chithunzi 3a). Zoyesera zonse ndi deta zikuwonetsa kuti Koch fractal monopole imatha kusintha magwiridwe antchito achikhalidwe (onani Chithunzi 3b). Izi zikuwonetsa kuti zitha kukhala zotheka "kuchepetsa" tinyanga tating'onoting'ono, kuwalola kuti azikwanira m'mavoliyumu ang'onoang'ono pomwe akugwira ntchito bwino.
chithunzi 3
Chithunzi 4a chikuwonetsa mlongoti wa fractal kutengera seti ya Cantor, yomwe imagwiritsidwa ntchito popanga mlongoti wa bandi lalikulu kuti agwiritse ntchito kukolola mphamvu. Katundu wapadera wa tinyanga tating'onoting'ono tomwe timayambitsa ma resonances oyandikana nawo amagwiritsidwa ntchito kuti apereke bandwidth yotakata kuposa tinyanga wamba. Monga momwe tawonetsera pa Chithunzi 1a, mapangidwe a Cantor fractal set ndi ophweka kwambiri: mzere wowongoka woyambirira umakopera ndikugawidwa m'magawo atatu ofanana, omwe gawo lapakati limachotsedwa; ndondomeko yomweyi ikugwiritsidwa ntchito mobwerezabwereza ku magawo omwe angopangidwa kumene. Masitepe a fractal iteration amabwerezedwa mpaka bandwidth ya mlongoti (BW) ya 0.8-2.2 GHz yakwaniritsidwa (ie, 98% BW). Chithunzi 4 chikuwonetsa chithunzi cha mlongoti wozindikirika (Chithunzi 4a) ndi mawonekedwe ake owonetsera (Chithunzi 4b).
chithunzi 4
Chithunzi 5 chimapereka zitsanzo zambiri za tinyanga tating'onoting'ono, kuphatikiza mlongoti wa monopole wa Hilbert, mlongoti wa microstrip patch wa Mandelbrot, ndi chilumba cha Koch (kapena "chipale chofewa").
chithunzi 5
Pomaliza, Chithunzi 6 chikuwonetsa makonzedwe osiyanasiyana amitundu yosiyanasiyana, kuphatikiza ma planar a Sierpinski carpet, Cantor ring arrays, Cantor linear arrays, ndi mitengo yodukaduka. Makonzedwe awa ndi othandiza popanga masinthidwe ochepa komanso/kapena kukwaniritsa magwiridwe antchito amagulu angapo.
chithunzi 6
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Nthawi yotumiza: Jul-26-2024
