Amakuru - Isuzuma rya Antena: Isuzuma rya Fractal Metasurfaces n'igishushanyo cya Antena

I. Intangiriro
Fractal ni ibintu bya mibare bigaragaza imiterere isa ku bipimo bitandukanye. Ibi bivuze ko iyo ushyize/usohokeye ku ishusho ya fractal, buri gice cyayo gisa cyane n'ikintu cyose; ni ukuvuga ko imiterere cyangwa imiterere isa isubiramo ku rwego rwo gukura gutandukanye (reba ingero za fractal mu Ishusho ya 1). Fractal nyinshi zifite imiterere igoye, irambuye, kandi igoye cyane.

Igishushanyo cya 1

Igitekerezo cy'amabara ya fractal cyatangijwe n'umuhanga mu mibare Benoit B. Mandelbrot mu myaka ya 1970, nubwo inkomoko y'imiterere ya fractal ishobora gukururwa mu mirimo ya mbere y'abahanga benshi mu mibare, nka Cantor (1870), von Koch (1904), Sierpinski (1915), Julia (1918), Fatou (1926), na Richardson (1953).
Benoit B. Mandelbrot yize isano iri hagati y’uduce duto n’ibidukikije azana ubwoko bushya bw’uduce duto kugira ngo twigane imiterere igoye cyane, nk’ibiti, imisozi, n’inkombe. Yahimbye ijambo "fractal" riva ku ijambo ry’ikilatini "fractus", risobanura "yacitse" cyangwa "yacitse", ni ukuvuga igizwe n’ibice byacitse cyangwa bidahinduka, kugira ngo asobanure imiterere idasanzwe n’icitsemo ibice idashobora gushyirwa mu byiciro hakurikijwe imiterere gakondo ya Euclidean. Byongeye kandi, yateje imbere ingero na algorithms by’imibare byo gukora no kwiga uduce duto, byatumye habaho itsinda rizwi cyane rya Mandelbrot, rishobora kuba ari ryo shusho izwi cyane kandi ishimishije cyane y’uduce duto dufite imiterere igoye kandi isubiramo kenshi (reba Ishusho ya 1d).
Ibikorwa bya Mandelbrot ntibyagize ingaruka gusa ku mibare, ahubwo byanagize ingaruka ku mikoreshereze mu nzego zitandukanye nka fiziki, ibishushanyo bya mudasobwa, ibinyabuzima, ubukungu, n'ubuhanzi. Mu by'ukuri, bitewe n'ubushobozi bwabyo bwo kwerekana no kwerekana imiterere igoye kandi isa, fractals zifite porogaramu nyinshi zigezweho mu nzego zitandukanye. Urugero, zakoreshejwe cyane mu nzego zikurikira zikoreshwa, ari zo ngero nke z'ikoreshwa ryazo rinini:
1. Ibishushanyo bya mudasobwa na animasiyo, bitanga imiterere karemano ifatika kandi ikurura amaso, ibiti, ibicu, n'imiterere;
2. Ikoranabuhanga ryo gukanda amakuru kugira ngo rigabanye ingano y'amadosiye ya digitale;
3. Gutunganya amashusho n'ibimenyetso, gukuramo ibintu bifatika mu mashusho, kumenya imiterere, no gutanga uburyo bwiza bwo gukanda no kongera kubaka amashusho;
4. Biology, isobanura imikurire y'ibimera n'imiterere y'uturemangingo tw'ubwonko;
5. Inyigisho ya antena n'ibikoresho bya metamateri, gushushanya antene nto/zifite imigozi myinshi hamwe n'ibihangano bishya.
Muri iki gihe, imiterere y'ibishushanyo mbonera bya fractal ikomeje kubona uburyo bushya kandi bugezweho bwo gukoresha mu bumenyi butandukanye, ubuhanzi n'ikoranabuhanga.
Mu ikoranabuhanga rya elegitoroniki (EM), imiterere ya fractal ni ingirakamaro cyane ku bikorwa bisaba miniaturization, kuva kuri antene kugeza kuri metamaterials na frequency selective surfaces (FSS). Gukoresha fractal geometry muri antene zisanzwe bishobora kongera uburebure bwazo bw'amashanyarazi, bityo bikagabanya ingano rusange y'imiterere ya resonant. Byongeye kandi, imiterere isa ya fractal ituma ziba nziza mu gukora imiterere ya multi-band cyangwa broadband resonant. Ubushobozi bwa miniaturization bwa fractals burimo burakurura cyane mu gushushanya reflectarrays, phased array antene, metamaterial absorbers na metasurfaces ku bikorwa bitandukanye. Mu by'ukuri, gukoresha ibintu bito cyane bya array bishobora kuzana inyungu nyinshi, nko kugabanya coupling cyangwa gushobora gukorana na arrays zifite intera nto cyane y'ibintu, bityo bigatuma habaho imikorere myiza yo gushakisha no ku rwego rwo hejuru rw'inguni.
Kubera impamvu zavuzwe haruguru, antene za fractal na metasurfaces bigaragaza ibice bibiri bishishikaje by’ubushakashatsi mu bijyanye na electromagnetics byakuruye abantu benshi mu myaka ya vuba aha. Ibi bitekerezo byombi bitanga uburyo bwihariye bwo gukoresha no kugenzura imiraba ya electromagnetic, hamwe n’uburyo butandukanye bwo gukoresha mu itumanaho ridafite insinga, sisitemu za radar no kumva. Imiterere yabyo isa nayo ituma biba bito mu bunini mu gihe bigumana igisubizo cyiza cya electromagnetic. Ubu buryo bworoshye ni ingirakamaro cyane cyane mu bikorwa bito byo mu kirere, nk'ibikoresho bigendanwa, tagi za RFID, na sisitemu z’indege.
Gukoresha antene za fractal na metasurfaces bifite ubushobozi bwo kunoza cyane itumanaho ridafite insinga, amashusho, na sisitemu za radar, kuko bituma ibikoresho bito kandi bifite imikorere myiza kandi binoze. Byongeye kandi, imiterere ya fractal iri gukoreshwa cyane mu gushushanya ibyuma bipima microwave kugira ngo bikoreshwe mu gusuzuma ibikoresho, bitewe n'ubushobozi bwayo bwo gukora mu mibare myinshi ya frequencies ndetse n'ubushobozi bwayo bwo kuba miniaturized. Ubushakashatsi buri gukorwa muri ibi bice bukomeje gushakisha imiterere mishya, ibikoresho, n'uburyo bwo gukora kugira ngo bigere ku bushobozi bwabyo bwose.
Iyi nyandiko igamije gusuzuma aho ubushakashatsi n'iterambere ry'ikoreshwa rya antene za fractal na metasurfaces bigeze no kugereranya antene na metasurfaces zisanzwe zishingiye kuri fractal, hagaragazwa ibyiza n'imbogamizi zabyo. Amaherezo, hagaragajwe isesengura ryimbitse ry'udushya twa reflectarrays na metamaterial units, kandi imbogamizi n'iterambere ry'izi nyubako za electromagnetic mu gihe kizaza biraganirwaho.

2. FractalAntenaIbice
Igitekerezo rusange cya fractal gishobora gukoreshwa mu gushushanya antene zidasanzwe zitanga imikorere myiza kurusha antene zisanzwe. Antene za fractal zishobora kuba nto mu bunini kandi zifite ubushobozi bwo gukoresha imiyoboro myinshi cyangwa interineti.
Imiterere ya antene za fractal ikubiyemo gusubiramo imiterere yihariye ya geometrike ku bipimo bitandukanye mu miterere ya antene. Iyi miterere isa ubwayo idufasha kongera uburebure rusange bwa antene mu mwanya muto ufatika. Byongeye kandi, radiateri za fractal zishobora kugera ku migozi myinshi kuko ibice bitandukanye bya antene bisa ku bipimo bitandukanye. Kubwibyo, ibice bya antene za fractal bishobora kuba bito kandi bifite imigozi myinshi, bigatanga ubwinshi bwa frequency kurusha antene zisanzwe.
Igitekerezo cya antene za fractal cyatangiye mu mpera za 1980. Mu 1986, Kim na Jaggard bagaragaje ikoreshwa rya fractal self-sanity mu guhuza antene.
Mu 1988, umuhanga mu bya fiziki Nathan Cohen yubatse antene ya mbere ku isi y’ikintu cya fractal. Yatanze igitekerezo cy’uko gushyiramo imiterere isa n’iya antene mu miterere yayo, ubushobozi bwayo n’ubushobozi bwayo bwo kuyihinduramo ibintu bushobora kunozwa. Mu 1995, Cohen yashinze Fractal Antenna Systems Inc., yatangiye gutanga ibisubizo bya mbere ku isi by’antene zishingiye kuri fractal.
Hagati mu myaka ya za 90, Puente n'abandi bagaragaje ubushobozi bwa fractals mu mibare myinshi bakoresheje monopole na dipole bya Sierpinski.
Kuva Cohen na Puente batangira gukora, ibyiza by’antene za fractal byakuruye amatsiko menshi y’abashakashatsi n’abahanga mu itumanaho, bituma habaho ubushakashatsi n’iterambere ry’ikoranabuhanga rya antene za fractal.
Muri iki gihe, antene za fractal zikoreshwa cyane muri sisitemu z'itumanaho ridafite insinga, harimo telefoni zigendanwa, router za Wi-Fi, n'itumanaho rya satelite. Mu by'ukuri, antene za fractal ni nto, zifite imiyoboro myinshi, kandi zikora neza cyane, bigatuma zikoreshwa mu bikoresho bitandukanye bya wireless na network.
Ibishushanyo bikurikira bigaragaza antene zimwe na zimwe za fractal zishingiye ku miterere izwi cyane ya fractal, izo zikaba ari ingero nke z'imiterere itandukanye yavuzwe mu nyandiko.
By’umwihariko, Ishusho ya 2a igaragaza monopole ya Sierpinski yatanzwe muri Puente, ishobora gutanga imikorere y’imirongo myinshi. Impandeshatu ya Sierpinski ikorwa no gukuramo mpandeshatu y’imbere ihinduriwe inyuma mu mpandeshatu nkuru, nk’uko bigaragara ku Ishusho ya 1b n’Ishusho ya 2a. Iyi nzira isiga mpandeshatu eshatu zingana ku miterere, buri imwe ifite uburebure bw’uruhande rw’igice cy’impandeshatu itangira (reba Ishusho ya 1b). Uburyo bumwe bwo gukuramo bushobora gusubirwamo kuri mpandeshatu zisigaye. Kubwibyo, buri gice cyayo cy’ingenzi kingana neza n’ikintu cyose, ariko inshuro ebyiri z’ingano, n’ibindi. Bitewe n’ibi bisa bidasanzwe, Sierpinski ishobora gutanga frequency bands nyinshi kuko ibice bitandukanye bya antene bisa ku bipimo bitandukanye. Nkuko bigaragara ku Ishusho ya 2, monopole ya Sierpinski ikora mu mirongo 5. Bigaragara ko buri imwe muri sub-gaskets eshanu (imiterere y’uruziga) mu Ishusho ya 2a ari verisiyo y’imiterere yose, bityo igatanga frequency bands eshanu zitandukanye, nk’uko bigaragara ku gipimo cyo kwerekana mu Ishusho ya 2b. Iyi shusho kandi igaragaza ibipimo bifitanye isano na buri frequence band, harimo agaciro ka fn (1 ≤ n ≤ 5) ku gaciro gato k'igihombo cyapimwe cyo kugaruka kw'inyongera (Lr), bandwidth ijyanye n'ubugari (Bwidth), n'ikigereranyo cya frequence hagati y'imirongo ibiri yegeranye (δ = fn +1 / fn). Ishusho ya 2b igaragaza ko imirongo ya monopoles za Sierpinski ishyirwa ku murongo wa logarithmic rimwe na rimwe na factor ya 2 (δ ≅ 2), ihuye n'umubare umwe wa factor ugaragara mu miterere isa mu ishusho ya fractal.

Igishushanyo cya 2

Ishusho ya 3a yerekana antene ntoya ndende ishingiye ku murongo wa Koch fractal. Iyi antene irasabwa kwerekana uburyo bwo gukoresha imiterere y’imiterere ya fractal kugira ngo hakorwe antene nto. Mu by’ukuri, kugabanya ingano ya antene ni yo ntego nyamukuru y’ikoreshwa ry’ibintu byinshi, cyane cyane ibikoresha terminals zigendanwa. Monopole ya Koch yakozwe hakoreshejwe uburyo bwo kubaka fractal bugaragara ku Ishusho ya 3a. Isubiramo rya mbere K0 ni monopole igororotse. Isubiramo rya K1 rikurikira riboneka hakoreshejwe impinduka isa na K0, harimo gupima kimwe cya gatatu no kuzunguruka na 0°, 60°, −60°, na 0°, uko bikurikirana. Iyi gahunda isubirwamo inshuro nyinshi kugira ngo haboneke ibice bikurikira Ki (2 ≤ i ≤ 5). Ishusho ya 3a igaragaza verisiyo ya monopole ya Koch isubiramo inshuro eshanu (ni ukuvuga K5) ifite uburebure h bungana na cm 6, ariko uburebure bwose butangwa na formula l = h ·(4/3) 5 = cm 25.3. Antene eshanu zijyanye n'impinduka eshanu za mbere z'umuyoboro wa Koch zarakozwe (reba Ishusho ya 3a). Igerageza n'amakuru byombi bigaragaza ko monopole ya Koch fractal ishobora kunoza imikorere ya monopole isanzwe (reba Ishusho ya 3b). Ibi bigaragaza ko bishoboka "gutobora" antene za fractal, bigatuma zijya mu ngano nto mu gihe zikomeza gukora neza.

Igishushanyo cya 3

Ishusho ya 4a igaragaza antene ya fractal ishingiye ku itsinda rya Cantor, ikoreshwa mu gushushanya antene ya broadband yo gukoresha mu gusarura ingufu. Imiterere yihariye ya antene za fractal zitanga resonance nyinshi zegeranye ikoreshwa kugira ngo itange umurambararo wagutse kurusha antene zisanzwe. Nkuko bigaragara ku Ishusho ya 1a, imiterere ya seti ya fractal ya Cantor iroroshye cyane: umurongo wa mbere ugororotse urimo gukoporora no kugabanywamo ibice bitatu bingana, aho igice cyo hagati gikurwaho; inzira imwe ishyirwa mu bikorwa inshuro nyinshi ku bice bishya byakozwe. Intambwe zo gusubiramo fractal zisubirwamo kugeza igihe umurambararo wa antene (BW) wa 0.8–2.2 GHz ugezweho (ni ukuvuga 98% BW). Ishusho ya 4 igaragaza ifoto y'urugero rwa antene (Ishusho ya 4a) hamwe n'igipimo cyayo cyo kugaragaza (Ishusho ya 4b).

Igishushanyo cya 4

Ishusho ya 5 itanga ingero nyinshi za antene za fractal, harimo antene ya monopole ya Hilbert curve, antene ya microstrip patch ya Mandelbrot, na antene ya fractal ya Koch Island (cyangwa "snowflake").

Igishushanyo cya 5

Amaherezo, Ishusho ya 6 igaragaza imiterere itandukanye ya fractal y'ibintu bya array, harimo Sierpinski carpet planar arrays, Cantor ring arrays, Cantor linear arrays, na fractal trees. Iyi imiterere ni ingirakamaro mu gukora arrays sparse cyangwa kugera ku musaruro wa multi-band.