I. Hoolauna
ʻO nā fractals nā mea makemakika e hōʻike ana i nā waiwai like ʻole ma nā unahi like ʻole. ʻO ia hoʻi, ke hoʻonui ʻoe i loko/i waho ma ke ʻano fractal, ʻano like loa kēlā me kēia ʻāpana me ke ʻano holoʻokoʻa; ʻo ia hoʻi, e hana hou nā ʻano geometric like ʻole i nā pae hoʻonui like ʻole (e nānā i nā laʻana fractal ma ke Kiʻi 1). Loaʻa i ka hapa nui o nā fractals nā hiʻohiʻona paʻakikī, kikoʻī, a paʻakikī loa.
huahelu 1
Ua hoʻokomo ʻia ka manaʻo o nā fractals e ka mea makemakika Benoit B. Mandelbrot i ka makahiki 1970, ʻoiai ʻo ke kumu o ka fractal geometry hiki ke huli ʻia i ka hana mua a nā mea makemakika he nui, e like me Cantor (1870), von Koch (1904), Sierpinski (1915). ), Julia (1918), Fatou (1926), a me Richardson (1953).
Ua aʻo ʻo Benoit B. Mandelbrot i ka pilina ma waena o nā fractals a me ke ʻano ma o ka hoʻokomo ʻana i nā ʻano fractals hou e hoʻohālike i nā hale paʻakikī, e like me nā kumulāʻau, mauna, a me nā kahakai. Ua haku ʻo ia i ka huaʻōlelo "fractal" mai ka Latin adjective "fractus", ʻo ia hoʻi, "haʻi" a "haʻi", ʻo ia hoʻi i haku ʻia me nā ʻāpana haki a ʻokoʻa ʻole paha, e wehewehe i nā ʻano geometric ʻaʻole hiki ke hoʻokaʻawale ʻia e ka geometry Euclidean kuʻuna. Eia kekahi, ua hoʻomohala ʻo ia i nā hiʻohiʻona makemakika a me nā algorithms no ka hana ʻana a me ke aʻo ʻana i nā fractals, i alakaʻi ʻia i ka hana ʻana o ka hui kaulana ʻo Mandelbrot, ʻo ia paha ke ʻano fractal kaulana loa a me nā hiʻohiʻona me nā hiʻohiʻona paʻakikī a pau ʻole (e nānā i ke Kiʻi 1d).
ʻAʻole i loaʻa ka hopena o ka hana a Mandelbrot i ka makemakika wale nō, akā loaʻa nō hoʻi nā noi ma nā ʻano like ʻole e like me ka physics, computer graphics, biology, economics, and art. ʻO ka ʻoiaʻiʻo, ma muli o ko lākou hiki ke hoʻohālike a hōʻike i nā hale paʻakikī a like like, loaʻa nā fractals i nā noi hou he nui i nā ʻano hana like ʻole. No ka laʻana, ua hoʻohana nui ʻia lākou i nā wahi noi ma lalo nei, he mau hiʻohiʻona wale nō ia o kā lākou noi ākea:
1. Kiʻi kiʻi kamepiula a me ka hoʻouluulu ʻana, e hana ana i nā ʻāina kūlohelohe maoli, nā kumu lāʻau, nā ao, a me nā ʻano ʻano;
2. ʻenehana hoʻopili ʻikepili e hoʻemi i ka nui o nā faila kikohoʻe;
3. Ka hana kiʻi a me ka hōʻailona, ka unuhi ʻana i nā hiʻohiʻona mai nā kiʻi, ka ʻike ʻana i nā mamana, a me ka hāʻawi ʻana i nā ʻano hoʻoemi kiʻi kūpono a me ke kūkulu hou ʻana;
4. Biology, e wehewehe ana i ka ulu ʻana o nā mea kanu a me ka hui ʻana o nā neurons i loko o ka lolo;
5. Antenna theory and metamaterials, designing compact/multi-band antennas and innovative metasurfaces.
I kēia manawa, hoʻomau ka ʻimi ʻana i nā hoʻohana hou a me nā mea hou i nā ʻano ʻepekema, ʻenehana a me nā ʻenehana.
Ma ka ʻenehana electromagnetic (EM), pono loa nā ʻano fractal no nā noi e koi ana i ka miniaturization, mai nā antennas a i nā metamaterials a me nā papa koho koho pinepine (FSS). ʻO ka hoʻohana ʻana i ka geometry fractal i nā antenna maʻamau hiki ke hoʻonui i ko lākou lōʻihi uila, a laila e hōʻemi i ka nui holoʻokoʻa o ke ʻano resonant. Eia kekahi, ʻo ke ʻano like ʻole o nā ʻano fractal e kūpono iā lākou no ka ʻike ʻana i nā ʻano resonant multi-band a broadband. ʻO nā mana liʻiliʻi liʻiliʻi o nā fractals he mea nani loa no ka hoʻolālā ʻana i nā reflectarrays, phased array antennas, metamaterial absorbers a me nā metasurfaces no nā noi like ʻole. ʻO ka ʻoiaʻiʻo, ʻo ka hoʻohana ʻana i nā mea hoʻonohonoho liʻiliʻi hiki ke lawe mai i nā mea maikaʻi, e like me ka hōʻemi ʻana i ka hui pū ʻana a i ʻole hiki ke hana pū me nā arrays me ka liʻiliʻi liʻiliʻi o ke kaʻawale ʻana, no laila e hōʻoiaʻiʻo ai i ka hana scanning maikaʻi a me nā pae kiʻekiʻe o ke kūpaʻa angular.
No nā kumu i ʻōlelo ʻia ma luna nei, ʻo nā antenna fractal a me nā metasurfaces e hōʻike ana i ʻelua mau wahi noiʻi hoihoi i ke kahua o ka electromagnetics i huki nui ʻia i nā makahiki i hala. Hāʻawi nā manaʻo ʻelua i nā ala kūʻokoʻa e hoʻopunipuni a hoʻomalu i nā hawewe electromagnetic, me kahi ākea o nā noi i nā kamaʻilio uila, nā ʻōnaehana radar a me ka ʻike. ʻO kā lākou mau waiwai like e hiki ai iā lākou ke liʻiliʻi i ka nui me ka mālama ʻana i ka pane electromagnetic maikaʻi loa. ʻOi aku ka maikaʻi o kēia compactness i nā noi i hoʻopaʻa ʻia i ka lewa, e like me nā polokalamu kelepona, nā inoa RFID, a me nā ʻōnaehana aerospace.
Hiki i ka hoʻohana ʻana i nā antenna fractal a me nā metasurfaces ke hoʻomaikaʻi nui i nā kamaʻilio uea, kiʻi kiʻi, a me nā ʻōnaehana radar, no ka mea hiki iā lākou ke hana i nā mea hana kiʻekiʻe me ka hana i hoʻonui ʻia. Eia kekahi, ke hoʻohana nui ʻia nei ka geometry fractal i ka hoʻolālā ʻana i nā mea ʻike microwave no nā diagnostics material, ma muli o kona hiki ke hana i nā kaha alapine he nui a me kona hiki ke hoʻonui ʻia. Ke hoʻomau nei ka noiʻi ʻana i kēia mau wahi i ka ʻimi ʻana i nā hoʻolālā hou, nā mea hana, a me nā ʻenehana hana e ʻike ai i ko lākou hiki piha.
Ke manaʻo nei kēia pepa e loiloi i ka noiʻi a me ka holomua noiʻi o nā antenna fractal a me nā metasurfaces a e hoʻohālikelike i nā antennas fractal-based a me nā metasurfaces, e hōʻike ana i ko lākou pono a me nā palena. ʻO ka hope, hōʻike ʻia kahi loiloi piha o nā reflectarrays hou a me nā ʻāpana metamaterial, a kūkākūkā ʻia nā pilikia a me nā hoʻomohala e hiki mai ana o kēia mau hale electromagnetic.
2. FractalAntennaʻElemu
Hiki ke hoʻohana ʻia ka manaʻo maʻamau o nā fractals e hoʻolālā i nā mea antenna exotic e hāʻawi i ka hana ʻoi aku ka maikaʻi ma mua o nā antenna maʻamau. Hiki i nā mea antenna Fractal ke paʻakikī i ka nui a loaʻa iā ia nā mana multi-band a / a i ʻole broadband.
ʻO ka hoʻolālā ʻana o nā antenna fractal e pili ana i ka hana hou ʻana i nā hiʻohiʻona geometric kikoʻī i nā unahi like ʻole i loko o ke ʻano antenna. Hiki i kēia ʻano hoʻohālike ponoʻī iā mākou ke hoʻonui i ka lōʻihi holoʻokoʻa o ka antenna i loko o kahi ākea kino. Eia kekahi, hiki i nā radiator fractal ke hoʻokō i nā ʻāpana he nui no ka mea ua like nā ʻāpana like ʻole o ka antenna i kēlā me kēia ma nā unahi like ʻole. No laila, hiki i nā mea antenna fractal ke paʻa a me ka multi-band, e hāʻawi ana i kahi ākea ākea ākea ma mua o nā antenna maʻamau.
Hiki ke huli ʻia ka manaʻo o nā antenna fractal i ka hopena o 1980s. I ka makahiki 1986, ua hōʻike ʻo Kim lāua ʻo Jaggard i ka hoʻohana ʻana i ka fractal self-similarity i ka synthesis array antenna.
I ka makahiki 1988, ua kūkulu ʻo Nathan Cohen i ka physicist i ka antenna fractal element mua loa o ka honua. Ua manaʻo ʻo ia ma ka hoʻokomo ʻana i ka geometry like-like i loko o ka hoʻolālā antenna, hiki ke hoʻomaikaʻi ʻia kāna hana a me nā hiki miniaturization. I ka makahiki 1995, ua hoʻokumu pū ʻo Cohen i ka Fractal Antenna Systems Inc., ka mea i hoʻomaka e hāʻawi i nā hoʻonā antenna fractal-based mua o ka honua.
Ma ka waena o 1990s, Puente et al. hōʻike i ka mana multi-band o fractals me ka monopole a me ka dipole o Sierpinski.
Mai ka hana a Cohen a me Puente, ua hoihoi nui nā mea pono o nā antenna fractal mai nā mea noiʻi a me nā ʻenekinia ma ke kahua o ke kelepona, e alakaʻi ana i ka ʻimi hou a me ka hoʻomohala ʻana i ka ʻenehana antenna fractal.
I kēia lā, hoʻohana nui ʻia nā antenna fractal i nā ʻōnaehana kamaʻilio uila, me nā kelepona paʻalima, nā mea ala Wi-Fi, a me nā kamaʻilio satelite. ʻO ka ʻoiaʻiʻo, he liʻiliʻi nā antenna fractal, multi-band, a maikaʻi loa, e kūpono ai ia no nā ʻano ʻenehana uila a me nā pūnaewele.
Hōʻike nā kiʻi ma lalo nei i kekahi mau antenna fractal e pili ana i nā ʻano fractal kaulana, he mau laʻana wale nō ia o nā hoʻonohonoho like ʻole i kūkākūkā ʻia ma ka palapala.
ʻO ke kikoʻī, hōʻike ka Figure 2a i ka monopole Sierpinski i manaʻo ʻia ma Puente, hiki ke hāʻawi i ka hana multi-band. Hoʻokumu ʻia ka huinakolu Sierpinski ma ka unuhi ʻana i ka huinakolu waena mai ka huinakolu nui, e like me ka mea i hōʻike ʻia ma ke Kiʻi 1b a me ke Kiʻi 2a. Ke waiho nei keia hana i ekolu huinakolu like ma ka hale, me ka hapalua o ka aoao o ka huinakolu mua (e nana i ke Kii 1b). Hiki ke hana hou i ke kaʻina hana unuhi like no nā huinakolu i koe. No laila, ʻo kēlā me kēia o kāna mau ʻāpana nui ʻekolu, ua like like me ka mea holoʻokoʻa, akā i ka pālua o ka hoʻohālikelike, a pēlā aku. Ma muli o kēia mau mea like kūikawā, hiki iā Sierpinski ke hāʻawi i nā ʻāpana alapine he nui no ka mea ua like nā ʻāpana like ʻole o ka antenna i kekahi i kekahi ma nā unahi like ʻole. E like me ka mea i hōʻike ʻia ma ke Kiʻi 2, e hana ana ka monopole Sierpinski i manaʻo ʻia ma 5 mau pūʻulu. Hiki ke ʻike ʻia ʻo kēlā me kēia ʻelima sub-gaskets (nā ʻāpana pōʻai) ma ke Kiʻi 2a he ʻano hoʻohālikelike o ka hale holoʻokoʻa, no laila e hāʻawi ana i ʻelima mau kaha alapine hana like ʻole, e like me ka mea i hōʻike ʻia ma ka helu hoʻohālikelike hoʻokomo ma ke Kiʻi 2b. Hōʻike pū ke kiʻi i nā ʻāpana e pili ana i kēlā me kēia ʻāpana alapine, me ka waiwai alapine fn (1 ≤ n ≤ 5) ma ka liʻiliʻi loa o ka poho hoʻihoʻi komo i ana ʻia (Lr), ka bandwidth pili (Bwidth), a me ka ratio alapine ma waena. ʻelua mau kaha alapine e pili ana (δ = fn +1/fn). Hōʻike ka Kiʻi 2b i ka logaritmiki i hoʻokaʻawale ʻia nā kaula o nā monopoles Sierpinski i kēlā me kēia manawa e ka helu o 2 (δ ≅ 2), e pili ana i ka mea hoʻohālikelike like i loaʻa i nā hale like me ke ʻano fractal.
huahelu 2
Hōʻike ke kiʻi 3a i kahi antenna uea lōʻihi liʻiliʻi e pili ana i ka pihi fractal Koch. Kuhi ʻia kēia antenna e hōʻike i ka hoʻohana ʻana i nā waiwai hoʻopiha piha o nā ʻano fractal e hoʻolālā i nā antenna liʻiliʻi. ʻO ka ʻoiaʻiʻo, ʻo ka hōʻemi ʻana i ka nui o nā antenna ka pahuhopu nui o ka nui o nā noi, ʻoi aku ka nui o nā mea e pili ana i nā terminal mobile. Hoʻokumu ʻia ka monopole Koch me ke ʻano hana fractal i hōʻike ʻia ma ke Kiʻi 3a. ʻO ka hoʻomaka mua K0 he monopole pololei. Loaʻa ka hoʻololi hou ʻana K1 ma ka hoʻohana ʻana i ka hoʻololi like ʻana me K0, me ka hoʻonui ʻana i ka hapakolu a me ka hoʻololi ʻana e 0°, 60°, −60°, a me 0°. Hoʻohana hou ʻia kēia kaʻina hana no ka loaʻa ʻana o nā mea hope Ki (2 ≤ i ≤ 5). Hōʻike ka Figure 3a i kahi mana ʻelima-iteration o ka monopole Koch (ie, K5) me ke kiʻekiʻe h like me 6 knm, akā hāʻawi ʻia ka lōʻihi holoʻokoʻa e ke kumu l = h ·(4/3) 5 = 25.3 knm. ʻElima mau antenna e pili ana i nā ʻelima mua o ka pihi Koch i ʻike ʻia (e nānā i ke kiʻi 3a). Hōʻike nā hoʻokolohua ʻelua a me nā ʻikepili e hiki i ka Koch fractal monopole ke hoʻomaikaʻi i ka hana o ka monopole kuʻuna (e nānā i ke kiʻi 3b). Hōʻike kēia i hiki ke "miniaturize" i nā antenna fractal, e ʻae iā lākou e komo i loko o nā puke liʻiliʻi aʻo ka mālama ʻana i ka hana kūpono.
huahelu 3
Hōʻike ka Figure 4a i kahi antenna fractal e pili ana i kahi hoʻonohonoho Cantor, i hoʻohana ʻia e hoʻolālā i kahi antenna wideband no nā noi ʻohi ikehu. Hoʻohana ʻia ka waiwai kūʻokoʻa o nā antenna fractal e hoʻolauna i nā resonances pili e hāʻawi i kahi bandwidth ākea ma mua o nā antenna maʻamau. E like me ka mea i hōʻike ʻia ma ke Kiʻi 1a, he maʻalahi loa ka hoʻolālā ʻana o ka hui fractal Cantor: kope ʻia ka laina pololei mua a māhele ʻia i ʻekolu mau ʻāpana like, kahi e wehe ʻia ai ka ʻāpana waena; a laila hoʻohana ʻia ka hana like i nā ʻāpana hou i hana ʻia. Hoʻopau hou ʻia nā ʻanuʻu fractal a hiki i ka loaʻa ʻana o kahi bandwidth antenna (BW) o 0.8–2.2 GHz (ʻo ia hoʻi, 98% BW). Hōʻike ka Figure 4 i ke kiʻi o ka prototype antenna i ʻike ʻia (Figure 4a) a me kāna coefficient noʻonoʻo hoʻokomo (Figure 4b).
huahelu 4
Hāʻawi ka Figure 5 i nā hiʻohiʻona hou aʻe o nā antenna fractal, me kahi antenna monopole e pili ana i ka curve Hilbert, kahi antenna patch microstrip ma Mandelbrot, a me kahi moku ʻo Koch (a i ʻole "snowflake") fractal patch.
huahelu 5
ʻO ka mea hope loa, hōʻike ʻia ke Kiʻi 6 i nā hoʻonohonoho fractal like ʻole o nā mea hoʻonohonoho, me nā ʻāpana planar carpet Sierpinski, nā pūlima kani Cantor, nā laina laina Cantor, a me nā lāʻau fractal. Pono kēia mau hoʻonohonoho no ka hoʻokumu ʻana i nā arrays sparse a / a i ʻole ka hoʻokō ʻana i ka hana multi-band.
huahelu 6
No ka ʻike hou aku e pili ana i nā antenna, e kipa:
Ka manawa hoʻouna: Iulai-26-2024
