Nkhani - Ndemanga ya Ma Antena a Metamaterial Transmission Line

I. Chiyambi
Zinthu zosinthika zitha kufotokozedwa bwino ngati zinthu zopangidwa mwaluso kuti zipange zinthu zina zamagetsi zomwe sizilipo mwachilengedwe. Zinthu zosinthika zomwe zili ndi chilolezo choyipa komanso kulowererapo koyipa zimatchedwa zinthu zosinthika ndi dzanja lamanzere (LHMs). Zinthu zosinthika ndi zamoyo zaphunziridwa kwambiri m'magulu asayansi ndi mainjiniya. Mu 2003, zinthu zosinthika ndi zamoyo zina zidatchulidwa kuti ndi chimodzi mwa zinthu khumi zapamwamba kwambiri zasayansi za nthawi yamakono ndi magazini ya Science. Ntchito zatsopano, malingaliro, ndi zida zapangidwa pogwiritsa ntchito zinthu zapadera za zinthu zosinthika ndi zamoyo zamoyo zamoyo. Njira yotumizira mzere (TL) ndi njira yothandiza yopangira zinthu zomwe zingathenso kusanthula mfundo za zinthu zosinthika ndi zamoyo zamoyo. Poyerekeza ndi zinthu zosinthika ndi zamoyo zamoyo, chinthu chofunikira kwambiri pa zinthu zosinthika ndi zinthu zosinthika ndi kusinthasintha kwa zinthu zosinthika ndi mphamvu yamagetsi. Kusinthasintha kwa zinthu zosinthika ndi zinthu zosinthika kumapereka malingaliro atsopano opangira zinthu zosinthika ndi kukula kochepa, magwiridwe antchito apamwamba, komanso ntchito zatsopano. Chithunzi 1 (a), (b), ndi (c) zikuwonetsa mitundu ya ma circuit osatayika a mzere woyipa wotumizira wamanja (PRH), mzere woyipa wotumizira wamanja (PLH), ndi mzere wotumizira wamanja wophatikizana (CRLH), motsatana. Monga momwe zasonyezedwera mu Chithunzi 1(a), chitsanzo cha PRH TL chofanana nthawi zambiri chimakhala kuphatikiza kwa ma inductance a mndandanda ndi shunt capacitance. Monga momwe zasonyezedwera mu Chithunzi 1(b), chitsanzo cha PLH TL ndi kuphatikiza kwa shunt inductance ndi series capacitance. Mu ntchito zothandiza, sizingatheke kukhazikitsa PLH circuit. Izi zimachitika chifukwa cha zotsatira zosapeŵeka za parasitic series inductance ndi shunt capacitance. Chifukwa chake, makhalidwe a mzere wotumizira wamanja omwe angathe kuchitika pakadali pano ndi onse ophatikizana a dzanja lamanzere ndi lamanja, monga momwe zasonyezedwera mu Chithunzi 1(c).

Chithunzi 1 Mitundu yosiyanasiyana ya ma transmission line circuit

Chokhazikika chofalitsa (γ) cha mzere wotumizira (TL) chimawerengedwa motere: γ=α+jβ=Sqrt(ZY), pomwe Y ndi Z zikuyimira kulowa ndi kuletsa motsatana. Poganizira CRLH-TL, Z ndi Y zitha kufotokozedwa motere:

CRLH TL yofanana idzakhala ndi ubale wotsatirawu wa kufalikira:

Gawo lokhazikika la β likhoza kukhala nambala yeniyeni kapena nambala yongoganizira chabe. Ngati β ndi yeniyeni kwathunthu mkati mwa ma frequency range, pali passband mkati mwa ma frequency range chifukwa cha γ=jβ. Kumbali ina, ngati β ndi nambala yongoganizira chabe mkati mwa ma frequency range, pali stopband mkati mwa ma frequency range chifukwa cha γ=α. Stopband iyi ndi yapadera kwa CRLH-TL ndipo siilipo mu PRH-TL kapena PLH-TL. Zithunzi 2 (a), (b), ndi (c) zikuwonetsa ma dispersion curve (monga, ubale wa ω - β) wa PRH-TL, PLH-TL, ndi CRLH-TL, motsatana. Kutengera ma dispersion curve, group velocity (vg=∂ω/∂β) ndi phase velocity (vp=ω/β) ya transmission line zitha kupezedwa ndikuyerekezeredwa. Kwa PRH-TL, zitha kuganiziridwanso kuchokera ku curve kuti vg ndi vp ndi ofanana (monga, vpvg>0). Pa PLH-TL, kapito imasonyeza kuti vg ndi vp sizili zofanana (monga, vpvg<0). Kapito yofalikira ya CRLH-TL imasonyezanso kukhalapo kwa dera la LH (monga, vpvg <0) ndi dera la RH (monga, vpvg > 0). Monga momwe tikuonera kuchokera pa Chithunzi 2(c), pa CRLH-TL, ngati γ ndi nambala yeniyeni yeniyeni, pali gulu loyimitsa.

Chithunzi 2 Ma curve ofalikira a mizere yosiyanasiyana yotumizira

Kawirikawiri, ma resonance a mndandanda ndi ofanana a CRLH-TL ndi osiyana, omwe amatchedwa unbalanced state. Komabe, pamene ma resonance a mndandanda ndi ofanana ali ofanana, amatchedwa balanced state, ndipo chitsanzo cha circuit chofanana chomwe chimachokeracho chikuwonetsedwa mu Chithunzi 3(a).

Chithunzi 3 Chitsanzo cha dera ndi mzere wogawanikira wa mzere wolumikizirana wa dzanja lamanzere

Pamene ma frequency akuwonjezeka, makhalidwe a dispersion a CRLH-TL amawonjezeka pang'onopang'ono. Izi zili choncho chifukwa liwiro la gawo (monga, vp=ω/β) limadalira kwambiri ma frequency. Pa ma frequency otsika, CRLH-TL imalamulidwa ndi LH, pomwe pa ma frequency apamwamba, CRLH-TL imalamulidwa ndi RH. Izi zikuwonetsa mtundu wa CRLH-TL wawiri. Chithunzi cha dispersion cha CRLH-TL chofanana chikuwonetsedwa mu Chithunzi 3(b). Monga momwe zasonyezedwera mu Chithunzi 3(b), kusintha kuchokera ku LH kupita ku RH kumachitika pa:

Kumene ω0 ndi ma frequency osinthira. Chifukwa chake, pankhani yolinganiza, kusintha kosalala kumachitika kuchokera ku LH kupita ku RH chifukwa γ ndi nambala yongoganizira chabe. Chifukwa chake, palibe stopband ya dispersion ya CRLH-TL yolinganiza. Ngakhale β ndi zero pa ω0 (yopanda malire poyerekeza ndi kutalika kwa mafunde otsogozedwa, mwachitsanzo, λg=2π/|β|), mafunde amafalikirabe chifukwa vg pa ω0 si zero. Mofananamo, pa ω0, kusintha kwa gawo ndi zero pa TL ya kutalika d (mwachitsanzo, φ= - βd=0). Kupita patsogolo kwa gawo (mwachitsanzo, φ>0) kumachitika mu LH frequency range (mwachitsanzo, ω<ω0), ndipo kuchedwa kwa gawo (mwachitsanzo, φ<0) kumachitika mu RH frequency range (mwachitsanzo, ω>ω0). Kwa CRLH TL, kuletsa kwa khalidwe kumafotokozedwa motere:

Pamene ZL ndi ZR ndi PLH ndi PRH impedances, motsatana. Pa mlandu wosalinganika, kukanikiza kwa khalidwe kumadalira pafupipafupi. Equation yomwe ili pamwambapa ikuwonetsa kuti mlandu wolinganika umadalira pafupipafupi, kotero ukhoza kukhala ndi bandwidth yofanana. Equation ya TL yomwe yachokera pamwambapa ndi yofanana ndi magawo omwe amafotokoza zinthu za CRLH. Kukanikiza kofalikira kwa TL ndi γ=jβ=Sqrt(ZY). Popeza kukanikiza kofalikira kwa zinthuzo (β=ω x Sqrt(εμ)), equation yotsatirayi ingapezeke:

Mofananamo, kuletsa kwa khalidwe la TL, mwachitsanzo, Z0=Sqrt(ZY), kuli kofanana ndi kuletsa kwa khalidwe la zinthu, mwachitsanzo, η=Sqrt(μ/ε), komwe kumafotokozedwa motere:

Chizindikiro cha refractive cha CRLH-TL yolinganizidwa komanso yosalinganizidwa (monga, n = cβ/ω) chikuwonetsedwa mu Chithunzi 4. Mu Chithunzi 4, chizindikiro cha refractive cha CRLH-TL mu LH range yake ndi negative ndipo chizindikiro cha refractive mu RH range yake ndi positive.

Chithunzi 4 Zizindikiro zodziwika bwino za ma CRLH TL olinganizidwa komanso osalinganizidwa.

1. Netiweki ya LC
Mwa kuyika maselo a LC a bandpass omwe akuwonetsedwa mu Chithunzi 5(a), CRLH-TL wamba wokhala ndi kufanana kogwira ntchito kwa kutalika kwa d ukhoza kupangidwa nthawi ndi nthawi kapena osati nthawi ndi nthawi. Kawirikawiri, kuti zitsimikizire kuti kuwerengera ndi kupanga kwa CRLH-TL kuli kosavuta, dera liyenera kukhala lozungulira nthawi ndi nthawi. Poyerekeza ndi chitsanzo cha Chithunzi 1(c), selo la dera la Chithunzi 5(a) lilibe kukula ndipo kutalika kwake ndi kochepa kwambiri (monga, Δz mu mamita). Poganizira kutalika kwake kwamagetsi θ=Δφ (rad), gawo la selo la LC likhoza kufotokozedwa. Komabe, kuti tizindikire bwino inductance ndi capacitance yogwiritsidwa ntchito, kutalika kwa thupi p kuyenera kukhazikitsidwa. Kusankha ukadaulo wogwiritsira ntchito (monga microstrip, coplanar waveguide, zigawo zoyika pamwamba, ndi zina zotero) kudzakhudza kukula kwa thupi kwa selo la LC. Selo la LC la Chithunzi 5(a) ndi lofanana ndi chitsanzo chowonjezera cha Chithunzi 1(c), ndipo malire ake p=Δz→0. Malinga ndi momwe zinthu zilili p→0 mu Chithunzi 5(b), TL ikhoza kupangidwa (ndi maselo a LC otuluka) omwe ndi ofanana ndi CRLH-TL yoyenera yokhala ndi kutalika kwa d, kotero kuti TL imawoneka yofanana ndi mafunde amagetsi.

Chithunzi 5 CRLH TL kutengera netiweki ya LC.

Kwa selo la LC, poganizira za mikhalidwe ya malire a periodic (PBCs) yofanana ndi chiphunzitso cha Bloch-Floquet, ubale wa kufalikira kwa selo la LC umatsimikiziridwa ndikuwonetsedwa motere:

Mzere wa impedance (Z) ndi shunt admittance (Y) wa selo la LC umatsimikiziridwa ndi ma equation otsatirawa:

Popeza kutalika kwa magetsi kwa dera la LC ndi kochepa kwambiri, Taylor approximation ingagwiritsidwe ntchito kupeza:

2. Kukhazikitsa Mwakuthupi
Mu gawo lapitalo, netiweki ya LC yopanga CRLH-TL yakambidwa. Ma netiweki otere a LC amatha kuchitika pokhapokha pogwiritsa ntchito zigawo zakuthupi zomwe zingapangitse capacitance yofunikira (CR ndi CL) ndi inductance (LR ndi LL). M'zaka zaposachedwa, kugwiritsa ntchito zigawo za chip za pamwamba (SMT) kapena zigawo zogawidwa kwakopa chidwi chachikulu. Microstrip, stripline, coplanar waveguide kapena ukadaulo wina wofanana ungagwiritsidwe ntchito popanga zigawo zogawidwa. Pali zinthu zambiri zoti muziganizire posankha ma chip a SMT kapena zigawo zogawidwa. Kapangidwe ka CRLH kochokera ku SMT ndi kofala kwambiri komanso kosavuta kugwiritsa ntchito pankhani yowunikira ndi kapangidwe. Izi zili choncho chifukwa cha kupezeka kwa zigawo za chip za SMT zomwe sizikufunika kukonzedwanso, zomwe sizifuna kukonzedwanso ndi kupangidwa poyerekeza ndi zigawo zogawidwa. Komabe, kupezeka kwa zigawo za SMT kumafalikira, ndipo nthawi zambiri zimagwira ntchito pama frequency otsika (monga, 3-6GHz). Chifukwa chake, kapangidwe ka CRLH kochokera ku SMT kali ndi ma frequency ochepa ogwirira ntchito komanso mawonekedwe enaake a gawo. Mwachitsanzo, mu ntchito zowunikira, zigawo za chip za SMT sizingakhale zotheka. Chithunzi 6 chikuwonetsa kapangidwe kogawidwa kochokera ku CRLH-TL. Kapangidwe kake kamachitika pogwiritsa ntchito mizera yapakati pa digito ndi mizere yafupikitsa, zomwe zimapangitsa kuti pakhale mizera ya CL ndi mizera ya LH yofanana. Mizere pakati pa mzere ndi GND imaganiziridwa kuti ndi RH capacitance CR, ndipo mizera yopangidwa ndi maginito opangidwa ndi kayendedwe ka magetsi mu kapangidwe ka mizera imaganiziridwa kuti ndi RH inductance LR.