Xov Xwm - Kev tshuaj xyuas ntawm cov kab xaim xaim xaim raws li metamaterials (Part 2)

2. Daim ntawv thov ntawm MTM-TL hauv Antenna Systems
Tshooj lus no yuav tsom mus rau cov khoom siv dag zog metamaterial TLs thiab qee qhov ntawm lawv cov kev siv ntau tshaj plaws thiab cuam tshuam rau kev paub txog ntau yam kav hlau txais xov nrog tus nqi qis, kev tsim khoom yooj yim, miniaturization, dav bandwidth, siab nce thiab efficiency, ntau yam scanning muaj peev xwm thiab tsawg profile. Lawv tau tham hauv qab no.

1. Broadband thiab ntau zaus kav hlau txais xov
Nyob rau hauv ib tug raug TL nrog ib tug ntev ntawm l, thaum lub angular zaus ω0 tau muab, qhov hluav taws xob ntev (los yog theem) ntawm cov kab sib txuas yuav raug xam raws li nram no:

Qhov twg vp sawv cev rau theem tshaj tawm ntawm cov kab sib kis. Raws li tau pom los ntawm cov saum toj no, lub bandwidth sib raug zoo rau cov pab pawg neeg ncua, uas yog cov derivative ntawm φ nrog rau cov zaus. Yog li ntawd, raws li qhov ntev ntawm cov kab sib kis tau luv dua, lub bandwidth kuj yuav dav dua. Hauv lwm lo lus, muaj kev sib raug zoo ntawm cov bandwidth thiab cov theem tseem ceeb ntawm cov kab sib kis, uas yog tsim tshwj xeeb. Qhov no qhia tau hais tias nyob rau hauv ib txwm faib circuits, kev khiav hauj lwm bandwidth tsis yooj yim los tswj. Qhov no tuaj yeem raug ntaus nqi rau cov kev txwv ntawm cov kab sib txuas ib txwm nyob hauv cov ntsiab lus ntawm kev ywj pheej. Txawm li cas los xij, cov khoom thauj khoom tso cai rau cov kev txwv ntxiv los siv rau hauv metamaterial TLs, thiab cov lus teb theem tuaj yeem tswj tau qee yam. Txhawm rau kom cov bandwidth nce ntxiv, nws yog ib qho tsim nyog yuav tsum muaj txoj kab nqes zoo sib xws nyob ze ntawm qhov kev khiav hauj lwm zaus ntawm cov yam ntxwv dispersion. Artificial metamaterial TL tuaj yeem ua tiav lub hom phiaj no. Raws li txoj hauv kev no, ntau txoj hauv kev los txhim kho qhov bandwidth ntawm cov kav hlau txais xov yog npaj rau hauv daim ntawv. Cov kws tshawb fawb tau tsim thiab tsim ob lub kav hlau txais xov broadband uas muaj cov nplhaib sib cais (saib daim duab 7). Cov txiaj ntsig tau pom hauv daim duab 7 qhia tau hais tias tom qab thauj khoom ntawm lub nplhaib sib cais resonator nrog cov pa kav hlau txais xov monopole, qhov qis resonant zaus hom zoo siab heev. Qhov luaj li cas ntawm lub nplhaib sib cais resonator yog optimized kom ua tau ib tug resonance ze ntawm lub monopole kav hlau txais xov. Cov txiaj ntsig tau pom tias thaum ob lub resonances coincide, bandwidth thiab radiation yam ntxwv ntawm tus kav hlau txais xov tau nce. Qhov ntev thiab dav ntawm lub kav hlau txais xov monopole yog 0.25λ0 × 0.11λ0 thiab 0.25λ0 × 0.21λ0 (4GHz), feem, thiab qhov ntev thiab dav ntawm lub kav hlau txais xov monopole loaded nrog lub nplhaib sib cais yog 0.29λ0 × 0.21λ0 (2.9GHz ), raws. Rau cov pa kav hlau txais xov F-shaped thiab T-shaped kav hlau txais xov tsis muaj lub nplhaib sib cais, qhov kev nce siab tshaj plaws thiab hluav taws xob hluav taws xob ntsuas hauv 5GHz band yog 3.6dBi - 78.5% thiab 3.9dBi - 80.2%, feem. Rau lub kav hlau txais xov loaded nrog ib tug split nplhaib resonator, cov tsis yog 4dBi - 81.2% thiab 4.4dBi - 83%, feem, nyob rau hauv lub 6GHz band. Los ntawm kev siv lub nplhaib sib cais resonator raws li qhov sib txuam ntawm cov kav hlau txais xov monopole, 2.9GHz ~ 6.41GHz thiab 2.6GHz ~ 6.6GHz bands tuaj yeem txhawb nqa, sib xws rau feem ntau bandwidths ntawm 75.4% thiab ~ 87%, feem. Cov txiaj ntsig no qhia tau tias qhov ntsuas bandwidth tau txhim kho los ntawm kwv yees li 2.4 npaug thiab 2.11 npaug piv rau cov kav hlau txais xov monopole ntawm kwv yees li qhov loj me.

Daim duab 7. Ob lub broadband kav hlau txais xov loaded nrog split-ring resonators.

Raws li pom nyob rau hauv daim duab 8, qhov kev sim tau tshwm sim ntawm lub compact printed monopole kav hlau txais xov yog qhia. Thaum S11≤- 10 dB, kev khiav hauj lwm bandwidth yog 185% (0.115-2.90 GHz), thiab ntawm 1.45 GHz, lub ncov nce thiab hluav taws xob efficiency yog 2.35 dBi thiab 78.8%, feem. Qhov kev teeb tsa ntawm tus kav hlau txais xov zoo ib yam li daim duab peb sab rov qab-rau-rov qab, uas yog pub los ntawm curvilinear fais fab faib. GND truncated muaj ib lub hauv paus stub muab tso rau hauv lub feeder, thiab plaub qhib resonant rings raug faib nyob ib ncig ntawm nws, uas widens lub bandwidth ntawm lub kav hlau txais xov. Lub kav hlau txais xov radiates yuav luag omnidirectionally, npog feem ntau ntawm VHF thiab S bands, thiab tag nrho cov UHF thiab L bands. Lub cev loj ntawm lub kav hlau txais xov yog 48.32 × 43.72 × 0.8 mm3, thiab hluav taws xob loj yog 0.235λ0 × 0.211λ0 × 0.003λ0. Nws muaj qhov zoo ntawm qhov me me thiab tus nqi qis, thiab muaj peev xwm thov kev cia siab rau hauv kev sib txuas lus broadband wireless.

Daim duab 8: Monopole kav hlau txais xov loaded nrog split nplhaib resonator.

Daim duab 9 qhia tau hais tias tus qauv kav hlau txais xov muaj xws li ob khub ntawm kev sib txuas ntawm cov hlau txuas txuas txuas rau hauv av rau lub dav hlau T-shaped hauv av los ntawm ob txoj kab. Tus kav hlau txais xov loj yog 38.5 × 36.6 mm2 (0.070λ0 × 0.067λ0), qhov twg λ0 yog qhov chaw dawb ntawm 0.55 GHz. Lub kav hlau txais xov radiates omnidirectionally nyob rau hauv E-plane nyob rau hauv kev khiav hauj lwm zaus band ntawm 0.55 ~ 3.85 GHz, nrog ib tug siab tshaj plaws nce ntawm 5.5dBi ntawm 2.35GHz thiab ib tug efficiency ntawm 90.1%. Cov yam ntxwv no ua rau cov kav hlau txais xov tsim nyog rau ntau daim ntawv thov, suav nrog UHF RFID, GSM 900, GPS, KPCS, DCS, IMT-2000, WiMAX, WiFi thiab Bluetooth.

Fig. 9 Daim phiaj xwm txheej kav hlau txais xov.

2. Leaky Wave Antenna (LWA)
Tus kav hlau txais xov leaky yoj tshiab yog ib qho ntawm cov ntawv thov tseem ceeb rau kev paub txog cov khoom siv metamaterial TL. Rau cov kav hlau txais xov xaim nthwv dej, qhov cuam tshuam ntawm theem tas li β ntawm lub kaum sab xis ntawm lub voj voog (θm) thiab qhov siab tshaj kab dav (Δθ) yog raws li hauv qab no:

L yog tus kav hlau txais xov ntev, k0 yog tus lej nthwv dej hauv qhov chaw dawb, thiab λ0 yog lub wavelength hauv qhov chaw dawb. Nco ntsoov tias hluav taws xob tshwm sim tsuas yog thaum |β|

3. Zero-order resonator kav hlau txais xov
Ib qho khoom tshwj xeeb ntawm CRLH metamaterial yog tias β tuaj yeem yog 0 thaum qhov zaus tsis sib npaug rau xoom. Raws li cov cuab yeej no, lub zero-order resonator (ZOR) tuaj yeem tsim tawm. Thaum β yog xoom, tsis muaj theem hloov pauv tshwm sim hauv tag nrho cov resonator. Qhov no yog vim hais tias cov theem hloov tas li φ = - βd = 0. Tsis tas li ntawd, lub resonance tsuas yog nyob ntawm lub reactive load thiab yog ywj siab ntawm qhov ntev ntawm cov qauv. Daim duab 10 qhia tau hais tias cov kav hlau txais xov tau tsim los ntawm kev siv ob thiab peb chav nrog E-puab, thiab tag nrho qhov loj yog 0.017λ0 × 0.006λ0 × 0.001λ0 thiab 0.028λ0 × 0.008λ0 × 0.001λ0, ntsig txog, qhov twg λeng 0. ntawm qhov chaw dawb ntawm kev khiav hauj lwm zaus ntawm 500 MHz thiab 650 MHz, feem. Lub kav hlau txais xov ua haujlwm ntawm zaus ntawm 0.5-1.35 GHz (0.85 GHz) thiab 0.65-1.85 GHz (1.2 GHz), nrog cov txheeb ze bandwidths ntawm 91.9% thiab 96.0%. Ntxiv nrog rau cov yam ntxwv ntawm qhov me me thiab dav bandwidth, qhov nce thiab kev ua haujlwm ntawm thawj thiab thib ob kav hlau txais xov yog 5.3dBi thiab 85% (1GHz) thiab 5.7dBi thiab 90% (1.4GHz), feem.

Fig. 10 Npaj ob-E thiab triple-E kav hlau txais xov.

4. Qhov kav hlau txais xov
Ib txoj hauv kev yooj yim tau thov kom nthuav dav lub aperture ntawm CRLH-MTM kav hlau txais xov, tab sis nws cov kav hlau txais xov loj yuav luag tsis hloov. Raws li pom nyob rau hauv daim duab 11, lub kav hlau txais xov muaj xws li CRLH units stacked vertically rau ib leeg, uas muaj thaj ua rau thaj thiab meander kab, thiab muaj ib tug S-shaped slot rau thaj. Lub kav hlau txais xov yog pub los ntawm CPW qhov sib txuam stub, thiab nws qhov loj yog 17.5 mm × 32.15 mm × 1.6 mm, sib xws rau 0.204λ0 × 0.375λ0 × 0.018λ0, qhov twg λ0 (3.5GHz) sawv cev rau lub wavelength ntawm qhov chaw dawb. Cov txiaj ntsig tau pom tias tus kav hlau txais xov ua haujlwm hauv qhov zaus ntawm 0.85-7.90GHz, thiab nws cov kev khiav hauj lwm bandwidth yog 161.14%. Qhov siab tshaj plaws hluav taws xob nce thiab kev ua haujlwm ntawm lub kav hlau txais xov tshwm sim ntawm 3.5GHz, uas yog 5.12dBi thiab ~ 80%, feem.