Antenna Vi Dai (2)

7/31/2019 Antenna Vi Dai (2)

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Ging vin:Nguyn Thanh Vit

ANTEN VI DI

TRNG H KHOA HC T NHINKHOA IN T VIN THNG

CHUYN NGNH VIN THNG


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Thchin: Nhm RFG

1. TrnBo Chu 09200082. BinNgc Duy 0920013

3. TrnVnDng 0920019

4. NguynKhc Duy Khnh 0920048

5. NguynVn Bnh 09201526. Nguyn Minh Hong 0920177

7. Phan Thanh Minh 0920200

8. Phm Nguyn Phc 0920214

9. Trn Trung Tn 0920236

10. L Bo Trung 0920240


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Content

Slctruyn thngkhng dy

Cbnvanten

Anten vi diThitk vm phng

Ktlun


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S LC V TRUYNTHNG KHNG DY

1 Hthng di ng (Cellular

System)Thi k u

2 Hthng di ng (Cellular

System)Hinti v tng lai

3 Cutointhoi di ng

(Cellular phone)


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Thi k u

Dchv in thoi cng cng u tin btuM vo nm 1946.

Dchv ny ch cung cpchb bn songcng (half duplex) vi bng thng truyn120kHz.

ngiathp nin 1960, vis pht trinca cng ngh, bng thng cho victruyn

ging ni gimxung cn 30kHz v c thcung cpdchv song cng (Full duplex).

Tuy nhin vic c qu t knh v nhu cus dng ngy cng tng lm cho dch vny nhanh chng b bo ha.


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Thi k u

Vo thp nin 1960, phng th nghimAT&T Bell v mt s cng ty vin thngkhc pht trin cng nghinthoi radiodi ng/t bo (cellular radiotelephony)

khi nimcavic chia nhng vng chungthnh nhngt bo nh, mit bo lisdng linhngphndcaph tngphsdng trong nhngh thngcshtng.

Hnh 1.1 thhinvic ti sdngtns.


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Thi k u

Hnh 1.1 M hnh tisdngtns


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Thi k u

Knh c th c s dng li ch khi khong cch gia cc btruyngim cannhiu.

Nm 1983, FFC (Federal Communications

Commission - y ban truyn thng lin bang)phn phi cc knh cho AMPS (AdvancedMobile Phone System h thngin thoidi ng ci tin) trong khong 824 894MHz.

AMPS s dng iu ch tn s tng tcng vi FDMA (Frequency Division Multiple

Accessa truy cp phn chia tns).


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Thi k u

Frequency Division Multiple Access


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Thi k u

Nm 1991, hthngsu tin cthitlpnhng thnh ph chnh caM.

H thng ny c gi l USDC (U.S. DigitalCellular) v s dng iu ch s cng vi

TDMA (Time Division Multiple Access) tc cng sutgp 3 ln.

Sdng cng ditnsvi AMPS (824 894MHz).

IS 95 l h thngs tip theo c thit lpvo nm 1993 v s dng CDMA (CodeDivision Multiple Access) vi bng thng knhkhong 1.25 MHz v s dng iu ch

QPSK/BPSK.


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Thi k u

Time Division Multiple Access and Code Division Multiple Access


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Thi k u

Nm 1995, dch v PCS (PersonalCommunication Services Dchv truyn thngc nhn) ra i.

Mt v d ca h thng PCS l DCS-1900 s

dngdi 1850-1900 MHz v vncsdngngy nay.

Hthng ny da trn TDMA v c ssptknh 200 kHz v 8 khe. Hthngcng cung cp

nhngdchvnhnhs, gi ID v email. Trong mththng PCS, t bo c chia hn

na thnh nhng macrocell, microcell v picocell c th kt hp mt cch linh hot hn nh

trong hnh 1.2.


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Thi k u

Hnh 1.2Cu trcdi ngtrong PCS


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Hinti v tng lai

Hnh 1.3Mnglidingngy nay vtnglai


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Hinti v tng lai

Mt h thng a phng tin mt t/vtinh s c tch hp. Truyn thng trnton cusch tr thng qua v tinhs dng cng v tinh kt ni vi cc

mngcnhmtt. Cp ngm, si quang hay sng radio c

sdngktni cc cngnmngcnh.

Mng c nh s kt ni ti trm c scung cp kt ni n in thoi hoc ccthitbcm tay.


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Hinti v tng lai

Cc trmcs trong nh tnhngvnphng v nhng ni cng cng nh trmxe but hay ga xe la, sn bay v ca hngcngscktnitimngcnh.

nhngni khng th cung cp thng tintibi cc trmmtt hay mngcnh,v tinh scsdngktniti ccthitb c nhn.

Do , thitbcm tay qu thtsh traphngtin: tch hpging ni, dliu,tn hiu video...


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Hinti v tng lai

Ngi dng s truy cp vo mt phm virt rngcadchvnhgiin, fax, thin t, web, hingh video, mua hng txa v nhngdchvkhncp


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Hinti v tng lai

Mt thitbcm tay c th cung cp ttc ccng dng. Thit b c th c s dng nh, ktni timng di ng khi li xe. Tinilm vic, thit b c th kt ni ti h thngkhng dy ca vn phng. V trong nhngchuyn cng tc, ngi dng c th s dng

thitb thng qua v tinh

C i h i


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Cutointhoi di ng(Cellular phone)

Cellularphone

Board mchvicc vi x l

Mn hnh tinh thlng (LCD)

Anten

Pin Bn phm

Loa Microphone


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Cutointhoi di ng

Hnh 1.6 (Motorola Inc) l in thoi cmtay s dng vi h thng AMPS vo nm1983.


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Cutointhoi di ng

Hnh 1.7 l cc loi thitb cm tay trcy, qua cc giai on thi gian, thitb trnn nh v nhhn.


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Cutointhoi di ng

t c nhng thit k nh hn nhvy, mi thnh phn trong in thoi di ngcn lm nhhn. Nhngiukin thun lica cng ngh VLSI m bo cho nhng

microchip tr nn nhhn c thsdngcho vicx l nhng tn hiucnthit.


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Cutointhoi di ng

Anten l mt trong cc bphncntr nnnh v mnghn. iu ny s gip cho mtchicinthoitr nn thon gn.

Thit k nhng anten gn v mng, dngtrong nhngthitb di ng/PCS, l mcchca ti ny.


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C BN V ANTEN

1 Gii thiu Anten

2 S pht xca Anten

3 Vng trnggn v xa

4 Pht xtrng xa t dy dn

5 Cc hshiusutca Anten

6 Cc loi Anten thng dng


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Gii thiu

Anten l vt c cu trc kim loicdng pht v nhnnng lngint.

Mt anten hot ngnhmt thitbchuyntipgia cc thitbdnng(ng dn,ngtruyn) v khng gian.

IEEE nh ngha theo Stutzman vThiele: l mtphn ca h thngtruyn hay nhn c thit k phthaynhn sngint.


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S pht xca Anten

Trong pht xca anten, pht x dy dnl yut chnh v dng bini theo thi gianhay gia tc(gimtc)cain tch.

Nu khng c s chuyn ng ca intch trong dy dn,s khng c pht xxyra, dnn khng xuthin dng in.

Pht xs khng xy ra ngay c khi in

tch chuyn ng vi vn tc u dc theody dnthng.


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S pht xca Anten

Tuy nhin in tch chuyn ng vivntcu theo ng cong hay dy bb cong sxuthin pht x.

Nu in tch thay i theo thi gianpht xsxy ra sau thm ch cnxuthin trong dy dnthngnhcgii thch bi Balais.


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S pht xca Anten

Hnh 2.1 Phtxcamtanten


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S pht xca Anten

S pht x t mt anten c gii thchbi hnh 2.1 cho thyngunin p ktnivi hai dy truyn.

Khi c mtin p hnh sin i qua ng

truyn,mtin trngsc hnh thnh, l hnh sin v tiptuynvingtruyn.

ln ca in trng c tnh bi

cng dng in. Cc electron t do trndy dnnhhngncng dng inv chuyn ng ca cc in tch ny lnguyn nhn dnnvic hnh thnh mtt

trng.


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S pht xca Anten

V in trng v t trng thay itheo thi gian, sng intc hnhthnh v c s dch chuyn qua li

cc sng in t ny gia cc dydn.

Khi cc sng int ny i vo khnggian, cc sng khng gian t do chnh thnh bisngtt dng in.


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S pht xca Anten

V ngun hnh sin lin tc to ra snhiu lon in, cc sng in t cngc tao ra lin tc v c schuyndchcc sng ny xuyn qua ng truyn,qua anten v c pht x vo khnggian.

Trong ng truyn v anten sng in

tc duy tr lin tcbi cc in tch,nhng nhanh chng cy vo khnggian, to thnh nhng vng kn v cpht x.


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Vng trnggn v xa

C nhiu kiu trng, kt hp vi mtanten, thay i theo v tng thch vi hailoinnglng: nnglng pht x v nnglngphnx. Khng gian xung quanh mt

anten chia lm ba vng.

ReactiveNearField

Region

FarField

Region

RadiatingNearField

Region


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Vng trnggn v xa

Vngphnxtrnggn:trong vng nytrng phn x chim u th. Nng lngphnx dao nghng ti v i t anten,do xuthinnh l in khng.

Trong vng ny nng lng ch c lum khng c tiu tn. Ranh gii ngoicng ca khu vc ny l khong cch

vi R1 l khong cch tnh tb mt anten, D l kch thc ln nht caanten v l bc sng.

3

1 0.62 / R D


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Vng trnggn v xa

Vng phtxtrnggn(cn gi l vngFresnel): l khu vcnmgia vng phnxtrnggn v trng xa.

Cc trng phn x trong vng xa chim

u th. Trong vng ny, s phn b trnggc l hm cakhong cch t anten. Ranhgii ln nht ca vng c khong cch

vi R2 l khong cch tnh t bmt anten.

2

2 2D /R


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Vng trnggn v xa

Vng trng xa (cn gi l vngFraunhofer): khu vc ngoi l vngtrng xa.

Trong vng ny cc trngphnx khngcn v ch tn ti cc trng pht x. Trongvng ny s phn b trng gc khng phthuc vo khong cch t anten v mt cng sut bin i theo nghch o bnhphngkhong cch.

2

2 2D /R


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Vng trnggn v xa

ReactiveNear Field

Region

Far FieldRegion

Radiating

Near FieldRegion

Pht x trng xa


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Pht xtrng xat dy dn

Pht x trng xa


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Pht xtrng xat dy dn

Pht x trng xa ca mt lng ccHertzian c thcgii thch vihthngta hnh cunh hnh 2.3.

Trc z l trcthngng v mtphng xyl mt nm ngang, l gc nng v lgc phngv . Mtphng xz l mtphngnng ( =0) (hay mt phng E) l mtphngcha vector in trng v c phtx ln nht. Mt phng xy l mt phnggc phngv(=/2) (hay mtphng H)l mtphngcha vector lntrng v

c pht xlnnht.

Pht x trng xa


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Pht xtrng xat dy dn

Pht x trng xa c th c giithch nh vo lngcc Hertzian hoclngcc vi phn l mtphnca dydn

thng

cchiu

di L vng

knhrt nh so vi mt bc sng (Gismt dng in u chy qua chiu didy ).

Pht x trng xa


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Pht xtrng xat dy dn

Nu lngcc dng ny n trc z, ta cthvit:

2

2

(0) sin 1 11

4 ( )

(0) cos 11

2

(0) sin 11

4

0, 0, 0

jkr

jkr

r

jkr

r

kI LeE j

r jkr kr

I LeE

r jkr

kI LeH j

r jkr

H H H

Pht x trng xa


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Pht xtrng xat dy dn

Trong pht xtrng xa, r2

v r3

c thbqua, nn ta c th rt gnphng trnh:

Trong : l tr khng t do bn trong.

k= 2/ l hstruyn sng.

r l bn knh hnh cu.

(0)sin

4

(0) sin4

0

jkr

jkr

r

kI LeE j

r

kI LeH jr

E

Pht x trng xa


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Pht xtrng xat dy dn

Trong tt c phng trnh trn, pha ctruyni v ginhttctrng l hnh sinbin thin theo thi gian. Trong cc phngtrnh trn ch c trng khng v khng v

chng nhhngln nhau. Ta c , nhvytr khng sngl 120 v cc trng c pha tlnghchvir. Cc thnh phn E, H v r hnh thnh mtquay phinh vector Poynting trong hng rv n cho bit hng truyn ca sng int.

/E H

Pht x trng xa


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Pht xtrng xat dy dn

Trung bnh vector Poynting c thvit:

y E v H biudin gi trnhcaintrng v ttrng.

Cng sut pht trung bnh camt anten :

Trong ds l vi phn vector

l ln trung bnh vector Poynting.

* 21Re ( / )

2av

W E H Watts m

( )rad rad P W ds Watts 2 sinr d d r

Pht x trng xa


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Pht xtrng xat dy dn

Cng pht l cng sut pht tanten trn nv gc:

U l cng pht Watts trn mtnv gc.

2

rad

U r W

Cc h s hiu sut


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Cc hshiusutca Anten

Hiu sut ca mt anten c th c hiuchnhbi cc thng s:

1. M hnh pht x.

2. Snhhng.

3. Tr khng li vo.

4. Tlinth sng dng.

5. Suy hao phnx (Return Loss).

6. Hiusut.7. li.

8. S phn cc.

9. Bng thng.


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M hnh pht x

L mt th v nhng c tnh pht xtrng xa ca anten v l mt hm ta khng gian c trng bi gc nng v gcphngv.

Xt trng hp ca mt anten ng hng(Anten pht xnh nhau timihng):

Nu tng cng sut pht xca anten nghng l P, do cng sut s tri khphnh cu bn knh r, v vymt cng sutS ti khong cch ny bt k hng nol:

2

ar 4

P PS

ea


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M hnh pht x

Mt pht xca anten nghng:

th pht x chung ca anten nhhng:

2

4i

PU r S


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M hnh pht x

HPBW:rng chm na cng sut. Main lobe: L bu sng pht x theo hngc pht xlnnht.

Minor lobe: Tt c nhng bu sng khc

main lobe cgi l minor lobes (bu sngph), i din cho s pht x theo nhnghng khng mong mun.

Back lobe: l minor lobe i din vi mainlobe.

Side lobe: L nhng minor lobes ngay cnhmain lobe v phn cch bi nhng khong

trng. Thnglnnht trong s minor lobe.

S nh hng


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Snhhng(Directivity)

S nh hng ca mt anten c nhngha l t s cng phtx theo mthngchotrctmtanten trncngphtx trung bnh theomihng.

Ni cch khc, s nh hng ca mtngun khng nghng l tscngpht x ca n theo hng cho trc trncng pht x ca mt ngun nghng .

4

i

U UD

U P

D lsnhhngcamtanten.U lcng phtxca anten.Ui lcng phtxcangunnghng.P ltngcngsutphtx.


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Snhhng i khi, khng th xc nhchngca

s nh hng. Trong trng hp ny,hng cacng pht xlnnhtcchn:

Dmax l nhhnglnnht.

Umax l cng pht xlnnht.

nhhng l mtilng khng c chiu.

N cbiudin theo dBi.nhhngcamt anten c thc lngtmu pht xca anten. Mt anten mun nh hng ttphi c main lobe rng.

max max

max

4

i

U UD

U P


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Tr khng li vo

L tr khng ca mt anten ti u cuica n hay l tsgiain p v dngcc cp u cui hoc l t s cc thnh

phn in t v t trng ti mt im.

Tr khng camt anten c thvit :

Trong :

Zin l tr khng anten ti cc ucui. Rin l intr anten ti cc ucui.

Xin l in khng anten ti cc ucui.

in in inZ R jX


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Tr khng li vo

Thnh phnoca tr khng li vo biudin cng sut cha trong trng nnglngca anten.

Thnh phn ca tr khng li vo gm 2

phn, tr pht x v trti. Cng sutcatr pht x l cng sut pht xthctbianten, trong khi cng sutb tiu tn bmt v nhit trong chnh anten do chtinmi hay dy dn.


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Tlinth sng dng


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Tlinth sng dng

anten hot ng hiu qu, cng suttruyntiaphixy ra giab truyn vanten.

Cng sut truyntiach c thxy ra khi

tr khng ca anten (Zin) iu hp vi btruyn (Zs).

Theo l thuyttruyn cng suttia, cngsut

ti

a

ch

cth

c

truyn

khitr

khng ca b truyn l lin hp phc vitr khng ca anten v ngcli.


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Tlinth sng dng

Do , iu kin cho iu hp l:

Vi:(nh hnh 2.5)

*

in sZ Z

in in inZ R jX

s s sZ R jX

T l i h d


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Tlinth sng dng

Nu iu kin iu hp khng c thamn, cng sut c th b phn x tr li vto ra sng dng, c trng bi h sVoltage Standing Wave Ratio (VSWR).

Trong :: H s phn x.

Vr: Bin sng phn x.

Vi: Bin sng ti.

1 | |1 | |

n sr

i in s

VSWR

Z ZV

V Z Z

T l i th d


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Tlinth sng dng

VSWR v c bn l s o lng trkhng khng iu gia b truyn vanten.

VSWR cng cao, khng iu hp cngln. VSWR nhnhttngng viiuhp hon ho. Mtthitk anten thctnn c tr khng vo l 50hoc 75 .

Suy hao phn x (Return


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Suy hao phnx (Returnloss)

L cng sut mt mt khi n ti (load)khng trvnhsphnx. Nhgiithiu, sng phnxto nn sng dng khitr khng b truyn v anten khng iu

hp. Do RL tng t VSWR.

Vi iu hp hon ho gia my pht vanten, =0, RL= khng c phnx, trongkhi =1, RL=0 dB phn x l hon ton.Trong ngdng thc t, VSWR bng 2 lmc cho php, bi v tngngvi RL

= -9.54 dB.

1020log | | ( )RL dB

Hi t A t


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Hiusutca Anten

Hiusut anten l mt thng sdavo tnh ton s tn tht u cui(terminal) ca anten v cu trc bntrong ca n. Nhngtntht ny chobi:

- Phn x(do khng iu hp).

- Tn tht I2

R (dn v in mi)

Hi t A t


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Hiusutca Anten

Do tng hiusutanten c vit:

Trong :

et: tng hiusut anten.

er: (1-|2|) hiusutphn x.

ec: hiusutdn.

ed: hiusutin mi.

t r c d e e e e

Hi t A t


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Hiusutca Anten

ec ,ed th kh c th tch ri, chng kthplito ra hiusut ecdc cho bi:

ecd: hiusut pht x anten (anten radiationefficiency) v c nh ngha nh t s

cng sut phn phi trn in tr pht xRr, Rrv RL.

r

cd c d

r L

Re e e

R R

l i


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li

C quan hmtthitvinhhngca anten.

Nu anten t 100% hiusut, lisbngnhhng v anten s l pht xnghng.

li l lngnng lngnhnctrn 1 hng v c cho bi:

nv dBi. d, ,cG e D

S h


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S phn cc

Lc tnh thhins thayihngtheothigian vmiquanhvibinca vectortrngin.

S phn ccca anten l s phn ccca vector trnginca sng pht x.

Thnggmtuyn tnh (ngang v ng)v vng (phn cc bn tay tri hay phi).

S h


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Sphn cc

S h


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S phn cc

Nungica vector trnginti v lui trn mt ng thng ta cphn cctuyn tnh.

Trong sng phn cc vng vectortrng in l mt hng s v dinhng xoay quanh mtngi vngtrn.

S h


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S phn cc

B thng


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Bng thng

L ditns c thsdngc cho shotngca anten.

ivi anten dirng th l tlgiatns trn v di c thhotng.

ivi anten dihp l phn trmcassai khc tns so vitns trung tm.

(%) 100

Hbroadband

L

H Lnarrowband

C

fBW

f

f fBW

f

fH= upper frequency

fL= lower frequencyfC= center frequency

Bng thng


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Bng thng

Mt anten c gi l di rng nuFH/FL=2.

Mt phng php nh gi hiu

sut hot ng ca mt anten trn ditn yu cu l ohs VSWR ca n.

Vi VSWR 2 (RL - 9.5bB) mbohiusuttt.

Bng thng


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Bng thng

Cc loi anten thng


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Cc loi anten thngdng

1. Lngccna sng. Chiu di anten bng chiu di sng. csdngrtrng ri.

Cc loi anten thng


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1. Lngccna sng (tt) Anten lngccc to nn bingtruyn 2 dy nn 2 dng trong dy dn cdng hnh sin c cng bin nhng

ngcchiu. liin hnh l 2 dB.

Bng thng khong 10%.

S phn cc l 1.64 (2.15dB). Tr khng pht x730 .

Cc loi anten thng


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M hnh phtxcalngccna sng

Cc loi anten thng


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2. Anten ncc L kt qu ca vic p dng nh l nhvo lngcc.

Hnh 2.11 Antenncc

Cc loi anten thng


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S phn ccgpi anten lngcc.

Tr khng bng anten lngcc.

Lngccna sng xpx sng ncc(L / 2 = / 4 ).

Rthudng trong anten in thoi dng xe hihocthitbcm tay.

li cho n cc chiu di sng l 2-6dB.

Bng thng khong 10%.

Tr khng pht x 36.5

nhhng l 3.28 (5.16dB).

Cc loi anten thng


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Hnh 2.12 M hnh phtxca antenncc

Cc loi anten thng


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3. Anten khung (Loop anten) L mt dy dnun cong thnh vng trnhay l hnh vung hto thnh ucuinh 2.13.

Cc loi anten thng


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C hai loi l anten khung in nh vanten khung inln.

Nutng chu vi l rtnh so vibc sng(L


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Nh hnh 2.14, ccm hnh pht xtng t nh lngcc, tuy nhin lng

cc phn cc thngng trong khi khungtrn nh phn cctheo chiu ngang.

Cc loi anten thng


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Anten khung thng c li t -2dB n3 dB v bng thng khong 10%.

Anten khung nh th rtphbinnh antenthu sng.

Anten khung vng n (single turn loopantena) c dng trong my nhn tin(pages) v anten khung nhiu vng(multiturn loop antena) c dng trong thusng AM qung b.

Cc loi anten thng


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Cc o anten t gdng

4. Anten xonc Mt anten xon c l

mt dy dnnit, vc cun thnh hnh

xonc (hnh 2.15). Anten c thhotng

mt s dng, tuynhin 2 dng chnh l

dng thng (pht xngang) v dng trc(pht xdc).

Cc loi anten thng


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Cc anten gdng

Khi ung knh xoncrtnh so vibcsng, anten hotngdngthng.

Tuy nhin khi chu vica vng xon l bcca bc sng, antenhotngdngtrc.

Cc loi anten thng


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Cc a te gdng

Trong ch hot ng bnh thng,trng anten l cc i trong mt phngthng ca trc xon c v cc tiu dctheo trc ca n. Ch ny cung cp

bng thng thp v thngcsdngcho cc ngdng di ngcm tay.

Trong hot ng dng trc, anten pht ramt pht xdcvimt chm tia ndctheo trcxonc. Dng ny cung cp li tt hn (ln n 15dB) v t l bngthng cao (1.78:1) so vichhotngbnh thng.

Cc loi anten thng


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Cc a te gdng

Do hot ng trongtrng thi bngthng rng, ccanten dng trc

c s dngchnh cho truynthng v tinh. Hnh2.16 cho thy cc

mu pht x ch thng hotngtthnchtrc.

Cc loi anten thng


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gdng

5. Anten sng (Horn anten) Anten sng c s dng ch yutrong vng sng vi ba (di GHz) m

ngdn sng l gii php chyu, vcbn anten sng bao gmmtngdn sng c phn cui loe ra ngoito thnh cu trc gingnhmt ciloa.

Cc loi anten thng


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gdng

Cc loi anten thng


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gdng

V c bn, hot ng ca sng lchuyn t dng ng dn sng thnhdng khng gian v vic chuyn iny lm gim sng phn x v tngsng truyn sng lm cho VSWR thpv bng thng rng.

Anten sng c s dng rng ritrong thin vnhc,v tinh v truynthng anten cho.

ANTEN VI DI


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ANTEN VI DI

1 Giithiu

2 uim v khuytim

3 Kthutcpngun choanten

Gii thiu


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Giithiu

Hnh 3.1 CutomtAnten vidi

Gii thiu


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Giithiu

Hu ht khi dng c bn, anten vi dibao gmmtdi (patch) kim loirtmng(b dy t


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Giithiu

Di v mt phng t c tch bit bimt lpin mi nn (substrate). Hngsin mi ca cht nn (r) nm trongkhong 2.2 r12.

Anten vi di c th c rtnhiudng, gmcc loi di hnh ch nht, hnh vung,trn, tam gic, elip, hnh vnh khn, v.v....Tuy nhin loiphbinnht l anten hnh

chnht v hnh vung do d phn tch vchto.

Gii thiu


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Giithiu

Hnh 3.2 Ccdngphbinca anten vidi

Gii thiu


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Giithiu

ivi anten c hiusuttt, mtchtnnin mi dy c hng s in mi thp liu cn thit v s lm anten hot nghiuquhn, bng thng lnhn v pht

xtthn. Tuy nhin nhng yu cu s lm choanten c kch thc ln. Khi sdngchtnnvihngsin mi cao hn th anten

vi di s c kch thc nh hn song likm hiuqu v bng thng hphn.

Do , vn l phi cn bng 2 yu t

kch thc v hiusut anten.

u v nhc im


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u v nhcim

Anten vi di ngy cng csdngrng ri trong cc ng dng khngdy do cu trc nnhca n.

V vy, cc anten vi di ny s vcng thch hp khi nhng vo ccthit b cm tay nh in thoi ding, my nhn tin, v.v...

u v nhc im


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u v nhcim

Mtsuimca anten vi di:- Khi lng v kch thc nh, mng, d

snxut .

- Gi thnh thp nn c thsnxutvis

lngln.- C th cho phn cctuyn tnh hay vng.

- Cng nghchto hon ton ph hpvi

cc mch tch hp vi sng- ng truyn cung cp v ghp nimng

anten c thc thchinng thivivicchto anten .

u v nhc im


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u v nhcim

Bn cnhuim, anten vi dicng c mtsnhcim:- Bng thng hp.

- lithp .- Hiusutnnglng c thsdng

cthp.

Cc k thut cp ngun


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Cc kthutcpngun

Cc phng php cpngun c thcphn lm hai loi: tip xc v khng tipxc.

Trong loi tip xc, nng lng RF c

cp trc tip vo di pht x bng mtphntninhmt dng vi di.

Vi loi khng tip xc, khp ni trngin t c thc hin chuyn nnglnggia dng vi di v di pht x.

Cc k thut cp ngun


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Cc kthutcpngun

Microstrip Line Feed(cpngunbngng

truyn vi di)

Aperture Coupled Feed(cpngun dng

phng php ghp gn)

Coaxial Feed (cpngunbng Probe ng

trc)

Proximity Coupled Feed(cpngun dng

phng php ghp khe)

Phng phpkhng tip xc

Phng php

tip xc

Microstrip Line Feed (cp b i di)


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ngunbngng vi di) Trong k thut ny, mtdidninc

nitrctipncnhcadinh hnh 3.3.

Hnh 3.3Cpngunbngngtruyn vidi

Microstrip Line Feed


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Didnin ny c chiurngnhhn sovidi.

Ngun cung cp c gn trn cng mtchtnnto ra mtcu trc phng cho

anten. Mcchcavic ghp ny l ph hp

tr khng ca ngun vi di pht x mkhng cn thm yutb sung no khc.



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iu ny stcbngvickim sotv tr ghp ni. Do vy, y l mtkthutcp ngun n gin, v n d ch to vm hnh ha cng nh l iu hp tr

khng. Tuy nhin, khi sdngmtchtnnin

mi dy th s lm tng cc sng b mt,cc ngun pht xtpnhiu v iu ny s

lm gimbng thng ca anten.

Coaxial Feed (cpngun t )


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ngtrc) L mt phng php rt ph bin cp

ngun cho anten vi di.

Hnh 3.4Cpngunbngphngphpngtrc

Coaxial Feed


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Coa a eed

Dy dn bn trong ca cc kt ni ngtrcc xuyn qua lpin mi v chn vo di pht x, trong khi dy dn bnngoi cnivimtphngt.

uim chnh caphng php ny l cthctbtcv tr mong mun no bn trong di ph hpvi tr khngu vo ca n.

Phng php ny cngdthchin v clng pht xtpnhiuthp.

Coaxial Feed


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Hn ch chnh ca phng php ny lcp ng trc ni t t n di c bngthng hp v s gy kh khn trong vicxy dng m hnh cho anten v 1 lc

khoan trong chtnn v nh ra ngoi mtphng t s lm cho cht nn dy hn(h>0.02 0).

Khi cht nn dy hn, chiu di u d

tng v lm cho tr khng u vo tngcmng.

Aperture Coupled Feed( h h h )


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(phng php ghp gn) Trong k thut ny, di pht x v ng

np vi dicngn cch bimtphngtnh trong hnh 3.5.

Hnh 3.5Cpngun dngphng php ghpgn

Coaxial Feed


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Khp ni gia di v ng cp nguncthchin thng qua mt khe cm haykhu trong mtphngt.

Khi mt phng t tch di v dng cp

ngun th ngun pht x tp nhiu cgimthiu.

Mtbt li lncak thutcpngun nychnh l n kh khnchto v c nhiu

lp v chnh iu lm cho anten dythm. V k thut ny cng s cung cpbng thng hp.

Proximity Coupled Feed(ph ng php ghp khe)


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(phng php ghp khe) K thut cp ngun ny cn c gi l

khpniint.

Hnh 3.6Cpngunbngphngphp ghp khe

Proximity Coupled Feed


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y p

Nh trong hnh 3.6, dng cp ngun nmgia hai chtnnin mi v di pht xth nm trn chtnnin mi cao hn.

uim chnh cak thut ny l n loi

b cc ngun pht x tp nhiu v cungcpbng thng rt cao (cao nht l 13%),do s tng ln v dy tng th caanten vi di.

Kthut ny cng cho php lachngiahai cht in mi khc nhau, mt cho dipht x v mt cho dng cpngun, tiu ha hiusutcami thnh phn.



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y p

Vic kt hp c th thc hin c bngviciukhin di ca dng cpngunv tlchiurng dng ca cc di.

Tuy nhin, kh khncakthut ny l vic

rt kh ch tobi hai lpin mi cs lin kt thch hp. Ngoi ra, cn ls gia tng dy tngthca anten.



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y p

c trngCpngun

bngngtruyn vi di

Cpngun

bng probengtrc

Cpngun

dng ghpgn

Cpngun

dng ghpkhe

Ngun phtxtpnhiu Nhiu Nhiu t hn t nht tin cy Tthn Thp do hn Tt TtChto D Cn hn v

khoanYu cu s

lin ktYu cu s

lin ktiuhptr khng D D D D

Bng thng 2-5 % 2-5 % 2-5 % 13 %

Bng 3.1 So snh gia cc k thut cp ngun khc nhau.

THIT K V M PHNG


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ANTEN VI DI

1 Tiu chunthitk

2 Cc bcthitk

3 M phng v ktqu

Tiu chunthitk


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Ba thng scn thit cho thitk anten vidi hnh chnht:

1. Tnshotng (f0): H thng thng tinc nhn sdng cc di tns t 1850-

1990 Mhz. Do anten phi c khnnghot ng trong di tn s ny. Tn scng hng c la chn cho thit kny l 1.9 GHz.

2. Hng s in mi ca cht nn (r):thng s dng silicon c hng s inmi 11.9. Cht nn c hng s in micao gip lm gim kch thccang-ten.

Tiu chunthitk


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3. Chiu cao ca cht in mi (h): i vicc anten vi disdng trong inthoi didngiucnthit l khng knh cng. Dochiu cao cachtin mi cchn

l 1.5mm. V vy cc thng tin cnthit cho victhit

k l:

fo = 1.9 GHz

r = 11.9

h = 1.5 mm

Cc bcthitk


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Anten vidinhnttrn

Cc bcthitk


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Bc1: Tnh tonrng (W): rngca anten vi di c cho bi cng thcsau:

Vi c = 3x108 m/s, r = 11.9 v fo = 1.9GHz

Suy ra W = 0.0311m = 31.1mm

0

( 1)2

2

r

cW

f

Cc bcthitk


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Bc 2: Tnh ton hng s in thmtngng(reff):

Vi r = 11.9, W = 33.1mm, h = 1.5 mm

Suy ra ta c: reff = 10.7871

1

21 11 12

2 2

r rreff

h

W

Cc bcthitk


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Bc3: Tnh dihiudngca anten(Leff):

Vireff = 10.7871, c = 3x108 m/s v fo =1.9GHz ta c:

Leff = 0.024m = 22.4mm

02eff

reff

cL

f

Cc bcthitk


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Bc4: Tnhchiudimrng(L):

Vireff=10.7871, W= 31.1mm, h = 1.5mm.

T ta tnh c: L = 6.3455e-4 mm.

( 0.3) 0.264

0.412

( 0.258) 0.8

reff

reff

W

hL h

W

h

Cc bcthitk


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Bc 5: Tnhchiu di thc tcadi(patch) (L):Chiu di thct thu c quaphng trnh sau:

Vi Leff= 22.4mm, L = 6.3455e-4 mm

Ta tnh c: L = 0.0228m = 22.8mm

2eff

L L L

Cc bcthitk


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Bc6: Tnh ton kchthcmtphngt(Lgv Wg):lnmtphngtctnh bi:

Lg = 6h + L = 6(1.5) + 22.8 = 31.8mm

Wg = 6h + W = 6(1.5) + 31.1 = 40.1mm

Cc bcthitk


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Bc 7: Xc nh im cp ngun(Xf,Yf):

- Ly trung tm cadi l imgc v v trim cp ngun l ta (Xf, Yf) tnh t

gc.- imcpngunphictim

trn di, ni m tr khng vo l 50 Ohmcho tnscnghng.

- Do , phng php th v li c sdng xc nhv tr imcpngun. Vithit k ny Yf = 0 v Xf thay i tm

im cp ngun ti u

M phng v ktqu


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Phn mm c s dng xy dng mhnh v m phng anten vi di l Zeland IncsIE3D.

N csdngrng ri trong thitkt MICs,RFICs, anten di, anten dy v cc loi antenRF/khng dy khc. N c thcsdng tnh ton v v th cc thng s S11,VSWR, phn phi dng cngnh pht x mhnh.

ngin, cc gi trchiu di, chiu rngcadi v mtphngtc lm trn nhsau L = 22 mm, W = 31 mm, Lg = 31 mm, Wg= 40 mm.

Suy gim v bng thngtrn anten


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trn anten



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trn anten Cc ktqu trong bngdiy thu c

sau khi thay iv tr cpngundliudctheo chiu di ca di t gc (trung tmcadi) n cc cnh bn phica n.

Cp ngun vi cp ng trc c bn knh0.5mm. Mt di tn s t 1.7-2.1 GHz v401 im tn s c chn trn phm viny c c kt qu chnh xc. Bng

4.1 cho thyktqut cc imcpngunkhc nhau.



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trn anten



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trn anten

Hnh 4.3 Suygimvicpngun nhngim khc nhau



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trn anten Tns trung tm cchn l tiim m

suy gimphnhi l nhnht.

Bng thng c thc tnh ton tthca s suy gim phn hi (Return Loss).

C th ni bng thng ca Anten c phmvi tnslnhn khi s suy gim thch nglnhn -9.5 dB (-9.5 dB tngngvimtVSWR=2).

Tbng 4.1, nhngimcpnguntiuc tm thyti (Xf,Yf)= (4,0) ni thu cRL l -31.3585 dB.



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trn anten Bng thng ca anten cho nhngimcp

ngun (hnh 4.4) c tnh ton l 23.28MHz v tn s trung tm thu c l1.9120 GHz rt gn vi tn s thit k

mong mun l 1.9 GHz. Khi imcpngun di chuyn ra xa trungtm trn di, tns trung tm btugimnh. N cng cho thyrng d s suy gim

thch ngtiac thu ti (Xf,Yf)= (4, 0),bng thng ti a li thu c ti(Xf,Yf)=(4.75, 0).



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trn anten

Hnh 4.4 Suygimphnhitiimcpngun (4, 0)

M hnh pht x (Pattern)


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Khi anten vi di pht x trung bnh trn bmtdica n, m hnh mtchiuivi = 0 v = 90 s tr nn rt quantrng.

Hnh 4.5 bn di cho thy li caanten tns 1.912 GHz cho = 0 v =90 .

th pht xmu(Pattern)


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(Pattern)

M hnh

mt

chiu

vi

= 0v

= 90

th pht xmu(Pattern)


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(Pattern) khuychitiatc theo hng

ngang ( bn - broadside) v o c l1.87 dBi cho c 2, = 0 v = 90 .

Pht x bu sng ph sau nh v o

c l -5.3 dBi cho th trn. Pht xbu sng ph sau thp thun li cho vicsdng anten ny vo trong in thoi ding, v n gim lng pht xintti

ngisdng.

th pht xmu(Pattern)


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(Pattern)

Hnh 4.6 (a) thphtx 3D nhndctheotrcY trongmtphngXZ(b) thphtx 3D nhndctheotrcZ trongmtphngXY

th pht xmu(Pattern)


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(Pattern) Khi anten vi di c thit k cho in

thoi di ng, n s c nh hng trc Z song song vibmtca tri t.

Hnh 4.7 (a) phtx 3D chointhoinhhngtrongmtphngYZ

(b) phtx 3D chointhoinhhng trongmtphng XZ

Mts thng s khc


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Mts tnh ton cc thng s khc nh

li, s nh hng, hiu sut anten, rng bu sng anten 3dB ti 1.912 GHzca ra diy:

li = 1.8717 dBi Hng tnh = 5.56 dBi

Hiusut anten = 42.77 %

rngbu sng 3 dB = (106.85, 110.24).

KT LUN


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Mc ch ca ti ny l thit k mtanten vi di thu gnsdng trong cc thitb khng dy/di ng.

Mt chic in thoi di ng in hnh c

kch thckhong 14.5cm v 4.5cm. Do vic thit k anten phi lm cho ph hpvinhngchicinthoi.

Nh trnh by, mt anten vi dic

thitkvitns trung tm 1.91 Ghz.

KT LUN


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Mt phng y c thit k khong 30

n 40mm v ln di l 22mm n31mm. Do gnt trong mtinthoi di ng thng thng.

th mu pht x t c nh yucu.

Gim pht x cng t c gip hnch pht x nng lng in t i vi

ngisdng.

KT LUN


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li 1.87 dBi v tinti 5.56 dBi cng

tc. Bng thng cho anten ny l 23.28 MHz

cho thitbcm tay trong di PCS bi v h

thng TDMA v GSM s dng knh 30KHz.

KT LUN


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V mtshnchvkin thccngnh

thi gian nn phm vi ca ti chacmrngcngnhhini. Mc tiu trongtng lai l mrng cho thitkadi.

Mt s thit b hin i (smartphone,tablet,) c ph cung cpnhiungdngcho ngi dng. lm c iu nyanten trong thitbphi c khnnghot

ngnhiutns ring bit. V ycngl iu m nhng nh thitk anten ang

Antenna Vi Dai (2)

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Transcript of Antenna Vi Dai (2)