Gioi Thieu Ve Anten

7/27/2019 Gioi Thieu Ve Anten

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ANTEN

TRUYN SNG


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TI LIU THAM KHO

1. TRUYN SNG V ANTEN L TIN THNG, TRN VN S

2. L THUYT V K THUT ANTEN PHAN ANH

3. ANTENNA THEORY ANALYSIS AND DESIGNCONSTANTINE A.BALANIS


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Phn 1 Anten

Chng 1 GiiThiuV Anten

Chng 2 Cc c Tnh Ca Anten

Chng 3 L Thuyt Anten

Chng 4 HBcX (Dy anten) Chng 5 Giithiumtsloi anten


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Phn 2 Truyn Sng

Chng 6 ngdn Sng

Chng 7 Truyn Sng Qua Cp Quang

Chng 8 Truyn Sng V Tuyn


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Phn 1 Anten

Chng 1 Gii Thiu V Anten


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I. GII THIU LCH S PHT TRIN CA ANTEN

nh ngha Anten:

Anten l thit b dng bc x v (hoc) thu nhn nng lng in t.Anten l thit b dng truyn nng lung in t gia my pht v mythu m khng cn phng tin truyn dn tp trung.

Lch s pht trin ca anten: 1886 Heinrich Hertz (c) kim tra s tn ti ca sng in t. ng

pht trin cc dipole n gin, cc anten vng v cc anten c thanh phnx n gin.

1897 Alexader Popov (Nga) thit lp tuyn anten tht u tin vikhong cch 3 dm.

1901 Marconi thc hin thng tin v tuyn xuyn i ty dng (tn s

60KHz).


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1916 ln u tin ting ni c truyn i bng v tuyn (iu bin).

1920 cc h thng c th t c n tn s 1MHz, do kch thcanten c gim nh.

1930 cc ngun pht dao ng c th t n tn s hng GHz (Klistron,magnetron).

1934 h thng v tuyn thng mi u tin gia Php v Anh c thitlp (1,8GHz).

1940-1945 nhm phc v th chin th 2 nhiu pht minh trong vic phttrin Rada, cc anten phn x, cc anten thu knh.

1945- nay: k nguyn ca anten hin i, vi nhiu cng ngh v k thut

mi p ng cho Mng li thng tin v tuyn c tnh ton cu v tc cao, bng thng rng : (GPS, GSM, CDMA, WiFi, WiMax, UWB,MIMO).


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II. CC LOI ANTEN


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Anten dy (thanh):

Dipole Anten vng : trn, vung

Anten Helix


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Anten khe

Anten dng loa kn hnh chp

Anten dng loa kn hnh nn (cone)

ng dn sng vi u cui h


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Anten vi di (patch - microstrip antennas):

Anten vi di vung, kch thch bng ng truyn vi di

Anten vi di trn, kch thch bng cp ng trc


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Anten phn x

Mt phn x parabol vi ngunkch thch t pha trc

2 Mt phn x parabol vi ngun

kch thch t pha sau

Mt phn x phng


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Anten thu knh

H s khc x n>1

H s khc x n


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H thng bc x (array antenna)

Anten Yagi Mng cc khe bc x

Mng anten vi di Mng cc khe trn ng dn sng


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Hnh minh hac tnhbcxcamtsloi anten

Anten dipole na bc

sng (/2=5mm)f=29,9GHz

Cng in trng o ti mt cu cch anten 100m


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Anten YagiVi chn t kch

thch l= /2=5mmf=29,9GHz

Cng trng in o ti mt cu cch anten 100m


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Anten Helix

D=4mm, f=1GHz

Cng in trng o ti mt cu cch anten 100m


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III. MT S H THC GII TCH VETOR

332211 ... iAiAiAA

Vector:

r

H to cu:


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M

ri

i

i

H to cu:

Ta im M xc nh bi: ),,( rM

Cc vector n v:

iiiiiiiii rrr

,,

321 ,, uuru

.sin .cos ,

.sin .sin ,

.cos

x r

y r

z r

Cc h s Larmor (metric):

sin.,,1 321 rhrhh


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Vector dch chuyn:

idridridrdl r

..sin....

2 2 2

. .sin .dl dr r d r d

Vi phn din tch:

idrdrdS

idrdrdS

idrdrdS rr

)..)((

)..sin.)((

)..sin.)(.(

Vi phn th tch:

).sin.)(.)(( drdrdrdV


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Mt s h thc vector

Tch v hng 2 vector: 332211 .... BABABABA

Tch vector:

321

321

321

BBB

AAA

iii

BA

Gradient: (tc ng ln v hng):

3

33

2

22

1

11

.1.1.1. iuf

hi

uf

hi

uf

hffgrad

Divergence:

)()()(

1. 321

3

213

2

132

1321

Ahhu

Ahhu

Ahhuhhh

AAdiv

0

.

lim SV

A dS

divAV


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Ton t Laplace:

Tc ng ln v hng: 2. .f f f div grad f

Tc ng ln vector: AAA

)..(

Curl:

332211

321

332211

321

1

AhAhAh

uuu

ihihih

hhhAArotAcurl

0

.

. lim lnS

A dl

curlA iS


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IV.BC X IN T

T nhng vng c in tch hay dng in bin thin c th bc x sngin t lan truyn trong khng gian. Cc vng c in tch hay dng in

bin thin gi l ngun bc x. Chng ta ch xt trng in t bin thin iu ho vi tn s . Cc i

lng ca trng c biu din bng cc bin phc.

Thng thng, xc nh trng bc x, chng ta phi gii phng trnhsng tm th vector A . Cc vector in trng v t trng c suy ra

t th vector nay.

Phng trnh sng: 2A k A J

2

k v

Vi:

1v

Nghim phng trnh ny:'

1 ( ').( ) '

4

jkR

V

J r eA r dv

R


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V

'

1 ( ').( ) '

4

jkR

V

J r eA r dv

R

'

',1

( , ) '4

V

RJ r t

vA r t dv

R


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1,

',1

( , ) .4

i

i N i

RJ r t

vA r t v

R

1 'J r

2 'J r

3 'J r1'r 2 'r

3'r

r

M

y

x

z

1R

2R

3R


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C

'

1 ( ').( ) '

4

jkR

C

I r eA r dl

R

Nu ngun l dng in phn b di trn mt on cong C, vi dngin th nghim tr thnh:)'(rI


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Bc x in t ca nguyn t anten thng


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'

1 .'.

4

jkR

z

C

I eA dl i

R

. .

'

. .

1 .'.

4

.. . .

4 .

j k r

z

C

j k r z z z

I eA dl i

r

l Ie i A i

r

iAiAA rr

.. . .

. .

..cos . .cos

4 .

..sin . .sin

4 .

j k r

r z

j k r

z

l IA A e

r

l IA A e

r

H A rotA iHH

.


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Cng sut bc x:


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Mt h t


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Mt s nhn xt:

1) T biu thc: virr itPtP

.)()( 0)( tPr

Nh vy min xa nng lng in t lun lun

truyn t ngun ra khng gian chung quanhtheo hng vector .ri

2) T biu thc:

2. . . .. . . . .sinsin . .

4 . 2. .

j k r j k rI l k j j I lH e e

k r r

Hzer

klIjE C

rkj ..sin..4

... ..2

Suy ra : cc vector E, H cng pha, vung

gc vi nhau v vung gc vi

phng truyn ri

3) Bin ca E, H t l nghch vi khong cch r. Cn mt cng sut bc x t l nghch vi bnh phng khong cch r.

sin lI


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Suy ra Cc mt ng pha E, H l cc mt cu c bn knh r=const

5) T biu thc:22

3

..

lIzP mCbx

Cng sut bc x t l nghch vi bnh phng bc sng (tc t l thun vibnh phng tn s f. Cng sut bc x cng ln khi tn s cng cao.

4) T biu thc: )2

..cos(.2

sin..)(

rkt

r

lItH m )(.)( tHztE C

6) T biu thc:

2. . . .. . . . .sinsin . .

4 . 2. .

j k r j k rI l k j j I lH e ek r r

Hzer

klIj

E Crkj

..sin..4

... ..2


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Cc nhn xt 1, 2, 3, 4 c rt ra i vi nguyn t anten thng , nhng cth chng minh rng chng cng ng vi ngun bc x phn b bt k.


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