-
Chng 1: Gii thiu v Anten
nh ngha
Mch tng ng Thevevin
Lch s pht trin
Cc loi Anten thng dng
H thng thng tin v tuyn
Qui c v di tn s
-
nh ngha
Anten l thit b dng thu hoc pht sng in t
Source
Transmission
lineAnten
Radiated Free-space wave2
-
Mch tng ng Thevenin ca anten pht
Vg: in p ngun
Zg: Tr khng ngun
Rr: in tr bc x
RL: in tr tn hao
jXa: in khng ca anten
3
-
Mch tng ng Thevenin ca anten thu
4
Ch : Phi hp tr khng gia Anten v ng truyn
-
Nguyn l bc x
Dng in thay i theo thi gian Cc in tch chuyn ng vi gia tc bc x
sng in t
-
ng sc in ca dipole ngn
(a) t = T/4 (b) t = T/2 (c) t = T/2
-
Lch s pht trin
James Clerk Maxwell (Scotland): M hnh ton hc v in t trngA
dynamical theory of the electromagnetic field, 1865
Heinrich Rudolph Hertz (c):
Thc hin th nghim truyn sng in t u tin, sdng anten dipole Hertz
hot ng bc sng 8m, 1886.
Pht hin ra hin tng quang inn gin ha cc phng trnh Maxwell
Alexander Popov (Nga): Gi in tn bng h thng thng tin v tuyn vi
khongcch 30 dm t tu hi qun n phng TN, 1895
Guglielmo Marconi (): Truyn nhn thnh cng bn tin bng tn hiu Morse
bngsng v tuyn vi khong cch ln 16 Km, 1897
-
Lch s pht trin (tt)
u th k 20 ~ chin tranh th gii ln 2 :nh du s bng n ca thng tin v
tuyn v kthut anten: anten dy, n ba cc dng cho my pht
v tuyn
Cc h thng v tuyn s dng tn s ln n500MHz vi c ly thng tin hng ngn
kilomet
Chin tranh th gii ln th 2nh du k nguyn ca thng tin v tuyn v
kthut anten
Vic pht minh ra my pht sng siu cao tn an s pht trin ca cc loi
anten siu cao tn nh
ming ng dn sng, anten loa, anten gng
-
Anten dy
Tn s lm vic thch hp : 1-2 GHz tn s thp: Kch thc anten s rt
ln
-
Anten ming
c nghin cu v pht trin vo trc v trong th chinth 2 cng vi ng dn
sng
Tn s lm vic thch hp: 1-20 GHz
-
Anten vi di
Rectangular and circular microstrip patch antennas
Printed dipole
-
Cc hnh dng ca anten vi di dng patch
-
Cc hnh dng ca anten vi di dng khe
-
Anten gng
Parabolic reflector with front feed Parabolic reflector with
Cassegrain feed
Corner reflector
-
Anten thu knh
Anten thu knh vi chit xut n > 1
Anten thu knh vi chit xut n < 1
-
Anten mng
-
H thng thng tin v tuyn vs hu tuyn
17
H thng thng tin hu tuyn
S dng h thng ng dy truynti
S dng nhiu trong cc thnh phln v cc khu dn c tp trung
Suy hao theo qui lut lm m
H thng thng tin v tuyn
S dng bc x in t thng qua anten pht v anten thu
C ly thng tin lnSuy hao ph thuc vo khong cchtheo qui lut ly
tha
Dy i: s dng trong cc h thngin thoi ni ht
Truyn tn hiu vi tn s thpSuy hao: 2~3 dB/km ( 10kHz)
Cp ng trc: s dng truyntn hiu Video
Suy hao: 4-5dB/kmCp quang: suy hao thp, dung lng ng truyn rt ln,
tc
cao
-
Cc h thng thng tin v tuyn
18
in thoi di ng
H thng thng tin di ng trong cc phng tin giao thng hng
hi, hng khng, ng b
H thng thng tin v tinh
Cc h thng pht thanh truyn hnh
H thng nh v ton cu
-
Qui c v di tn s
Di tn s Tn, k hiu ng dng
3 30 kHz Very low frequency (VLF) Dn ng, nh v
30 300 kHz Low frequency (LF) Dn ng
300 3000 kHz Medium frequency
(MF)
Pht thanh AM, trm thng tin duyn hi,
ch dn, tm kim
3 30 MHz High frequency
(HF)
in thoi, in bo, pht thanh quc t
sng ngn, hng hi, hng khng
30 300 MHz Very high frequency
(VHF)
TV, pht thanh, dn ng, iu khin
khng lu, h thng thng tin v tuyn
ca cnh st, taxi
300 3000 MHz Ultrahigh frequency
(UHF)
TV, thng tin v tinh, do thm, rada gim
st, dn ng
3 30 GHz Superhigh frequency
(SHF)
Rada cho my bay, h thng thng tin
Viba , thng tin v tinh, thng tin di ng
30 300 GHz Extremely high frequency
(EHF)
Rada, nghin cu khoa hc
19
