Bo co thc tp h thng vin thng 2

Thc tp vin thng 2

B GIO DC&O TOTRNG I HC S PHM K THUT THNH PH H CH MINHKHOA IN-IN T

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BO CO ANTEN

GVHD: Trng Quang PhcSVTH: Nhm 51. Nguyn c Anh2. Tng Th Thm3. Trn Vn Ton

Tp.H Ch Minh, thng 11/2014

I. MC TIUSau khi hc xong bi ny ngi hc c kh nng: Trnh by c khi nim anten, phn bit c cc loi anten Trnh by c cc c tnh ca anten o c, tin hnh c 1 s bi th nghim v ATS05 Tnh ton v v c th bc x ca anten S dng phn mm PCADD v th bc x C thi hc tp nghim tc Chp hnh ng ni quy ti phng thc tp

II. C S L THUYT V ANTEN1. NH NGHA 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 my thu m khng cn phng tin truyn dn tp trung. Bc x in t: t nhng vng c in tch hay dng in bin thin c th bc x sng in t lan truyn trong khng gian. Cc vng c in tch hay dng in bin thin gi l ngun bc x.2. CC LOI ANTEN Dipole di rng

Hnh 1.1: Dipole di rngC cc loi: Dipole c ng knh ln Dipole nn kp Dipole b vng Anten Yagi

Hnh 1.2: Anten Yagi

Anten Helic Anten Parabol Anten Vi di

Hnh 1.3: Anten vi di

3. CC THNG S C BN CA ANTEN Bc x ca mt phn t dng in cn c gi l bc x lng cc. c dng nh ngha cc thng s c bn ca anten ni chung. Kiu bc x: Phn b tng i ca cng sut bc x nh l hm ca hng bc x trong khng gian Tia na cng sut: Gia cc im m cng sut bc x= cng sut cc i H s nh hng cc i(thng vit tt l h s nh hng) c trng cho kh nng ca anten tp trung nng lng bc x theo mt hng cho trc. li G(,)nca 1 anten c nh ngha tng t nh h s nh hng, nhng cng sut bc x c thay bng cng sut ton phn t vo anten Pin. in tr bc x Ra: l in tr tng ng tiu th cng 1 lng cng sut nh anten bc x khi dng cung cp nh nhau.4. H THNG BC X H thng bc x l kt hp nhiu anten n l thnh h thng bc x nhm ci thin th bc x, tng nh hng.

Hnh 1.4: H thng bc x

iu khin nh hng bng cch thay i bin v pha kch thch tng anten ring l.5. CC C TNH CA ANTEN5.1 TR KHNG Mc ch : Phi hp tr khng vi ng truyn tn hiu v t c hiu sut cao Trng hp l tng : tr khng vo Ra, khi ni trc tip anten vi ng truyn c tr khng c trng Zc (Zc= Ra). H s phn x ti sng u vo:

Tr khng ca anten:Za =

Tr khng tng h: khi 2 anten dipole t gn nhau, phn b dng trn anten chu nh hng bi trng bc x ca anten cn li.

5.2 HIU SUT

PD-PR=(1-e)PA

PA= RA|IA|2PR= RR|IA|2PD= RD|IA|2

6. TRNG IN T BC X T CA ANTEN

(=[F(,). + F(,).]

5.3 MT CNG SUT

W (=||= [+]

III. GII THIU THIT B1. GII THIU S LC ATS05 V CC BC HNH TH NGHIM

1.1 GII THIUDOWN: Nt nhn ny dng gim tn s theo bc nhy c chn. Ngoi ra nt ny cn dng cun xung menu la chn v v tr nh.MENU: Nt nhn ny dng la chn ch lm vic cng nh l bc nhy tn s t 50Khz n lOOMhz.ENTER: Dng lu cc tn s ring bit ti cc v tr hin thi ca b nh. V cng c dng la chn v lu tr li cc bc nhy tn s v thit lp truyn d liu ni tip.ESCAPE: Dng lu cc tn s ring bit ti cc v tr hin thi ca b nh. V cng c dng la chn v lu tr li cc bc nhy tn s v thit lp truyn d liu ni tip.FM/CW: Cng tc gt dng o c anten khi cc mc cn li mc n nh. FM dng iu tn ting ni trong thng tin vi di tn gii hn lOOKhz.MIC/INT 1KHZ: Cng tc gt dng la chn tn hiu iu ch c a vo t microphone hoc l tn hiu sin lKhz c pht ra t bn trong.FM DIVIATION: Chic p c dng thay i di tn ca tn hiu FM, khi xoay theo chiu kim ng h s lm tng di tn v ngc li.MIC: Dng kt ni vi microphone nhn tn hiu ting ni vo iu tn theo tn s sng mang c hin th trn mn hnh.MOD EXIT IN: Dng kt ni vi cc tn hiu m tn t bn ngoi vo iu tn theo sng mang c lo ra.RF OUT: Ti y tn s c pht theo tn s t 86Mhz-860Mhz, tr khng ng ra ca n l 50 Ohms. Anten pht c kt ni vi ng ra ny dng cc u ni BNC. Vi mc ng ra khong 110 dBuV.RF IN: Ti y tn hiu c thu vi dy tn s t 86-860Mhz. Tr khng ca n l 50 ohms.RS 232: Dng truyn d liu vi my tnh thng qua cp RS 232. e truyn c d liu thng qua cp RS232 vi my tnh ta cn m nt MENU nhiu ln n khi hin ch truyn d liu ni tip chn yes. Ket ni cp RS2323 vi my tnh m giao din phn mm AMITEC ANTENNA PLOTTING lc ny xut hin hp thoi yu cu chn cng kt ni. Ta chn Comport 1 v bt u qu trnh truyn d liu.HIGH LOW: mode high nhy ca my thu l cc i. mode low nhy ca my thu xp x 40dB tr xung.DOWN CONVER TER: Ti ng ra ny tn hiu c tn s 39Mhz, c th dng kt ni vo cc my phn tch ph xem iu ch FM v mc tn hiu cao tn thu c. Khi tn hiu thu c cao tn thu c gim th tn s ny cng gim theo xu hng ca b thu.RSSI: L b ch bo mnh ca tn hiu thu c. in p ng ra ti DC ti y tng ng vi mc ca tn hiu cao tn thu c.FM DEMODULATION: Cho ra tn hiu gii iu ch FM. Ta c th nghe c tn hiu gii iu ch ny thng qua loa.VOLUME: iu chnh m lng ca tn hiu c gii iu ch.STEPPER IN: Cp stepper c cng tc ti u cui ca cp c th dng kt ni vi ng vo. iu chnh b thu ch auto n cng tc ng vi mi v tr.

1.2 CC LOI ANTEN KHO ST

Hnh 2.1: Anten dipole

Hnh 2.2: Anten yagi 4el

Hnh 2.3: Anten patch

Hnh 2.4: Anten vng vung

Hnh 2.5: Anten ch v

Hnh 2.6:Mng broadsite

Hnh 2.8:Mng Enfire

IV. CC BC TIN HNH TH NGHIM

Bc 1: Lp rp 2 gi 1 bn pht v mt bn thu.

Bc 2: Tin hnh kt ni anten thu vi anten pht vi my o ATS05.

Bc 3: o v c kt qu ghi vo bng s liu4.1 KT QU TH NGHIM (ANTEN YAGI)4.1.1 Bng s liu

Ln oGi tr(dB)Ln oGi tr(dB)

10543818554

25623919064

310574019559.4

415604120056.9

520594220557.8

625604321061.8

730604421562.8

835574522061.5

94059.64622562.8

1045614723061.2

1150564823559.5

1255534924060.1

1360605024560.7

1465555125059.7

1570665225562.2

167563.25326061.4

178063.85426561.7

188561.45527061.7

199062.45627562.2

209564.25728061.9

2110063.15828559.4

2210560.45929057

23110656029558.9

2411561.86130056.7

2512062.96230558.6

2612561.56331058.3

2713061.16431559.9

28135626532058.9

29140646632557.3

3014552.26733058.7

3115057.96833557.2

3215560.36934057.9

3316060.37034559.1

3416559.57135061.9

3517057.87235562.9

36175547336064.1

3718054

4.1.2 V bng excel

4.2 KT QU TH NGHIM (ANTEN DIPOLE)4.2.1 Bng s liu

Ln oGi tr(dB)Ln oGi tr(dB)

1061.13818561.3

2562.53919060.7

31063.44019561.1

41563.84120061.3

52063.94220561.44

625634321061.2

73059.54421560.4

835594522061.5

94060.34622560.7

104559.74723060.9

1150594823560.5

1255624924060.8

136061.75024560.3

146562.55125061.7

1570655225562.8

1675615326062.7

178060.75426562.8

1885515527062.9

1990605627562.7

209561.55728061.7

21100595828560.8

2210560.55929060.3

23110616029561.7

2411560.56130062.8

2512060.76230562.7

26125596331062.8

2713058.76431562.9

28135586532062.7

2914059.76632562.8

3014558.86733062.9

3115058.16833563.1

3215560.66934063

3316060.57034562.7

3416560.77135062.8

3517060.67235563

3617561.37336062.9

3718060.9

4.2.2 V bng excel

4.3 KT LUN4.3.1 Anten yagi Trong qu trnh lm th nghim ta thy rng c tnh ca anten b nh hng bi chiu di, khong cch v v tr ca chng. Cc phn t dn x l phn quan trng nht trong vic thit k yagi, n iu khin tr khng ng vo, cc mc bc x ph v t s trc sau ca anten.4.3.2 Anten dipole Khi thay i chiu di ca anten dipole th gc na cng sut gim4.4 M PHNG4.4.1 GII THIU PHN MM PCAAD l mt cng c m phng cc c tnh ca anten gip ngi dng c th kho st c cc c tnh nh: tnh hng tnh, h s nh hng ca anten, li (hay tng ch), tnh bc x ca anten... Chng trnh cho php ngi kho st v c cc th trong cc h ta cc, h ta vung gc dng 2-D v 3-D. Ngi kho st c th kho st c cc c tnh tr khng sng v t s sng ng v tnh ton phi hp tr khng theo s Smith.4.4.2 KT QU M PHNG Anten yagi-uda l mt h thng bc x gm mt s phn t dipole thng nh sau: Mt phn t c cp in trc tip bng ng dy truyn dn gi l Driven (phn t c cp in), cn cc phn t cn li c gi l cc b bc x k sinh m dng ca n c cm ng bng cch ghp tng h, thng thng phn t c cp in ca yagi l dipole b vng nhng trong th nghim ny phn t c cp in c dng l dipole thng. B bc x ny c thit k hot ng nh l h thng bc x trc, cc phn t k bc x ny c thit k hot ng nh l h thng bc x trc, cc phn t k sinh theo chiu bc x thun l cc thanh hng x.

Yagi 4(Space=15cm)Director #2Director #1Fed elementReflector

20cm22cm24cm26cm

Yagi 3

Director #1Fed elementReflectorSpace

22cm24cm26cm7cm

Yagi 4

Hnh1.6 th bc x yagi 4 Yagi 3

Hnh1.7 th bc x yagi 3

Hnh 1.8 th bc x yagi3 (2D)

V. NG DNG Trong thng tin v tuyn, anten l mt h thng cho php truyn v nhn nng lng trng in t. Anten cng c th c xem nh l mt thit b dng truyn nng lng trng in t gia my pht v my thu m khng cn bt c phng tin truyn dn tp trung no: nh cp ng, cp quang hay ng dn sng. Trongnhiu ng dng, anten hon ton c th so snh c vi cc phng tin truyn dn khc chuyn ti nng lng trng in t. Chnh do hiu ng da nn vic s dng dy dn truyn ti thng tin tr nn km hiu qu trong cc h thngthng tin tn s cao, lc ny anten cng th hin c s vt tri ca mnhtrong vic trong vic chuyn ti cc trng in t. c bit trong cc h thngthng tin cc khu vc c a hnh phc tp hoc cc khu vc t dn c, vic xy dng cc h thng hu tuyn tr nn tn km v kh khn th thng tin v tuyn c chn l gii php ti u Nm1886: nh vt l ngi c, Heinrich Hertz kim tra bng th nghim s tn tica sng in t, ng pht trin cc lng cc n gin v cc anten vng. Nm1987: nh vt l ngi Nga, Alexander Popov pht trin tuyn anten u tinv c kh nng truyn tn hiu khong cch ba dm. Nm1901: Guglielmo Marconi ng thnh cng vi h thng thng tin v tuyn xuyn i Ty Dng vi tn s hot ng l 60Khz. Nm1916: ln u tin s dng k thut iu bin truyn tn hiu ting ni. Nm1920: vic to ra cc tn hiu c tn s cao ln n 1Mhz nn lm cho cc antenc kch thc nh v in. Nm1930: cc ngun dao ng cao tn c tao ra vi tn s ln n dy Ghz. Nm1934: h thng v tuyn in thoi thng mi u tin c to ra hot ng giaAnh v Php vi tn s hot ng 1.8Ghz. Nm1940-1945: t c nhiu kt qu nghin cu trong vic pht trin radar, cc mng v cc anten thu knh. Nm1945 n nay: k nguyn ca anten hin i. Anten hin i cho php phn phicc tn hiu v tuyn trn phm vi ton th gii, cho php thng thoi c tnhton cu nhanh chng. Cc ng dng trong cng ngh thng tin v tinh, v sbng n ca cng ngh vin thng dn n lnh vc anten ang thu ht c rtnhiu s quan tm.

VI. TI LIU THAM KHO1. L Tin Thng Trn Vn S, Truyn sng v awnten, nh xut bn i hc Quc gia TP.H Ch Minh, nm 20112. http://www.academia.edu/6150182/B%C3%A1o_c%C3%A1o_b%C3%A0i_t%E1%BA%ADp_l%E1%BB%9Bn_He_thong_vien_thongNhm 5 GVHD: Trng Quang PhcTrang 17