Microwave Noise and LNA Design

Transcription

1 Mcrwav and LA Dgn Mcrwav Crcut,6, JJEOG

2 Outln Bac cncpt : thrmal n Equvalnt n tmpratur, n fgur maurmnt f pav ntwrk Rcvr dgn f trantr hry Maurmnt LA dgn bac LA dgn xampl Mcrwav Crcut,6, JJEOG

3 Bac 3 Mcrwav Crcut,6, JJEOG

4 What? gnal randm varatn n currnt r vltag (ndtrmntc) (g) ultra ntv vltmtr cnnctd t a rtr hrmal mvmnt f lctrn randm vltag : thrmal n : ndtrmntc crrupt gnal! 4 Mcrwav Crcut,6, JJEOG

5 n Amplfr 5 Mcrwav Crcut,6, JJEOG

6 Vltag Man : v n lm t t v n ( t) dt 0 Man-quar : vn lm t t v n ( t) dt "avrag pwr" ( vn v, rm n : rt - man - quar ) 6 Mcrwav Crcut,6, JJEOG

7 Rtr R at tmpratur (K) n pwr v n hrmal 4hfBR xp( hf / k ) (quantum mchanc) h J c Plank' cntant -3 k.380 J / K Bltzmann' Cntant B th bandwdth f th ytm n Hz f th cntr frquncy f th bandwdth n Hz PD 4kR =4K f (0. Hz) f (6Hz) =90K 7 f at mcrwav, thrmal n : wht n v n 4kBR Mcrwav Crcut,6, JJEOG

8 Mdl f Rtr v n 4kBR n 4kBG 8 Mcrwav Crcut,6, JJEOG

9 Maxmum pwr tranfr Maxmum Avalabl Pwr P max vn R R vn 4R kb A B 0, Pmax 0 : mallr bandwdth cllctr l n pwr A 0, Pmax 0 : clr dvc l n pwr pwr at 0 = 90 K n pwr dnty (pr Hz) = k 0 = -74 dbm/hz = -4 dbm/mhz (x) pctrum analyzr wth a rlutn bandwdth f MHz n flr=-4 dbm 9 Mcrwav Crcut,6, JJEOG

10 Equvalnt mpratur Arbtrary wht n urc quvalnt thrmal n urc quvalnt n tmpratur kb, : n pwr 0 Mcrwav Crcut,6, JJEOG

11 Equvalnt mpratur f Amplfr G kb " Input rfrrd " Mcrwav Crcut,6, JJEOG

12 Maurmnt f Gk B Gk B Gk B Gk B Y Y Y Fgur 0-6 (p. 49) h Y-factr mthd fr maurng th quvalnt n tmpratur f an amplfr. Mcrwav Crcut,6, JJEOG

13 Fgur () f mcrwav cmpnnt Equvalnt n tmpratur, fgur Cmmuncatn ytm gnal pwr gnal-t-n rat (R) pwr : n pwr frm a matchd R at 0 = 90 K, r = k 0 B 3 Mcrwav Crcut,6, JJEOG

14 Mcrwav Crcut,6, JJEOG Fgur () fgur = nput R/utpu R l ntwrk y ntwrk 4 F / / F G G ) /( / B G B G G B F B G G G k k k k

15 Fgur (3) F (F -) In db, F 0 db F 0 fgur a. Dfnd fr a matchd R at 0 =90 K x) f LA = 464 K F =.6 = 4.5 db a : nput rfrrd n f addd n pwr nd amplfr. F> : n fgur dgradd whnvr crcut ar cnnctd. x) LA : dn t mprv n fgur. LA add jut lw n (lw ) 3. factr v n fgur 5 Mcrwav Crcut,6, JJEOG

16 Fgur f -prt Pav twrk (matchd ca) x) attnuatr, ly tranmn ln hld at kb R gan G L L:l factr n thrmal qulbrum at, utput n pwr mut b =kb kb GkB G a G kb G a, a: addd n pwr by th ln (nput rfrd) G (L ) G F ( L ), ( F L, r fgur L whn ) 6 Mcrwav Crcut,6, JJEOG

17 Fgur f a Cacadd ytm w cacadd ntwrk (a) Gk BGk B G :avalabl gan 0 G G G G kb( k G G kb( B ca G Fr th quvalnt ytm (b) ) ) ca G F ca ca G F F G In gnral, ca G 3 G G... F F F3... G G G => n charactrtc f th frt tag : mt mprtant! frt tag huld hav a lw n fgur and hgh gan. Ex) LA n th rcvr ca F 7 Mcrwav Crcut,6, JJEOG

18 Prblm 0. An amplfr wth a gan f db, a bandwdth f 50 MHz, and a n fgur f 4.0 db fd a rcvr wth a n tmpratur f 900 K. Fnd th n fgur f th vrall ytm. an).7 4.3dB 8 Mcrwav Crcut,6, JJEOG

19 Ex0. Analy f Wrl Rcvr Cmput th vrall n fgur f th ytm. If th nput n pwr frm a fdng antnna =k A B, whr A =50K, fnd th utput n pwr n dbm. If w rqur a mnmum gnal-t-n f 0 db at th utput f th rcvr, what th mnmum gnal vltag that can b appld at th rcvr nput? Aum th ytm at tmpratur 0, wth a charactrtc mpdanc f 50 hm, and an IF bandwdth f 0 MHz. 9 Mcrwav Crcut,6, JJEOG

20 G F a a 0dB 0, db.58, Ff Fm F Fa.8. 55dB G G G a a G db 0.79, G f f f F db.6, F Ex0. lutn m m 3.0dB dB.5 Ovrallgan G 3.95 V k( G F ) 3K ( 0 Z A )BG.08 0 G μV(rm) 3 W 96.8dBm W 8.8dBm t: F FG k BFG ncrrct, F dfndat A 0 A 3 W 0 Mcrwav Crcut,6, JJEOG

21 HW5. A 0~ GHz amplfr ha a gan f 0 db, a n fgur f 3.5 db, and an utput pwr f 0 dbm at t -db cmprn pnt. What th dynamc rang f th amplfr? GF 57.5 dbm DR 0 ( 57.5) 67.5 db * flr 74dBm / Hz( k 74dBm / Hz 3.5dB 0lg X0 77.5dBm 0 ) F 0lg B 9 Mcrwav Crcut,6, JJEOG

22 HW5. Prblm 0.7 A PC cllular rcvr frnt-nd crcut hwn blw. h pratng frquncy MHz, and th phycal tmpratur f th ytm 300 K. A n urc wth =-95 dbm appld t th rcvr nput. (a) What th quvalnt n tmpratur f th urc vr th pratng bandwdth? (b) What th n fgur (n db) f th amplfr and tranmn ln? (c) What th n fgur (n db) f th cacadd tranmn ln and amplfr? (d) What th ttal n pwr utput (n dbm) f th rcvr vr th pratng bandwdth?) an) a)305.5k,b)f.db,f a l.43,c)f.3 3.6dB,d) Mcrwav Crcut,6, JJEOG

23 HW5.3 Prblm 0.8 Cndr th wrl lcal ara ntwrk (WLA) rcvr frnt-nd hwn blw, whr th band-wdth f th bandpa fltr 00 MHz cntrd at.4 GHz. If th ytm at rm tmpratur, fnd th n fgur f th vrall ytm. What th rultng gnal-t-n rat at th utput, f th nput gnal pwr lvl 90 dbm? Can th cmpnnt b rarrangd t gv a bttr n fgur? / /( F) 0. 36dB 3 Mcrwav Crcut,6, JJEOG

24 (kp) Fgur f -prt Pav twrk (mmatchd ca) GkBGadd G : avalabl pwr gan pwr avalabl frm ntwrk pwr avalabl frm urc ( Γ Γ ( Γ ) ut ) In thrm dynamc qulbrum, kb(avalabln pwr) G G F G G 4 Mcrwav Crcut,6, JJEOG

25 (kp) Fgur f a Mmatchd Ly Ln G (L)(L Γ G L( Γ ) ) ) 0 (L) : matchdly ln )L (ll) 0 3) ly and mmatchd L, 0 (L) avalabl n pwr frm ly lnprt and prt rflctd n pwr at prt appar at prt!! 5 Mcrwav Crcut,6, JJEOG

26 (kp) Ex0.3 Applcatn t a Wlknn Pwr dvdr An antnna cnnctd t a lw-n amplfr wth a pc f caxal tranmn ln. h amplfr ha a gan f 5dB, a bandwdth f 00MHz, and a n tmpratur f 50K. h caxal ln ha an attnuatn f db. Fnd th n fgur f th tranmn ln-amplfr cacad. What wuld b th n fgur f th amplfr wr placd at th antnna, lmnatng th tranmn ln? Aum all cmpnnt ar at an ambnt tmpratur f =300K. 6 Mcrwav Crcut,6, JJEOG

27 .4 ntvty and Dynamc Rang ntvty : mnmum nput gnal pwr that th ytm can dtct wth accptabl gnal-t-n rat,mn R,mn R F R / R FR, mn FR, mn R n k0 B Rcvr (F) R Baband (dmdulatn) n db,mn 0lg( k0 ) 0lgBF R,mn 74dBm/Hz0lgBF R (nput)nflr,f,mn 여러가지응용분야에서요구되는 R 변조 typ 에서요구하는 R Mcrwav Crcut,6, JJEOG

28 Maurmnt f 8 Mcrwav Crcut,6, JJEOG

29 urc Actv n urc : dd, tub - quvalnt n tmpratur - xc n rat (ER) ER n ff ff n ff ff n ff n ff n pwr whn dd n n pwr whn dd ff k 0 B quvalnt n tmpratur whn dd n quvalnt n tmpratur whn dd ff 9 Mcrwav Crcut,6, JJEOG

30 Maurmnt f mpratur pwr n tmpratur can b maurd wth 0 K nput trmnatn mpractcal Y-factr mthd : u an nput wth tw dffrnt w unknwn :, GB Gk B Gk B GkB Gk B Y n ff Y Y ER Y Y Y Y (, :gvn by n urc ) ( Y : maurd ) 30 Mcrwav Crcut,6, JJEOG

31 Ex 0. tmpratur maurmnt An X-band amplfr ha a gan f 0 db and a GHz bandwdth. It quvalnt n tmpratur t b maurd va th Y-factr mthd. h fllwng data btand: fr 90K, dbm fr 77K, Dtrmn th quvalnt n tmpratur f th amplfr. If th amplfr ud wth a urc havng an quvalnt n tmpratur f =450K, what th utput n pwr n dbm? dbm l). Actv n urc can b httr Or cldr(n lqud ntrgn/hlum) Y ( ) db.7 db.86 Y Y 70k Gk B Gk B W -60.7dBm 3 Mcrwav Crcut,6, JJEOG

32 fgur maurmnt DC Fgur Mtr urc DU Rcvr Y-factr mthd Y Gan and F f DU urnng n ad ff th n urc wth a gvn ER Maur n pwr n ach ca n n Gk B Cmput Y F, G n ff n ff ff Gk ff Gk B B Gk B Y n ( ) / ff / ff ff ER F F ER Y G n k B( n ff ff ) 3 Mcrwav Crcut,6, JJEOG

33 Rmark 33 Mcrwav Crcut,6, JJEOG