Microwave EngineeringMicrowave NetworksWhat are Microwaves?S-parametersPower DividersCoupers!iters "mpi#iers Microwave engineering$ Engineering and design o# communication%navigation s&stems in the microwave #re'uenc& range(Microwave EngineeringApplications$ Microwave oven) *adar) Sateite communi-cation) direct +roadcast sateite ,D-S. teevision)persona communication s&stems ,PCSs. etc( What are Microwaves? ,Po/ar Sec( 0(0.1 23 cm$f 1 2 4 035% 23 4 03-6 1 0 78/1 0 cm$f 1 2 4 035% 04 03-6 1 23 78/Microwaves: 30 cm 1 cm Millimeter waves: 10 mm 1 mm,centimeter waves.1 03 mm$f 1 2 4 035% 03 4 03-2 1 23 78/1 0 mm$f 1 2 4 035% 04 03-2 1 233 78/( )( )( ) ms mHz / 10 3wavelengthc lightof velocity f frequency 8 Note$ 0 7iga 1 039 What are Microwaves? 1 cm# 103 k8/) 1 c%# 1 2 4 035% 03 4 032 1 2333 mPhase dea& 1 ,2 or 360) x Ph&sica ength%Waveength# 103 78/) 1 2 4 035% 03 4 039 1 2 cmEectrica ength 10 cm%2333 m 1 3.3 x 10-6 ) Phase dea& 1 3(3306RFMicrowave Eectrica ength 1 0.33 ) Phase dea& 1 005(5 !!!1 360 Electrically long - The phase of a voltage or current changes significantly over the physical extent of the deviceEectrica ength 1 Ph&sica ength%Waveength ,e4pressed in ) 8ow to account #or the phase dea&?

! ! !Low FrequencyMicrowave !!Propagation dea& negigi+eTransmission line section! lPrinted Circuit Trace:o$ characteristic impedance ,1;ossess Networks[ ] [ ] [ ]$#tS S U 1 0% & .0 1U 1 1 ]where ?U@ is the unitar& matri4 !or a 6-port network) the product o# the transpose matri4 and the compe4 con) at the ith port o# a network is de#ined as20log 20log .ii iiVRLV+ =he insertion oss) A>) de#ines how much o# a signa is ost as it goes #rom a E E(02 * 1Anput Port is matched Anput AmpedanceAngoring the E*S[ ]0 1 1 01 0 0 1.1 0 0 120 1 1 0jS 1 1 1 1 1 ][ ]0 1 00 0 111 0 020 1 0#jjSjj 1 1 1 1 1 ]=he 'uadrature h&+rid ,or +ranch-ine h&+rid. is a 2 d- couper(=he 'uadrature term comes #rom the 93 deg phase di##erence +etween the outputs at ports 6 and 2( =he couping and insertion oss are +oth e'ua to 2 d-( *ing h&+rid ,or rat-race. couperJuadrature h&+rid Couper" microwave signa #ed at port 0 wi spit even& in +oth directions) giving identica signas out o# ports 6 and 2(-ut the spit signas are 053 deg out o# phase at port G) the isoated port) so the& cance and no power e4its port G( =he insertion oss and couping are +oth e'ua to 2 d-(Not on& can the ring h&+rid spit power to two ports) +ut it can add and su+tract a pair o# signas( !iters!iters are two-port networks used to attenuate undesira+e #re'uencies( Microwave #iters are common& used in transceiver circuits( =he #our +asic #iter t&pes are ow-pass) high-pass) +andpass and +andstop(>ow-pass 8igh-pass-andstop -andpass " ow-pass #iter is characteri/ed +& the insertion oss versus #re'uenc& pot in !igure(Notice that there ma& +e rippe in the pass+and ,the #re'uenc& range desired to pass through the #iter.) and a ro o## in transmission a+ove the cuto## or corner #re'uenc&) #c( Simpe #iters ,ike series inductors or shunt capacitors. #eature 63 d-%decade ro o##(Sharper ro o## is avaia+e using active #iters or mutisection #iters("ctive #iters empo& operationa ampi#iers that are imited +& per#ormance to the ower *! #re'uencies(Mutisection #iters use passive components ,inductors and capacitors.) to achieve #itering(=he two primar& t&pes are the -utterworth and the Che+&shev(" -utterworth #iter has no rippe in the pass+and) whie the Che+&shev #iter #eatures sharper ro o##(!iters>ow-pass !iters >ow-pass !iters8igh-pass !iters -and-pass !iters>umped Eement !itersSome simpe umped eement #iter circuits are shown +eow( >ow-pass !iter E4ampe>umped Eement !iters2#lLovPR.2ol soRv vR j L +20log 1 .2oj LILR + _ ,=he 2 d- cuto## #re'uenc&) aso termed the corner #re'uenc&) occurs where insertion oss reaches 2 d-( 1#2oLR 20log 123oj LR+ _ ,3201 10 22oj LR+ .ocRfL ( )22 22.2sl sAo o ovv vPR R R 10logLAILPP _ ,Power deivered to the oadAnsertion >ossMa4imum avaia+e Power$ >ow-pass !iter E4ampeE4ampe 03(06$ >et us design a ow-pass #iter #or a H3(3 s&stem using a series inductor(=he 2 d- cuto## #re'uenc& is speci#ied as 0(33 78/(>umped Eement !iters.ocRfL =he 2 d- cuto## #re'uenc& is given +&( )4'01'.4.1 10 1oR HL nHf s x s _ ,=here#ore) the re'uired inductance vaue is !iters=he insertion oss #or a +andpass #iter is shown in !igure(8ere the pass+and rippe is desired sma(=he sharpness o# the #iter response is given +& the shape #actor) S!) reated to the #iter +andwidth at 2d- and K3d- +&603.dBdBBWSFBW" #iterLs insertion oss reates the power deivered to the oad without the #iter in pace ,P>. to the power deivered with the #iter in pace ,P>#.$10log .LLfPILP _ ,-and-pass !iters "mpi#ier DesignMicrowave ampi#iers are a common and crucia component o# wireess transceivers(=he& are constructed around a microwave transistor #rom the #ied e##ect transistor ,!E=. or +ipoar