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The document discusses microwave transmission lines, defining microwaves as electromagnetic waves with frequencies ranging from 1 GHz to 1000 GHz, and highlights their unique properties compared to lower frequency waves. It covers the advantages of microwaves, such as increased bandwidth, improved directive properties, and reduced fading effects, making them more reliable for communication. Additionally, it explains the use of waveguides for transmitting electromagnetic waves and the mathematical principles governing their propagation.
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|
MICROWAVE TRANSMISSON LINES. |
Igtraduction:
¥ MiCOWaVeS aye electvomagnetic waves whose frequencies nange
F10M [GHz 10 1000GHZ Microwaves Ave So cated since they defined
interms of thein Wavelength in the Sense thal Micro nefers to tinyness '
tiNyness neferring to the Waverength and the period of cycle ofem
| wave: |
NQte: A Microwave is a signal that has a wavelength oF | 4004 oy
less iS that Az30-Scms -This is converted 10 a Frequency of Q8yMHZ
approxi Mateiy = Ganz
Bands and Spectrum:
The higher frequency edge of microwave bonders on the infrared
and visible light negions or spectrum. |
This explains why Microwaves behave Move like vays Of light
than ordinary xadio waves: Bue to this unique behaviour the micro- |
‘wave freq's are classified seperately from nadio waves |
Eur |scr | ver [ce-| me] ae [vnr]one| Bue [ene] indrared [Aight |x-vays | yng [osm ||
| 300HZ B0KHZ BKHz) 300m 30GHX Ygoraz lolsT HZ ode
| ELF - Exieremely row frequency |
(SUP - Super low frequency
lvLF - very tow fyequency
| Fuecwgmoaanetic Frequency Spectyyin
|
Microwave band Millimeter
| & |s [ec [x|eu[k [ka
|
submillimeter | |
|
SoHe | gone] iBaAZ
4YOGHZ
GHZ z
IGH. Yow GHZ = 29GHZ 9 .300THZ
2SS eS ee ee
[Advantages of microwaves: dee .
Theve ave Some unique advantages of microwaves over iow
!
frequencies: |)
i Toceased Bandaiaih AVAIAB ty:
Microwaves have lavge bandwidih compared to common bands
Microwave negiON contains thousand Sections of the frequency band
0-107 Hz and hence any one of these thousand sections may be used |
40 transmit all the Tv, radio and other Communications
& enproved Directive proper es:
AS frequency incveases, divectivity incyeases and beamwidth decye-
ases. Hence the beamwidth of nadiation 6 is propoytional 10 Ya
For @ payabolic antenna 8 = !40"
(ra)
ushere 8- Hiameier of an antenna in cm
| A~ waverength in cm |
| B- Beamwidth in degrees
| AS frequency increases ,4 decreases hence power gadiated and
| gain increases
seeding ailet ane feulehulty
Fading eect due 10 vavialion in the transmission medium is
lmore effective at lower Frequencies Due to line of sight propagation
land high frequencies there is 15s fading effect and hence microwave |
{communication is More seliabie |
Fading def: A Signal experiences multipaih propagation vahich Causes
lnapid Signal (ever fiuctuations in time caied Fading
Hepower Requirement:
avansMittey /Receiven powen nequinement aye pretty row at
micaowave frequencies compaye tO that of short Wave bands1: Vxne TH Ba > Ampere's haw (Moditred) .
B.Jxes - 38 ~> Faraday's haw of Enduceron,
3. V-0= Py = Gauss hawfor slectrestatic.
7? V-G-0 —Gauss raw of Magnetisry .
* The above
Zquations describe how Llectric charges
+ Electric Current Creat Sleceric # Magnetic Field,
V2 Nabla > Zndicate Partial derivative
= Vector aradrene -
* EF - Electric Field: * P= Free Lleerric Chage
Density.
J = Current Pesity,
* GB > Slagnetic Hax Density 1 _ elegerre Displacement
# H —> Magnetic Fires.
Re Divergence FJ > graaient- freld.
Wx —Curl
oes Eine Sirgre Mm}.
eee
z
z & Three dimensional] i
x
y: .
y
2 2 a
fax t Sa ta
Doe 1 oy te aeRylindzical Loordinate Biysrem*:
Reordinate
z
ye Radial Distance
og = Azinuthal Angle
(Nf ®) Z = Height:
a = ay + 24 3
+542.
ay y2¢e os z
K Cylindtical To Caxeesiah
oe apa cence
cosf= > sings &
a : Z-z
x aves g y = vsing
Lylinazical :
aaa
# Cartesian To
ae ee
* o Ete|
p . ; a.
Ethericl Coordinate Fysten ! 6 = polar Angle
id Yr Radial Distance
Gz Azimuthal Angle:
|
r
(8/9)
|
a
|
|
Cb ge
et “ Y
|
| aA Dart dae
2¥ x06
| eles non 5
| ysihe
|
|
|
| F ehencal Kovrdinate iysrem 15 Loartesian.
| TN I ne Re
| Fron Triangle a From Triangle
= 4
| | > 2-4 ce. = &
i y = xCcoS 6 g= aa
: Xa
‘ =e Lie a cos
ine y a2 a = xYSsIhe eo he
From Triangle A sing =
ms oe Yrasing
OME xe ye = Bihosih g
HWieT From Triangle B= ¥ te ghyar
tee xXMSyhb2*
v sige oo
A : yee!
a oY Tata .From trangie 6
ee
COS B=
cose =
ayer
iy
————
Or CoS (FS)
gb?
m1 Triangle A
Fro
tang a
* Gr tan! ) :
| * have Equations :-
* The chavacrerisrics of the Medium in which
the fields enrse ave needed te. specify the flux
| * 0-22
* B=MH
| x eeJ=o-E
* E=LxES
+ A= Ly,
* With the above Equatrons.
Vx = T4222 rete dk
De DE-
VxE = —-%8 -~ 498
De we
Th terms of the fields in a specific Mediurm-Hearc.et ISE actamed phar gine elewsic & Magnetic
Follow an Exponential form of Lime
Variation , we
freids
can write
Twt
E= ee
a CeosusteTsinwe)
* Tn the above Lanation real pare is
Considered 4 Tmaginasy Part is Retained for
Sinusoidal Varia tion
Jue:
PE=AE,e
#% Partial differential Equation.
Ee Tuk
OF = 3 E,e
de De
Tur
= £0 (me
DE. esw
DE
Es JWE
VE
Partial djfferential Equation
OK : x 5
—— Tue we
DE Sa RHoe = Hols) e7Vxn = (— + Iwe)eE
VxE = - adn
7 - MIwH
* Apelying Carl to above Equation.
VXE = — JWHH
YXUXE = - Iw (yxn)
Wve) - Ves -TwM(ce + swe)
BT TWMT ER + ~The
- VES -INMeR TUE
* Free Charge
akfzo
vies L
6
oe -G
V-D=Me6
k Using above Equations.
UME) = Oo = (-1u Ee
~NVCE) = wraee
Vee] Soe
> Lleciric Wave Equaroh
Similarly 2 aa
VOH =~ a cH Magnetic Wave Lquahes
*In time domain, ElecwedMagnetig Wave Equations ave
L, 1 mn
vz a £equide: ®
frog's highey that 3GHZz , transmission of En waves along
Lransmission lines and cables becomes difficult Mainty due to 105Ses
Ahad OccUM both iM ANAM Solid diolectric Needed io Support the
conducion
hervefove, A metallic tube i Can be used’: te" ~ transmit
electromagnetic wave at these freq's
A HONOW Metallic {Ube OF UNITOYM CYOSS- SECLION For AYaNSsMilting
EP) waves by SUCcessive mefIeCLONs from innen walis Of the tube
iS cayied @ Y Waveguide’:
Comparison Qf Waveguide With 2 wine TWANsMiIssion Anes:
| wave travelling in a waveguide has a phase velocity and will be
aitenuaied as a transmission line.
2 when the wave neaches the end of ihe wavequide i is neflected
uniess the load tmpedance 1S Adjusied 10 absevve the wave.
2 ANY invequidvity iN @ Waveguide produces meflecion just like an
inaeguianity in a lyansmission tine
JOR OF waveguides:
Any shape of cross-sectional of waveguide can support EM Waves
But Since inneguian shapes ave difficult 10 ANatyxe and aye rarely
used, rectanquiay and ciyculay wave guides have become move common.
recianquiay wave quide is MOS common
C/4i9: OP Wen =
(6) Cifeulay wave (C) Elliptical Wave
Copper wails
|
|
| quide pulde
inner Surdace hin tining of
AU and Ag.(ei
@) Single kidged (©) Bouble Ridged
Crculay wave guide iends 10 twist the Waves as these travel
ibyough dhom. civcwlan Wave quides ave used With nolating antennas
as in nadars
Propagation of Waves in Reclanguian wave Guidescewa)
Consider A RWh SitUaied FM the Nectanquian coondinaied system
with 18 breadth along x axis Width aiong yanis and the wave is
assumed 10 Propagate along the z direction wave vide is filed
. . Hive ction)
with ain as dielectric q i
The wave eqn fon 7E and 7M Waves on.
are given by To
width
Viz =-usuenz for 1E Wave (éz=0) | = air
-—3%
2 i oO a
Wey = -us ek, 101 TM WAVE (Hz =0) %— breadih —}
\Expanding vtéz in nectanguian coondinate sysiem
P
| Oke , Okey Er . uw peke
Ou oy On
| Since the wave is propagating in z direction we have operate —
O24
one
|
| substituting
| > Pee, tesa
ox yt
- OSU BE
Oke 4 ke 4 Pru eyk, = 0
ou OgPrutue- be a constant then @
zi dkeyRe, -0 for 7M wave
ay
emidiy GAR 4a Az yh Hy=0 for T£ wave
on Oy
oidal EM wave
= Mt riNsic propagation (Measure of changes ina Sinus
‘ough a medium)
sorms of amplitude and phase while propagating thr
from marwol's frst eqn
Vx i= jusee |
expanding gx,t § &- unit vectors along a1 yz direction
2 2 S|, jue[teatdeytRer]
Rea
jek
6 @ 3] = j Oey dey
noi 3 juse [PEx 4) Eytk Ec]
Hy Hy Az
ip On ap az riba} +h { Sty 3h] . jue [teaad EythE
Rp Oke + any) 3 [ Gt ajre fp ha at). juse [Tend &y 2]
equating coeH's of *,F,k
am +dHy = Jwelx 90
OHz 4 5ny = -jwefy 9@
rt
dHy da. jwetz a@
On BY
similaviy drom maxwen's a4 eqn gre = -juspt
£xpanding vxeE«Tai ¢ “0 3fe 43 c{aey -o€
[oe veg] 3p 8 13ex) RLY aa
Equating coefficients of 7, and &
Okz, dky = -jophy 3
“<
dE pak, = jWUKY AO
3
aéy - dk ~ -jupnz 9©
“oxy
subsiituling Hx from ean @ in eqn @ we get £y
Hy > -1 Oke - 3 £y
JOP OY jsp
Sub Hx iN eqn@®
| 2
ax jus oy
Jwp de _ 4
ox
|
| L
| sunstituring Hy from eqn® in eqn® we get Fy
Hy = 1 Oke 4a gy
|
|
| Just Ox — wo
| Sub Hy in @
|
BHe, 2 akea FP kx 2 huey
jue GHz 4» 3 Bee 4 (344 usWe)Er =0
8y Oe
~jup (Ta F hy sh He]he ox
Sub Fx eqn > in > eqn® we gel Hy
f,- 2h Ole 4
jue OY jwe
gub in ®
2
GHz 43° vy = fuouH
ine OY juve ee)
jure Gk 43 die 4 PHyTUPMEHY =0
a
b> dy |
substituting £y fom egn@® in eqn@ Hx from eqn®
fys -+ He -3 py
jwWe OX Swe
sub £y in @
kz 3 OHe ~ a py = -jwylle
3 jue OX use
juse O42 ~ 3 Hz _9%yy - wea = 0
ay ox |
|| juse OF adhe phy
| ay Ox
+ quse
fe
these agns gives a TeLAtionship bIw dietd components within ie
wave guide: : |
Propagation 2 TM wave ia wave quide:
| For 7M Wave, Hz=0 and £240
2
Bee, Ok abr ex 20
ovr ay
det US consider a Solution &z=xY
where x > pure function of 2, ¥> pure dunttion of y
|1 POY) speyy=0
a Op |
VOX 4 xPy shy -0
or ay
Divide the entise eqn by xy’
SA Pe LAY she
Xow Y oy
LOV Lop
Vv ay
=) - Be M4b 20 =) phe A248? b= JAB
10 Solve the eqn we have to use seperation Method
det us CONSidey, 1 BX 2-9,
x or
X= (C,COSBX 4 Cy SIN BA)
Y= (CgC0SAY + Cy Sin AY)
Herve Ci,G,&, cy ave constants
Boundary conditions:
For TM wave, 2=0 along the walls
ISt boundary condition (bottom Walls): :
| Fz =0 at YrOVxX FO10a
20! Be Cleft side wan):
42
| Fz=0 at 1-04 y 4 010b
aid Be (top wain:
fz=0 al Y=b¥ 19014
ath Bc C Right Side wars
| &zg-0 al x2a¥Ys0tob
|
NOW CONSider £7 =xy
ee
F = (C1COSBX4 G SINBX) (63. COSAY 4¢y
Sub iSt boundary and in®
2-0 aly-o¥ 00a0 = [COS B1 46) SiN Bx] C3
AS X varies from 0 t0a Xt0
370 i010
| Ez = [cc0sBa4 G sin6x) éy sinay [> Q
Sub aNd bouNd-cond in ©
=0 at X=0 VY Otob
0 = Ci [Cy Sinay}
| | C120 in@
| | [e=lesnadiqsmyt | @
| Sub 3'd Bc in@
| | he £20 at y=b ¥ x 50000
0=[ 4 SIN Bx] [Cy sin ab)
i SiN Ab=0 =) Ab= SIN) = AT
A- on
b
| 3Ub yth B-cin @
ie kz=0, at ta ¥y70 0b
0 = G CySiNBASINAY = SINBA=0 =) Ba=SiM'ol=MN
8= (mn) in®
Fz = Gcy sin [ MJx sin (al) y
| ey considering divection of propagation te &*? and vaviation
with time Wt and consider qty =¢
Kz = ¢ sin (HP) xsin (O8 )y. 9 iut 32
we have
~4 dk - jw ote
wh On nm Oy
- Sy)
4G SIN BY] [G,COS(.0)4 Cy SiN} ®=
| fOr IM Wave Hy=0
ky = -3 Ok
Wax
Sub kx eqn in above eqn
Ey: -i 8 [c sin (mn) x sin (OM Jy put a)
cach! BU Pe ei an |
Re ic (ej cos (Ma si0( AN) elit 34
a ON es a
now take ky
Ry> 2 dks 1 jun oe
hoy be 0
fut Hz=0 =) ky> -2 Okx
boy
oe
Hz=0 and Sub Az
| y= Jue can on Ty x eiust-a
f= Le & (OP) C08 OB): im UT)
NoW Hy= -2 OHz _ Jue oke
OY pe OF
Hz=0 and Sub kz
era esa)
Hy = Jue ¢. (mm A Jude -3Z,
qe “208 c- (enn nn) ete (2! )a- sin (OB )y @
[oe Sh ed
TM modes for a RWG:
WE ARO
ow
~
the modes of 7M WAVeS AYe eperesenied as IMmn
|
| ky 4 c( (a) Cos (MMM) x sin (22 )y. ela
Eyes ae {ott Sin (OP yx C05 ( (an)y-e oiuot- az
1-3
Mg IME c Of) Sin (OT )x cosa yee iz.
“UWE ¢. (MT) cos (BM)x sin (OT )ye oles
befor M=0 aNd N=O
Subst 19 &,£y, Ha, Py
=) £,=£y =Ha=hy=0
TMoo Mode does NOL exists.
case wis for m=O and n=!
we
2) Ey = Fy = Ha = Hy 20
<-TMp; mode doesnt exisis
MMSE Nis fOr Mel and n=0
=) £y ys Hn = Hy 20
“= 7M 19 Mode doesn't exists
case ve for Mz! ANd N=
=) Eye kyr Ha By #0
TM y MOde exists
Propagation of TE wave in B:W-6:
For 9€ Wave: &x=0 and Hx +0
Sz 4 DH she 20
om byt
| ket Hx 2xy
|
BY 4 OKY +iry =o
| av oy
YOK 4 xd thhxy 20
me Oe
BAe hs 0 =) hs A486
7 Soe the above eqn we have to use seperation meth
ave WO solutions of this MOde.
od, theseX = [Gc05B4 4 G sin Ba)
Y= [escos Ay + cysin ay)
Beexy
Hz = (QCOSBA 1G SIMBA) (C3 COS AY +y SiDAY) AO
From 4 sield components
Ez, = Jug Bz +@
he OY
Fy jw ane 5@
h> Ox
Hy>-2 . he
| a Boon 26
| Hys-a die
a 34 3@
‘Bouedary codivions
|) Botlom wal:
|
£420 at Yeo¥1 30 toa
R. zefl side wall:
[OKAY AAS TA
Ky=o at x0 ¥y 2010b
#70 wal"
Ay=0 at Yeb¥x 30100
i, RiQDE Side WAI
ky20 at WA ¥Y 40t0b
ee 4mM £4 = -—jusu OH
bh? Oy
= -JwH 2 [a cosex+gsinay) [cacosays cysinay]
we Oy
Ey = eee
he
Subst ISt bound-cond
Oo = ae [cicos6x4 G8inbx) [ACU]
7
cy
Subst in ©
Hz = [c:C0SBX + GSiNBx] C,C0SAY 7O
| from £ys juss ate
pe Ox
3 Just 9
ar be & (Hz)
0 = jus not
jee [- c1Qin8-B +GCOSBa 8) [¢3cosAy 4Cy SiMAY J
SUbSE- aNd bound cond
O = jut BG [C3COsAY 1 Cysin AY]
he
G=o] in®
=) Hz =((iC0SB1) (GCOSAY)
| om Ka > -JUS atte
be ox
av
Fy= jus .
= ee (cveqsinex. 8) [ %3C0sAg]
| Subst 31d bound-cond
|
| €x=0 at yeb¥ 2 a0tob
=) O= jwp [ersinx-8][ cos Ab)- OO
COS Abs0 =) Ab=fn =] A = aio 8
6
Hz= C3 COSBx- cos at .y aM
6
From £y = jw Bx
hr Ot
ys JUast cj¢3 sina. 6: COSA )Y
fe b
subst uth pound. cond
fy =0 aixrzav¥yrotob
SiNBI=0 =) Gen n@
: Moh \ x= c0$ (00 \Y -
Ha = CiC3 COS( mE) cos(E\¥
By considering the divection Of propagation 6 and variation wrt
time elut
Tr ar
Ha= Cr 63 cos(") a cos(O)y
Sub I Arby Crd
pr
=Ey = J mi) 1.510 (OH piugt 3%
| Ex jak rey (0m )eos( Bt) * (Bi)y-e
. -. pit -8Z
bayey = TWH acs (i) sin (220) x-cos (AE) 9 é
;
d | Hy =
jus t-32
Jt
: on 4 juot~
tye 2 4G (mr) sin can) 1-208 22) 4 e
)
°
O03 os Cos (Gt Si (
casey:
M=0, N20
Subsi above eqns ihe mode is
TE) =) x= Fy= Ay= by =0
T£oo Mode doesn't exist-(
'
jQgsedle mo, n=!
| Kxchy go
ithe Mode Teo: exists
case ditt M=1,N=0 |
RRS a
Ky Ha #0
The mode 1Ei9 exists |
case iv! m=, n=l
Ea, ky, Ha, Hy $0
The mode is 7, ANd it exisis which ais0 get higher order modeys
UU! frequenry oy Cu oty dregs
From Nodal analysis p= Ar+B>
he Prusue -/onyy 2
je Pere = (og Pacey
At lower fveq’s
ine 2
(BE OL) > utue
JF becomes neal and dinite and attenuation constant x exists,
because 3-a4j)p ANd phase CONSt becomes xC10
The wave will NOL propagate through the wave guide
AL bigher freq's
Y mm), (OT \*
use > (M0) + (22)
NOW 9 iS IMaginary and finite aNd phase const exists, attenuation
ipecomes evo
The 41¢q at Which w-0 aNd 3 becomes o al ffe aNd us=We is |
KNOWN as critical freq oy Cut off freq
aleGuides woaye length (9):
ithe disiance tvavelled by the wave 10 undergo a phase Shift OF
fan nadians iS KNOWN as Guided wavelength (Ag)
| 1. ;
phase youoctty (yer
Wk Upe dg
|Multedivid by am a
ee [2 at .p som az 20]
[vps fdg al =) Wedge q a
| an amr Mag
jhe vate at which the wave change its phase inierM of its
guided wavelength ag.
(Aagup veudity (gr
|the yale ai which wave propagates thyvough @ wave quide
jusith certain velocity will be reymed as group velocity (vg)
|: n for rigse velocity: —@]
we have, 9- (mn)? ONY. as, =
(my ) 1 (2°) usue 20
For wave propagation , at cnitical freq al f= 4c 1Ud= We and 3-0
miry? 4 /ony i
0 (ary vay Ue ME
tue = (Mmy?y (OM |
Ue WE (a) 4 (LY +e
for wave propagation =o =) aejp ind |
c) Bt L Load ;
yjet= (DE)* + (DE)*- use from @}
apt = usdpe -udue = pe [usc v9")
aan eae
B= (Hel use)
Subst Bin Vp
=) vp = Us
wy -
Jeo we] usyae [fi S|
in critical WAvele Agth ,
iEaparssion for qigup yogeity:
Nike Vg= qe a ae
dB
dw - fs [etewe )- gue
= dye Sue . Jie
2M3: cf C5)
Reiation Blw Ng ane and Mpi-
Vp-Vq = 2 x € 1 be
———
JT epg)?
|
Relation b/w blw 4gido and Act
weke7 phase veloc ty Vp = Fg = & al 40
Ue .
p= —L_— 3@ in tems of A
I Aa)
From © and ©
Qe et
Foe Io? AeA
» sy
0, ACAD. I= Ak =) ah 4 d=
gr Adcave impedance ip @ RWS Gri, oe = Oe
qhe wave impedance in a RWG is defined as the natio of
Istvengih of electric field 19 one transverse dine ction 10 the styength
|
£ magnetic Field in Other tyansverse dinectiOn.
zz - Ver vey
ra ae
ov
Ky Hx
we have the dieid component varues |
a> 3 Ok — jut ane and Hy = 3. dhe ie ok
Wh ox Ar OY he dy Dx
Kee Fa 2 -3fpr OKs - jw,
Hy ox
3 pe bHz
ay
For T™M,Hz=0 and 3= jp
-d Oke
oc aura py dd
| ~juse aée «Ewe
| “he OL
| Zr coh ee pe (Us We?)
oe we
|
|
Zz: OEJAI-M) 1-{ies)?
eae . -
eve
dee Bn
| Ze (amy? WEY
\for TE , £2=0 and a= jp
Zz - SwL. dhe
Se Te a du. wn
i. Obl Tee | eB
A ogie
“Etre JEU-&)
power Transyited in Awe
the power txed in a RWH IS defined as the powen at a freq
greater than 4c critica req.
Pir Gx ids
[Pure Eg CEI as
Also power transmitted
[irs ae [eras Ba)
pur tyed from TM Wave With the Consideration of dimensions a+b
Payerm) = ae at re!" elt ds
bw
t
OF ogy be ole on
"CM ap Te f ft (Ex? 4leyfrdady
For 1& wave
|
|
|
| oe
Perv (ne) => I~ fs) fof teat Legh dady
| 0
4
Power L0S50S in @ Rw:
[ihe Pwr (05525 IN a RWh due to attenuation , below the cut-oH
| freq, fe due 10 dissipation within a wave quide wats and 105ses
due i the dielectric within the waveguide.a +
At fiveq 125s than fe % becomes yeat and B becomes imaq
Equating x and iMag value OF B is given as
jp: at + dg = do (cet) |
Ag Jt Co fag |
|
jee Jani fi- @o%ac)*, an Ji- Geac)t . ant fr-fe ye
ip ee diatiei) : le
0 f
Equating « and p
a= ant fi =)
Ar AC
«= 546 [T-Eep apjiength
| We @ } ae] "9
‘Ablenuadion due £0 lapartRst CONAUCHNG HABEAS: walls:
ae is given as a&e = I+ 82 (#)* aanengih for TEI |
[-feye
| I)
“Avenuation due to imperfect diectre:
| aq > 233 Jer 448 4p) ength
do Ire)
dominant and gegeneyate modes:
BALA BAS Anda A
‘he Mode of plopagation ¢on which the field components exist
|4vom lower cut off freq IS Calléd a8 Hominant Mode
|
For TE wave, a7b
|
| dhe dominant mode in TE wave is TEIo
| for 1M wave, the dominant Mode is tmy,
| prom, ac = —22b
| Jo Penta |
|the dominant Modes are TED he M=t N=0
[4c =2a]
| TMy be menzt dee AAb
Jartb*
For higher modes any & values Of TE and TM ane equal in tems
of Ac that Pain IS called degenerate Modes
the degenerate Mode in 1& wave is TE}.
TM wave 1s TMi
Met Met =) Ac= aab
Jat
-TEmn ANd TMmp are degenerate modes for NFO and m #0
Here TEy and Tmy ave degenerate modes.
pagbyerns a
1) Caicuiaie the dominant mode cut-off freq Waveiength in RWG Of
dimensions qycm xacm
|
| Jim? brane
[ROY REND des Ax x2
| Jaa 1
|
| por TEIp Ac= Ad= 3CM
a] A Wave IS propagated iN KWH At 6HHZ- Cali Ac for dominant
[MOde- ik Ac IM & guide Ag for dominant Mode sir. Vp aNd Vg given,
| a= 30m |
sd Given a= 3m
| Here dominant Mode is 7Ej9 M=1,020ce 8a 60M = 6xIO-M
ag? Jo = 005 = g.09m |
a |
T(r)? fr- (@05\* |
Vi= Go/Ac) ey |
sii Vp = 2s Gs sey axioms
Vi Goyac)® 0-882
1Vg= Jim Aoyy)r= ¢x0°55 = 165x io M/S
5) A RWG has a=acm and Cayries dominant Mode of a signal oF |
~ |
4:63 GHIE: Find Zz |
sh Given a>3cm, f= 7-63GHE
Pov TE) zz = n £ Ac =~ ab
Ji fon oF + 00)-
For Tin 1 dc= Q0b 22a
pe
| de = ax3= ecm
| az & 2 3x10. 9.939m = 3:9em
763x109
Z el
Zz = 493-8
y)| For an ain filed RuDh Of ex1CM-CAIC Ac for TEI and TMn Modes
jaiso caicuiate dg at (0H
|
sd Given dimensions - acmx1a@
For TElor Ac=@a= YOM
bo. awa) :
For 1M; dez ROb = BOP = 8) Ly Lj gem |
Voie: PHO TG & |uided wavelen Hb Ag:
q ge fo
T= Co /ac)*
2 3xip® -9.03¢m= 3CM
to x109
es
dow $
Ags 3 - yssem
“ay
5) AD ain filled RWh has dimensions of 6emx4ucM propagates Signal
at aGHz for TE{o Mode Cal Ade ding aly B iv, Vp Mg Mu TE
st given a= 6cm, b=YCM, f= 3GHZ
re Flere"
For 1&0 , de> £ [) Jor) aa = Bxtol?. a5 GHZ
aa axe
dg = _do
I> be /ag)*
doz = 3x10!0. (gem
F 3x04
Acz= aa a @) =1acm |
s '
dg= HO = 10 , 10. 78-050
RB)’ froey reve. > Bx1!9 | 5.y2x10!cmis
a Ts lo\
Vt @orac)* J(R)ye
- = 3. gai-ay
‘Ag \2 1/10)
x) ()
eldhe dimensions of WG ave a-ScmxicM ,the 410g iS B6GHZ -Caiculcde
+ possible Mobe Ji cul off freq Jil aq
J Dominant Modes:
wee
fe § (UB) ay)
| [et fre
( 30x10" 770. )*
B6GHZ 7 sb (ee) + (2).
Bb > ovens (BL)
Bbxa5 M \t qr ans Py ph L
BERR? af yyar - 8b5 > mPenrcasy® - |
| pos gs) 9 ras |
sh Given as aSlm ,b= tem ,f2 86GHK |
|
19333, paren (a-5)*
8705 vi04 >M*4N* (a-5)>
|
| check*
| [ [a condition
| TEo} 0 1 doesn't eaist
| TEl0 i 0 exist
| El
TeM I ! doesn't exist
AT | \ doesn't exist
TM) & ' doesn't exist
™ eet es doesn'texistFE(o 1S possible mode
Wh fe= (BYE coy) : SHI" [ gzim \+) = 6aHz
die dg = _4o
Ut Aoyag?
f Scat
doe 3:48 2 y.eyem
Trey
7 S
4) Tn a RW axIcM Operating at a freq Of GGHZ in TE[p Modes. Calc
the MAX pwr handling capacity of WG If max potential qvadient
of asignal is SkvicM
sf pwn handting capacity , p= (6:63x10%) yay (061 (4)
fC. £ 2 0:03m= 8-3CM
°F 4G
| | ag= for 1€10 dc= aa= Gem
| Ag
La
| q= res 395M = Y
ie P= (63x (03k) (30M x ICM) (32 3) = 1y.46 kw
a] the TEip Mode iS plopagating in a RWh OF dimensions 6xuCm
iby means of travelling detection , the dist bw max and min Is
dound 40 be Yy.ASEM-FINd Freq of wave.
si dhe successive seperation bw max and min in a WH is a
7iQ . y.s5(m =)dg=
u
1
1a-Rom - For Tip Ac= aa =(acm
ee a
He bey al “a at a) 3
Be ke a ap ae ee
Av*= 100-36 =) do=l0cm ; freq f=lications of microwaves: |
MicvoWaves have a broad yange Of applications in Modern
dechnology.
iJelecommunication: mtercontinental tetephone and F-v space
communication (karth 10 space and space to earth) telemetry comm-
uNication tink for airways etc
Radars: Detect aincratt ,tvatk/guide supensonic observe and ack
weather patterns , Air traffic Control (ATO etc
s-commerciar and ingustrian appucatos:
These applications use heat property of microwaves
Microwave OVEN (a-4aHZ, B0W)
a Oty ing Machines
3)FO0d processing industry
W Rubber induStry pias tics | chemical
5) MINING / Public WOTkS
§) Biomedical applications
muna and peace Lime Armen ions:
Ra
All the above 3 forms of applications ave peace time applications
ipnticrowave weapon sustenns:
AN EriCssions PYoduct Known as MINIS 1s Q highty moduiay and |
multifunctionar detensive information System thai meets requirement
for situation awareness, survivability and sensor fusion in {omorouwg
dense and complex Signal environment
aphase quay gaday:
This WAS aN impor lant development in Military rarge 10 Make
MQ battle there May be no time to wait for a large, slow dish
antenna t0 Move -A phased array is a set Of huNdreds or thousands
of little yadar sets thai al emit Microwaves.
|
seen ee ee---— Magnetic Pied
Electotc freld a
| e Entering Plane |_| i EnoVrew
| x Leawrg plane. | ——|-—-
Field ; ;
Hacles Pater MOE TE | In a RWG
Side view
Topview
poorTE agp
Stde vrew
Top view
End view
TE20
Side view
Top viey