(Horizontal Antenna)1232.1

2.12.1.1 (Horizontal Symmetrical Dipole)36mm23m/4

211 l=12m22m1000H=10m60044m2H+2l64m0.390300km

1. 212-1

213213214213

213213214214

EH l

1

212=0xOz=0213, fxOz(,=0)=|1-oskl||2sin(kHsin)| (214) xOz1174

1fxOz(,=0)=|1-coskl||2sin(kHsin)| (214) (1)H/l/H/ (2)H/=0 (3)H/0.25H/0.3=90=60900300km

(4)H/>0.3H/m1m1172m100H

0(5),

2 213: f1()215216l/=0.25l/=0.50

215216l/=0.25l/=0.50215 l/=0.25216 l/=0.5

(1) H/ (2)l/,l/,l/0.7=0,l/0.7 (3)cossin215 l/=0.25216 l/=0.5

(1) (2)H/0.3,,0300km (3) (4)=0l/0.7

2. ,217217 l=20mH=6m

3. ,f(m1,)m1 2 15;Rrf(m1,)RrRr=R11-R12R11R122H218H>/2l/H 218 D~l/

4. 1) l (1) l

(2) l/Al/0.1219l0.2 l0.2max (2110)219 K~l/ 0.2maxl0.7min (2111) ,230MHz210MHz,2l=222m1030MHz2l=212m

2) H

300km,H=(0.10.3)815m m10216H r

2.1.2 64m210222=64m4mm1k350

1.75ma

(Cage Antenna)21106835mm13m250400 2110

34m ae:

abna2mmb1.5mn8ae0.85m64m353.6

2111a2111b354637434(2111(a)) 2111 (a)(b)

211221132114 2112 2113 2114

2.1.3 V20 1l/=0.635Dmax=3.296 l=90202115V(Vee Dipole) V1.4,Im;l;r; 12

V

2116 V ,V2116V=0V12

2116 V l/ 202optl/2opt0.5l/3.0V,V20VV2opt

0.5V 3V 2l,123 4LPDA

1. 2.1.4

2. (1):,

(2)(3)

1. 112VHF48.5~223MHz1368UHF470958MHz

888()

2. (Turnstile Antenna) 211790

A2119kr E=E1+E2=Asin(t+-kr) (2120) 21182120kr 2120t=08E882118a

5%2118b

8

2118

3. VHF(Batty Wing Antenna)2119EE2120EE2119

AEEDCBADA150/2

2121 11.12025% 2 3 2121

75

2.2 H/,(Vertical Antenna)221(Monopole Antenna)

221

H(HH) 1 2Q 3Pin=RinI2in/2Uin=Iin(Rin+jXin)jIinXin f/f02f

2.2.1 (Whip Antenna)221222 222 (a)(b)1. 1 2 1.72H/

3 1.2.8 He223,I0;H H/

H

5: H1%

5.1. 225(TopLoading)226 225 226

H226(a)226(b)CaZ0H: ,H;ah0=h+h 1/5~3/10h(0.1~0.2)h 226

(h+h)/ h/2h/2

,zI0he

5.2.Induction Coil 227 227 1/31/2hh

5.3. 2280.20.5m151503mm h/=300m15mA6.5%,1203mm90m93.3% 2290.51m380.150.2 228 229

2.2.2 T T 1. T T2210TT lhhTh/0.15T2211 2210 T 2211 T

THT22122212 T 2.22139.22214a30602214(b)

3. L22152216 Tl

2216

1l2217(a)hhl2217(b)

2217 l,h l,h l,h l,h

2lH2217c3lH221822 17(d)2217 2218 hl l,h l,h

HEEz2219(a)122219(b) EEz Ez 2219

2.2.3 Helical Whip Antenna 22202/32220

(Helical Antenna)DD/2221D/0.46

N2222EDE 2222 lsin90 AR

D

2.2.4 VHF/4(Elevatedfeed Whip Antenna)

2223 (a)(b)(c) 2223

2223 (a)(b)(c)

2223 (a)(b)(c)

2223 (a)(b)(c) 2223(c)10

2223 (a)(b)(c) 3076MHz3m30MHz0.376MHz0.77

2.2.5 (Biconical Antenna)22242224

2225 1. (Discone Antenna)19452225 VHFUHF51501.5 DCminCminSS=0.3CminD=0.7Cmaxh=30Cmin=L/22L1.571291

HE2226

2226

22272227

2. 2228(Sleeve Monopole)2228aL+L/2

2228

Haeai

, L/L=2.2541,221

221

2231 (Opensleeve Antenna)2231310MHz510MHz,501.8

2.3 C=2b0.2 ,

Im

l

a

f=0

2.3.1 1231(Small Loop Antenna)231 ISRl:

ab

D=1.5

As the current is along the x direction,b is the length of the block, and w c is the equivalent cross-sectionsl area with w as its width and c as its thickness

231/25 10

/2/42300MHzNN2(NNINE1N2P1) N ,Rp;R0,

232b=/25a=10-4410-45.7107(S/m)f=100MHz8Rp/R0=0.38 888

232R'r Rre Q

232

2.3.2 1. J.E.Storer,233231=2ln(2b/a)ab

233 kb=0.1,kb=0.2 kb,kb=0.20.030.04kb=1=0180=90270

C2b=23 1231 A,r-1

R

RA2311A yOz90kb=1 ,J0J202xOz0180

2312 ;yOz: f()=cosJ0(sin)+J2(sin) (2317) xOz: f()=J0(sin)-J2(sin) (2318) 234 234 (a)yOz(b)xOz0.27

235 (a)(b)236 0kb=2b/=C/2.5 C()2Xin=2ln(2b/a) 9 kb>1(kb=18100 236z

2. 237(0.30.5),0.52L4L6L2381234

237 238 (a)2L(b)4L(c)6L

kb1100239a0.272L239b,,

239 2L(a)(b)

2L4L6L2310a2310bH=0.252L4L6L2310c

2310 (a)(b)(c)

1.05161.1202.3.3 ()(Loaded Circular Loop Antenna)2311VHF

2311

RLZ0 kb2312a=2ln(2b/a)bRL3259.4300kbkb2003002312 (a)(b)

kb1,2311kb>1,C/,C/min1 1 2311

8.6.1 Surface resistanceLet the electric field intensity in a good conductor be Neglecting the displacement current density in a good conductor, the total current is The average power dissipated per unit volume is

Let us concentrate on a region bounded by 0

Comparing (6.68)and (6.69),we obtain the resistance of the block asAs the current is along the x direction,b is the length of the block, and w c is the equivalent cross-sectionsl area with w as its width and c as its thicknessThe skin resistance() or surface resistance() is defined as the resistance of a plane conductor of unit length (b=1),unit width(w=1),and thickness c

As the current is along the x direction,b is the length of the block, and w c is the equivalent cross-sectionsl area with w as its width and c as its thickness

Although we have computed the skin resistance on the basis that a plane wave is propagating through a flat block,(8.71)can also be used to obtain an approximate value of the skin resistance for a cylindrical conductor.when the current is along the length of a cylindrical conductor of radius a such that a> c ,the skin resistance per unit length is

2.4 P91YagiUdaantenna (YagiUda Antenna)Uda1926Yagi1927241() 241 241

242 (a)2(b)2a212();b212()1.(Director)(Reflector)1.1

242 (a)2(b)2a=0E=1.5E1,=180E=0.5E1,122 211/2E2E1

d0.1~0.4212MN2432M2I2=mI1ejd=0.1~0.4ME2E1=+kdNE2E1=-kdd0.1~0.4,36kd1440

2.4.1

2.4.2 244 ?24412l122l2dI2,I22

U1=I1Z11+I2Z12U2=I1Z21+I2Z22 =0m(2l1,2l2)d

241 2l1/=0.475

245 245 ;12l1/2l2/d/d/ 2d/2l2/=0.450d/=0.1d/0.25 3d/d/

3.(Multiple Element Antenna) 246a246 (a)(b)E (c)H(d)

24112132zz246bcd2lr=0.52l0=0.472l1=2l2=2l3=2l4=0.43dr=0.25d1=d2=d3=0.302a=0.0052EH246 (a)(b)E (c)H(d)

2470.150.0025247 N=3N=41dB78N=9N=100.2dB

2.4.2 242EH

242

1. 70()U(5075)2 ,2

2. MoM248L(244)248,HEHE248L/>220.5L/

248 20.5~L/

HE(242)242249

249

3. 2410L/10, 90%1, G=DD 2452410 D~L/

4. 5. S210% d/

X2411X 2411 X(a)(b)X

2.4.3 U1/4KK>1 (HalfWave Folded Dipole)24122l/2D

/22413D

2412aIM1=IM2IM=IM1+IM2=2IM1 ,Rr,70 IM1IM

=1PinPr246247IM=2IM14

42412bDa1a22412b 2410 a1=a2 a1>a2 a1

a1a22414/4a1>a2Zc1

,DDD=(0.01~0.03) K

4.9

:zz

0z

11, ZLZ0

2 (1)ZLZ0l ZinZG ZGZ0(2) Z*GZin

c

,,,.,,...,,.1 ? ?

1.2 .(1)I4=0(2)3(I4)I1 I2 I2I3I4I3

22.1 l/4 l/4 l/4 I40I4 I4I4=0I1I3

2.2 (l/4 )Z0 l/4 ,4I4I44I4I1I2I2I4I4I4I1

2.3 UU2

UZA2ZA1475ZA475300AA

2.4.5 (Loop Element YagiUda Antenna)2421 3.2dB100 2421

brdr 1d=(0.1~0.3)kb=0.9 2kbd0.3dkb=0.7d0.15dd

3HE, 4kb0=1.1kbr=1.05dr=0.1kb1 1200MHz1.22520dB

2.4.6 2060-20dB-30dB 1.(Back Fire Antenna) T24 22T13dB3dB

24 22

/22dB8dB

1530dB,

2.(Short Back Fire Antenna) 24230.40.62W=/4~/2

8.517dB1/10

2423

2.12.32.42.72.82.102.122.13123