Extra Class License Class Antennas and Transmission lines

November 1, 2011Steve Long AC6T

long@ece.ucsb.edu

9-1: Dipole 3D and Azimuth Pattern

9-2: Isotropic reference antenna

9-4: Beamwidth of directional antenna

9-5: Pattern ratios

F/B = front/back

F/R = front/rear

F/S = front/side

9-6: Elevation pattern of typical Yagi antenna

Shortened antennas: low RR ; series XC

9-10: Traps for multiband operation

9-16: Phased vertical array

9-17: Circular Polarization

9-19: Loop antenna

9-22: Impedance Matching at the antenna: delta match

Bad idea!

9-23: Impedance Matching at the antenna: Gamma Match

Widely used. Works well. Can be adjusted from the tower.

9-24: Impedance Matching at the antenna: Hairpin Match

Better solutionFully balanced

9-25: Impedance Matching at the antenna: stub matching

Important! A + B is not equal to ¼ wavelength as claimed!

A: transform real(ZR ) to 50 ohms.

B: cancel remaining imaginary part (susceptance, B)

Quarter-wave transformer

Z1 Zo

Z2λ/4

210 ZZZ =

TYPICALLY 50Ω

Smith chart: Plot reflection coefficient on real and imaginary plane

1 + j0

0 + j1

-1 +j0

0 - j1

Im (Γ)

0 Re (Γ)

Smith Chart: map impedance onto reflection coefficient

Constant reactance circlecenters on vertical axis

Constant resistancecircles on horiz. axis

z = r + jx

Plot is normalized toZo = 1

INDUCTIVEREACTANCE

CAPACITIVEREACTANCE

Series Z0 transmission line

Γ(0)

Δθ

ZL

One complete 360o rotation corresponds to ½ wavelength

Quarter Wave Transformer

Open circuited t-line

ZoZIN

Add series capacitive reactance

Add series inductive reactance

Admittance chart

Example: series – shunt stub match

ZL

Step 1: series line to g=1 circle

Shorted and open stubs λ/8

Z = jZo

Z = -jZo

Step 2: shunt L with shorted stub of length 0.092λ

References

• Transmission lines and Smith Chart– www.ece.ucsb.edu/~long/ece145a/index.htm

• Class notes set #2 and 3

• Impedance matching networks• Class notes set #5

• Smith Charts – pdf files are on this website– Color printer needed for ZY chart

RADIALLY SCALED PARAMETERS

TOWARD LOAD —> <— TOWARD GENERATOR1.11.21.41.61.822.5345102040100

SWR 1∞

12345681015203040dBS

1∞

1234571015 ATTEN. [dB]

1.1 1.2 1.3 1.4 1.6 1.8 2 3 4 5 10 20 S.W. L

OSS C

OEFF

1 ∞0 1 2 3 4 5 6 7 8 9 10 12 14 20 30

RTN. LOSS [dB] ∞

0.010.050.10.20.30.40.50.60.70.80.91

RFL. COEFF, P0

0.1 0.2 0.4 0.6 0.8 1 1.5 2 3 4 5 6 10 15 RFL. LOSS

[dB]

∞0

1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.5 3 4 5 10 S.W. P

EAK (CONST

. P)

0 ∞0.10.20.30.40.50.60.70.80.91

RFL. COEFF, E or I 0 0.99 0.95 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 TRANSM. C

OEFF, P

1

CENTER1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 TRANSM

. COEFF, E

or I

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

ORIGIN

0.1

0.1

0.2

0.2

0.2

0.3

0.3

0.4

0.4

0.4

0.50.5

0.5

0.60.6

0.6

0.70.7

0.7

0.80.8

0.80.9

0.9

0.9

1.01.0

1.0

1.21.2

1.2

1.41.4

1.4

1.61.6

1.6

1.81.8

1.8

2.02.0

2.0

3.0

3.0

3.0

4.0

4.0

4.0

5.0

5.0

5.0

10

10

10

20

20

20

50

50

50

0.2

0.2

0.2

0.2

0.4

0.4

0.4

0.4

0.6

0.6

0.6

0.6

0.8

0.8

0.8

0.8

1.0

1.0

1.01.0

0.1

0.1

0.1

0.2

0.2

0.2

0.3

0.3

0.3

0.4

0.4

0.4

0.50.5

0.5

0.6

0.6

0.6

0.7

0.7

0.7

0.8

0.8

0.8

0.9

0.9

0.9

1.0

1.0

1.0

1.2

1.2

1.2

1.4

1.4

1.4

1.6

1.6

1.6

1.8

1.8

1.8

2.02.0

2.0

3.0

3.0

3.0

4.0

4.0

4.0

5.0

5.0

5.0

10

10

20

20

20

50

50

50

0.2

0.2

0.2

0.2

0.4

0.4

0.4

0.4

0.6

0.6

0.6

0.6

0.8

0.8

0.8

0.8

1.0

1.0

1.01.0

20-20

30-30

40-40

50

-50

60

-60

70

-70

80

-80

90

-90

100

-100

110

-110

120

-120

130

-130

140

-140

150

-150

160

-160

170

-170

180

±

90-9

085

-85

80-8

0

75-7

5

70-7

0

65-6

5

60-6

0

55-5

5

50-5

0

45

-45

40

-40

35

-35

30

-30

25

-25

20

-20

15

-15

10

-10

0.04

0.04

0.05

0.05

0.06

0.06

0.07

0.07

0.08

0.08

0.09

0.09

0.1

0.1

0.11

0.11

0.12

0.12

0.13

0.13

0.14

0.14

0.15

0.15

0.16

0.16

0.17

0.17

0.18

0.18

0.190.19

0.20.2

0.21

0.210.22

0.220.23

0.230.24

0.24

0.25

0.25

0.26

0.26

0.27

0.27

0.28

0.28

0.29

0.29

0.3

0.3

0.31

0.31

0.32

0.32

0.33

0.33

0.34

0.34

0.35

0.35

0.36

0.36

0.37

0.37

0.38

0.38

0.39

0.39

0.4

0.4

0.41

0.41

0.42

0.42

0.43

0.43

0.44

0.44

0.45

0.45

0.46

0.46

0.47

0.47

0.48

0.48

0.49

0.49

00

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WA

VEL

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AR

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ATO

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AR

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IND

UC

TIV

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EAC

TAN

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COM

PON

ENT (+

jX/Zo), O

RIN

DUCTIVE SUSCEPTANCE (- jB/Yo)

EACTANCE COMPONENT (-jX

/Zo),O

RCAP

ACIT

IVE

SUSC

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jB/Y

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RESISTANCE COMPONENT (R/Zo), OR CONDUCTANCE COMPONENT (G/Yo)

SMITH CHART FORM ZY-01-N

NAME TITLE

COLOR BY J. COLVIN, UNIVERSITY OF FLORIDA, 1997

DWG. NO.

DATE

NORMALIZED IMPEDANCE AND ADMITTANCE COORDINATES

RVE I TI CAPAC