Investigation of a Curtain Antenna Array for TIGER Quang Nguyen, Dr - - PowerPoint PPT Presentation

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Investigation of a Curtain Antenna Array for TIGER Quang Nguyen, Dr - - PowerPoint PPT Presentation

Aug 19, 2023 163 likes •506 views

Investigation of a Curtain Antenna Array for TIGER Quang Nguyen, Dr John Devlin Electronics Engineering Dept La Trobe University Australia Problems of currently used antennas Structural problem 1. Broken long elements (wind 47 m/s) 2.

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SLIDE 1

Investigation of a Curtain Antenna Array for TIGER

Quang Nguyen, Dr John Devlin Electronics Engineering Dept La Trobe University Australia

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SLIDE 2

Problems of currently used antennas

  • Structural problem
  • 1. Broken long elements (wind 47 m/s)
  • 2. Tower bent along wind direction
  • 3. Twisted of horizontal boom
  • Questioning of antenna performance
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SLIDE 3

Objectives

  • Modification of the Log periodic antenna

to achieve a robust structural that requires minimal maintenance.

  • Implementation of frequency independent

array to ensure a broadband operation.

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0.8 0.85 0.9 0.95 tau 0.05 0.1 0.15 0.2 0.25 sigma 10 20 30 40 alpha 0.8 0.85 0.9 0.95 tau

Possibility of compact LPDA

      − =

−

σ τ α 4 1 tan

1

n n

l l

1 +

= τ

n n n

l s 2

1 , +

= σ

α

1 , + n n

s

n

l

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SLIDE 5

5 10 15 20 25 30 35

α

0.5 1 1.5 2 2.5 3 3.5 4 L Bs = 3.46 Bs = 2

L/Alpha/Bs relationship

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SLIDE 6

A Different Approach

1 2 , 1

1 1

−

− − =

N

L s τ τ

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SLIDE 7

0.8 0.85 0.9 0.95 1

τ

5 10 15 20 25 30 35 n Bs = 3.46 Contour lines of s1/L L / 1 s g n i s a e r c n I

Bs/Tau/N/S1/L relationship

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SLIDE 8

Broaden Structure Bandwidth

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SLIDE 9
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SLIDE 10
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SLIDE 11
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SLIDE 12

Control of electrical height

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SLIDE 13

Dipole over ground

h

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SLIDE 14

Inverted-V dipole over ground

h

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SLIDE 15

New LPDA Structure

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SLIDE 16

8 10 12 14 16 18 20 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 F (MHz) Gain (dB)

Gain over 8-20 MHz band

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SLIDE 17

0.2 0.5 1 2 5

0.2

  • 0.2

0.5

  • 0.5

1

  • 1

2

  • 2

5

  • 5

Smith Chart of lp8m1.nec Zc=100

Smith Chart and VSWR

8 10 12 14 16 18 20 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 MHz VSWR VSWR of lp8m1.nec

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SLIDE 18
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SLIDE 19

Lp8m1f8c.dat

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SLIDE 20
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Lp8m1f14c.dat

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SLIDE 22
  • 40 -30 -20 -10

30 210 60 240 90 270 120 300 150 330 180 Azimuth pattern of lp8m1f17.dat G=8.39dB,F/B=24.74dB(theta=51,phi=180)

  • 25 -20 -15 -10 -5

30 210 60 240 90 270 120 300 150 330 180 Vertical pattern of lp8m1f17.dB G=8.39dB,F/B=20.66dB(theta=68,phi=0)

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SLIDE 23

Lp8m1f17c.dat

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SLIDE 24
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SLIDE 25

Lp8m1f20c.dat

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SLIDE 26

LPDA Linear Array

  • Non constant electrical spacing
  • Variation of gain
  • Impedance effects
  • Beamwidth variation
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SLIDE 27

−3π/2 −π −π/2 π/2 π 3π/2 2π ψ 0.2 0.4 0.6 0.8 1

E Broaden

Electrical Spacing

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SLIDE 28

Beamwidth Variation

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SLIDE 29
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SLIDE 30

Semi-Circular Array

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SLIDE 31

Conclusion

  • Inverted-V LPDA
  • Implementation of semi-circular array
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SLIDE 32