Cellular Basestation Antennas

MLS Azimuth Site (Taichung, Taiwan)

TACAN : L-Band Military Aid providing range and bearing

Secondary Surveillance Radar

S-band 3 Beam Primary Array Radar

Aerospace Products - quantities

Foreign Governments

US, Spain, PRC, Taiwan

Microwave Landing

Systems

10

Design and Manufacture

RAAF Electronic TACAN 10 Design and

manufacture

Alenia (Italy) SSR Antenna 22 Design and

manufacture

Alenia (Italy) S-band Primary Radar 2 Design and

manufacture

Racal (UK) Simple AMPS basestation

antenna

100 (manufacture only)

Typical Basestation Antenna using Patch Radiating Elements

Low-band Antenna with patches in boxes

Combined Phaseshifter and Power Divider

Use of Motor to Control Downtilt Remotely

Principle of Dielectric Phaseshifter

Operation of Dielectric Phaseshifter

Multibeam Antenna Array

Multibeam Antenna – Feed Network

Multibeam Stadium Antenna

-150 -100 -50 0 50 100 150-30

-25

-20

-15

-10

-5

0

Attachment 10.1-07: 1.920 GHz, DT=6.0

Rel Gain (dB)

Angle (deg)

High band and Low band Element Configuration

Driven

element

Parasitic

element

Special

‘long dipole’

340 mm wide (RVV)

Prototype dual band ultra-wide band antenna

Element Pattern of Crossed Dipoles => Squint problem

-1 -.8 -.6 -.4 -.2 0 .2 .4 .6 .8 1-1

-.8

-.6

-.4

-.2

0

.2

.4

.6

.8

1

-12

-9

-6

-3

For 10 deg downtilt, beam squints to the left by 10 deg

Low-band Element Configuration

Low-band Element Pattern

-1 -.8 -.6 -.4 -.2 0 .2 .4 .6 .8 1-1

-.8

-.6

-.4

-.2

0

.2

.4

.6

.8

1

-18

-15-1

2

-18

-15

-12

Co-Polar X-polar

Sledkov Radiating Element to minimise Squint

High-band (Sledkov) Element Pattern

-1 -.8 -.6 -.4 -.2 0 .2 .4 .6 .8 1-1

-.8

-.6

-.4

-.2

0

.2

.4

.6

.8

1

-12

-9

-6 -3

-1 -.8 -.6 -.4 -.2 0 .2 .4 .6 .8 1-1

-.8

-.6

-.4

-.2

0

.2

.4

.6

.8

1

-18

-18

-18

-18

Co-polar X-polar

High-band Radiating Elements

Low-band Azimuth Patterns – affected by high-band elements

-180

-170

-160

-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

Bottom frequencies => Pattern distorted

Common mode dipole resonance

+ +

+ +

- -

-

LB Currents on HB Stalk cause minimum disturbance to VP Pattern

-180

-170

-160

-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

LB Currents on HB Stalk cause significant distortion of HP Pattern

-180

-170

-160

-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

Pattern distorted at low frequencies – Horizontal Polarization

Low band gain curve

698722

747771

790821

834862

880915

935960

14.40

14.60

14.80

15.00

15.20

15.40

15.60

15.80

16.00

16.20

16.40

16.60

Gain ‘suck out’ due

to HB dipole

resonance

Capacitance of

dipoles increased

with Cu tape

Frequency MHz

Ga

in (d

Bi)

Modelling to find Common Mode Resonance

Tuning common mode resonance to outside band

Starting point Tune up in frequency (reduce inductance)

Tune down in frequency (increase inductance)

High band and Low band Element Configuration

Driven

element

Parasitic

element

Special

‘long dipole’

340 mm wide (RVV)

Matching of Long Dipole

Choked dipole arm

Spherical Luneburg Lens- Matsing

Sperical Luneburg lens 0.8m dia (15kg) with patch feeds has a beamwidth at 2 GHz of about 11°

Principle of Luneburg Lens. Dielectric constant is higher near the centre

Artificial dielectric

6 mm cubes with wires are packed with random orientation in plastic casings.

Modifying Azimuth Beamwidth of Conventional Basestation Antenna

Multibeam Luneburg Lens Antenna

12-beam Luneburg Lens – Stadium Antenna 1710 MHz – 2690 MHz

Promising configuration for Basestation Antenna with reduced element count

Interaction with Government and Universities

R&D Tax Incentive

Export Market Development Grant

‘START’ programme grant

Equity to company staff – Tax treatment

Cooperation with University, CSIRO etc.