 Simulation of Antenna Placement on Aircraft



Determine whether to use HFSS or FEKO
 Compare FEKO and HFSS antenna models
 Create simplified simulation models of antenna on aircraft
 Build up to Full Antenna on free aircraft model
Acquire more accurate 3D model of chose aircraft
 Twin Otter or Bassler
 Simplify geometry for more efficient simulations
Determine optimal location for antenna placement
 Design Feeding and Deployment Mechanisms



Design/Acquire Telescopic deployment mechanism
 Choose weather and temperature resistant material
 Electric motor and other methods
Match antenna impedance to RF input of receiver
Antenna monitoring systems
 Thermistor
 Camera
 Effects of Wind Resistance



Determine effects of wind for speed ranges of 120-115 knots
 Possible faster speeds as well
Choose most resilient materials for antenna and telescopic structure
Simulation of the antenna and structures in full.
1
Frequency: 0.5 - 2.0 GHz @ 0.1 GHz Steps
Realized Gain
FEKO
Base Dia = 7.2 in
Height = 36 in
30 Turns
GND Dia = 12 in
HFSS
Realized Gain
Realized Gain40
Ansoft LLC
30_turns_H36in_B7_GP12
15
Curve Info
Setup1 : Sw eep1
Setup1 : Sw eep1
3dB BW ~64°
10
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
5
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
Base Dia = 7.2 in
Height = 36 in
30 Turns
GND Dia = 12 in
Realized Gain (dBic)
0
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
Setup1 : Sw eep1
-5
Setup1 : Sw eep1
Setup1 : Sw eep1
-10
-15
-20
-25
-30
-35
-180
-150
-120
-90
-60
-30
0
Theta [deg]
30
60
90
120
150
180
2
Frequency: 2 GHz
HFSS
FEKO
3
FEKO
HFSS
Frequency: 0.5 GHz
4
FEKO
400.00
HFSS
300.00
Real
Y1
200.00
100.00
Imaginary
0.00
-100.00
-200.00
0.50
0.75
1.00
1.25
Freq [GHz]
1.50
1.75
2.00
5
Free Aircraft Model
 Simulate Antenna on Aircraft Fuselage
o
Utilized free model to obtain
approximate results
o
Determine whether HFSS or FEKO is
more useful (FEKO model is not yet
resolved)
• Simulation time
• Memory
• Accuracy
Underside
Fuselage
Antenna
6
7
 Low Cross-section telescoping structure
o Also consider a fixed-length
pivot/tilting mechanism
 Depending on chosen aircraft
o Minimum Collapse Depth
o Number of stages
o Material to be used
• Cold resilience
• Wind resistive
o Deploying Motor
• Will consider manual
deployment
Expanding Antenna
 Additional antenna support structures
o Maintain Antenna wire spacing
o Prevent mechanical resonance
 Mount to aircraft fuselage
 Match 50 Ohm input to 300 Ohm
Antenna Impedance
Example of pneumatic telescoping
cylinder
8