Research Associate Professor Domenic Belgiovane Graduate Student The Ohio State University ElectroScience Laboratory Electrical and Computer Engineering Department 1330 Kinnear Road Columbus OH 43212 ID: 640526
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Slide1
Antenna Design Progress
Chi-Chih Chen
Research Associate Professor
Domenic
Belgiovane
Graduate Student
The Ohio State University
ElectroScience
Laboratory
Electrical and Computer Engineering Department
1330 Kinnear Road, Columbus, OH 43212
TEL: (614) 292-3403, FAX: (614) 292-7297, Chen.118@osu.eduSlide2
Current Progress
Antenna Design
Current antenna is 36 inches tall
10 dB gain across 500 MHz to 2 GHz bandwidth
Impedance between 150-180
Ω
, but should be uniform across frequency bandwidth.
Antenna
Feeding Network
Current design offers good performance across the frequency bandwidth.
Short board allows for cheap fabrication.
Impedance transforming transmission
line (
50
Ω
to
170
Ω
) Fabrication
and testing to be completed.
Deploying Mechanism
Some possible design have been presented .
No current final design has been determined.
Antenna Structure
ABS material for use of
R
adome
Deformation should have little affect on gain pattern.
Large amount of stress at conical base may need additional consideration when mounting to deployment base. Slide3
Current Antenna Design Objectives
Move towards Prototyping Structure and Deployment Design
Determine suitable material for antenna structure.
Study Viable options for mechanical deployment
Fly on airplane to as preliminary test
Design Antenna
Feeding Network
Impedance transforming transmission line
50
Ω
to 170
Ω tapered lineBalanced line output to feed antennaFabrication and Testing of AntennaFabrication of feed networkAntenna gain pattern measurements
Feeding Network
Conical Spiral AntennaSlide4
Antenna Feeding Network
1.93”
193mil
40mil
10”
3.3”
Port 1
170
Ω
Port 2
50
ΩTop ViewBottom View0.2”Microstrip tapered line to balanced parallel stripShorter PCB will allow for cheap in-house fabricationProvides good S11 and S21 across the frequency band
Rogers, RT/Duroid
5880εr = 2.20 h
= .062 in tanδ = 0.0009
t = 17
μ
mSlide5
Air Pressure Stress Analysis
Yield stress of
ABS:10
MPa
(very minimum possible value)
Predicted stress due to air resistance will not cause the ABS to
fail
Magnitude of pressure applied to front surface
area: 4.6
kPa
Stress is distributed evenly across the
faceDirection of air flowDirection of air flowMPa4 mm thickConical Radome Slide6
Air Pressure Displacement of Geometry
These renderings of deformation are purposefully
very exaggerated
in order to show regions of slight indentation and
protrusion
The maximum displacement is experienced at the tip of the
cone
Displacement will likely not have an effect on the Antenna gain Pattern
mm
Direction of air flow
Direction of air flowSlide7
Concepts for Antenna Deployment
Antenna
Air Cylinder
Deployed
Position
Non-Deployed
Position
Transition
Considerations for Antenna deployment
Pivoting Mechanism
Deployment follows air drag
Low Profile
Close to fuselage surface
Total footprint approximately antenna diameter.
Electronic Motor controlled
Double acting air-cylinder
Scissoring arm extension
Crank window opener
Weather and Temperature resilient
Air Cylinder Concept
Scissoring Arm
Crank Window Hinge
Direction of air flowSlide8
Future Work
Antenna Design
Determine method for antenna fabrication.
Study affects of ABS
Radome
on antenna gain pattern.
Simulate effects of connecting the feeding network to the antenna.
Finalize and prototype antenna design.
Measure Gain pattern and Impedance
Reconfigure feed network impedance accordingly
Deploying Structure
Obtain ABS radome structure. Finalize and build deploying mechanism.Determine placement on fuselage.Mount and test deployment on aircraftFinalize the DesignCombine Antenna and Mechanical designs