1. 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) , FAX: (614) ,

2. Current Progress Antenna Design Antenna Feeding Network
Current antenna is 36 inches tall
10 dB gain across 500 MHz to 2 GHz bandwidth
Impedance between 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 (50Ω to 170Ω) 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 Radome
Deformation should have little affect on gain pattern.
Large amount of stress at conical base may need additional consideration when mounting to deployment base.

3. 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 line
Balanced line output to feed antenna
Fabrication and Testing of Antenna
Fabrication of feed network
Antenna gain pattern measurements
Feeding Network
Conical Spiral Antenna

4. Antenna Feeding Network
Microstrip tapered line to balanced parallel strip
Shorter PCB will allow for cheap in-house fabrication
Provides good S11 and S21 across the frequency band
1.93”
193mil
40mil
10”
3.3”
Port 1
170Ω
Port 2
50Ω
Top View
Bottom View
0.2”
Rogers, RT/Duroid 5880
εr = h = .062 in
tanδ =
t = 17μm

5. 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 face
Direction of air flow
MPa
4 mm thick
Conical Radome
Direction of air flow

6. 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
Direction of air flow mm
Direction of air flow

7. Concepts for Antenna Deployment
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
Antenna
Air Cylinder
Deployed
Position
Non-Deployed
Transition
Direction of air flow
Scissoring Arm
Crank Window Hinge

8. Future Work Antenna Design Deploying Structure Finalize the 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 aircraft
Finalize the Design
Combine Antenna and Mechanical designs