device development for nasa space communications novel power combiner for solid state power...
TRANSCRIPT
Device Development for NASA Space Communications
Novel Power Combiner for Solid State Power Amplifiers
Andrew AbrahamEdwin Wintucky
Communications, Instrumentation, & ControlsElectron & Opto-Electron Device Branch
July 9, 2009
Why Use Microwaves?
• Provides good bandwidth• FCC allocated 30GHz for Deep Space
– Some attenuation from atmosphere
30 GHz
100 MHz
Microwave
Radio
The Need for Space-Based Microwave Communication
• Moon to Earth Communications– Crew Exploration Vehicle– Lunar Lander, Lunar Outpost– Lunar Relay Satellite
• Moon to LEO Communications– Moon to ISS communication– Moon to Tracking & Data Relay Satellite System
(TDRSS)• Deep Space to Earth Communications
– Manned/Unmanned Missions to Mars– Missions to the outer planets
Power Requirements For Space-Based Microwave Communications
• Inverse square law– Mandates 10-15W of power for deep space missions
• Limitations on SSPAs (Solid State Power Amplifier)
– One SSPA can get up to 5-6W
Typical SSPA
How to Increase Power
• Approach 1: Engineer more powerful SSPAs– Problem: Inefficiency (Heat)
• Approach 2: Combine multiple SSPAs– Create a microwave power combiner– 3-way power combining is necessary for current
SSPA technology
Project Goals
• Design and construct testing circuitry to evaluate the performance of: “Novel 3-Way Rectangular Waveguide Hybrid Combiner”
• Characterize the hybrid combiner– S-Parameters– Efficiency– Frequency Response– Phasing
Step 1: S-Matrix Parameters• Network Analyzer
• S-Matrix enables efficiency predictions
S-MatrixInbound Signal
Outbound Signal
Step 2: Construct a 3-Way Circuit
Preliminary Data
Ou
tpu
t P
ort
(N
orm
aliz
ed)
Planned Activities
• Measure efficiency of 3-way combiner• Quantify frequency response • Measure and compare other combining
methods– Multiple 2-way power combiners– Multiple “Magic-T” hybrid couplers– Mix of Magic-T and power combiners
Questions