Device Development for NASA Space Communications Novel Power Combiner for Solid State Power Amplifiers Andrew Abraham Edwin Wintucky Communications, Instrumentation, & Controls Electron & 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-Matrix Inbound Signal Outbound Signal

Step 2: Construct a 3-Way Circuit

Preliminary Data Output Port (Normalized)

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