N093-221 TITLE: Highly Efficient Transmitter for High Peak to Average Power Ratio (PAPR) Waveforms

TECHNOLOGY AREAS: Information Systems, Sensors

ACQUISITION PROGRAM: Joint Program Executive Office Joint Tactical Radio System, ACAT I

OBJECTIVE: Develop a compact highly efficient transmitter for complex waveforms and other waveforms with a high Peak to Average Power Ratio (PAPR)

DESCRIPTION: Modern military and most commercial waveforms utilize complex non-constant envelope waveforms incorporating Orthogonal Frequency Division Multiplexing (OFDM) modulation schemes. This adds significant challenges to transmitter efficiency and signal fidelity. It is well known that Class E amplifiers are highly efficient for constant envelope waveforms. However, it has proven difficult to amplitude modulate a Class E amplifier while maintaining reasonable efficiency and signal fidelity.

The desired innovation is a transmitter that employs highly efficient class E operation for both constant and non-constant envelope waveforms, while maintaining signal fidelity. To avoid redundancy, a single transmitter device should be capable of modulation of commercial waveforms such as GSM, WiMAX and LTE, military waveforms such as SRW, and should have the ability to switch from one waveform to another seamlessly. It should also be capable of OFDM modulation of military waveforms. The transmitter should handle the entire analog and RF processing burden, and should have digital I and Q and frequency as inputs.

The transmitter should be capable of transmitting over a wide carrier frequency range, and should be capable of output power up to 40dBm. It should have the capability of up to 20MHz Carrier Bandwidth at 1 GHz carrier frequency.

PHASE I: Conduct a study to determine the feasibility of a transmitter that can simultaneously provide:
� Employment of Class E operation for constant and non-constant envelope waveforms
� High Efficiency and Signal Fidelity for High PAPR waveforms
� Broad Carrier Band Operation (~1-2 octaves at 1GHz)
� Provide up to 40dBm power output

PHASE II: Develop Proof of Concept board or boards that demonstrate:
� Employment of Class E operation for constant and non-constant envelope waveforms
� High Efficiency and Signal Fidelity for High PAPR waveforms
� Broad Carrier Band Operation (~1-2 octaves at 1GHz)
� Provide up to 40dBm power output

PHASE III: Develop a Broad Carrier Band transmitter capable of simultaneously providing:
� Employment of Class E operation for constant and non-constant envelope waveforms
� High Efficiency and Signal Fidelity for High PAPR waveforms
� Broad Carrier Band Operation 30MHz � 6GHz
� Up to 40dBm power output
� 20MHz bandwidth at higher frequencies (i.e. 1GHz and higher)

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Significant commercial applications for this technology are anticipated for use in telecommunications applications (i.e. Pico cells, Femto cells, and other Wide Area Network Communication Devices)

REFERENCES:
1. http://www.ee.ucl.ac.uk/lcs/prog01/LCS077.pdf

2. http://www.waset.org/pwaset/v33/v33-51.pdf

KEYWORDS: Transmitter; Class E amplifier, OFDM, waveforms, efficiency, Peak to Average Power Ratio

** TOPIC AUTHOR (TPOC) **

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