TECHNOLOGY AREAS: Air Platform, Sensors, Weapons

ACQUISITION PROGRAM: PMA-265 (EA-18G);PMA-234 (EA-6B) - Next Generation Jammer; JSF

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: Reduce intermodulation distortion in wide bandgap solid state amplifiers that result from multi-tone input signals.

DESCRIPTION: When an amplifier is driven into saturation, frequency components other than the intended signal are created and amplified due to device non-linearity. In addition to robbing power from the fundamental frequency, these spurious frequencies create interoperability problems with devices sharing the frequency spectrum. The problem just described becomes increasingly worse as additional frequencies (multi-tones) are added to the input signal of an amplifier. The combined input signal of multiple frequencies causes potentially high peak-to-average drive level ratios (crest factors). If the input signal is adjusted so that the average power of the combined signal drives the amplifier just into compression, the peak levels will saturate the amplifier causing intermodulation distortions (IMD). IMD can be reduced by decreasing the drive levels of the individual tones, but this reduces the output levels of the desired frequencies and decreases amplifier efficiency.

The Navy is seeking a technology that will allow multiple simultaneous frequencies to be amplified with reduced IMD by means other than input back-off. Such technologies are often referred to as linearization schemes. Currently, linearization is being done in narrow bandwidth commercial communication devices using methods such as pre-distortion, feed-forward, and envelope feedback. The Navy seeks to extend this concept to jamming signals characterized by high power, high duty cycle (up to continuous wave), and wide instantaneous bandwidth. This technology will be used to create a power amplifier module that is capable of being integrated into a high power transmit phased array architecture and flown on a tactical aircraft.

Up to eight simultaneous tones are desired in an input signal with an instantaneous bandwidth of more than 500MHz. IMDs should be reduced as much as possible, with the goal of having all products at least 30dB down from the fundamental frequency levels. Furthermore, a desirable linearizer would have minimal impact on the power added efficiency (PAE) of the amplifier module.

PHASE I: Determine the feasibility of reducing IMD over a wide instantaneous bandwidth in the L-C bands with minimal impact to amplifier efficiency. Provide supporting evidence in the form of analysis, modeling and simulation, calculations and empirical test. Provide a preliminary design or suggested approach.

PHASE II: Develop a prototype of the linearizer technology and demonstrate its performance by dynamically changing the amplitudes and frequencies of the input signals over the instantaneous bandwidth of the linearizer.

PHASE III: Incorporate any design improvements from Phase II and design an amplifier/linearizer module suitable for integration into high power phased array apertures. The target operational environment for such an aperture is the EA-18G tactical aircraft. Conduct reliability testing and analysis with respect to this operational environment.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This technology supports effective use of the frequency spectrum. All transmitting devices, both military and commercial, must be concerned with this issue for interoperability and efficiency reasons. By enabling the amplification of multiple frequencies through a single amplifier, total system hardware can be reduced, packaging can become smaller, and system price can be reduced. Cell phones, wireless networks, and point-to-point microwave links could all directly benefit from this technology.

REFERENCES:
1. Pedro, Jose Carlos; Carvalho, Nuno Borges. Intermodulation Distortion in Microwave and Wireless Circuits. Artech House, 2003.

2. Cripps, Steve C. Advanced Techniques in RF Power Amplifier Design. Artech House, 2002.

KEYWORDS: linearization; amplifier; wide bandgap; intermodulation; solid state; crest factor

TPOC: (812)854-5392
2nd TPOC: (301)757-7885

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 13 and December 9, 2007, you may talk directly with the Topic Author(s) to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 10, 2007, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (08.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 08.1 topic under which they are proposing.

If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (866) 724-7457 or email weblink.