N141-060 TITLE: Flexible Solid State High Power Radio Frequency (HPRF) Test Capability

TECHNOLOGY AREAS: Electronics, Battlespace, Weapons

RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.

OBJECTIVE: Develop HPRF architectures capable of generating arbitrary waveforms with frequency and bandwidth agility using solid-state systems for counter electronics vulnerability testing.

DESCRIPTION: Most current high power (MW class) radio frequency (HPRF) test sources are limited to commercial off-the-shelf (COTS) vacuum electronics based technologies. These sources are inherently limited in waveform flexibility with respect to frequency, bandwidth, pulse-width and duty cycle [1]. While solid-state power amplifiers offer increased waveform flexibility and continuous wave (CW) operation, they are limited to single kW levels. Navy laboratories require a flexible test capability to support both vulnerability and susceptibility work at power levels greater than the current state-of-the-art amplifier technology can provide. The test capability will provide critical data to inform future technology development efforts for emerging high power solid state technology. A core dataset is required for these novel waveforms to provide technology maturation goals.

Potential technological solutions include, but are not limited to, non-linear transmission lines (NLTL) and photoconductive semiconductor switches (PCSS). In the case of the NLTLs, the output is varied via physical alteration of the system, variable driver parameters and magnetic biasing. PCSS systems have the potential to achieve purely arbitrary outputs, but require large and costly laser systems. In both cases, materials research has, and will continue to, play a leading role in their development. A potential solution may also take advantage of a modular design, arrayed elements, or other power combining techniques; however, a high power, broadband power combiner design will require special attention and should be described in detail.

The proposed concept demonstrator should be able to transmit an arbitrary waveform at power levels of 10 MW at a minimum, with an objective power output of 100 MW and a rep-rate on the order of kHz in the range of VHF to S-band. The prototype design should include all elements of the devices including prime power, power conditioning, control hardware, thermal management, RF source, RF transition, and antenna.

PHASE I: Conceptualize, design, and model key elements for an innovative, all solid-state, arbitrary waveform, HPRF source. The design should establish realizable technological solutions for a device capable of achieving output power levels of 10 MW, at a minimum, and rep-rates on the order of kHz in the frequency range of VHF to S-band. The proposed design should be an 80% complete solution and include all sub-systems from prime power up through the RF source and antenna. The design should include circuit modeling and analysis of both the HPRF source and any critical support system elements such as a high voltage (HV) driver. The proposed brassboard system should be designed for vehicle portability, i.e. contained in/on a pallet or trailer. The antenna design is not the focus of this SBIR; however, the chosen solution, whether a novel design, COTS or interchangeable antenna arrangement should be supported by modeling and simulation efforts. Additional modeling and simulation should be performed to determine predicted efficiency, prime power, and thermal management requirements. An overview of the current state of the art for each of the key prototype elements along with manufacturer information should also be provided, focusing on the solid state components required for this application. Cost analysis as well as material development should be included so as to ascertain critical needs not yet fully developed or readily available given current technology.

PHASE II: Phase II will involve the design refinement, procurement, integration, assembly, and testing of a proof of concept brassboard prototype leveraging the Phase I effort. The Phase II brassboard prototype will be capable of greater than 500 kW output at a rep-rate of 100�s of Hz. The brassboard system should be capable of operating in a laboratory environment, such as an anechoic chamber or Gigahertz Transverse Electromagnetic (GTEM) test cell. This brassboard prototype must demonstrate a clear path forward to a full scale concept demonstrator based on the selected technology. Data packages on all critical components will be submitted throughout the prototype development cycle and test results will be provided for regular review of progress. The use of actual hardware and empirical data collection is expected for this analysis. A refined design package should also be submitted that meets the solicitation threshold of an HPRF arbitrary waveform source capable of power levels exceeding 10 MW, with an objective of 100 MW, and a rep-rate on the order of kHz.

PHASE III: The performer will apply the knowledge gained during Phase I and II to build and demonstrate a full scale prototype device capable of transmitting an arbitrary waveform at power levels exceeding 10 MW and a rep-rate on the order of kHz. The prototype will represent a complete solution and include all system elements including prime power, power conditioning, control hardware, thermal management, RF source, RF transition, and antenna. The prototype should be ruggedized for, at a minimum, testing in an outdoor environment and be environmentally enclosed. The prototype will be applicable for direct test range use within government or with a commercial partner against candidate test articles relevant to EMI or HERO testing and validation relative to perceived threats and system vulnerabilities. Potential utility in a non-lethal, non-kinetic engagement option against a wide variety of electronic targets will be considered depending on potential platforms, pulse flexibility as well as size/weight/power requirements.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: HPRF sources are used in a wide variety of commercial applications including communications, sensor and medical applications. A source of this type would also be highly valuable in industrial EMI testing.

REFERENCES:
1. High Power Microwaves, J. Benford, J. Swegle, E. Schamiloglu, Taylor & Francis, New York, 2007.

2. Microwave Engineering, 3rd Ed., M. Pozar, John Wiley & Sons Inc., New Jersey, 2005.

3. R. Pouladian-Kari, A. J. Shapland, T. M. Benson, "Development of ferrite line pulse sharpeners for repetitive high power applications," Microwaves, Antennas and Propagation, IEE Proceedings H, 1991, Vol. 138, pp. 504�512.

4. Characterization of a Synchronous Wave Nonlinear Transmission Line, P. Coleman, et al., Proc. Pulsed Power Conf., pp. 173-177, 2011.

5. Wide Bandgap Extrinsic Photoconductive Switches, J. Sullivan, Lawrence Livermore Nation Laboratory Report, LLNL-TH-523591, Jan. 2012.

KEYWORDS: High Power Radio Frequency; High Power Microwave; Frequency Agile, Solid State, Directed Energy

** TOPIC AUTHOR (TPOC) **

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