SBIR-STTR Award

We propose herein the exploration and design of a spatially-distributed electron gun capable of generating approximately 1.25 A at a beam voltage of around 20 kV. The actual beam current and voltage is subjected to considerations of the power supply in terms of size and weight. The electron gun will incorporate a focus electrode to effect a high-repetition rate operation and to reduce stresses on the power supply with a reduced voltage swing. An evaluation of various potential beam-wave circuit interaction circuits will also be performed to ensure efficient RF performance and to avoid potential spurious oscillations once the interaction circuit is integrated with the gun and magnet into a fully functional amplifier upon transition. The resulting electron beam will be matched with a light weight magnet system, which depending on the outcome of the evaluation can potentially be either a periodic permanent magnet (PPM) system or a circuit only solenoidal permanent magnet system. The overall goal is to maximize the RF power to weight ratio of future amplifiers. In the Phase-I Option, a preliminary mechanical layout will be developed. This layout will include specifications for gun, magnet, and collector to form the foundation for the Phase-II engineering plan

Benefit:
Successful completion of this project will result in baseline designs for the electron gun and transport system. The electron gun beam optic and magnet designs will form the foundation for the Phase-II engineering design and fabrication. Successful development of the electron gun will enable the development of a new class of spatially-distributed beam amplifiers, which are compact and broadband, for DoD and civilian applications in radar, communications, and electronic warfare. For example, the enhanced performance of the amplifiers promises to provide improved target discrimination, greater engagement ranges, improved performance in poor weather, higher data rates, and more compact and affordable amplifiers. Such enhancements are required to meet future radar performance specifications, including lower noise, higher peak and average power, improved linearity, and increased bandwidth.

Keywords:
solenoidal permanent magnet, solenoidal permanent magnet, traveling-wave-tube (TWT), Sheet Beam, collector, Amplifier, periodic permanent magnet (PPM), Electron gun

Achieving high specific amplifier power density (RF Power/Weight) is the key objective to achieve compact form factor, particularly, for airborne platforms. Our innovative electron gun design approach permits the creation of high-current 20 kV electron beams suitable for use in high specific power amplifiers while maintaining ease of gun manufacturing and assembly. In addition, there is an enormous amount of flexibility with our design methodology for our electron beam guns, which allows us to design a large number of beam shapes with excellent beam performance. The latter turns out to be of critical importance for the extremely challenging task of matching the resulting electron beam to the periodic-permanent magnet (PPM) stack, which is the key to ensure light overall amplifier weight. Under the proposed Phase-II program, we will finalize the gun and magnet designs, build and test a beam stick to demonstrate the proof-of principle, and design a high-power, efficient, and broadband RF circuit that can be integrated with the demonstrated beam transport system in a future follow-on.

Benefit:
Compact, broadband, high power millimeter-wave amplifiers are a key technology that enables a wide variety of applications including high resolution radar, high data rate communications, and electronic warfare. For example, future millimeter-wave based systems will be required to operate at longer ranges and with improved target discrimination capabilities. Communication systems will have to transmit higher data rates, more securely, and in all kinds of weather. As the performance specifications of these systems are strengthened, the millimeter-wave amplifiers must be significantly upgraded. Moreover, these systems will have to be placed on a variety of platforms, sometimes requiring very compact and high-efficiency sources. By developing a high current, moderate voltage, light weight beam generation and transport system that can work in conjunction with high-power, efficient, and broadband RF circuits, the results from this proposed program will address these urgent upgrade needs.

Keywords:
Broadband, High Current, high specific power, Electron gun, efficient, Low Voltage, periodic permanent magnet (PPM), Amplifier