Extremely High Frequency Transmitter for Radar Applications

Vacuum electron devices (VEDs) are critical components for DoD systems that require high power, high frequency (wide bandwidth), and high efficiency. There continue to be needs to push the technology to higher frequency to again support high power, wide bandwidth requirements for power devices. Robust short and medium-range air surveillance is an essential capability for the security of critical assets and areas as unmanned aerial vehicles commonly known as drones are gaining increased attention in various fields due to their vast application potential. This SBIR project calls out the need to push the power amplification into the upper region of the extremely high frequency millimeter wave (MMW) band of frequencies between 100 and 300 GHz to enable high frequency MMW Radar to finally reach instrumented ranges that are useful for cued air surveillance applications and to produce another frequency band for meeting the challenge of short-range air surveillance. To address this need, we propose to develop a 220 GHz, targeted 50 Watt with > 15 Watt, > 10% instantaneous bandwidth (BW) microfabricated compact traveling wave tube (TWT) amplifier. Operation at MMW high frequencies poses significant challenges as the available power from both solid state and VEDs dramatically decreases with the frequency according to the underlying scaling physics. At the high MMW frequency, the construction of VEDs is an intricate, labor-intensive process often requiring exotic materials, and expensive, high-precision machining, which significantly increases the cost and duration of the device design, build, and test cycle. The proposed development of compact upper MMW high power TWT based on microfabricated quasi-optical spatial power combining (QOPC) array of beam-wave interaction structures will involve developing innovative approaches in both advanced manufacturing and design of components. In addition, the integration of the high power TWT with its associated high voltage switching power supply will require extensive mechanical design and thermal management. InnoSys will employ its solid state vacuum deviceTM (SSVDTM) technologies which produce VEDs employing solid state microfabrication designs and technologies, have demonstrated both batch processing of the radio frequency (RF) interaction circuit and microfabrication as the production "tool" of the RF interaction circuit at frequencies up to W-band towards this proposed 220 GHz TWT amplifier. Although highly challenging, we believe this proposed 220 GHz TWT high power amplifier can be successfully developed based on our extensive experiences and successes of our MMW high power amplifier products. This proposed development will produce significant advancement toward advanced VED manufacturing and VED capability improvements in power, bandwidth, reliability, efficiency, and manufacturability and toward advancement of the science and technology base for the next generation of VEDs for sub-THz applications.