High Efficiency, Low Size Weight and Power (SWaP) Solid State Power Amplifiers (SSPAs) for Sensor Applications

Radar systems provide all-weather, day & night sensing and ranging by transmitting a radio-frequency (RF) signal, a part of which is reflected from the target or area of interest back to the radar system.  The range-resolution of the radar is inversely proportional to the bandwidth of the transmitted signal, so a high-resolution radar requires a large bandwidth.  In SAR imaging, a fine azimuth resolution is achieved through the coherent combination of multiple pulses from across the radar platform’s path while a target is within the radar beam.  The large bandwidths required for high-resolution SAR imaging are typically achieved at higher frequencies. The sensitivity of a radar system is another key performance parameter, and is dependent on system and scenario parameters such as antenna-gain, transmit-power, range-to-target, frequency, and receiver noise characteristics.  Increasing the power output of the transmitter can improve radar performance.  SSPAs are increasingly being used in radar applications, replacing older technologies such as traveling-wave-tube amplifiers (TWTAs).  SSPAs are typically more efficient at lower frequencies, but modern Gallium Nitride (GaN) monolithic microwave integrated circuit (MMIC) technology allows for higher efficiencies at these frequencies, compact packaging, and higher reliability. ARTEMIS, Inc. proposes to develop, design, and demonstrate SSPA technology with high-efficiency and compact SWaP, operating with wide bandwidth at Ku-band.  We will leverage our SSPA technology experience developed through over a decade of work with T/R modules and small-SWaP SSPAs which have been part of our past radar projects, including our next-generation SlimSDR radar system development (Army C5ISR Airborne Radar Branch, Phase II Sequential and AFRL/RWWI Phase II). In Phase I, ARTEMIS will create a detailed design of the Ku-band SSPA and show how the design meets the system requirements from the SBIR topic.  We have already found a commercially available 70-Watt, 40-volt GaN HEMT MMIC die suitable for this application with delivery from stock.  ARTEMIS will acquire the parts and work detailed design and packaging so that Phase I can culminate in a Detailed Design Review from which prototyping and building can commence in Phase II. Phase II consists of building and demonstration of the SSPA prototype.  The SlimSDR can be used as a stand-in for other radar systems, and, as a bonus, this SSPA will add exquisite Ku-band capabilities to the SlimSDR’s already formidable portfolio of functions.  SSPA performance will be demonstrated through lab tests and flight tests, including SAR imaging, on ARTEMIS’ test-bed aircraft. Plans for application-specific qualification testing will be completed along with transition plans.  The plans and prototype will be delivered to the Navy.  The proposed technology will be useful for a wide variety of radar and RF systems, including extreme-environment applications (missiles/hypersonics).