Low-Cost, Highly Efficient, Digitally Beam Formed, X-Band Transmit ESA for Radar (9735)

Hittite proposes to develop a low-cost, digitally programmable waveform distribution and beamforming architecture for transmit electronically scanned arrays (ESAs). A four-element Digital Sub-Array (DSA) will serve has the basic building block to construct large (1,000 to 10,000+ element) arrays. High efficiency will be achieved using switched-mode power amplifier (PA) techniques. Digital transmit data will be distributed and true-time-delayed directly at the X-band (nominally 10 GHz) transmit frequency, eliminating the need for upconversion, minimizing part count, power consumption, and cost. Each element will radiate 3.2 W with a PA power-added efficiency of 70%. Notionally, 16 DSAs (64 elements) will be assembled to form a Tile, and 16 Tiles (1,024 elements) will be assembled into Panels. Large ESAs will be assembled from one or more Panels. For illustrative purposes, a single-Panel ESA (1,024 elements) would radiate nearly 3.3 kW (70.2 dBW EIRP) with a 3.17¢X beamwidth. A nine-panel square ESA (9,216 elements) would radiate 29.5 kW (89.3 dBW EIRP) with a 1.06¢X beamwidth. The DSA will enable scan angles up to „b70„a. With the exception of the GaN PA, all active circuitry will be realized in IBM's 8HP SiGe BiCMOS process via DoD's ITAR-compliant, Trusted Foundry contract. The Phase I effort will result in the preliminary design of a Digital Sub-Array (DSA) with which to build X-band ESAs for radar. Critical technology will be developed and demonstrated in Phase II leading to the complete antenna system development in Phase III. In a complementary effort, true-time-delay, digital beamforming receive circuitry can be developed directly at X-Band to provide a complete transmit/receive DSA.