Digital beamforming receiver technology

A recent digital beamforming (DBF) receiver module effort is described. Each individual receiver module is divided into four mechanical packages. The element submodule is in stripline and contains the radiating element, C-band filtering, and calibration signal coupling functions. The RF submodule performs two downconversions and, like the element submodule, must fit into a one-half wavelength element spacing. The IF submodule contains a SAW filter for setting the signal bandwidth and a final downconversion to a low intermediate frequency (IF). The digital submodule contains the A/D converter for digitizing the downconverted RF information. The receivers considered represent the state-of-the-art in readily producible receiver modules; the components have been integrated and packaged to reduce module size for a relatively high-performance radar receiver. The quantity of receiver modules built dictated that tweaking to obtain desired performance be minimized. There was a tradeoff between tactical performance, prototype performance, and cost that resulted in the decision to implement the 400-kHz signal bandwidth.<>