Concurrent multifunction transmit and receive applications with dynamic filtering

This paper demonstrates a concept for transmitting on one set of elements of a phased array while concurrently receiving on another set at a separate frequency. Cases are analyzed using measured data from an 8×8 microstrip stacked patch panel array operating at 33.8GHz, and relative coupling levels from interfering elements to receive elements are characterized over various scan angles for two array configurations - side-by-side contiguous blocks and for interleaved elements at separate frequencies. It is shown that an optimum transmit frequency exists that minimizes coupled power to receiving elements in the array for a given scan angle. Additional isolation between elements is achieved with a tunable bandpass-bandstop filter cascade that, when paired with a high-linearity low-noise amplifier, reduces interference from transmitting elements to within the receiver analog-to-digital converter´s (ADC) dynamic range, such that receiving elements can operate concurrently next two 25W transmitting elements.