Photonic Links for High-Performance Arraying of Antennas

An architecture for arraying microwave antennas in the next generation of NASA’s Deep Space Network (DSN) involves the use of all photonic links between (1) the antennas in a given array and (2) a signal processing center. As used here, “arraying” refers generally to any or all of several functions that include control and synchronization functions; coherent combination of signals received by multiple antennas at different locations in such a way as to improve reception, as though one had a single larger antenna; and coherent radiation of signals for transmission of an intense, narrow beam toward a distant spacecraft or other target. This all photonic arraying architecture can also be adapted to arraying of radio antennas other than those of the DSN. In this architecture, all affected parts at each antenna pedestal [except a front-end low-noise amplifier for the radio-frequency (RF) signal coming from the antenna and an optical transceiver to handle monitor and control (M/C) signals] would be passive optical parts. Potential advantages of this all photonic link architecture over the RF architecture now in use include cost savings, increased stability of operation, increased reliability, and a reduction in the time and materials expended in maintenance at each antenna.