A Novel Photonic T/R Module

Future MDA missions will require greater bandwidth and flexibility from their phased array antennas. One of the bottlenecks in present antenna systems is the transmit-receive (T/R) module. The limited bandwidth (<2:1) and T/R isolation (<20 dB) of present RF circulators severely restrict radar system design. RF switches provide better performance (~10:1 bandwidth, ~40 dB T/R isolation) but do not permit transmitting and receiving on separate bands simultaneously. Photonic Systems proposes an innovative, photonics-based T/R module that has the potential to provide a previously un-attainable combination of features, prime among them: 20:1 bandwidth (e.g. 2 to 40 GHz), 80 dB effective T/R isolation and simultaneous T/R (on different bands). Laboratory measurements of the PSI T/R module built with COTS components have confirmed its basic operating principals. However, connection to an antenna and antenna range measurements are required to confirm other aspects of its performance, especially its ability to transmit and receive on different bands simultaneously. The results of the Phase I analysis and measurements will provide the basis for planning the further development of PSI's novel antenna interface.