Technologies for Simultaneous Transmit and Receive

The RF Technology Group is developing an array of technologies for simultaneous transmit and receive (STAR) applications. These technologies include layered approaches to improving isolation between antennas utilizing both active and passive methods. Our development approach for STAR applications begins with extremely wideband antennas that achieve more than 55 dB of isolation (co-located transmit and receive), along with sidelobe control approaches that allow for isolation improvement in array applications (spatially separated transmit and receive arrays), and adds additional methods that further improve isolation.

These methods include the use of electromagnetic bandgap (EBG) materials for surface wave suppression, RF and digital canceller circuits for coupled signal cancellation, and multiple-input, multiple-output (MIMO) channel sounding and spatial cancellation techniques. All of these technologies are brought together within the group to demonstrate subsystems with extremely high isolation in support of simultaneous transmit and receive operation.

Ring Array Antenna with optimized beamformer for simultaneous Transmit & Receive Ring array antenna with optimized beamformer for simultaneous transmit and receive.


Passive adaptive RF cancellerPassive adaptive RF canceller between transmit and receive ports with measured results. (Click on image to view larger version.)




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