An S Band Tile of 16 T-R Modules for Fully Digital Array (DAR Technology)

Abstract

The radar AESA technology is evolving towards two main directions. First, the digital Transmit/Receive Modules will allow to avoid the use of analog RF Beam Forming Networks and to exploit the Digital Beam Forming technique. Second, the use of Gallium Nitride High Power Amplifiers will allow to increase the antenna MTBF Virtualabs developed a module, called VBR, of 16 TRMs, fully digital, working in the S band. Each TRM is fully controlled in digital form, thanks to the use of System On Chips (SoCs). Gallium Nitride High Power Amplifiers (HPA) are used for final RF amplification. The echo received by each TRM is immediately transformed in digital data in the SoCs, allowing an easy Digital Beam Forming (DBF) in the FPGA that controls the SoCs. DBF is used also in transmission, in fact the waveform is generated directly in the VBR and converted to analog in the SoCs. More VBRs can be synchronized using a synchronization board, and the digital echoes provided by more VBRs can be combined by Digital Beam Forming Network boards. With such architecture, any type of radar AESA antenna can be designed by combining different numbers of VBRs (modular architecture). The FPGA inside the VBR has enough computational power to allow to perform tests on a digital phase compensation technique to keep the beam pointed correctly also in case of LFM pulses with bandwidth up to 200 MHz. Experimental results achieved with the realized VBR are presented.