US 12,088,341 B2
Photonic beamforming for active antennas
Victor Manuel Fernandez Laguna, Portsmouth (GB); Katarzyna Balakier, Portsmouth (GB); Stephen Brown, Portsmouth (GB); and Niall Macmanus, Portsmouth (GB)
Assigned to Airbus Defence and Space Limited, Stevenage (GB)
Appl. No. 18/564,837
Filed by Airbus Defence and Space Limited, Stevenage (GB)
PCT Filed Jun. 10, 2022, PCT No. PCT/EP2022/065853
§ 371(c)(1), (2) Date Nov. 28, 2023,
PCT Pub. No. WO2022/258815, PCT Pub. Date Dec. 15, 2022.
Claims priority of application No. 21179110 (EP), filed on Jun. 11, 2021.
Prior Publication US 2024/0275487 A1, Aug. 15, 2024
Int. Cl. H04B 10/118 (2013.01); H04B 10/112 (2013.01); H04B 10/2575 (2013.01)
CPC H04B 10/118 (2013.01) [H04B 10/1129 (2013.01); H04B 10/25759 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A photonic beamforming system for a satellite payload, comprising:
a modulation stage configured to modulate a plurality of N electrical signals from a plurality of N antenna elements receiving one or more signal beams, onto an optical carrier, to output a respective plurality of N optical signals,
wherein N=2L for integer L>1; and
a network having an input to receive the plurality of N optical signals, the network arranged to resolve the one or more signal beams into each of a predetermined plurality of N beam angles with respect to the N antenna elements to output, from an output of the network, a plurality of N beamformed signals corresponding to each of the predetermined plurality of N beam angles by, for each one of the plurality of N optical signals, summing the one of the plurality of N optical signals with each of the other N−1 of the plurality of optical signals phase shifted relative to the one of the plurality of N optical signals by a respective phase shift;
wherein each of the respective phase shifts is such that the one of the plurality of N optical signals interferes with each of the other N−1 phase shifted plurality of optical signals when summed, to form a beamformed signal having a respective one of the predetermined N beam angles;
wherein the network comprises a plurality of L·2L−1 2×2 optical couplers, each of the plurality of 2×2 optical couplers having two optical signal inputs and two optical signal outputs, each 2×2 optical coupler having a control input to control a phase shift applied by the 2×2 optical coupler between a respective pair of the plurality of N optical signals input to the two optical signal inputs of the 2×2 coupler;
wherein an optical fast Fourier transform, OFFT, is applied to the plurality of N optical signals by controlling the respective phase shift applied at each of the plurality of 2×2 optical couplers, and by arranging the plurality of 2×2 optical couplers in a sequence of L ranks of 2L−1 couplers between the input and the output of the network, wherein the L ranks comprise an output rank at the output of the network, and one or more further ranks preceding the output rank in the sequence,
such that, for each of the plurality of 2×2 optical couplers in the one or more further ranks, a first of the two optical outputs is connected to an input of a first coupler in a subsequent rank in the sequence, and a second of the two optical outputs is connected to an input of a second coupler in the subsequent rank in the sequence.