Mitigating beam squint in multi-beam forming networks
Systems and methods relating to multi-beam forming networks using an antenna array. A matrix circuit for feeding elements of an antenna array to produce multiple beams is provided. To address beam squint issues, beam squint is mitigated by using a series of phase shifters with specific phase-delay performances between the matrix circuit and the antenna array elements. A linearly increasing or decreasing phase difference in the signals fed into adjacent antenna array elements across the array mitigates or eliminates beam squint in the resulting multiple beams. The phase shifters are programmed to provide this increasing or decreasing phase differences.
1. A circuit for use in simultaneously generating multiple beams using an antenna array having multiple antenna array elements, the circuit comprising:
a matrix circuit comprising a plurality of hybrid couplers and delay lines, said matrix circuit being coupled between a plurality of loads and said antenna array; and
a plurality of phase shifters coupled between said matrix circuit and said antenna array,
wherein
each row of said matrix circuit comprises a plurality of hybrid couplers coupled in series row-wise, with each row-wise pair of hybrid couplers being joined by at least one delay line;
each column of said matrix circuit comprises a plurality of hybrid couplers coupled in series column-wise;
a top row of said matrix circuit is coupled to antenna elements of said antenna array such that each hybrid coupler of said top row is coupled to an antenna element of said antenna array by way of a phase shifter of said plurality of phase shifters, each hybrid coupler of said top row being coupled column-wise between a phase shifter of said plurality of phase shifters and a hybrid coupler of a preceding row of said matrix circuit;
a bottom row of said matrix circuit is coupled to a plurality of matching loads such that each hybrid coupler of said bottom row is coupled column-wise between a matching load of said plurality of matching loads and a hybrid coupler of an immediately succeeding row of said matrix circuit; and
said phase shifters are used to generate linearly increased phase differences between adjacent antenna array elements for signals from said matrix circuit.
2. The circuit according to claim 1 , wherein a phase of a signal sent from a specific hybrid coupler to a specific antenna element in said antenna array is controlled by a specific phase shifter to which said specific hybrid coupler is coupled, said specific hybrid coupler being in said top row of said matrix circuit.
3. A circuit for use in simultaneously generating multiple beams using an antenna array having multiple antenna array elements, the circuit comprising:
a matrix circuit comprising a plurality of hybrid couplers and delay lines, said matrix circuit being coupled between a plurality of loads and said antenna array;
a first plurality of phase shifters coupled between adjacent rows of said matrix circuit; and
a second plurality of phase shifters coupled between said matrix circuit and said antenna array,
wherein
each row of said matrix circuit comprises a plurality of hybrid couplers coupled in series row-wise, with each row-wise pair of hybrid couplers being joined by at least one delay line;
a top row of said matrix circuit is coupled to antenna elements of said antenna array such that each hybrid coupler of said top row is coupled to an antenna element of said antenna array by way of a phase shifter of said second plurality of phase shifters, each hybrid coupler of said top row being coupled column-wise between a phase shifter of said second plurality of phase shifters and a phase shifter of said first plurality of phase shifters;
a bottom row of said matrix circuit is coupled to a plurality of matching loads such that each hybrid coupler of said bottom row is coupled column-wise between a matching load of said plurality of matching loads and a phase shifter of said first plurality of phase shifters;
each phase shifter of said first plurality of phase shifters is coupled between hybrid couplers of adjacent rows in said matrix circuit such that each hybrid coupler of said matrix circuit is coupled in series column-wise to at least one phase shifter of said first plurality of phase shifters; and
said phase shifters of said first and second plurality of phase shifters are used to generate linearly increased phase differences between adjacent antenna array elements for signals from said matrix circuit.
4. The circuit according to claim 3 , wherein a phase of a signal sent from a specific hybrid coupler to a specific antenna element in said antenna array is at least partially controlled by a specific phase shifter in said second plurality of phase shifters, said specific phase shifter being a phase shifter to which said specific hybrid coupler is coupled, said specific hybrid coupler being in said top row of said matrix circuit.
5. A circuit for use in simultaneously generating multiple beams using an antenna array having multiple antenna array elements, the circuit comprising:
a matrix circuit comprising a plurality of hybrid couplers and delay lines, said matrix circuit being coupled between a plurality of loads and said antenna array; and
a plurality of phase shifters with each phase shifter being coupled to at least one hybrid coupler,
wherein
each row of said matrix circuit comprises a plurality of hybrid couplers coupled in series row-wise, with each row-wise pair of hybrid couplers being joined by at least one delay line;
a bottom row of said matrix circuit is coupled to a plurality of matching loads;
said phase shifters are used to generate linearly increased phase differences between adjacent antenna array elements for signals from said matrix circuit; and
a top row of said matrix circuit is coupled to antenna elements of said antenna array such that each hybrid coupler of said top row is coupled to an antenna element of said antenna array by way of a phase shifter of said plurality of phase shifters, each hybrid coupler of said top row being coupled column-wise between a phase shifter of said plurality of phase shifters and a hybrid coupler of a preceding row of said matrix circuit.
6. The circuit according to claim 5 , wherein each column of said matrix circuit comprises a plurality of hybrid couplers coupled in series column-wise to at least one phase shifter or at least one hybrid coupler.