Frequency-independent receiver and beamforming technique
Example systems and methods described herein relate to radio communication architectures and techniques for beamforming and down-conversion without a priori knowledge of the source location or frequency. An example radio receiver includes a plurality of antenna elements that include a first element, a second element, and a third element. The radio receiver also includes a plurality of mixers coupled to the plurality of antenna elements and a combiner coupled to the plurality of antenna elements. A signal incident on the first element is mixed with itself via a first mixer of the plurality of mixers. An output of the first mixer is mixed with a signal incident on the second element via a second mixer of the plurality of mixers, and an output of the second mixer is combined via the combiner with a signal incident on the third element.
1. An antenna array comprising:
a plurality of antenna elements arranged in a matrix, the matrix having a number of columns and a number of rows, wherein each antenna element of the plurality of antenna elements exists at a position within the matrix at an intersection of a column and a row and wherein each antenna element of the plurality of antenna elements comprises a mixer configured to produce a phased superposition mix of a first signal and a second signal, wherein each antenna element comprises:
a respective antenna;
an output mixer coupled to the respective antenna and configured to produce a mix between a signal incident at the respective antenna and the phased superposition mix of the first signal and the second signal; and
an input mixer coupled to the respective antenna and configured to produce a mix between a third signal and the phased superposition mix of the first signal and the second signal;
a first set of phase shifters, each phase shifter of the first set of phase shifters being configured to apply a respective phase shift to an input signal; and
a second set of phase shifters, each phase shifter of the second set of phase shifters being configured to apply a respective phase shift to an input signal,
wherein the first set of phase shifters are arranged such that the first signal is applied with a same phase shift to each mixer of each antenna element in a respective column of the matrix, and
wherein the second set of phase shifters are arranged such that the second signal is applied with a same phase shift to each mixer of each antenna element in a respective row of the matrix.
2. The antenna array of claim 1 ,
wherein the first set of phase shifters comprises a number of phase shifters equal to the number of columns in the matrix, and
wherein the second set of phase shifters comprises a number of phase shifters equal to the number of rows in the matrix.
3. The antenna array of claim 1 , wherein the third signal is a baseband input signal.
4. A method comprising:
applying a first signal to each antenna element of a plurality of antenna elements, the plurality of antenna elements being arranged in a matrix, the matrix having a number of columns and a number of rows, wherein each antenna element of the plurality of antenna elements exists at a position within the matrix at an intersection of a column and a row, wherein each antenna element comprises:
a respective antenna;
an output mixer coupled to the respective antenna and configured to produce a mix between a signal incident at the respective antenna and a phased superposition mix of the first signal and the second signal; and
an input mixer coupled to the given antenna and configured to produce a mix between a third signal and the phased superposition mix of the first signal and the second signal; and
applying a second signal to each antenna element of the plurality of antenna elements;
shifting a phase of the first signal such that for each application of the first signal to mixers positioned in a given column of the matrix, the first signal is applied with a same phase shift;
shifting a phase of the second signal such that for each application of the second signal to mixers positioned in a respective row of the matrix, the second signal is applied with a same phase shift; and
at each respective antenna element of the plurality of antenna elements, mixing the phase-shifted first signal applied to the respective antenna element with the phase-shifted second signal applied to the respective antenna element.
5. The method of claim 4 , wherein the step of shifting the phase of the first signal such that for each application of the first signal to mixers positioned in a respective column of the matrix, the first signal is applied with the same phase shift comprises: shifting the phase of the first signal using a number of phase shifters equal to the number of columns in the matrix.
6. The method of claim 4 , wherein the step of shifting the phase of the second signal such that for each application of the second signal to mixers positioned in a respective row of the matrix, the second signal is applied with the same phase shift comprises: shifting the phase of the second signal using a number of phase shifters equal to the number of rows in the matrix.
7. The method of claim 4 , wherein the third signal is a baseband input signal.