Broadband Non-Reciprocal Coupling Between Asymmetric Transmission Lines

A device for non-reciprocal signal transmission comprising:

• a first transmission line having a first set of electromagnetic modes supporting propagation of electromagnetic waves at a first phase velocity;
• a second transmission line having a second set of electromagnetic modes supporting propagation of electromagnetic waves at a second phase velocity distinct from the first phase velocity;
• a set of first tunable impedance elements distributed along the first transmission line;
• and
• a controller configured to control the set of first tunable impedance elements to generate a set of impedance modulations in the first transmission line, each impedance modulation of the set producing new tones in the electromagnetic waves propagating in the first transmission line;
• wherein the controller is configured to individually control each first tunable impedance element to generate the set of impedance modulations with a particular set of associated phases, such that:
• for a first direction of propagation of the electromagnetic waves in the first transmission line, the new tones in the electromagnetic waves in the first transmission line constructively interfere and couple to modes of the second transmission line, and
• for an opposite second direction of propagation of the electromagnetic waves in the first transmission line, the new tones in the electromagnetic waves in the first transmission line destructively interfere and do not couple to the modes of the second transmission line.