Nonreciprocal transmission line apparatus having asymmetric structure of transmission line

An antenna apparatus comprising a nonreciprocal transmission line apparatus having forward and backward propagation constants different from each other,

• wherein the nonreciprocal transmission line apparatus comprises a cascade connection of at least one unit cell between first and second ports, each of the at least one unit cell comprises a transmission line part for a microwave signal, and first and second shunt branch circuits, and each of the first and second shunt branch circuits is branched from the transmission line part and equivalently include an inductive element,
• wherein each of the at least one unit cell has spontaneous magnetization or is magnetized by an external magnetic field so as to have gyrotropy by being magnetized in a magnetization direction different from a propagation direction of the transmission line part, and
• wherein in each of the at least one unit cell, the first shunt branch circuit is formed on one side with respect to a plane composed of the propagation direction and the magnetization direction, and the second shunt branch circuit is formed on the other side with respect to the plane, and an impedance of the first shunt branch circuit seen from the transmission line part is different from an impedance of the second shunt branch circuit seen from the transmission line part,
• wherein the transmission line part of each of the at least one unit cell is a microstrip line,
• wherein, when a microwave signal propagates in a predetermined propagation direction of the nonreciprocal transmission line apparatus at a predetermined operating frequency, the nonreciprocal transmission line apparatus radiates an electromagnetic wave with a radiation pattern having a main beam of a leaky wave in a direction substantially the same as the propagation direction, and radiates an electromagnetic wave with a radiation pattern having a main beam of a leaky wave in a direction substantially opposite to or substantially perpendicular to the propagation direction,
• wherein the antenna apparatus further comprises:
• a controller being configured to:
• input a microwave signal to at least one of a first port and a second port of the nonreciprocal transmission line apparatus, make the nonreciprocal transmission line apparatus operate as a forward transmission line or a backward transmission line at a predetermined operating frequency, and control at least one of an amplitude and a phase of the inputted microwave signal using nonreciprocity of the nonreciprocal transmission line apparatus, so as to form a main beam including a leaky wave from the nonreciprocal transmission line apparatus as a radiation wave.

An antenna apparatus comprising a nonreciprocal transmission line apparatus having forward and backward propagation constants different from each other,

• wherein the nonreciprocal transmission line apparatus comprises a cascade connection of at least one unit cell between first and second ports, each of the at least one unit cell comprises a transmission line part for a microwave signal, and first and second shunt branch circuits, and each of the first and second shunt branch circuits is branched from the transmission line part and equivalently include an inductive element,
• wherein each of the at least one unit cell has spontaneous magnetization or is magnetized by an external magnetic field so as to have gyrotropy by being magnetized in a magnetization direction different from a propagation direction of the transmission line part, and
• wherein in each of the at least one unit cell, the first shunt branch circuit is formed on one side with respect to a plane composed of the propagation direction and the magnetization direction, and the second shunt branch circuit is formed on the other side with respect to the plane, and an impedance of the first shunt branch circuit seen from the transmission line part is different from an impedance of the second shunt branch circuit seen from the transmission line part,
• wherein the nonreciprocal transmission line apparatus operates as a microwave resonator,
• wherein each unit cell of the nonreciprocal transmission line apparatus has such a circuit configuration that the nonreciprocal transmission line apparatus has a predetermined phase constant in dispersion curves indicative of a relation between an operating frequency of a microwave signal inputted to the nonreciprocal transmission line apparatus and a phase constant of the nonreciprocal transmission line apparatus,
• wherein the nonreciprocal transmission line apparatus further comprises:
• a first reflective impedance circuit connected to the first port, and having a first impedance seen from the first port at a predetermined operating frequency, and
• a second reflective impedance circuit connected to the second port, and having a second impedance seen from the second port at the operating frequency,
• wherein the first impedance is a complex number having substantially no real part, and
• wherein the second impedance is a complex number having substantially no real part and substantially conjugate with the first impedance,
• wherein the antenna apparatus further comprises a feeding circuit connected to one of the first reflective impedance circuit and the second reflective impedance circuit, the feeding circuit being configured to supply a microwave signal to the nonreciprocal transmission line apparatus.

An antenna apparatus comprising a nonreciprocal transmission line apparatus having forward and backward propagation constants different from each other,

• wherein the nonreciprocal transmission line apparatus comprises a cascade connection of at least one unit cell between first and second ports, each of the at least one unit cell comprises a transmission line part for a microwave signal, and first and second shunt branch circuits, and each of the first and second shunt branch circuits is branched from the transmission line part and equivalently include an inductive element,
• wherein each of the at least one unit cell has spontaneous magnetization or is magnetized by an external magnetic field so as to have gyrotropy by being magnetized in a magnetization direction different from a propagation direction of the transmission line part, and
• wherein in each of the at least one unit cell, the first shunt branch circuit is formed on one side with respect to a plane composed of the propagation direction and the magnetization direction, and the second shunt branch circuit is formed on the other side with respect to the plane, and an impedance of the first shunt branch circuit seen from the transmission line part is different from an impedance of the second shunt branch circuit seen from the transmission line part,
• wherein the nonreciprocal transmission line apparatus operates as a microwave resonator,
• wherein each unit cell of the nonreciprocal transmission line apparatus has such a circuit configuration that the nonreciprocal transmission line apparatus has a predetermined phase constant in dispersion curves indicative of a relation between an operating frequency of a microwave signal inputted to the nonreciprocal transmission line apparatus and a phase constant of the nonreciprocal transmission line apparatus,
• wherein the nonreciprocal transmission line apparatus further comprises:
• a first reflective impedance circuit connected to the first port, and having a first impedance seen from the first port at a predetermined operating frequency, and
• a second reflective impedance circuit connected to the second port, and having a second impedance seen from the second port at the operating frequency,
• wherein the first impedance is a complex number having substantially no real part, and
• wherein the second impedance is a complex number having substantially no real part and substantially conjugate with the first impedance,
• wherein the antenna apparatus further comprises a feeding circuit connected to one of the first reflective impedance circuit and the second reflective impedance circuit, the feeding circuit being configured to output a microwave signal received by the nonreciprocal transmission line apparatus.