A marchand balun with a reduced plane size is disclosed. The marchand balun provides two coupling units each having two transmission lines coupled to each other and having a length of λ/8, where λ is a characteristic wavelength of a signal subject to the marchand balun. The marchand balun further provides an additional unit, where two coupling unit and the additional unit are connected in series to each other. The additional unit is one of a transmission line with a length of λ/16 with one open end and a capacitor with one grounded end.

A WIFI antenna, including: a dipole including a first radiator and a second radiator that are arranged opposite to and spaced apart from each other; a feeding port provided at adjacent ends of the first radiator and the second radiator; a balun structure including a first access portion, a second access portion provided opposite to the first access portion, and an intermediate portion connecting the first access portion with the second access portion, and the intermediate portion having an annular structure; the first access portion of the balun structure is connected to the first radiator at the feeding port, and the second access portion is connected to the second radiator at the feeding port. Setting of the WIFI antenna provides characteristics of omnidirectional radiation, high gain and high physical stability, which not only improves the gain, but also fully covers the WIFI frequency band.

A balun assembly is provided. The balun assembly includes a first substrate having first and second surfaces opposite to each other, a first transmission electrode on the first surface of the first substrate, a ground electrode having an opening therein and on a side of the first substrate distal to the first transmission electrode, a first dielectric layer on a side of the ground electrode distal to the first substrate, and second and third transmission electrodes both on a side of the first dielectric layer distal to the ground electrode, the second and third transmission electrodes being spaced apart from each other. Orthographic projections of the first, second and third transmission electrodes on the first substrate intersect with an orthographic projection of the opening on the first substrate at first, second and third intersection points, respectively, and the first intersection point is between the second and third intersection points.

An example balun includes a center conductor that passes through a printed wiring board having multiple dielectric layers and cage vias arranged relative to the center conductor. The cage vias include a first set of cage vias that extend between an unbalanced connection to the balun and a balanced connection to the balun. The first set of cage vias are part of a first circular arc and are connected to electrical ground through a first ground ring. The cage vias include a second set of cage vias that extend from the unbalanced connection part-way through the printed wiring board. The second set of cage vias are part of a second circular arc and are connected to the electrical ground through a second ground ring. The second circular arc is longer than the first circular arc.

An example balun includes a center conductor that passes through a printed wiring board having multiple dielectric layers and cage vias arranged relative to the center conductor. The cage vias include a first set of cage vias that extend between an unbalanced connection to the balun and a balanced connection to the balun. The first set of cage vias are part of a first circular arc and are connected to electrical ground through a first ground ring. The cage vias include a second set of cage vias that extend from the unbalanced connection part-way through the printed wiring board. The second set of cage vias are part of a second circular arc and are connected to the electrical ground through a second ground ring. The second circular arc is longer than the first circular arc.

A balun includes first to fourth lines and a stack. A plurality of first conductor layers forming the first and third lines are located in a first region in the stack. A plurality of second conductor layers forming the second and fourth lines are located in a second region in the stack. A ground conductor layer is located closer to the second region than to the first region. The plurality of second conductor layers include a conductor layer pair where a distance between two conductor layers is smallest.

A balun includes first to fourth lines and a stack. A plurality of first conductor layers forming the first and third lines are located in a first region in the stack. A plurality of second conductor layers forming the second and fourth lines are located in a second region in the stack. A ground conductor layer is located closer to the second region than to the first region. The plurality of second conductor layers include a conductor layer pair where a distance between two conductor layers is smallest.

A combining balun includes: a first input side conductive member wound around a first axis on a first surface, which intersects with the first axis, and has a first portion between a second axis and the first axis and through which a first input current flows; a second input side conductive member wound around the second axis on the first surface and has a second portion between the second axis and the first portion and through which a second input current flows; a first output side conductive member wound around the first axis on a second surface, which faces the first surface, and has a third portion which faces the first portion; and a second output side conductive member wound around the second axis on the second surface and has a fourth portion which faces the second portion.

The invention discloses a cavity-based dual-band filtering balun, which includes a first cavity resonator and a second cavity resonator which are connected by a metal plate, the first cavity resonator is provided with an input PCB board, a metal ground layer of the input PCB board is provided with an input trough line, the other side of the input PCB board is provided with an input microstrip line, and the first cavity resonator is provided with an input slot corresponding to a position of the input trough line; and two opposite outside surfaces of the second cavity resonator which are adjacent to the metal plate are each provided with an output PCB board, metal ground layers of the two output PCB boards are respectively provided with an output trough line, the other sides of the two output PCB boards are each provided with an output microstrip line, and the second cavity resonator is provided with an output slot corresponding to a position of the output trough line and communicated with the output trough line. A main body of the dual-band filtering balun includes two cavity resonators, its structure is high in quality factor and low in insertion loss, and meanwhile, the requirement of two passbands is realized by using two fundamental modes of the cavity resonators, thus reducing a size of a circuit.

Embodiments of this application provide a radiation apparatus and a multi-band array antenna, and relate to the field of antenna technologies. The radiation apparatus includes a radiation module, a first conductor balun, and a second conductor balun. The first conductor balun is mechanically connected to the second conductor balun under the radiation module. The radiation module includes a first radiation unit and a second radiation unit in a +45° polarization direction, and a third radiation unit and a fourth radiation unit in a −45° polarization direction. The first conductor balun is configured to feed a first differential signal to the first radiation unit and the second radiation unit. The second conductor balun is configured to feed a second differential signal to the third radiation unit and the fourth radiation unit. The first conductor balun and the second conductor balun are disposed in the same plane.