A full duplex communication system comprises a magnet-less ring circulator that comprises a set of ports extending from a circumference of the magnet-less multi-port ring combiner. The set of ports are positioned at increments around the circumference of the magnet-less multi-port ring combiner.

A full duplex communication system comprises a magnet-less ring circulator that comprises a set of ports extending from a circumference of the magnet-less multi-port ring combiner. The set of ports are positioned at increments around the circumference of the magnet-less multi-port ring combiner.

A branch-line coupler, adapted to radio frequency circuits, includes an input port, a first output port, a second output port, an isolated port, a first transmission line, a second transmission line, a first bent branch line, and a second bent branch line. The first transmission line is electrically connected between the input port and the first output port, and carries two open branches. The second transmission line is electrically connected between the isolated port and the second output port, and carries two open branches. The first bent branch line is electrically connected between the input port and the isolated port. The second bent branch line is electrically connected between the first output port and the second output port. The open branches of the first transmission line and the second transmission line resemble the bone structure of a fish skeleton.

A hybrid coupler includes a 90° hybrid coupler and a first quarter wavelength conductive stub. The 90° hybrid coupler includes a coupling section, a first input transmission line that is coupled to the coupling section, a second input transmission line that is coupled to the coupling section, a first output transmission line that is coupled to the coupling section and a second output transmission line that is coupled to the coupling section. The first quarter wavelength conductive stub is coupled to the second output transmission line.

The present application discloses embodiments that relate to an electromagnetic apparatus. In one aspect, the present apparatus includes a circuit board configured to propagate an electromagnetic signal. The apparatus also includes a waveguide configured to propagate an electromagnetic signal. The apparatus further includes a coupling port configured to couple a signal between the circuit board and the waveguide, where the coupling port has dimensions based on a desired impedance of the port.

Embodiments of a method and an apparatus for a quadrature hybrid are disclosed. In an embodiment, a quadrature hybrid includes a first port, a second port, a third port, a fourth port, first, second, and third inductors, first, second, third, and fourth capacitors, and a first variable capacitor tuning network connected between the first port and the fourth port, and a second variable capacitor tuning network connected between the second port and the third port.

An antenna system. The antenna system includes a central antenna, and a plurality of peripheral antennas positioned symmetrically around the central antenna. A first coupler provides a first radio connection and a second radio connection. A first 180 degree hybrid coupler is coupled to a first two diametrically opposed antennas of the plurality of peripheral antennas. A second 180 degree hybrid coupler is coupled to a second two diametrically opposed antennas of the plurality of peripheral antennas. A third 180 degree hybrid coupler coupled to the first and second 180 degree hybrid couplers, and having a third radio connection and a fourth radio connection. The first, second, third, and fourth radio connections are decoupled from each other, and the first, second, and third system radio connections are also decoupled from the central antenna.

An antenna system. The antenna system includes a central antenna, and a plurality of peripheral antennas positioned symmetrically around the central antenna. A first coupler provides a first radio connection and a second radio connection. A first 180 degree hybrid coupler is coupled to a first two diametrically opposed antennas of the plurality of peripheral antennas. A second 180 degree hybrid coupler is coupled to a second two diametrically opposed antennas of the plurality of peripheral antennas. A third 180 degree hybrid coupler coupled to the first and second 180 degree hybrid couplers, and having a third radio connection and a fourth radio connection. The first, second, third, and fourth radio connections are decoupled from each other, and the first, second, and third system radio connections are also decoupled from the central antenna.

A device and a method for creating and/or maintaining an obstruction free upper respiratory passages. The device is configured to fit under the chin of a subject adjacent to the subject's neck at an external location corresponding approximately with the subject's internal soft tissue associated with the neck's anterior triangle. The device is capable of exerting negative pressure on the surface of a subject's neck, displacing the soft tissue forward and enlarging the airway.

An antenna device is formed by arranging radiation elements each radiating a circularly polarized wave in a matrix of three rows and four columns. The radiation elements include three sets of radiation elements of four types having a positional relationship rotationally symmetric with each other. The radiation elements are arranged such that adjacent elements are of different types.