A hybrid coupler is disclosed. The hybrid coupler comprises a printed circuit board having a first metallization layer and a second metallization layer arranged below the first metallization layer. The first metallization layer comprises at least two input ports and at least two output ports. The hybrid coupler further comprises a plurality of couplers coupled adjacent to each other on the first metallization layer. Each coupler of the plurality of couplers comprises transmission traces electrically coupled with the transmission traces of an adjacent coupler and the transmission traces of the plurality of couplers extend between the input ports and the output ports of the first metallization layer. The hybrid coupler furthermore comprises a defective ground structure having a pre-defined shape defined in the second metallization layer below each coupling junction formed between the transmission traces of the plurality of couplers.

A transmission conduit for RF signal, comprising: a dielectric plate; a conductive circuit positioned on one surface of the dielectric plate; a conductive ground positioned on opposite surface of the dielectric plate; wherein the dielectric plate comprises a sandwich of at least one high-dielectric constant layer and one foam plate. The dielectric plate can be made of a sandwich of glass and foam plate, such as Rohacell. The glass and foam plates have thickness calculated to give the sandwich the required overall dialectic constant.

Present invention is an antenna system and a wireless device comprising a negative resistance amplifier, the antenna system further comprises a first antenna element, said first antenna element being adapted to receive an incident wave for generating a first signal proportional to the incident wave, wherein the antenna system comprises a signal generating device for generating a second signal that is essentially 90 degrees phase shifted to the first signal, the first signal and the second signal being adapted to be applied to a hybrid coupler such that the first signal and the second signal are adapted to essentially destructively combine at a first hybrid coupler port, and the first signal and the second signal are adapted to be essentially constructively combined at a second hybrid coupler port, the second hybrid coupler port being adapted to operatively connect to the negative resistance amplifier, and the first hybrid coupler port being adapted to connect to a termination unit. Please invention is also a method for reflection of an incident wave.

A duplexer includes a 90 hybrid connected to an antenna terminal, a 90 hybrid connected to a terminating resistor, a transmission-side filter connected to the 90 hybrid connected to the antenna terminal, and notch filters connected to both of the 90 hybrids and mutually having the same filter characteristics, where each of the notch filters is a band elimination filter configured to reflect a radio frequency signal of a transmission band and allow a radio frequency signal of a band other than the transmission band to pass through.

A transmission conduit for RF signal, comprising: a dielectric plate; a conductive circuit positioned on one surface of the dielectric plate; a conductive ground positioned on opposite surface of the dielectric plate; wherein the dielectric plate comprises a sandwich of at least one high-dielectric constant layer and one foam plate. The dielectric plate can be made of a sandwich of glass and foam plate, such as Rohacell. The glass and foam plates have thickness calculated to give the sandwich the required overall dialectic constant.

To provide an optical 90-degree hybrid formed of a silicon waveguide capable of suppressing an optical loss and a phase error, and facilitating electronic packaging and optical packaging. In the optical 90-degree hybrid circuit including two optical branching units facing each other and two optical coupling units facing away from each other, four arm waveguides are arranged including bent waveguides each of which guides an output light of the optical branching unit to the optical coupling unit, and is formed in a curved shape.

Circuits for wireless communication on multiple frequency bands are provided. In accordance with some embodiments, transceivers are provided, the transceivers comprising: a first quadrature hybrid having a first in port, a first iso port, a first cpl port, and a first thru port; an antenna coupled to the first in port; a first transmitter having an output coupled to the first cpl port; and a first receiver having an input coupled to the first cpl port.

A radar system (200, 200a) and a method of operating a radar system are described, the radar system (200, 200a) comprising: a plurality of ICs (210, 220), each IC (210, 220) comprising: a respective LO output (212, 222) for selectively outputting a respective LO signal, and a respective LO input (214, 224); and a coupling device (230, 330), the coupling device (230, 330) comprising: a plurality of inputs (232, 234; 341, 342, 351, 352), each input being coupled to the LO output (212, 222) of a respective IC (200, 200a), and a plurality of outputs (236, 238; 363, 364, 373, 374), each output being coupled to the LO input (212, 222) of a respective IC (214, 224); wherein the coupling device (230, 330) is configured such that a LO signal arriving at any one of said plurality of inputs (232, 234; 341, 342, 351, 352) is distributed to each of said plurality of outputs (236, 238; 363, 364, 373, 374). The coupling device (230, 330) may comprise at least one directional coupler.

According to various embodiments, a quadrature hybrid coupler included as part of a phase shifter is used to provide variable phase shift to an input signal. The quadrature hybrid coupler includes an input port, an output port, and two terminated ports. The phase shifter includes one or more static lumped elements connected to the QHC to reduce at least one electrical dimension of the QHC to substantially less than a quarter wavelength. The phase shifter also include one or more variable lumped elements connected to the QHC to provide a variable phase shift to the input signal between the input port and the output port of the QHC.

An energy absorbing circuit includes a power divider that is configured to divide an incoming RF signal into a plurality of RF component signals; a plurality of transmission lines that are connected with the power divider, each of the transmission lines configured to transmit a respective RF component signal of the plurality of RF component signals; and a plurality of matching elements, each matching element being terminated to a respective one of the transmission lines.