A branch line directional coupler has a first line, a second line, a first open-ended coupled circuit, and a second open-ended coupled circuit. The first and second lines have a first characteristic impedance and a quarter wavelength length. The first open-ended coupled line has one end connected to the first line and the other end connected to the second line. The second open-ended coupled line has one end connected to the first line and the other end connected to the second line. The first open-ended coupled line has two coupled lines having a coupling length of a quarter wavelength, an open stub, and a connecting line, and has a total length of one-half wavelength. The second open-ended coupled line includes two coupled lines having a coupling length of ¼-wavelength, open stubs, and a connecting line, and has a total length of ½-wavelength.

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.

An antenna device (4) includes a first phase shifter (24) having one end connected to a fourth terminal (23d) of a directional coupler (23); a second phase shifter (25) having one end connected to a first terminal (23a) of the directional coupler (23); a third phase shifter (26) having one end connected to a second terminal (23b) of the directional coupler (23); a first matching circuit (27) having one end connected to an other end of the second phase shifter (25) and having an other end connected to a first input/output terminal (11); and a second matching circuit (28) having one end connected to an other end of the third phase shifter (26) and having an other end connected to a second input/output terminal (12).

A digital power amplifier comprising at least two individually activatable amplifiers connected to an output network comprising a first hybrid coupler. An output of a first amplifier is connected to a first input of the first hybrid coupler and an output of a second amplifier is connected to a second input of the first hybrid coupler such that activating an amplifier of the at least two amplifiers causes the amplifier to load modulate another activated amplifier of at least two amplifiers.

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.

A small-scale branch-line coupler suitable for use in mobile devices includes a first, second, third, and fourth ports, respectively acting as input, transmission, coupled, and isolated ports. A first, second, third, and fourth connection parts are connected to the ports and transmission lines. First angular transmission lines are between first and second ports, third angular transmission lines are between third and fourth ports. A third long strip transmission line connects the first port and the fourth port. A fourth long strip transmission line connects the second port and the third port. The branch-line coupler occupies a small area and has high performance.

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.

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 circuitry for feeding an antenna structure includes an input for LHCP signals, an input for RHCP signals as well as four antenna outputs. In addition, the circuitry includes first, second and third quadrature hybrids as well as at least two delay lines. The first quadrature hybrid is coupled, on the input side, to the first and second inputs and is coupled, on the output side, to the second and third quadrature hybrids. The second quadrature hybrid is coupled, on the output side, to two of the four antenna outputs, the third quadrature hybrid being coupled, on the output side, to two further ones of the four antenna outputs. The at least two delay lines are arranged at two of the four antenna outputs.

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.