A directional coupler (1) includes a substrate (10), a main line (20) formed directly or indirectly on the substrate (10), sub-lines (21, 22 and 23) at least part of each of which is formed directly or indirectly on the substrate (10) along the main line (20), a switch (30) switching connections among end portions of the plurality of sub-lines (21, 22 and 23), and detection output terminals (FWD and REV) connected to the sub-line (21), wherein, when looking at the substrate (10) in plan, the end portions of the sub-lines (21, 22 and 23) are disposed on the opposite side to the detection output terminals (FWD and REV) relative to the main line (20), and the sub-line (21) to which the detection output terminals (FWD and REV) are connected is overlapped with or surrounded by the sub-lines (22 and 23).

A coupler module includes a coupler component formed with a main line and a sub-line that configure a directional coupler, and a module substrate on which the coupler component is mounted and on which a wiring conductor coupled in series with the main line is formed. At least a part of the wiring conductor is along the main line in plan view of the module substrate, and a direction of a main signal flowing through the main line and a direction of the main signal flowing through the part of the wiring conductor are opposite to each other.

Doherty power amplifiers with coupled line combiners are provided herein. In certain embodiments, a power amplifier system includes a carrier amplifier having a carrier output that provides a first radio frequency signal, a peaking amplifier having a peaking output that provides a second radio frequency signal, and a coupled line combiner including a first conductor line connected to the peaking output, a second conductor line electromagnetically coupled to the first conductor line, a third conductor line connected to the carrier output, and a fourth conductor line electromagnetically coupled to the third conductor line and in series with the second conductor line. The power amplifier system further includes an inductor in series with the fourth conductor line and the second conductor line and operable to provide a radio frequency output signal to an output terminal.

The disclosure relates to a 5.sup.th generation (5G) or pre-5G communication system for supporting a higher data transfer rate than a 4.sup.th generation (4G) communication system, such as long-term evolution (LTE). An antenna module is provided. The antenna module includes a filter for filtering a radio frequency (RF) signal, and a sub printed circuit board (PCB), the sub-PCB comprises a passive circuit for processing the RF signal, and, the sub-PCB may be coupled to the filter such that the filter operates as a bumper when being coupled to a filter board.

A high frequency coupler is disclosed that is configured for grid array-type surface mounting. The coupler includes a monolithic base substrate having a top surface and a bottom surface. A first thin film microstrip and a second thin film microstrip are each disposed on the top surface of the monolithic base substrate. Each microstrip has an input end and an output end. At least one via extends through the monolithic base substrate from the top surface to the bottom surface of the monolithic base substrate. The via(s) are electrically connected with at least one of the input end or the output end of the first microstrip or the second microstrip. The coupler has a coupling factor that is greater than about −30 dB at about 28 GHz.

A radio calibration system includes an FPGA that generates a calibration signal by a pseudo noise generator and mixes the calibration signal with a carrier generated by a carrier generator. The FPGA injects the calibration signal into an analog electronic device which couples the calibration signal into a receiver channel. The receiver channel measures calibration signal power, group delay, and phase, and performs calibration based on these measurements. A reference clock synchronizes the pseudo noise generator, the carrier generator and the receiver channel.

A filter circuit includes a branch line coupler and a balun circuit having an input terminal connected to the branch line coupler to receive a signal, a first line connected to the input terminal and having a length comparable to a quarter of an electrical length of one wavelength at a frequency of the signal, a second line connected to the input terminal and having a length comparable to the quarter, a third line connected to the second line and having a length comparable to the quarter, and a fourth line connected to the third line and electromagnetically coupled to the first line, the fourth line having a length comparable to the quarter, wherein an end of the first line and an end of the fourth line are both connected to a ground or open-circuited, or are connected to two respective terminating resistors whose resistance values are equal.

A directional coupler disclosed herein may include a main line provided on a substrate, the main line having a first end connected to an input port and a second end connected to an output port. The coupler may include a coupled line disposed on the substrate, the coupled line having a first end connected to a coupled port and a second end to an isolated port. The main line is electrically isolated from the coupled line. The coupled line includes multiple turns forming a winding, and a portion of the winding overlaps with the main line. The coupled line forms a plurality of windings inductively coupled with the main line. The main line and the coupled line are routed to propagate electric signals on both lines in a same direction, and enhance inductive coupling by mutual inductance.

A solidstate amplifier includes at least one interconnection, between a microstrip and a linearized impedance matching waveguide ridge, the interconnection being provided with a clamping device.

A directional coupler including a main line, a sub-line, an input terminal, an output terminal, a coupling terminal and an isolation terminal, wherein the main line includes a first main-line section formed on a first layer, and a second main-line section formed on a second layer; the first and the second main-line sections are connected in parallel between the input and the output terminals; the sub-line includes a first sub-line section formed on the first layer, and a second sub-line section formed on the second layer; the first and the second sub-line sections are connected in parallel between the coupling and the isolation terminals; the first main-line section and the first sub-line section are disposed in close proximity to each other to generate electromagnetic coupling; and the second main-line section and the second sub-line section are disposed in close proximity to each other to generate electromagnetic coupling.