Abstract: A directional coupler according to the present invention includes a primary line for transmitting a transmission signal; an input port for inputting the transmission signal to the primary line; an output port for outputting the transmission signal from the primary line; a secondary line for electromagnetically coupling with the primary line to extract part of the transmission signal; a coupling port provided at one end of the secondary line; an isolation port provided at the other end of the secondary line; and a low pass filter unit having a function of low pass filter, disposed between the secondary line and the coupling port.

Abstract: A directional coupler according to the present invention includes a primary line for transmitting a transmission signal; an input port for inputting the transmission signal to the primary line; an output port for outputting the transmission signal from the primary line; a secondary line for electromagnetically coupling with the primary line to extract part of the transmission signal; a coupling port provided at one end of the secondary line; an isolation port provided at the other end of the secondary line; and a low pass filter unit having a function of low pass filter, disposed between the secondary line and the coupling port.

Abstract: A directional coupler according to the present invention includes a primary line for transmitting a transmission signal; an input port for inputting the transmission signal to the primary line; an output port for outputting the transmission signal from the primary line; a secondary line for electromagnetically coupling with the primary line to extract part of the transmission signal; a coupling port provided at one end of the secondary line; an isolation port provided at the other end of the secondary line; and a low pass filter unit having a function of low pass filter, disposed between the secondary line and the coupling port.

Abstract: A composite balun includes a plurality of baluns, at least one capacitor, a ground terminal, and a DC voltage supply terminal. The plurality of baluns and the capacitor are built into a single chip. Each of the baluns includes first to fourth connection lines, a first balanced terminal, a second balanced terminal, and an unbalanced terminal. The first connection line is connected at one end to the unbalanced terminal. The second connection line is connected at one end to the other end of the first connection line. The third connection line is electromagnetically coupled to the first connection line and connected at one end to the first balanced terminal and at the other end to the DC voltage supply terminal. The fourth connection line is electromagnetically coupled to the second connection line and connected at one end to the second balanced terminal and at the other end to the DC voltage supply terminal.

Abstract: A composite balun includes a plurality of baluns, at least one capacitor, a ground terminal, and a DC voltage supply terminal. The plurality of baluns and the capacitor are built into a single chip. Each of the baluns includes first to fourth connection lines, a first balanced terminal, a second balanced terminal, and an unbalanced terminal. The first connection line is connected at one end to the unbalanced terminal. The second connection line is connected at one end to the other end of the first connection line. The third connection line is electromagnetically coupled to the first connection line and connected at one end to the first balanced terminal and at the other end to the DC voltage supply terminal. The fourth connection line is electromagnetically coupled to the second connection line and connected at one end to the second balanced terminal and at the other end to the DC voltage supply terminal.

Abstract: A balun comprises an unbalanced terminal, two balanced terminals, and two ground terminals. The balun further comprises: a low-pass filter provided between the unbalanced terminal and one of the balanced terminals; and a high-pass filter provided between the unbalanced terminal and the other of the balanced terminals. The low-pass filter incorporates two coils and a capacitor. The high-pass filter incorporates two capacitors and a coil. The coils and the capacitors are made up of conductor layers of a multi-layer substrate.

Abstract: A balun comprises an unbalanced terminal, two balanced terminals, and two ground terminals. The balun further comprises: a low-pass filter provided between the unbalanced terminal and one of the balanced terminals; and a high-pass filter provided between the unbalanced terminal and the other of the balanced terminals. The low-pass filter incorporates two coils and a capacitor. The high-pass filter incorporates two capacitors and a coil. The coils and the capacitors are made up of conductor layers of a multi-layer substrate.