A switchable reactance unit includes an RF terminal configured to connect to a transmission line for transmitting a signal at a frequency in a range of 1-200 MHz, and a switching arrangement comprising a plurality of switching elements used in parallel. Each switching element has a control terminal, and is connected to the RF terminal via at least one individual reactance assigned to the switching element and connected in series with the switching element. The switching elements are controllable or controlled via their control terminals in such a way that they switch simultaneously.

A filter apparatus includes input and output terminals, a ground terminal, a ground electrode connected to the ground terminal, a plate electrode, and first to four lines. A multilayer body of the filter includes a first and second main surface. The input and output terminals and the ground terminal are provided on the second main surface. The plate electrode is closer to the first main surface than the ground electrode. The first line is electrically connected to the input terminal and the plate electrode. The second line is electrically connected to the output terminal and the plate electrode. The first line is capacitively coupled to the second line. When the multilayer body is viewed in a plan view from a layering direction, the plate electrode covers a portion of a space providing capacitive coupling between the first line and the second line.

The present disclosure provides a filter device with which good characteristics can be obtained even when an attenuation band due to parallel resonance and a passband due to series resonance are close to each other. The filter device according to the present disclosure includes a first terminal, a second terminal, and a first inductor. A first path and a second path are provided in parallel with each other between the first inductor and the second terminal. A series resonator is in the first path and includes a second inductor, a capacitor connected in series with the second inductor, and a third inductor connected in series with the second inductor and the capacitor. Magnetic coupling between the first inductor and the third inductor is weaker than magnetic coupling between the first inductor and the second inductor.

A filter device includes a plurality of resonators and a stack. The plurality of resonators include a first parallel resonator and a first serial resonator. The first parallel resonator includes a conductor structure wound around an axis extending in a direction orthogonal to a stacking direction. The first serial resonator includes a conductor layer wound around an axis extending in a direction parallel to the stacking direction. The conductor layer includes three portions each located between a corresponding one of three side surfaces and at least part of the conductor structure when seen in the stacking direction.

A filter, an integrated passive device and an electronic device are disclosed. The filter includes a first port, a second port, a first band-pass filter circuit, a second band-pass filter circuit, and a third band-pass filter circuit; the first band-pass filter circuit is configured to input a first signal with a frequency between a first frequency and a second frequency in an initial signal input from the first port to the second band-pass filter circuit; the second band-pass filter circuit is configured to receive the first signal, and input a second signal with a frequency between a third frequency and a fourth frequency in the first signal to third band-pass filter circuit; the third band-pass filter circuit is configured to receive the second signal, and input a third signal with a frequency between a fifth frequency and a sixth frequency in the second signal to the second port.