A filter and array of filters providing inductive coupling are disclosed. According to one aspect, an RF filter includes a plurality of dielectric layers with a first ground plane on one side of the dielectric layers and a second ground plane on an opposite side of the dielectric layers. One of the first and second ground planes provides an input port and one of the first and second ground planes provides an output port. Two parallel strip line resonators, lie in a first plane parallel to, and between, the first and second ground planes, the two parallel strip line resonators, having a gap there between. An inductive coupling plate in proximity to the gap, is grounded at an edge and lies in a second plane, the second plane parallel to the first plane and lying between the first plane and one of the first and second ground planes.

An elastic wave device includes a substrate, a multilayer film located on the substrate, an LT layer located on the multilayer film and made of a single crystal of LiTaO.sub.3, and an IDT electrode located on the LT layer. The LT layer has a thickness of 0.3λ or less, where λ is twice a pitch of electrode fingers of the IDT electrode. The LT layer has Euler angles of (0°±10°, −25° or more and 15° or less, 0° or more and 360° or less).

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

The disclosure relates to a filter including dielectric substrate, ground and microstrip line layers, and signal and ground vias. The ground layer is formed on the dielectric substrate and has a ground plane and signal terminal contacts. The microstrip line layer is located on the dielectric substrate and includes microstrip resonators, common electrode and input and output terminal contacts. The input and output terminal contacts are connected to the microstrip resonators. The signal and ground vias extend among the ground layer, the dielectric substrate, and the microstrip line layer. The signal terminal contacts are connected to the input and output terminal contacts through the signal vias. The ground plane is connected to the common electrode through the ground vias. The filter further includes at least one capacitive coupling unit capacitive-coupled with two of the microstrip resonators adjacent to each other.

The present application provides an LTCC band-pass filter, including a shell and a filtering assembly. The shell includes a top wall and a bottom wall. The filtering assembly includes a first layer, two second layers respectively overlapped on two opposite sides of the first layer, two third layers respectively overlapped on two sides of the two second layers far away from the first layer, and a fourth layer sandwiched between one of the second layers and the third layers. The first layer is served as an inductance L. The second layer is served as a grounding capacitor C. The second layer and the first layer are coupled together to form an LC resonance unit. The third layer is connected with the ground, and is served as a shielding layer of the LTCC band-pass filter.

A free-from radio frequency (RF) media includes a substrate having a first dielectric layer formed thereon and a second dielectric layer on an upper surface of the first dielectric layer. A first conductive layer is formed on an upper surface of the first dielectric layer and has a first overall profile. A second conductive layer having a second overall profile is formed on an upper surface of the second dielectric layer such that the second dielectric layer is interposed between the first and second conductive layers. The first overall profile of the first conductive layer is different from the second overall profile of the second conductive layer.

An antenna module includes a substrate that includes a first dielectric layer and a second dielectric layer with a dielectric constant different from a dielectric constant of the first dielectric layer, a first antenna that is disposed on or in the first dielectric layer and transmits and receives a signal in a first frequency band, a second antenna that is disposed on or in the second dielectric layer and transmits and receives a signal in a second frequency band which is a lower frequency band than the first frequency band, and a radio frequency circuit that is disposed on or in the substrate and is electrically connected to the first antenna.

An electrically controllable RF circuit that includes an EC cell and an EAP-based actuator configured to produce relative movement of an electrode of the electrochromic cell and an electrically conducting patch or another electrode electromagnetically coupled thereto. In one embodiment, the RF circuit operates as a tunable patch antenna whose frequency characteristics can be changed by changing the bias voltages applied to the EC cell and EAP-based actuator. Advantageously, the capability to tune the antenna using two different tuning mechanisms (i.e., a dielectric-permittivity based tuning mechanism implemented using the EC cell and a geometry-based tuning mechanism implemented using the EAP-based actuator) provides more degrees of control over the pertinent antenna characteristics compared to what is available in some other antenna designs. In another embodiment, the RF circuit can operate as a tunable RF filter whose frequency characteristics can similarly be changed using these two different tuning mechanisms.

A filter circuit includes an input node, an output node, a first filtering element and a second filtering element. The first filtering element has a first terminal coupled to the input node and a second terminal, and is configured to provide a first signal conducting path toward the second terminal for conducting a first signal received at the input node to the second terminal. The second filtering element has a first terminal coupled to the input node and a second terminal, and is configured to provide a second signal conducting path toward the output node for conducting a second signal received at the input node to the output node. The second terminal of the first filtering element and the second terminal of the second filtering element are open-circuit terminals.