A band elimination filter includes a plurality of parallel resonators, each including a piezoelectric substrate and an IDT electrode on a surface of the piezoelectric substrate. The IDT electrode includes a pair of comb-shaped electrodes opposing each other, and the IDT electrode includes electrode fingers, a pitch of the electrode fingers being different between an end portion of the IDT electrode in a propagation direction of an elastic wave and a central portion of the IDT electrode different from the end portion.

A microstrip capacitor structure includes a substrate having a first side and a second side opposite the first side wherein the first and second sides of the substrate are spaced apart in a vertical direction, first and second conductive microstrip transmission line segments on the first side of the substrate, a conductive ground plane on the second side of the substrate, first and second microstrip capacitor plates connected to respective ones of the first and second microstrip transmission line segments, wherein the first and second microstrip capacitor plates are separated by a dielectric gap, and a complementary resonator comprising a removed portion of the conductive ground plane that is aligned in the vertical direction with at least a portion of the dielectric gap. The first and second microstrip transmission line segments extend in a first direction of RF signal propagation and the complementary resonant structure comprises first and second complementary resonant structures spaced apart in a second direction that is perpendicular to the first direction, and a transverse portion that extends in the second direction and connects the first and second complementary resonant structures.

A microwave or radio frequency (RF) device includes a substrate and a cover. The substrate has a first surface and an opposing second surface, the first surface including a first RF component and a second RF component electrically coupled to the first RF component in series. The cover is disposed over the first surface of the substrate, where the cover includes a first portion with a first width covering the first RF component, where the first portion and the first surface define a first waveguide cavity having the first width, and a second portion with a second width, less than the first width, covering the second RF component, where the second portion and the first surface define a second waveguide cavity having the second width.

A filter circuit may include a transmission line, a quarter wave resonator, and an electrical component coupled in series with the quarter wave resonator at a first end and to the transmission line at a second end. The electrical component may be have a frequency dependent impedance. The electrical component may be an inductor, a capacitor, or an inductor in series with a capacitor. In another aspect, a filter circuit may include a transmission line, a first quarter wave resonator coupled to a first electrical component and a second quarter wave resonator coupled to a second electrical component. Each of the first and second electrical components may be coupled to the transmission line in parallel with each other. The first and the second electrical components may have a frequency dependent impedance. The first electrical component may be the same as or different from the second electrical component.

A tunable bandpass filter (1A) includes a waveguide (11); a plurality of resonators (12) housed in the waveguide (11) and arranged in the lengthwise direction of the waveguide (11); a coupling member (13) disposed between two adjacent resonators (12); a ridge member (14) extending in the lengthwise direction of the waveguide (11) and connected to one end of the coupling member (13); and a dielectric plate (17) extending in the lengthwise direction of the waveguide (11), disposed adjacent to the plurality of resonators (12) in a direction orthogonal to the lengthwise direction of the waveguide (11), and movable in the direction orthogonal to the lengthwise direction of the waveguide (11).

A band-pass filter includes first to sixth stage resonators. Each resonator includes a resonator conductor portion formed of a conductor line. The resonator conductor portion has a first end and a second end which are opposite ends of the conductor line. The resonator conductor portion of each of the first and sixth stage resonators includes a narrow portion, a first wide portion located between the narrow portion and the first end, and a second wide portion located between the narrow portion and the second end. Each of the first and sixth stage resonators is lower in unloaded Q than the other resonators.

A process-invariant RC circuit is formed by patterning a metal layer using the same mask pattern to form a metal layer resistor and a metal layer capacitor. The same mask pattern results in the metal layer resistor and the metal layer capacitor each having a plurality of longitudinally-extending fingers having the same width and separation.

An acoustic wave device includes a piezoelectric layer, an IDT electrode, a high-acoustic-velocity support substrate, and a low-acoustic-velocity film. The high-acoustic-velocity support substrate is located on an opposite side of the piezoelectric layer from the IDT electrode in the thickness direction of the piezoelectric layer. The low-acoustic-velocity film is disposed between the high-acoustic-velocity support substrate and the piezoelectric layer in the thickness direction. The high-acoustic-velocity support substrate includes a base region and a surface region disposed nearer to the low-acoustic-velocity film than the base region in the thickness direction and whose crystal quality is worse than that of the base region. The surface region includes first and second layers disposed nearer to the base region than the first layer in the thickness direction and whose crystal quality is better than that of the first layer.

The present invention includes a method of creating electrical air gap low loss low cost RF mechanically and thermally stabilized interdigitated resonate filter in photo definable glass ceramic substrate. Where a ground plane may be used to adjacent to or below the RF filter in order to prevent parasitic electronic signals, RF signals, differential voltage build up and floating grounds from disrupting and degrading the performance of isolated electronic devices by the fabrication of electrical isolation and ground plane structures on a photo-definable glass substrate.

A suspended microstrip filtering device comprises a printed circuit board that includes a substrate having at least one resonator thereon, a ground plate, and an insulating separator interposed between the printed circuit board and the ground plate, the insulating separator having a plurality of air-filled openings.