Abstract: A vibrator includes: a vibration element that includes a pair of first excitation electrodes formed at the first vibration portion, a pair of second excitation electrodes formed at the second vibration portion, and a pair of third excitation electrodes formed at the third vibration portion, in which one second excitation electrode of the pair of second excitation electrodes is formed at a first inclined surface that is inclined with respect to two main surfaces, and one third excitation electrode of the pair of third excitation electrodes is formed at a second inclined surface that is inclined with respect to the two main surfaces and the first inclined surface; and a package that houses the vibration element. The vibration element includes a fixing portion to be fixed to the package. The fixing portion is provided between the first vibration portion and the second and third vibration portions.

Abstract: A resonator for a filter is described. The resonator includes a resonator housing, in which a resonator space is formed, a container with a cavity, in which a liquid crystal is contained, the container being at least partially arranged in the resonator space, and a compensating element, which is arranged in the cavity. The compensating element has a coefficient of thermal expansion that is lower than a coefficient of thermal expansion of the liquid crystal.

Abstract: Power combiner/divider includes a transmission line (TL) resonator having an inner conductor, an outer conductor that surrounds the inner conductor, and a cavity between the inner conductor and the outer conductor. The inner conductor and the outer conductor are electrically connected at a proximal end of the TL resonator. The power combiner/divider also includes coupling elements extending through respective openings of the outer conductor and into the cavity. The power combiner/divider also includes a capacitive element connected to at least one of the inner conductor or the outer conductor. The capacitive element capacitively couples the inner conductor and the outer conductor at a distal end of the TL resonator.

Abstract: A dielectric resonator antenna (DRA), includes: an electrically conductive ground structure; a plurality of volumes of dielectric materials disposed on the ground structure comprising N volumes, N being an integer equal to or greater than 3, disposed to form successive and sequential layered volumes V(i), i being an integer from 1 to N, wherein volume V(1) forms an innermost first volume, wherein a successive volume V(i+1) forms a layered shell disposed over and at least partially embedding volume V(i), wherein volume V(N) at least partially embeds all volumes V(1) to V(N?1); wherein a portion of the dielectric material of volume V(N) bifurcates at least a portion of volumes V(1) to V(N?1); and a signal feed electromagnetically coupled to one or more of the plurality of volumes of dielectric materials.

Abstract: A dielectric resonator antenna (DRA) includes: an electrically conductive ground structure; a plurality of volumes of dielectric materials disposed on the ground structure comprising N volumes, N being an integer equal to or greater than 3, disposed to form successive and sequential layered volumes V(i), i being an integer from 1 to N, wherein volume V(1) forms an innermost volume, wherein a successive volume V(i+1) forms a layered shell disposed over and at least partially embedding volume V(i), wherein volume V(N) at least partially embeds all volumes V(1) to V(N?1); and a signal feed disposed and structured to be electromagnetically coupled to one or more of the plurality of volumes of dielectric materials.

Abstract: A thermal insulation waveguide between a high-temperature unit and a low-temperature unit in a vacuum, chamber of an embodiment, the thermal insulation waveguide includes, a first substrate including a first line in the high-temperature unit, a second substrate including a second line in the low temperature unit, and a thermal insulation element connecting the substrates, and including a third line including an inductance component and connecting the first and second lines. The first substrate includes a first capacitor unit connected with the first line. The second substrate includes a second capacitor unit connected with the second line.

Abstract: The present invention provides filter assemblies, tuning elements and a method of tuning a filter. A filter assembly includes a housing having a top cover, a bottom cover and at least one sidewall, the top cover, the bottom cover and the at least one sidewall defining an internal cavity, the housing configured to receive first through third radio frequency (“RF”) transmission lines; a top metal sheet mounted within the internal cavity that has a plurality of openings that form a first hole pattern; and a bottom metal sheet mounted within the internal cavity that has a plurality of openings that form a second hole pattern. The top and bottom metal sheets are vertically spaced-apart from each other in a vertically stacked relationship within the internal cavity. The top metal sheet and the bottom metal sheet each include at least one resonator.

Abstract: A filter includes a plurality of resonance cavities, where a resonance tube and a tuning bolt penetrating into space enclosed by the resonance tube are disposed in each resonance cavity; further includes a tuning part disposed between the tuning bolt and the resonance tube, where the tuning part and the resonance tube form a first capacitor, and the tuning part and the tuning bolt form a second capacitor; and further includes an adjusting structure used for rotating the tuning part, so as to change relative areas between the tuning part and the resonance tube and between the tuning part and the tuning bolt, so that the first capacitor and the second capacitor change synchronously. In the present invention, the tuning part is disposed between the tuning bolt and the resonance tube, so that the tuning part forms a double-capacitor structure with the resonance tube and the tuning bolt.

Abstract: A waveguide busbar for converting a plurality of high-frequency input signals into high-frequency output signals, includes a waveguide, a plurality of input ports, which are arranged along the waveguide, such that each input port is intended to receive a high-frequency input signal, an output port on the waveguide for delivering the high-frequency output signal and at least one parallel resonator, which is connected to the waveguide busbar between two input ports. The parallel resonator has a mechanically adjustable volume with which a phase relation of the waveguide is adjustable between the two input ports.

Abstract: Embodiments relate to a force arrangement (50, 60) adapted to be mounted on a surface of a radio frequency filter that comprises a housing and a filter part extending along a first axis (A), the filter part being connected to a first side of the housing arranged perpendicular to the first axis (A) in a connection, the connection forming a contact seam between the filter part and the first side of the housing, wherein the force arrangement (50, 60) comprises a first spring part (56, 62) that is arranged, when mounted against the first side of the housing, to provide a first force in a first direction along the first axis (A) being opposite a direction of a stress force on the contact seam generated along the first axis (A) due to expansion of the housing (20) along the first axis (A) in the opposite direction of the provided force.

Abstract: A resonator having an effective spring constant (kz) and comprising a beam having a beam spring constant (kB) adapted to resonate in an oscillation direction, and extending at a non-zero angle (?) to the oscillation direction, wherein the resonator has a predetermined geometry and is formed from one or more materials, the or each material having a coefficient of thermal expansion (CTE), the CTE of the or each material together with the predetermined geometry of the resonator causing ? to vary with temperature, such that the temperature dependence of the beam spring constant is compensated for, resulting in the effective spring constant of the resonator remaining substantially constant within an operating temperature range.

Abstract: A cavity resonator having temperature compensation which comprises a pot and a cover, which together enclose a cavity resonance volume. The pot comprises a first material, which has a first temperature expansion coefficient and the cover comprises a second material, which has a second temperature expansion coefficient. The second temperature expansion coefficient is greater than the first temperature expansion coefficient, and an expansion of the pot and a deformation of the cover results upon a temperature increase, which each independently and also together cause an enlargement of the cavity resonance volume. Simultaneously, the resonance frequency remains essentially constant.

Abstract: A temperature compensation apparatus for a cavity filter including a plunger barrel, a compensation barrel having a first coefficient of thermal expansion, wherein the compensation barrel is housed with the plunger barrel, a tuning rod housed primarily within the compensation barrel, the tuning rod having a second coefficient of thermal expansion, and wherein the compensation barrel is physically in contact with the plunger barrel and the tuning rod for allowing a direct transfer of heat between the compensation barrel, the tuning rod, and the plunger barrel.

Abstract: A resonator cavity for supporting a plurality of resonant modes and filtering electromagnetic energy includes a cavity and a resonator element with a mounting flange. The cavity is defined by a top end wall, a bottom end wall and a sidewall and has a longitudinal axis along its length is defined. The resonator element is positioned within the cavity along the longitudinal axis and includes a mounting flange. The resonator element is only in physical contact with the cavity through the mounting flange at a mounting location and where at least one resonant mode of the electromagnetic energy exhibits a local minima. The dimensions of the cavity and the resonator element are selected so that the associated electromagnetic energy is defined by an electromagnetic field pattern that substantially repeats itself at least twice along the length of the resonator.

Abstract: A cavity resonator (20) having temperature compensation which comprises a pot (21) and a cover (22), which together enclose a cavity resonance volume (V). The pot (21) comprises a first material, which has a first temperature expansion coefficient (?1) and the cover (22) comprises a second material, which has a second temperature expansion coefficient (?2). The second temperature expansion coefficient (?2) is greater than the first temperature expansion coefficient (?1), and an expansion of the pot (21) and a deformation of the cover (22) results upon a temperature increase, which each independently and also together cause an enlargement of the cavity resonance volume (V). Simultaneously, the resonance frequency remains essentially constant.

Abstract: Filter and manifold compensation assemblies for thermal compensation of a filter cavity and a manifold which include at least one a lever element pivotally coupled to the filter or manifold at a first pivot point, an anchoring element pivotally coupled to the lever element at the second pivot point and secured to the housing of the filter or manifold, and a thermal expansion element having a lower coefficient of thermal expansion than the filter cavity or manifold and pivotally coupled to the lever element. The relative thermal expansion of the thermal expansion element in comparison with the thermal expansion of the filter or manifold causes the lever element to articulate and to displace the housing for thermal compensation. The degree of each displacement is proportional to the ratio between the distance between the second and first pivot points and the distance between the second and the third pivot points.

Abstract: Filter and manifold compensation assemblies for thermal compensation of a filter cavity and a manifold which include at least one a lever element pivotally coupled to the filter or manifold at a first pivot point, an anchoring element pivotally coupled to the lever element at the second pivot point and secured to the housing of the filter or manifold, and a thermal expansion element having a lower coefficient of thermal expansion than the filter cavity or manifold and pivotally coupled to the lever element. The relative thermal expansion of the thermal expansion element in comparison with the thermal expansion of the filter or manifold causes the lever element to articulate and to displace the housing for thermal compensation. The degree of each displacement is proportional to the ratio between the distance between the second and first pivot points and the distance between the second and the third pivot points.

Abstract: A device comprises a microwave resonator having at least one cavity having a predefined resonant frequency. The device also comprises a temperature compensation system that is made from a material having a coefficient of thermal expansion that is very low compared to that of the material from which the cavity is made and includes a structure for counteracting the effects of temperature variations on the resonator so that the resonant frequency of the cavity remains within a predetermined range. The device further comprises a temperature compensation adjustment device adapted to modify the volume of the cavity to adjust the value of the resonant frequency to a predefined value.

Abstract: A temperature compensation apparatus for a cavity filter including a plunger barrel, a compensation barrel having a first coefficient of thermal expansion, wherein the compensation barrel is housed with the plunger barrel, a tuning rod housed primarily within the compensation barrel, the tuning rod having a second coefficient of thermal expansion, and wherein the compensation barrel is physically in contact with the plunger barrel and the tuning rod for allowing a direct transfer of heat between the compensation barrel, the tuning rod, and the plunger barrel.

Abstract: An interface that provides minimum changes in contact pressure over a thermal range is disclosed. The interface is a mated joint of given material, typically metallic, joined by a mechanical fastener or fasteners. The fastener(s) create contact pressure at the joint surface wherein the contact pressure variation over a temperature range is minimized by the use of a thermal compensator having a predetermined length. The thermal compensator's length is chosen by setting the thermally induced expansion delta to offset an equal delta created by the fastener and interface configuration. The difference in expansion of the mated joint and fastener is canceled by the equal, but negative, difference between compensator and fastener. This cancellation of expansion minimizes the change in contact pressure at the joint interface. Maintaining a constant pressure provides PIM reliability during temperature changes.

Abstract: A method and an arrangement for temperature compensation at circular resonators with dual mode utilization, which includes a material with a low coefficient of thermal expansion and for which the tensile or compressive forces are transferred to the resonator wall and produce elastic deformations there. The resonator wall is deformed in two mutually perpendicular directions in each case by the same absolute amount at one or more places along the axial e extent, the deformation forces being introduced into the resonator war over at least one flange. This has the advantage that the peripheral shape of the casing of the circular resonator is deformed so that both orthogonal dual modes experience uniform shortening with simultaneous expansion of the material, as a result of which a high compensation effect is achieved.

Abstract: Filter and manifold compensation assemblies for thermal compensation of a filter cavity and a manifold which include at least one a lever element pivotally coupled to the filter or manifold at a first pivot point, an anchoring element pivotally coupled to the lever element at the second pivot point and secured to the housing of the filter or manifold, and a thermal expansion element having a lower coefficient of thermal expansion than the filter cavity or manifold and pivotally coupled to the lever element. The relative thermal expansion of the thermal expansion element in comparison with the thermal expansion of the filter or manifold causes the lever element to articulate and to displace the housing for thermal compensation. The degree of each displacement is proportional to the ratio between the distance between the second and first pivot points and the distance between the second and the third pivot points.

Abstract: An RF cavity resonator that includes: a resonator chamber for containing an RF field; an RF coupling element coupled to the resonator chamber for introducing the RF field into and extracting the RF field from the resonator chamber; a tuning assembly for causing the RF field to resonate at a desired frequency, wherein at least a portion of the tuning assembly is coupled within the resonator chamber; and a heat transport element included in the tuning assembly for transporting heat from the RF cavity resonator, the heat transport element comprising a phase change material, a housing for enclosing the phase change material, means for circulating the phase change material within the housing, and an electrically conductive surface for isolating the phase change material from the RF field, wherein the phase change material undergoes a phase change during circulation within the housing.

Abstract: A dielectric-based filter includes a thermally insulated housing, at least one filter formed from a dielectric material disposed inside the insulated housing, and a temperature maintenance device having a heating component and a cooling component for maintaining the temperature of the filter inside of the insulated housing within a temperature range. In a preferred aspect of the invention, the temperature maintenance device includes a thermoelectric cooler. The device permits the use of temperature-dependent low loss, high dielectric constant materials in filtering/resonator applications. During operation of the device, the dielectric-based filter is maintained at substantially room temperature.

Abstract: An RF cavity resonator (400) that includes: a resonator chamber (410) for containing an RF field; an RF coupling element (450, 452) coupled to the resonator chamber for introducing the RF field into and extracting the RF field from the resonator chamber; a tuning assembly (420) for causing the RF field to resonate at a desired frequency, wherein at least a portion of the tuning assembly is coupled within the resonator chamber; and a heat transport element (440) for transporting heat from the RF cavity resonator, wherein at least a portion of the heat transport element is coupled within the resonator chamber, the heat transport element including a phase change material, a housing for enclosing the phase change material, means for circulating the phase change material within the housing, and an electrically conductive surface for isolating the phase change material from the RF field.

Abstract: The specification discloses embodiments of an apparatus comprising a film bulk acoustic resonator (FBAR) filter comprising a piezoelectric membrane having a portion thereof sandwiched between a first electrode and a second electrode, the piezoelectric membrane being suspended from at least two edges thereof, and a heat transfer layer placed on the piezoelectric membrane surrounding, but not in contact with, the first electrode. Also disclosed are embodiments of a process comprising sandwiching a portion of the piezoelectric membrane between a first electrode and a second electrode, suspending a piezoelectric membrane from at least two edges thereof, and placing a heat transfer layer on the piezoelectric membrane surrounding, but not in contact with, the first electrode. Other embodiments are disclosed and claimed.

Abstract: A resonant cavity device comprises a waveguide body having a lateral wall extending in a longitudinal direction, having a first coefficient of thermal expansion, and delimiting a resonant cavity in conjunction with opposite first and second end walls. The first end wall has a second coefficient of thermal expansion lower than the first coefficient and has an internal face fastened to a first assembly comprising at least one main plate having a third coefficient of thermal expansion lower than the first coefficient and dimensions in a plane perpendicular to the longitudinal direction less than but substantially equal to those of the cavity.

Abstract: A waveguide assembly for operation over a range of temperatures includes a waveguide body and a plurality of restraining strips coupled to the waveguide body. The waveguide body includes a pre-curved narrow sidewall of material having a first coefficient of thermal expansion (CTE). The restraining strips are coupled to the waveguide body at first and second lateral points on either side of the pre-curved narrow sidewall laterally and are spaced apart along the length of the waveguide body, and are made from a material having a second CTE much less than the first CTE.

Abstract: A resonant cavity device comprises a waveguide body having a lateral wall extending in a longitudinal direction, having a first coefficient of thermal expansion, and delimiting a resonant cavity in conjunction with opposite first and second end walls. The first end wall has a second coefficient of thermal expansion lower than the first coefficient and has an internal face fastened to a first assembly comprising at least one main plate having a third coefficient of thermal expansion lower than the first coefficient and dimensions in a plane perpendicular to the longitudinal direction less than but substantially equal to those of the cavity.

Abstract: A microwave filter having a temperature compensating element includes a housing wall structure, a filter lid, a resonator rod, a tuning screw and the temperature compensating element. The housing wall structure defines a cavity. The filter lid closes the cavity. The resonator rod is within the cavity. The tuning screw is adjustably mounted through the filter lid and has a portion that protrudes into the cavity and is coaxial with the resonator rod. The temperature compensating element is joined to the filter lid or the housing and forms a bimetallic composite with the filter lid or housing that deforms with a change in ambient temperature.

Abstract: A waveguide assembly for operation over a range of temperatures includes a waveguide body and a plurality of restraining strips coupled to the waveguide body. The waveguide body includes a pre-curved narrow sidewall of material having a first coefficient of thermal expansion (CTE). The restraining strips are coupled to the waveguide body at first and second lateral points on either side of the pre-curved narrow sidewall laterally and are spaced apart along the length of the waveguide body, and are made from a material having a second CTE much less than the first CTE.

Abstract: A test system having a shielded enclosure and common air interface for testing the transmit and receive functionality of wireless communication devices such as mobile phones. A test system according to the present invention provides improved fault coverage by permitting robust testing of the entire signal path of a wireless device, including the antenna structure. In one embodiment of the invention, an RF-shielded enclosure having a test chamber is provided. The structure of the shielded enclosure blocks ambient RF energy from entering the test chamber and interfering with testing operations. The shielded enclosure may be lined with an RF absorbing material to improve test repeatability. A novel test antenna structure is disposed in the test chamber for wirelessly communicating test signals to a device under test.

Abstract: The present invention relates to a device at filters for filtering unwanted signals from radio transmitters and/or for use during combination of radio transmitters. Said filter (1) has at least one cavity (2 and/or 3) for filtering radio signals. At least one compensating means (13 and/or 16) is provided to compensate for deviations in frequency depending on expansion or contraction of the cavity (2 and/or 3) due to expansion or contraction of the filter (1) when said filter is heated or cooled during operation. The filter (1) has at least one cavity (2 and/or 3) which is designed for simultaneous filtering of radio signals of at least three different modes (A, B and C and/or D, E and F) and the same frequency. The compensating means (13 and/or 16) is provided in said cavity (2 and/or 3) for compensating deviations in frequency by simultaneously affecting the radio signals of the at least three different modes (A, B and C and/or D, E and F).

Abstract: An externally temperature-compensated microwave resonator comprises a microwave resonator and an external temperature compensator. The microwave resonator is a multi-cavity waveguide. The cavities are configured side-by-side and coupled through irises. The external temperature compensator is oriented and configured to effect a change in volume of the cavities when the resonator and compensator undergo a temperature gradient. The compensator deflects a wall portion of the resonator to accordingly counteract a change in volume of the cavity caused by a temperature gradient.

Abstract: A bandpass filter makes use of at least one waveguide cavity that is thermally compensated to minimize drift of a resonant frequency of the cavity with thermal expansion of cavity components. The compensation relies on deformation of the shape of at least one cavity surface in response to thermally induced dimensional changes of the cavity. A control rod is used to limit the movement of a point on the deformed surface, while the rest of the surface moves with the thermal expansion. The control rod is made of a material having a coefficient of thermal expansion that is significantly different than that of other filter components. The rod may also be arranged to span more thermally expandable material than defines the filter such that, as the filter expands, the point of deflection is moved toward the interior of the filter beyond its original position.

Abstract: The present invention relates to a duplexer set up by two decoupling filters for high frequency transceivers of the temperature self-compensating type and implemented by means of a pair of mechanic bodies (2), each one of which including a plurality of resonance cavities (3). Inside of the cavity (3) of the superior body (2) of the duplexer, a corresponding adjustment disc (7) is lodged in a removable and coaxial way which is provided with a supporting stem (8) coming out of a passage hole (12) obtained on the summit of the cavity (3). The bodies (2) are bound between them, so that the cavities of one or the other turn out to be coaxially facing each other. The passage hole (12) of the filter according to the invention is threaded. Moreover at each filter at least one bush (9) is associated having one portion (11) engaged in the hole (12) and inside of which the stem (8) of the disc (7) is housed.

Abstract: A waveguide arrangement for microwaves and the like has a first waveguide composed of a material having a first thermal expansion coefficient, a second waveguide composed of a material having a second thermal expansion coefficient which is different from the first thermal expansion coefficient, and a transition element provided between the first and second waveguides for mechanical uncoupling of the different thermal expansion coefficients of both the waveguides.

Abstract: This invention discloses an improved thermal compensation arrangement for a microwave filter of the type comprising at least one cavity defined by a metal side wall having a low coefficient of thermal expansion, such as invar, and lightweight metal end walls, such as aluminum, having good thermal and electrical conductivity, but a high coefficient of thermal expansion. The present invention comprises a characteristic arrangement of annular grooves and slots in the end walls that mechanically isolate the end walls from the side wall fixed thereto, to avoid distortion of the cavity with changes in temperature.

Abstract: A waveguide arrangement for microwaves and the like has a first waveguide composed of a material having a first thermal expansion coefficient, a second waveguide composed of a material having a second thermal expansion coefficient which is different from the first thermal expansion coefficient, and a transition element provided between the first and second waveguides for mechanical uncoupling of the different thermal expansion coefficients of both the waveguides.

Abstract: The present invention relates to a device at filters for filtering unwanted signals from radio transmitters and/or for use during combination of radio transmitters. Said filter (1) has at least one cavity (2 and/or 3) for filtering radio signals. At least one compensating means (13 and/or 16) is provided to compensate for deviations in frequency depending on expansion or contraction of the cavity (2 and/or 3) due to expansion or contraction of the filter (1) when said filter is heated or cooled during operation. The filter (1) has at least one cavity (2 and/ /or 3) which is designed for simultaneous filtering of radio signals of at least three different modes (A, B and C and/or D, E and F) and the same frequency. The compensating means (13 and/or 16) is provided in said cavity (2 and/or 3) for compensating deviations in frequency by simultaneously affecting the radio signals of the at least three different modes (A, B and C and/or D, E and F).

Abstract: A method and apparatus for frequency stabilization of cavity filters of the class including an outer tubular conductor and an inner conductor is effected by supporting the inner conductor of the resonant cavity by an apparatus comprised of a reference collar and an interface collar connected together by a means having a first coefficient of thermal expansion. The reference collar is structurally connected to the reference end of the outer tubular conductor by adjustable tuning means. It is not connected directly to the inner conductor. The inner conductor is structurally connected to the interface collar by a means having a second coefficient of thermal expansion. The first coefficient of thermal expansion and the second coefficient of thermal expansion are selected to provide compensation for the difference in thermal expansion between the outer conductor and the inner conductor of the cavity filter.

Abstract: This invention discloses an improved thermal compensation arrangement for a microwave filter of the type comprising at least one cavity defined by a metal side wall having a low coefficient of thermal expansion, such as invar, and lightweight metal end walls, such as aluminium, having good thermal and electrical conductivity, but a high coefficient of thermal expansion. The present invention comprises a characteristic arrangement of annular grooves and slots in the end walls that mechanically isolate the end walls from the side wall fixed thereto, to avoid distortion of the cavity with changes in temperature.

Abstract: A bandpass filter makes use of at least one waveguide cavity that is thermally compensated to minimize drift of a resonant frequency of the cavity with thermal expansion of cavity components. The compensation relies on deformation of the shape of at least one cavity surface in response to thermally-induced dimensional changes of the cavity. A control rod is used to limit the movement of a point on the deformed surface, while the rest of the surface moves with the thermal expansion. The control rod is made of a material having a coefficient of thermal expansion that is significantly different than that of other filter components. The rod may also be arranged to span more thermally expandable material than defines the filter such that, as the filter expands, the point of deflection is moved toward the interior of the filter beyond its original position.

Abstract: The thermal expansion of a microwave device such as a microwave resonator is partially or completely compensated by an externally mounted thermal expansion element. The microwave device includes a sidewall and an endwall affixed at its periphery to the sidewall. The thermal expansion compensation element is disposed external to the microwave device, between the endwall of the microwave device and a rigid external support. As the sidewall lengthens with increasing temperature, the thermal expansion compensation element expands to flex the endwall in the opposite direction to the growth in length of the sidewall, so that the central portion of the endwall remains in approximately the same position regardless of the temperature change.

Abstract: An electromagnetic wave component uses one or more diaphragms secured to the interior of a waveguide structure to tune its resonant frequency, with each diaphragm engaged by one or more adjustment members that deform it. The adjustment members are preferably screws that are threaded through the structure to push and/or pull on the diaphragms, thereby tuning the electromagnetic wave component. The shift in the resonant frequency of the electromagnetic wave component due to temperature-induced dimensional changes is mitigated if the materials used for the diaphragm, the adjustment members and the structure which houses the diaphragm are chosen to have an appropriate combination of thermal coefficients of expansion.

Abstract: An electromagnetic resonator comprises a waveguide body having a generally tubular side wall and a pair of end wall assemblies. The end wall assembly includes a bowed aluminum plate and an INVAR disk, attached to one another at the periphery thereof. The INVAR disk includes a relatively thick outer annular portion and a relatively thin inner circular portion. The bowed aluminum plate bows in response to increased temperature, thereby counteracting expansion of the waveguide body.

Abstract: A temperature compensated microwave filter has end caps and irises that each contain a projection that extends into a cavity to reduce the volume change of the cavity that would otherwise occur with changes in temperature due to an expansion or contraction of the side walls. The end caps and irises are formed from a single material. The material has a more positive coefficient of thermal expansion than the coefficient of thermal expansion of the side walls of each cavity. While one material is used to make up each end cap or iris, it is not necessary that the same material be used for all of the end cap and iris components.

Abstract: An inductive strip waveguide band-pass filter includes a conductive movable wall which can be set to various positions to allow a varying "A" dimension, thereby setting controllably the center frequency of the filter over a predetermined range. If the inductive strip filter includes multiple synchronized resonant cavities, the resonant cavities remain synchronized for all positions of the movable wall. The position of the movable wall can be set manually or by a motorized control mechanism.

Abstract: An electromagnetic bandstop filter comprises a microwave circuit, at least one microwave resonator, coupling means that couples electromagnetic energy to and from the microwave resonator, and an impedance transformer coupled to, and in series with, the coupling means, wherein the transformer is coupled to the resonator only through the coupling means, and wherein the impedance transformer is shunt coupled to the microwave circuit. The impedance transformer comprises at least two series-connected transmission line sections of different impedances.

Abstract: A bandpass filter makes use of at least one waveguide cavity that is thermally compensated to minimize drift of a resonant frequency of the cavity with thermal expansion of cavity components. The compensation relies on deformation of the shape of at least one cavity surface in response to thermally-induced dimensional changes of the cavity. A control rod is used to limit the movement of a point on the deformed surface, while the rest of the surface moves with the thermal expansion. The control rod is made of a material having a coefficient of thermal expansion that is significantly different than that of other filter components. The rod may also be arranged to span more thermally expandable material than defines the filter such that, as the filter expands, the point of deflection is moved toward the interior of the filter beyond its original position.