Abstract: A manifold is constructed with a primary manifold section to which the input wave guides are connected and a tuning section attached to the output of the primary manifold section. The tuning section is constructed of a deformable material which allows the dimpling of the internal wall to alter the impedance of the waveguide system for the purpose of fine tuning the impedance matching of the manifold.

Abstract: Two helical resonator filters for applications in wireless and satellite communication systems. The present invention provides for single mode and dual mode microwave filters that employ evanescent waveguide cavities loaded with helical resonators. The structure of the present invention provides for a high Q factor in a miniature package. Two helical resonator filters are well adapted for use in wireless and satellite communication systems. The present invention provides for miniature filters utilizing single mode, high dielectric constant material loaded helical resonators, as well as higher order dual mode helical resonator loaded cavities. Both configurations can be used to realize advanced filters with non-adjacent coupling. The helical resonators may be loaded with high dielectric constant materials or ferrite materials for additional miniaturization and tunability. Either voltage or current tuning may be provided by the single mode and dual mode microwave filters.

Abstract: An extended band, multiple channel multiplexer 10 well-suited for use with satellite communications systems. The multiplexer utilizes a low attenuation, contiguous diplexer 18 containing contiguous diplexer filters 18a to combine two sections 11a, 11b of the multiplexer respectively containing contiguous channel filters 14a, 14b. The multiplexer comprises low attenuation, contiguous diplexer filters 18a tuned in tandem with channel filters 14a, 14b to provide contiguous multiplexing. This approach takes advantage of the constructive interaction between these filters to realize an equivalent contiguous multiplexer. This enables realization of a wide band contiguous multiplexer, which heretofore was impossible to tune. The contiguous diplexer eliminates spurious modes of the channel and diplexer filters, spurious waveguide modes, and out of band interaction between the two portions of the multiplexer. Therefore, tuning of the multiplexer is possible.

Abstract: An electromagnetic wave propagation structure, suitable for the transmission of an electromagnetic wave and the formation of resonators within filters, is constructed of both high and low dielectric-constant materials wherein the high dielectric-constant is in excess of approximately 80 and the low dielectric-constant is less than approximately 2. A boundary between the high and the low dielectric-constant materials serves as an electric wall to waves propagating in the low dielectric-constant material and as a magnetic wall to waves propagating in the high dielectric-constant material. This permits substitution of the high dielectric-constant material for metal elements, such as resonators and feed structures in filters. Furthermore, the use of a cladding of dielectric material of one of the foregoing dielectric ranges about a core of material of the other of the foregoing dielectric ranges enables construction of waveguides having rectangular and circular cross-sections.

Abstract: A plurality of dual mode, dielectric resonator loaded cavity filters may be coupled to respective ones of a plurality of radiators of an array antenna, such as a phased array antenna. Each of the filters is provided with a thin annular, electrically conductive ring disposed on a resonator surface facing the corresponding radiator of the antenna. The ring greatly increases the coupling of electromagnetic power for circularly and linearly polarized waves between the filter and the radiator for radiation of the power from the radiator into space, as well as during reception of radiation from outer space. The filter is operative also, if desired, to provide such coupling of electromagnetic power to a waveguide, as well as directly into the external environment. The ring may be located at the opening of the cavity through which the power is coupled between the filter and the radiator or the waveguide or the empty space.

Abstract: A dielectric resonator filter has a series of cavities enclosing respective ones of a series of dielectric resonators, wherein each cavity includes a resonator support configured as a cylinder of thermally conductive, electrically insulating material such as boron nitride. The support is positioned coaxially with the resonator along a central axis of the cavity, and is located in tandem with the resonator. Physical connection of the support to the resonator is facilitated by provision of a thread along an inner surface of the support, and the provision of an outer thread on the resonator surface to be received within the thread of the support. The support is mounted to an end wall of the cavity, thereby to complete a thermally conductive path for withdrawal of heat from the resonator to the exterior of the filter. Each support is provided with windows through which tuning and/or mode coupling screws can be inserted, thereby to locate a screw behind an end surface of the resonator.

Abstract: A push-push microwave oscillator has two branch oscillators fabricated of a transistor and transmission line elements extending from terminals of the transistor, and a resonator which is fabricated of an annulus of superconductor material and serves to phase lock oscillations of the two branch oscillators. The superconductor material is a composite of a rare earth element and copper oxide such as yttrium-barium-copper oxide. A first transmission line in each of the branch oscillators extends past the resonator with a spacing to provide for electromagnetic coupling between the branch oscillator and the resonator. A second transmission line in each of the branch oscillators has a length equal to approximately one-quarter wavelength of the oscillation frequency to tune the branch oscillator to a common oscillation frequency.

Abstract: A conducting plane resonator (10) is used to stabilize an oscillating means (12) typically operating at microwave frequencies. The conducting plane resonator (10) is in proximity to the oscillating means (12) and is magnetically coupled thereto. In a first implementation, the conducting plane resonator (10) is magnetically coupled to an input conductor (16) of the oscillating means (12). In a second implementation, the conducting plane resonator (10) is magnetically coupled to an output conductor (18), which is coupled to the oscillating means (12). In a third implementation, the conducting plane resonator (10) is magnetically coupled to both the input conductor (16) and the output conductor (18). The conducting plane resonator (10) preferably comprises a thin, substantially planar conducting plane and is dimensioned such that it is resonant at the desired operating frequency. The conducting plane resonator (10) is preferably fabricated of a superconductor material to achieve high-Q performance.

Abstract: A waveguide cavity filter having a conductive housing, a plurality of high dielectric constant ceramic resonators disposed within the conductive housing and at least a portion of a sheet of superconductive material which is constrained to be at an ambient temperature below the critical temperature of the superconductor and disposed in contact with at least one of the side walls of the conductive housing and with an opposing surface of each of the resonators, such that the resonators are in close superconductive contact with the side walls of the conductive housing. In particularly, the superconductive sheet is a layer of high temperature superconductor. In a first embodiment of the invention, the resonators in the shape of cylindrical plugs are disposed with a flat surface juxtaposed to the side wall.

Abstract: Planar dual mode filters (30) are formed by a conductive resonator (20) having circular symmetry and two pairs of symmetrically oriented planar conductive leads (22, 26 and 24, 28). The conductive leads (22, 26 and 24, 28) are aligned colinearly with two orthogonal diameters (32, 34, respectively) of the circular conductive resonator (20) and are electrically isolated from said resonator (20). A perturbation (38) located on an axis (36) oriented symmetrically with respect to the two pairs of conductive lead (22, 26 and 24, 28) couples electromagnetic modes which are injected into the resonator (20) by the planar conductive leads (22, 26 and 24, 28). Higher order filter circuits can be realized by combining multiple filters (30) of the present invention. The filters (30) are amenable to printed circuit (microstrip to stripline) fabrication using superconductors for the conductive elements.

Abstract: A dual mode microstrip resonator (1) usable in the design of microwave communication filters. The substantially square resonator (1) provides paths for a pair of orthogonal signals which are coupled together using a perturbation located in at least one corner of the resonator (1). The perturbation can be introduced by notching (3) the resonator (1) or by adding a metallic or dielectric stub (5) to the resonator (1).

Abstract: A dielectric resonator probe for measuring surface resistance of a test material, particularly at cryogenic temperature, is provided. A dielectric resonator is mounted near to but spaced from a conductive plate and is positioned in contact with a test material. Preferably, a low-loss dielectric spacer separates the resonator from the upper plate. The dielectric resonator has a larger lower surface area than upper surface area. The dielectric resonator includes a hole therethrough for increasing mode separation and for accommodating a mounting bolt. The mounting bolt is preferably nonconductive and is coupled to a spring for resiliently mounting the resonator and spacer to the plate so as to accommodate differential thermal expansion of the components.

Abstract: A frequency discriminator (1) stabilizes a voltage controlled oscillator (5), particularly one operating at microwave frequencies. A single dielectric resonator (2), typically positioned within a housing (8), is excited by an r.f. input (30). The dielectric resonator (2) generates in response to the excitation first and second orthogonal modes of r.f. electromagnetic energy at slightly different frequencies. The two orthogonal modes are converted to d.c. output signals (39, 40) of opposite polarity and substantially the same magnitude, e.g., by diodes (35, 36). Frequency offsets are obtained by tuning screws (43, 44) and/or by changing the amount of dielectric (2) in the path of the characterizing vector corresponding to the mode being frequency-offset.

Abstract: An extremely narrow-band bandpass electromagnetic filter comprises a waveguide (1) dimensioned below cutoff and having two or more active sections (30) each containing a dielectric resonator (6). The number of resonators (6) corresponds to the number of poles of filtering. The physical dimensions of the waveguide (1) can advantageously be further reduced by means of passive coupling means (40), where the waveguide (1) cross-section is smaller than in the active sections (30). Each passive coupling means (40) inductively couples adjacent active sections (30). Mode suppression rods (10) electrically connect opposing waveguide walls (2, 3) midway between each pair of adjacent dielectric resonators (6). Preferred embodiments are illustrated, in which the resonators (6) are tranversely oriented within the waveguide (1). Electromagnetic energy travels within the waveguide (1) in a single TE.sub.10 evanescent mode (TE.sub.01.delta. within the resonators (6)).

Abstract: A double dielectric resonator (1) having lower and upper preferably cylindrical dielectric elements (3, 5, respectively) is used to stabilize an oscillator operating at microwave frequencies. The dielectric elements (3, 5) are separated by a distance (d) which is greater than zero but less than an amount that will eliminate magnetic coupling between the dielectric elements (3, 5), and preferably less than an amount that will push the oscillator into a nonlinear region of the frequency versus separation (d) curve. The major axes (43, 45, respectively) of the dielectric elements (3, 5) are aligned, or else parallel but offset slightly. The invention may be used with reflection type, parallel feedback, and series feedback oscillators.

Abstract: A stable electromagnetic oscillator (30) comprises an amplifying element (3) in feedback association with a dual mode resonant cavity (12) that provides a double pole bandpass filter function. Two orthogonal modes (1 and 2) of electromagnetic energy resonate within the cavity (12). An output from the amplifying element (3) excitationally couples into the first mode (1), while the second mode (2) couples into the input of the amplifying element (3). The output (8) of the oscillator (30) is obtained from the first mode (1). Optional injection lock can be used for greater stability by means of coupling a stable a.c. reference (9) into the cavity (12) in alignment with the second mode (2). Optional electronic frequency tuning comprises a phase or frequency comparator (11) and a reference a.c. source (13), producing a d.c. feedback signal fed to varactor diodes (10). Coupling ports (4, 5, 6, 7) of the cavity (12) can be, e.g., irises, capacitive probes, coaxial probes, or any combination thereof.

Abstract: A ceramic resonator element having high Q, high dielectric constant, and a low temperature coefficient of resonant frequency is enclosed within a cavity to form a composite microwave resonator having reduced dimensions and weight as compared to a simple cavity resonator. A pair of tuning screws extend into the cavity along orthogonal axes to tune the structure to resonance along these axes at frequencies near the fundamental resonance of the ceramic element. Several such cavities can be formed in a short length of waveguide by the use of transverse partitions at spaced intervals and coupling between cavities can be accomplished by using simple slot, cross or circular irises. In each cavity, a mode-perturbing screw is positioned along an axis 45.degree. from each of the orthogonal tuning screws, such that resonance along either of the orthogonal axes is coupled to excite resonance also along the other.

Abstract: An electromagnetic cavity filter (10) is formed by at least two cavities (12) having electrically conductive walls (40, 15). When more than two cavities (12) are employed, their midpoints do not have to be colinear; rather, it is sufficient that the angle formed by the midpoints of any three successively coupled cavities is an integral multiple of 90.degree.. Thus, a folded "engine block" geometry can be realized such that the filter's input cavity (12) is proximate to the output cavity (12). This allows a canonic filter response. Each cavity (12) is the equivalent to two filter poles because two orthogonal modes of electromagnetic radiation can resonate therewithin. Electrically nonadjacent modes of proximate cavities (12), as well as electrically adjacent modes, can be coupled, permitting elliptic filter functions. Electrically nonadjacent modes are coupled by means of an iris (30) opening between the two cavities (12).