Abstract: In a laminated dielectric resonator, two-fold strip line is formed and resonant frequency is lowered. Accordingly, the length of the resonator is reduced, and the length of the strip line becomes shorter than one fourth of the wavelength with the lowered resonant frequency, which leads to further reduction of the length of the resonator. By lowering the resonant frequency, dielectric material with less relative permittivity can be used, with a result of resonator with high unloaded Q and excellent temperature characteristic. Further, at least one coupling electrode is formed as external or internal electrode to compose a capacitor together with a second strip line, and a laminated dielectric resonator is connected to an external circuit via the coupling electrode. A dielectric filter such as band pass filter, band elimination filter is so composed that the dielectric resonators are cascade-connected to one another.

Abstract: A solar lamp drive circuit is arranged to delay start-up while a current is supplied to the lamp filament to warm up the filament. During operation, the back e.m.f. induced in the lamp is sampled, and, if operating conditions deteriorate, the current to the filament is reapplied automatically and the power supply to the lamp increased.

Abstract: A tunable electromicromechanical resonator structure incorporates an electrostatic actuator which permits reduction or enhancement of the resonant frequency of the structure. The actuator consists of two sets of opposed electrode fingers, each set having a multiplicity of spaced, parallel fingers. One set is mounted on a movable portion of the resonator structure and one set is mounted on an adjacent fixed base on substrate, with the fingers in opposed relationship and their adjacent ends spaced apart by a gap. An adjustable bias voltage across the sets of electrodes adjusts the resonant frequency of the movable structure.

Abstract: An acoustic wave filter (200, 300) having a substrate for supporting propagation of acoustic waves, and first (220, 315), second (235, 330) and third (210, 310) acoustic wave transducers disposed on the substrate. The first acoustic wave transducer (220, 315) includes at least one bus bar (221, 316) electrically coupled to a first electrical port (205, 305) of the acoustic wave filter (200, 300). The second acoustic wave transducer (235, 330) is disposed on the substrate in line with the first acoustic wave transducer (220, 315) and is acoustically coupled thereto. The second acoustic wave transducer (235, 330) includes at least one bus bar (236', 331) electrically coupled to a second electrical port (240, 345) of the acoustic wave filter (200, 300). The third acoustic wave transducer (210, 310) includes at least one bus bar (211, 311') electrically coupled to the first electrical port (205, 305).

Abstract: The invention relates to a resonator shell construction, comprising at least two metallic shell modules (41-44) connected to each other to form a modular shell construction, each module enclosing at least one resonator cavity (42-52). The modules comprise wall portions (41a-41c, 42a-42c, 43a-43c, 44a-44c) projecting from the modules, said wall portions being connected to one or more modules, whereby one or more new resonator cavities (61-68) are formed between the modules.

Abstract: A SAW filter includes a first SAW resonator having a pair of terminals and a predetermined resonance frequency (f.sub.rp), the first SAW resonator being provided in a parallel arm of the SAW filter. A second SAW resonator has a pair of terminals and a predetermined resonance frequency (f.sub.rs) approximately equal to a predetermined antiresonance frequency of the first SAW resonator (f.sub.ap). The second SAW resonator is provided in a series arm of the SAW filter. An inductance element is connected in series to the first SAW resonator.

Abstract: An array of hollow cathodes can be made by mounting a housing connected to a source of plasma precursor gas and to a source of power in a vacuum chamber, said housing having a plurality of uniformly spaced openings in a wall thereof into which a plasma can be generated. A substrate to be treated is mounted parallel to and spaced a preselected distance from said openings. In operation, a plurality of plasma torches is created extending from the openings which can plasma etch and remove coatings on said substrate.

Abstract: An advantageous embodiment of the invention is the filter of the receiver branch of the duplex filter in a multi-channel radio transmitter/receiver having reception and transmission bands composed of plural radio-frequency channels. In the first state of the filter, when the radio transmitter/receiver is only receiving radio signals, the width of the pass band of the filter corresponds to said reception band. In the second state, in which the radio transmitter/receiver additionally transmits radio signals, the pass band of the filter is switched by current control to cover only part of the reception band. By constructing the filter in the manner proposed it is possible to use current control in the first resonator in the filter of the receiver branch. Because of its power consumption current control is otherwise unsuitable for use in e.g. the duplex filter of a portable radio-telephone.

Abstract: In order to regularly properly define cavities for vibrating spaces in a chip-type piezoelectric-resonator which is protected with resin to be capable of surface mounting, a mother substrate comprising a piezoelectric substrate, a plurality of piezoelectric resonance elements formed thereon is prepared and bank-shaped adhesive layers are formed on respective major surfaces of the mother substrate to enclose the vibrating region, and mother sheets provided with plural cover sheets are arranged to cover both major surfaces of the mother substrate, thereby defining cavities for vibrating spaces. Then, protective resin members are applied to cover both major surfaces of the mother substrate, which in turn is divided to obtain a plurality of chip-type piezoelectric-resonators.

Abstract: A strip dual mode loop resonator includes a loop-shaped strip line having a pair of straight strip lines arranged in parallel, an electric length of the loop-shaped strip line being equivalent to a wavelength of a microwave circulated in the loop-shaped strip line in two different directions according to a characteristic impedance of the loop-shaped strip line, and the straight strip lines being coupled to each other in electromagnetic coupling to change the characteristic impedance of the loop-shaped strip line. The microwave is transferred from an input strip line to the loop-shaped strip line through electromagnetic field induced by the microwave. Thereafter, the microwave is reflected in the straight strip lines of the loop-shaped strip line to produce reflected microwaves circulated in opposite directions. Thereafter, the reflected waves are resonated and filtered in dual mode in the loop-shaped strip line.

Abstract: The invention relates to a coaxial resonator comprising an inner conductor (12) with walls defining therebetween a free space (24), and a housing portion (13) surrounding the inner conductor (12) and forming an outer conductor of the resonator. In order that connection to the inner conductor could be made very simply, the inner conductor (12) is made of sheet material in which slits (21; 33) extending in the direction of the inner conductor are made so that they form between them a tongue-like connecting part (22; 34) having its free end connected to a printed circuit board (11).

Abstract: A high Q multi-layer ceramic transmission line resonator (100) used for RF applications. The resonator (100) includes a plurality of strips (102) which are separated by a ceramic substrate (104). Each of the strips are interconnected using vias (110) passing through the ceramic substrate (104). The invention utilizes current manufacturing processes to fabricate an equivalent thick center conductor to effectively increase the Q factor. This allows for the resonator to be used in miniature RF communication devices utilized in high tier devices such as voltage controlled oscillators (VCOs) or integrated filter circuits.

Abstract: An illumination unit comprises an electrodeless low-pressure discharge-lamp and a high-frequency power supply unit. The lamp has a gastight closed discharge vessel with an ionizable fill and a coil with turns of a primary and a secondary winding around a core of soft-magnetic material. The power supply unit has input terminals, a first output terminal, electrically neutral with respect to ground, that is connected to a first end of the primary winding, and a further output terminal that is connected to a second end of the primary winding. During nominal lamp operation the primary winding excites a high-frequency magnetic field that maintains an electrical discharge in the discharge vessel and that induces in the secondary winding a potential drop in the direction of a first, with respect to the electrically neutral end, to a second free end that varies in a sense opposite to the potential drop from the first to the second end in the first winding.

Abstract: A filter operating with acoustical harmonic waves includes at least one resonator being formed of an interdigital converter and reflectors. An electrical resistor is connected parallel to at least one filter component for protecting against electrostatic discharge from contact with electrostatically charged parts. The electrical resistor is integrated with one or both of the reflectors of the resonator.

Abstract: A filter (500) including a first resonator (505) coupled in shunt with a first port (507), a first bridging network (510) coupled between the first port (507) and a first node (509), a second resonator (515) coupled in shunt with the first node (509) and a second port (547) coupled to the first node (509). The first (505) and second (515) resonators each include acoustic resonators (15) and the first bridging network (510) has an electrical length .THETA. at a frequency .omega. in a system having a characteristic admittance Y in accordance with .omega.C.sub.o =Ycot.THETA. where C.sub.o is a shunt capacitance including the clamping capacitance of the first resonator (505) and .omega. is a center frequency of the filter (500).

Abstract: A layered stripline filter has input and output electrodes formed on a dielectric layer, two resonant elements disposed on the dielectric layer and having ends connected to a ground electrode, providing a quarter-wave stripline resonator, an inductive coupling adjustment electrode disposed on the dielectric layer intermediate between the two resonant elements and having opposite ends connected to the ground electrode, and a coupling electrode disposed on the dielectric layer in overlapping relationship to portions of the two resonant elements. The layered stripline filter is small in size and has a desired bandwidth achieved by adjusting the inductive coupling between the two resonant elements. The layered stripline filter has an attenuation peak spaced from the passband thereof, resulting improved attenuation and spurious characteristics.

Abstract: A high-frequency signal transmission system for use as a microwave antenna or filter has a plurality of cascaded conical or planar inner conductors each having a unitary exponential gradient, a pair of circular lines or impedance-matching lines having identical dimensions and connected respectively to opposite ends of the conical or planar inner conductor for providing a predetermined characteristic impedance, and a cylindrical or rectangular tubular outer conductor covering the conical or planar inner conductor and the circular or impedance-matching lines with a cavity defined between the conical or planar inner conductor and the cylindrical or rectangular tubular outer conductor.

Abstract: A multi-mode piezoelectric filter includes a piezoelectric substrate made of a LiTaO.sub.3 single crystal, a plurality of spaced electrodes which are formed adjacently on a front major surface of the substrate, and a counter electrode which is formed on a rear major surface of the substrate in opposition to the spaced electrodes. The spaced electrodes and the counter electrode coact with the intervening portion of the substrate to form two or more energy trapped type multi-mode filter elements vibrating in the thickness shear mode such that the filter elements are coupled to form a cascade connection. Damping material such as silicone gel is applied at least on the filter elements.

Abstract: The present invention relates to a coupling element (21) by which the coupling of a resonator (24) is adjusted in a radio frequency filter. The coupling element of the invention is a strip made of flexible conductor material being shaped symmetrical relative to the normal, that is, the symmetry axis of the longitudinal axis extending via the centrepoint of the strip in the longitudinal direction. The strip (21) is fixed at least at two points of an edge in the longitudinal direction to the circuit board (25) either by surface mounting on pads (33, 35, 36) or by soldering into holes borred in the circuit board to be at appropriate space from the resonator coil (34) and from the surface of the circuit board (25). One (33) of the fixing points is grounded and another (36) is connected to the signal conductor in the filter. The coupling can easily be adjusted by bending the board relative to the symmetry axis either one-sidedly or on both sides.

Abstract: A method and apparatus for an acoustic wave filter (110) with reduced bulk-wave scattering loss and a ladder filter (30, 40) incorporating same. The method includes steps of providing an acoustic wave propagating substrate (111) and disposing a first reflector (112) on a first surface thereof. The method also includes disposing a first transducer (115) to a first side of the first reflector (112). The first transducer (115) is separated from the first reflector (112) by a first gap (118) having a first width (114) exceeding one-fourth of the acoustic wavelength. The method also includes disposing a second reflector (112') to a side of the first transducer (115) opposite the first reflector (112). The first (112) and second (112') reflectors each include a group of periodically disposed reflective elements (113, 113'). The second reflector (112') is separated from the first transducer (115) by a second gap (140) having a second width (139).