Abstract: The present invention relates to a microwave filter, having U-type resonators, which passes a desired frequency signal and removes an undesired frequency signal when used in a high frequency antenna circuit for wireless communication systems. In accordance with the trend of reducing communication system terminals, it is required to reduce a high frequency filter. The high frequency filter is required to attenuate signals very sharply at the stop band especially near to a passband transmitting and receiving frequency, so as to improve the efficiency of the frequency. The filter may be reduced in weight by forming U-type resonators instead of straight-type resonators. Excellent attenuation characteristics may be achieved at the stop band lower than the passband, using the difference of the characteristic impedance between the open end portion and the shorted portion of the resonator by forming the coupling control grooves at the outer walls of the dielectric block.

Abstract: A compound testing machine for testing mechanical properties used for an optical connector does not additionally have each testing machine for each of mechanical properties (such as a tensile force including both a straight pull and a side pull, a flex, a twist and an impact) in testing a mechanical property between optical connectors and other mechanical property between optical fibers of the optical connectors, and includes only one testing machine for simultaneously testing various mechanical properties in order to enhance a test machine's efficiency.

Abstract: A dielectric microwave filter includes a dielectric body, a trinity of first, second and third resonant slots, a pair of cavities for transmitting input/output signals, a pair of slits, and a trinity of first, second and third resonant holes. Each of the resonant slots (and an associated resonant hole in some embodiments) functions as a resonator having a quarter wavelength. Each of the slits modulates a coupling of electromagnetic fields among the resonant slots (and resonant holes if present). All surfaces of the dielectric microwave filter are completely covered with an electrically conducting material, except for front and top surfaces of the dielectric body. Since the resonators having a quarter wavelength may have reduced surface dimensions, the filter may accommodate associated surface input/output coupling cavities and also be more easily manufactured in a miniaturized structure.

Abstract: A material for microwave band devices used by the general people and in industrial electronic apparatuses is disclosed. Particularly, a magnetic ceramic composition for use in microwave devices, a magnetic ceramics for use in microwave devices and a preparation method therefore are disclosed, in which the saturation magnetization can be easily controlled, and a low ferri-magnetic resonance half line width and an acceptable curie temperature are ensured. The magnetic ceramic composition for microwave devices includes yttrium oxide (Y.sub.2 O.sub.3), iron oxide (Fe.sub.2 O.sub.3), tin oxide (SnO.sub.2), aluminum oxide (Al.sub.2 O.sub.3) and a calcium supply source. The magnetic ceramics for the microwave devices are manufactured by carrying out a forming and a sintering after mixing: yttrium oxide, iron oxide, tin oxide, aluminum oxide and calcium carbonate (or calcium oxide) based on a formula shown below.

Abstract: A duplexer having dual coupled line characteristics is disclosed. With a small number of resonators and without using an external device such as a chip inductor or a chip capacitor, the signals of the receiving frequency can be improvingly damped. The diameters of the transmitting terminal dielectric filter resonators and the receiving terminal dielectric filter resonators are not same, but their diameters at an open terminal and at a short circuit terminal are made different from each other so as to differentiate a coupling amount at the short circuit terminal from that at the open terminal. Further, the transmitting terminal filter resonators and the receiving terminal dielectric filter resonator are provided in a form of grooves, and sizes of the grooves near the open terminal are made different from those of the grooves near the short circuit terminal so as to differentiate a coupling amount of the resonators at the short circuit terminal from those at the open terminal.

Abstract: An improved multifiber optical connector is disclosed which concurrently transmits an optical signal and provides for optical signal transmission with a lower transmission loss.

Abstract: The present invention relates to a dielectric ceramic composition for microwave which consists of BaO, Sm.sub.2 O.sub.3, TiO.sub.2 and PbO, and has a compositional formula of x(Ba.sub.1-.alpha., Pb.sub..alpha.)O-- ySm.sub.2 O.sub.3 -zTiO.sub.2, wherein 6 mol % .ltoreq.x.ltoreq.20 mol %, 6 mol %.ltoreq.y.ltoreq.20 mol %, 60 mol %.ltoreq.z.ltoreq.75 mol % and 0 mol % .ltoreq..alpha..ltoreq.0.2 mol %. Accordingly, since the dielectric ceramic composition for microwave according to the present invention has the dielectric constant more than 85, the temperature factor of the resonant frequency within .+-.5 ppm/.degree.C., and the quality factor more than 6000 in 1 GHz, it can be utilized in the filter for microwave, the dielectric for the resonator, the laminated ceramic capacitor, the dielectric for the filter for electromagnetic wave obstacle and the dielectric for capacitor.

Abstract: A multifiber optical connector for optical ribbon cable which must be essentially used in the optical line that requires a repeated connection and separation to transfer or to interrupt simultaneously optical signals with low loss by attaching to an end of the optical ribbon cable arranged in a line. In order to overcome a difficulty of production technique and to constitute a suitable net, the optical cable consists of a short circuit which must be connected for the maintenance of the optical path, in which the optical cable must be very precisely connected so as to minimize a loss.

Abstract: A single core optical fiber connector is disclosed in which an optical signal transmitting line between optical fibers is maintained or short-circuited with a low power loss by utilizing a sectional contact of a single core optical fiber. An elastic deformation energy of a polymer material is utilized so as to achieve the sectional contact for minimizing the loss, and precisely machined alignment devices are utilized so as to reduce the misalignment between the optical fibers, thereby improving the assemblability and the economy. The optical fiber sections which are lightly ground on a grinding paper are contacted by using a precisely machined alignment device and by utilizing the elastic deformation energy of the elastic ferrule. This contact is maintained by a coupling between a specially designed plug and an adaptor, thereby forming a structure of an optical fiber connector and an alignment device.