Abstract: A surface acoustic wave device has a high electromechanical coefficient and reflection coefficient, and also has an improved frequency-temperature characteristic that is achieved by forming a SiO2 film on an IDT so as to prevent cracking from occurring on a surface of the SiO2 film so that desired properties can be reliably obtained. The surface acoustic wave device includes at least one IDT, which is composed of a metal or an alloy having a density higher than that of Al and is formed on a 25° to 55° rotation-Y plate X propagation LiTaO3 substrate, and a SiO2 film disposed on the LiTaO3 substrate so as to cover the at least one IDT for improving the frequency-temperature characteristic.

Abstract: A package module includes a module case and an adapter case attached to the module case. The module case accommodates a circuit board, and the adapter is used for connecting an external connector. An opening at an end of the adapter case functions as an entry to receive the external connector. Another opening at the other end functions as a connection hole to be attached to the module case. A fit-receiving portion is mounted on the upper wall adjacent to the connection hole of the adapter case in such a way that a fit-receiving opening faces down. When the module case is moved upward relative to the adapter case, a fit projection is fit into a fit-receiving portion to connect the module case and the adapter case.

Abstract: A band-pass filter includes a metal film provided on a dielectric body. The shape and size of the metal film and the coupling points of input-output coupling circuits are selected such that first and second resonance modes are generated. The metal film has protruding portions or concavities provided thereon such that resonance electric field strength in the first or second resonance mode is controlled to couple the first and second resonance modes to each other.

Abstract: A multi-layer capacitor including a capacitor body having four sides including a first pair of opposed sides and a second pair of opposed sides, the capacitor body including a plurality of dielectric layers and at least a pair of first and second internal electrodes that oppose each other via one of the dielectric layers, the first internal electrode having first lead-out portions, the second internal electrode having second lead-out portions, the first and second lead-out portions being arranged to interdigitate with each other. The first polarity external electrode terminals are electrically connected to the first lead-out portions. At least one of the first polarity external electrode terminals is arranged on each of the first pair of opposed sides and at least one of the first polarity external electrode terminals being arranged on each of the second pair of opposed sides of the capacitor body. Second polarity external electrode terminals are electrically connected to the second lead-out portions.

Abstract: A piezoelectric resonator vibrates in a square vibration mode and includes a piezoelectric substrate having a first major surface and a second major surface, electrodes provided on the first major surface and the second major surface of the piezoelectric substrate and a groove provided in at least one of the first major surface and the second major surface of the piezoelectric substrate. The groove divides at least one of the electrodes into a plurality of areas such that the electrostatic capacitance of the resonator is changed by varying the position, the width and the depth of the groove provided on the piezoelectric substrate.

Abstract: A piezoelectric resonator adapted to generate a third harmonic wave of a thickness extensional vibration mode in which the fundamental wave is lead out of the vibrating portion and suppressed effectively. The piezoelectric resonator includes a vibrating portion with vibration electrodes opposing each other in the middle of a piezoelectric plate, lead-out electrodes electrically connected to the vibration electrodes, and a floating electrode disposed along the short side edge on at least one major surface of the piezoelectric plate or in the vicinity of the edge.