A high-frequency module has a structure wherein transmitting filters, receiving filters and high-frequency power amplifiers are mounted on a multilayered substrate and wherein matching circuits are inserted between input terminals of the receiving filters and output terminals of the transmitting filters. Transmission lines as components of the matching circuits, and the like are formed internally of the multilayered substrate. Thus, the whole body of the high-frequency module can be downsized.

High-frequency module and communication apparatus

A surface acoustic wave device includes a piezoelectric substrate having a first surface on which comb-like electrodes, first pads connected thereto, and a first film are provided. The first film is located so as to surround the comb-like electrodes. A base substrate has a second surface on which second pads joined to the first pads and a second film joined to the first film are provided. The first and second films joined by a surface activation process define a cavity in which the comb-like electrodes and the first and second pads are hermetically sealed.

Surface acoustic wave device and method of fabricating the same

A second substrate 21 composed of a material having a lower dielectric constant than that of a piezoelectric substrate 2 having a transmission-side filter region 12 and a receiving-side filter region 13 formed therein is joined to the other main surface of the piezoelectric substrate 2, and a conductor layer 22 is formed throughout the other main surface of the second substrate 21. The effective dielectric constant of the substrate is reduced, thereby making it possible to reduce a parasitic capacitance formed between an input electrode section 5 in the transmission-side filter region 12 and an output electrode section 6 in the receiving-side filter region 13 and to improve isolation characteristics.

Surface acoustic wave device, surface acoustic wave apparatus, and communications equipment

In a surface acoustic wave device according to the present invention, a transmitting filter element TX and a receiving filter element RX are formed on one main surface of a piezoelectric substrate 300 , and are mounted by face down on an upper surface of a circuit board 200 . A ground electrode 322 in the receiving filter element RX is connected to three linear via conductors 221 ′ formed on the circuit board 200 , and a ground electrode 312 in the transmitting filter element TX is connected to a crank-shaped via conductor 211 ′ formed on the circuit board 200.

Surface acoustic wave device and communication apparatus

A SAW-filter device includes a piezoelectric substrate carrying thereon a first interdigital electrode pair connected to an input terminal and a second interdigital electrode pair connected to an output terminal. The first interdigital electrode pair is grounded to a first ground pad, while the second interdigital electrode pair is grounded to a second ground pad different from the first ground pad. The piezoelectric substrate is accommodated into a space formed in a package body, wherein the space is covered by a metal cap member connected to one of the first and second ground pads.

Surface-acoustic-wave filter having an improved suppression outside a pass-band

PURPOSE:To obtain a steep shoulder characteristic and to design freely a desired group delay characteristic by providing a weighted apodized electrode formed to an input side and a tilt electrode finger formed to an output side to the device. CONSTITUTION:A surface acoustic wave stimulated by an input side weighted apodized electrode 2 is propagate from a position A to a position B and the surface acoustic wave propagated in the direction B is transduced again into an electric signal at the output side tilt electrode finger 8 through a shield electrode 4. The surface acoustic wave passing through the tilt electrode finger 8 is attenuated by a sound absorbing agent 6 coated to an end face. Then the propagated surface acoustic wave depends on number of electrode fingers and in the case of the tilt electrode finger at the output side, the characteristic results from multiplication of frequencies equivalent to pitches of each split electrode thereby realizing the broad band characteristic, resulting that a steep shoulder characteristic is realized by the characteristic of the weighted apodized electrode 2.

Yamamoto Yoshiaki

Papers

Surface acoustic wave device