Wave demultiplexer

Abstract

A compact elastic wave duplexer is provided. The elastic wave duplexer includes a transmission filter chip and a reception filter chip mounted on a laminated board. An impedance matching circuit is formed inside the laminated board. The isolation characteristics in a transmission band and a reception band are improved. The balance between the two is improved. The elastic wave duplexer (1) includes a transmission filter chip (6) and a reception filter chip (7) each formed from an elastic wave filter chip and flip-chip bonded to a laminated board (43). A coil-shaped line including coil-shaped line patterns (52, 54, and 56) is formed inside the laminated board (43). The coil-shaped line serves as an impedance matching circuit. In plan view, the transmission filter chip (6) is disposed on one side of a center line (X) passing through the center of the laminated board (43) and extending between a first edge (43A) and a second edge (43B), and the reception filter chip (7) is disposed on the other side. The coil-shaped line is disposed on the side on which the reception filter chip (7) is disposed.

Description

technical field [0001] The present invention relates to an elastic wave duplexer using an elastic wave filter such as a surface acoustic wave filter or a boundary acoustic wave filter, and more specifically, to a multilayer substrate having a facedown method, flip-chip (flip chip) An elastic wave duplexer with a structure in which a transmit side filter chip and a receive side filter chip are soldered. Background technique [0002] In order to promote miniaturization, mobile communication devices such as mobile phones require composite electronic components that are formed by integrating a plurality of electronic components. In order to meet such demands, conventionally, a demultiplexer configured by integrating a transmission-side filter and a reception-side filter connected to an antenna terminal has been widely used. In addition, conventionally, surface acoustic wave filters utilizing surface acoustic waves have been widely used in the reception-side filter and transmiss...

AI Technical Summary

Problems solved by technology

[0017] However, when a coiled line pattern is formed on a laminated substrate, electromagnetic coupling occurs between the coiled line pattern and the transmission side filter or reception side filter, and the isolation characteristic may deteriorate.

In particular, if electromagnetic coupling occurs between the transmission-side filter and the coiled line pattern, there is a problem that the isolation characteristic deteriorates.

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