Communication device

Patent metadata

Field	Value
Publication number	US-9520858-B2
Application number	US-201414475724-A
Country	US
Kind code	B2
Filing date	Sep 3, 2014
Priority date	Apr 4, 2012
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A communication device is provided with a band elimination filter that has one end connected to an antenna terminal, and a first multiplexer that is connected to the other end of the band elimination filter. The band elimination filter is configured to eliminate signals of a frequency band that is different from the frequencies of signals transmitted and received in the first multiplexer, and is configured from a filter circuit that includes a bulk wave element.

First claim

What is claimed is:

1. A communication device that is configured to perform transmission and reception at the same time in a plurality of frequency bands, the communication device comprising:
an antenna terminal connected to an antenna;
a band elimination filter including a first end connected to the antenna terminal and second end; and
a first multiplexer connected to the second end of the band elimination filter; wherein
the band elimination filter is configured to eliminate signals of a frequency band that is different from a frequency of signals transmitted and received in the first multiplexer, and the band elimination filter is configured from a filter circuit that includes a bulk wave element; and
the first multiplexer includes a filter circuit that includes an elastic wave element.

2. The communication device according to claim 1 , wherein the band elimination filter includes a plurality of serial arm resonators and a plurality of parallel arm resonators.

3. The communication device according to claim 2 , wherein the serial arm resonators and the parallel arm resonators are each configured from a bulk acoustic wave resonator.

4. The communication device according to claim 1 , wherein the band elimination filter includes a ladder circuit.

5. The communication device according to claim 1 , further comprising a second multiplexer that is connected to the antenna terminal and is configured to transmit and receive signals of a frequency band that is different from that of the first multiplexer.

6. The communication device according to claim 5 , wherein a stop frequency band of the band elimination filter includes at least a portion of a transmission band of the second multiplexer.

7. The communication device according to claim 6 , wherein the transmission band of the second multiplexer is included within the stop frequency band of the band elimination filter.

8. The communication device according to claim 1 , wherein the first multiplexer includes a first transmission filter and a first reception filter.

9. The communication device according to claim 8 , wherein the first transmission filter is connected to a first transmission terminal.

10. The communication device according to claim 8 , wherein the first reception filter is connected to first and second reception terminals.

11. The communication device according to claim 8 , wherein the first reception filter includes first, second and third 3-IDT longitudinally coupled resonator-type surface acoustic wave filters.

12. The communication device according to claim 11 , wherein input terminals of the first, second and third longitudinally coupled resonator-type surface acoustic wave filters are connected in common, and are connected to an unbalanced signal terminal via a 1-port-type surface acoustic wave resonator.

13. The communication device according to claim 11 , wherein the first, second and third longitudinally coupled resonator-type surface acoustic wave filters include first, second and third IDTs arranged in a propagation direction of surface acoustic waves and a plurality of reflectors.

14. The communication device according to claim 1 , wherein the bulk wave element includes a bulk wave resonator.

15. The communication device according to claim 14 , wherein the bulk wave element includes a piezoelectric layer and excitation electrodes provided on both surfaces of the piezoelectric layer.

16. A communication device that is configured to perform transmission and reception at the same time in a plurality of frequency bands, the communication device comprising:
an antenna terminal connected to an antenna;
a band elimination filter including a first end connected to the antenna terminal and second end; and
a first multiplexer connected to the second end of the band elimination filter; wherein
the band elimination filter is configured to eliminate signals of a frequency band that is different from a frequency of signal transmitted and received in the first multiplexer, and the band elimination filter is configured from a filter circuit that includes a bulk wave element;
the first multiplexer includes a first transmission filter and a reception filter; and
the first reception filter includes a balanced longitudinally coupled resonator-type surface acoustic wave filter.

Assignees

• Murata Manufacturing Co

Inventors

• Miyake Takashi
• Nosaka Koji
• Nakagawa Ryo
• Kyouya Haruki

Classifications

• H03H9/706

  Duplexers · CPC title

• H04L5/14

  Two-way operation using the same type of signal, i.e. duplex · CPC title

• H01Q1/50

  Structural association of antennas with earthing switches, lead-in devices or lightning protectors · CPC title

• H03H9/14576

  Transducers whereby only the last fingers have different characteristics with respect to the other fingers, e.g. different shape, thickness or material, split finger · CPC title

• H04B1/50

  using different frequencies for the two directions of communication · CPC title