# US 9,520,858 B2 · Communication device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,858 B2 - Document ID: US9520858B2 - Status: Granted - Kind: B2 - Application number: 14/475,724 - Filed: 2014-09-03 - Published: 2014-12-18 - Granted: 2016-12-13 - Earliest claimed: 2012-04-04 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Takashi Miyake; Koji Nosaka; Ryo Nakagawa; Haruki Kyouya - Web page: https://patentgrep.com/patent/US9520858B2 ## CPC - H03H 9/725: {Duplexers} - H01Q 1/50: Structural association of antennas with earthing switches, lead-in devices or lightning protectors - H03H 9/0038: {the balanced terminals being on the same side of the track} - H03H 9/542: {including passive elements (H03H9/545 takes precedence)} - H03H 9/703: {Networks using bulk acoustic wave devices} - H03H 9/706: {Duplexers} - H03H 9/72: Networks using surface acoustic waves - H04L 5/14: Two-way operation using the same type of signal, i.e. duplex - H03H 9/14576: {Transducers whereby only the last fingers have different characteristics with respect to the other fingers, e.g. different shape, thickness or material, split finger} - H04B 1/50: using different frequencies for the two directions of communication - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 2) 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. ### Claim 4 (depends on 1) The communication device according to claim 1, wherein the band elimination filter includes a ladder circuit. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 5) 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. ### Claim 7 (depends on 6) 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. ### Claim 8 (depends on 1) The communication device according to claim 1, wherein the first multiplexer includes a first transmission filter and a first reception filter. ### Claim 9 (depends on 8) The communication device according to claim 8, wherein the first transmission filter is connected to a first transmission terminal. ### Claim 10 (depends on 8) The communication device according to claim 8, wherein the first reception filter is connected to first and second reception terminals. ### Claim 11 (depends on 8) 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. ### Claim 12 (depends on 11) 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. ### Claim 13 (depends on 11) 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. ### Claim 14 (depends on 1) The communication device according to claim 1, wherein the bulk wave element includes a bulk wave resonator. ### Claim 15 (depends on 14) 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. ### Claim 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.