Communication device
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.
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.