Surface acoustic wave filter and surface acoustic wave duplexer
View Patent ↗A surface acoustic wave filter which includes a first terminal at the input side, a second terminal at the output side, a plurality of resonators electrically connected between the first and the second terminals, and a piezoelectric substrate provided on the upper surfaces of first and second terminals and the plurality of resonators. The piezoelectric substrate is made to have a thickness that is not thicker than 0.2 mm. The filtering characteristic of surface acoustic wave filter can be improved by taking advantage of the above structure.
1. A surface acoustic wave filter comprising:
a first terminal;
a second terminal;
a resonator electrically connected between the first terminal and the second terminal; and
a piezoelectric substrate provided on the upper surfaces of the first terminal, the second terminal, and the resonator,
wherein a thickness of the piezoelectric substrate is not thinner than 0.075 mm and not thicker than 0.2 mm.
2. The surface acoustic wave filter of claim 1 , wherein
the piezoelectric substrate is mounted flip chip on a base substrate, and
the piezoelectric substrate is resin-sealed and packaged.
3. The surface acoustic wave filter of claim 1 , wherein
the piezoelectric substrate is formed of a material LiTaO 3 or LiNbO 3 .
4. The surface acoustic wave filter of claim 1 , wherein
a signal of 1800 MHz˜2300 MHz transits between the first terminal and the second terminal.
5. A surface acoustic wave duplexer comprising:
a transmitting terminal;
a receiving terminal;
an antenna terminal;
a first resonator electrically connected between the transmitting terminal and the antenna terminal;
a second resonator electrically connected between the receiving terminal and the antenna terminal; and
a piezoelectric substrate provided on the upper surfaces of the transmitting terminal, the receiving terminal, the antenna terminal, the first resonator, and the second resonator,
wherein a thickness of the piezoelectric substrate is not thinner than 0.075 mm and not thicker than 0.2 mm.
6. The surface acoustic wave duplexer of claim 5 , wherein
the piezoelectric substrate is mounted flip chip on a based substrate, and
the piezoelectric substrate is resin-sealed and packaged.
7. The surface acoustic wave duplexer of claim 5 , wherein
the piezoelectric substrate is made of a material LiTaO 3 or LiNbO 3 .
8. The surface acoustic wave duplexer of claim 5 , wherein
a signal of 1800 MHz˜2300 MHz transits between the antenna terminal and at least one of the transmitting terminal and the receiving terminal.