WAVE SEPARATOR

• US 20180262178A1
• Filed: 05/11/2018
• Published: 09/13/2018
• Est. Priority Date: 06/30/2015
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: NAKAMURA, Soichi
• Granted Patent: US 10,447,241 B2
• Time in Patent Office: Days
• CPC Class Codes: H03H 9/0009 using surface acoustic wave devices
• CPC Class Codes: H03H 9/0566 for duplexers
• CPC Class Codes: H03H 9/059 consisting of mounting pads or bumps
• CPC Class Codes: H03H 9/1064 for surface acoustic wave [SAW] devices
• CPC Class Codes: H03H 9/14541 Multilayer finger or busbar electrode
• CPC Class Codes: H03H 9/14552 comprising split fingers
• CPC Class Codes: H03H 9/14597 Matching SAW transducers to external electrical circuits
• CPC Class Codes: H03H 9/25 Constructional features of resonators using surface acoustic waves devices for manipulating acoustic surface waves in general G10K11/36
• CPC Class Codes: H03H 9/6436 having one acoustic track only
• CPC Class Codes: H03H 9/6483 Ladder SAW filters
• CPC Class Codes: H03H 9/706 Duplexers
• CPC Class Codes: H03H 9/725 Duplexers
• CPC Class Codes: H04B 1/0057 using diplexing or multiplexing filters for selecting the desired band

Abstract

A wave separator includes an n number (n being a natural number of 3 or larger) of band pass filters having an n number or larger of mutually different pass bands, and a common terminal. For a first of the band pass filters that is one of a band pass filter having a center frequency of a pass band at a lowest side and a band pass filter having a center frequency of a pass band at a highest side and that has a larger or equal difference in a center frequency of a pass band from an adjacent band pass filter as compared with the other band pass filter satisfies a predetermined configuration for a second band pass filter having a pass band adjacent to the first band pass filter.

Claims

1. A wave separator comprising:

an n number of band pass filters including an n number or larger of mutually different pass bands where n is a natural number of 3 or larger; and

a common terminal commonly provided for the n number of band pass filters;

wherein

at least one of the n number of band pass filters includes a surface acoustic wave filter or a bulk acoustic wave filter;

among the n number of band pass filters, for a first band pass filter that is one of a band pass filter having a center frequency of a pass band at a lowest side and a band pass filter having a center frequency of a pass band at a highest side and that has a larger or equal difference in a center frequency of a pass band from an adjacent band pass filter as compared with the other of the lowest side band pass filter and the highest side band pass filter and a band pass filter adjacent thereto, when f(1) is a center frequency of a pass band and B(1) is a susceptance value with the center frequency viewed from the common terminal; and

among the n number of band pass filters, for a second band pass filter having a pass band adjacent to the first band pass filter, when f(2) is a center frequency of a pass band and B(2) is a susceptance value with the center frequency viewed from the common terminal;

the first band pass filter satisfies one of a configuration (i) and a configuration (ii) for the second band pass filter as follows;

(i) B(2)×

{2×

f(2)−

f(1)}/f(1)<

B(1)<

B(2) if the first band pass filter is the band pass filter at the highest side; and

(ii) B(2)<

B(1)<

B(2)×

{2×

f(2)−

f(1)}/f(1) if the first band pass filter is the band pass filter at the lowest side.

2. The wave separator according to claim 1, wherein

among the n number of band pass filters, for a k-th (2≤

k≤

n) band pass filter, when f(k) is a center frequency of a pass band, and B(k) is a susceptance value with the center frequency viewed from the common terminal;

the first band pass filter satisfies one of a configuration (iii) and a configuration (iv) for each of the second to n-th band pass filters as follows;

(iii) B(k)×

{2×

f(k)−

f(1)}/f(1)<

B(1)<

B(k) if the first band pass filter is the band pass filter at the highest side; and

(iv) B(k)<

B(1)<

B(k)×

{2×

f(k)−

f(1)}/f(1) if the first band pass filter is the band pass filter at the lowest side.

3. The wave separator according to claim 1, wherein the first band pass filter is an elastic wave filter including a series arm resonator connected to the common terminal.

4. The wave separator according to claim 3, wherein the first band pass filter further includes a parallel arm resonator connected between one of nodes of the series arm resonator and a reference terminal.

5. The wave separator according to claim 1, further comprising:

a matching circuit connected to the common terminal;

wherein

the first band pass filter satisfies one of the configuration (i) and the configuration (ii) for the second band pass filter without matching by the matching circuit.

6. The wave separator according to claim 5, wherein

the matching circuit includes an inductor including a first end connected to the common terminal and a second end connected to the reference terminal;

the inductor is embedded in a multilayer substrate; and

the n number of band pass filters are mounted on the multilayer substrate.

7. The wave separator according to claim 1, wherein the wave separator is a multiplexer.

8. The wave separator according to claim 1, wherein the wave separator is a quadplexer.

9. The wave separator according to claim 1, further comprising an antenna and an inductor connected to the common terminal.

10. The wave separator according to claim 1, wherein each of the n number of band pass filters includes surface acoustic wave filters or bulk acoustic wave filters.

11. The wave separator according to claim 1, wherein each of the n number of band pass filters includes a chip inductor and a chip capacitor.

12. The wave separator according to claim 1, wherein each of the n number of band pass filters includes series arm resonators, a parallel arm resonator, and a longitudinally coupled filter.

13. The wave separator according to claim 3, wherein the series arm resonator is directly connected to the common terminal with no elements interposed therebetween.

14. The wave separator according to claim 12, wherein the parallel arm resonator is located between one of nodes of one of the series arm resonators and a reference terminal.

15. The wave separator according to claim 1, wherein the wave separator is a multiplexer including a matching circuit.

16. The wave separator according to claim 15, wherein the multiplexer includes a multilayer substrate including therein the matching circuit.

17. The wave separator according to claim 16, wherein the n number of band pass filters are piezoelectric chips mounted on the multilayer substrate.

18. The wave separator according to claim 17, further comprising a sealing resin provided to seal the n number of band pass filters on the multilayer substrate.

19. The wave separator according to claim 1, wherein the n number of band pass filters are reception side filters that filter a reception wave input from the common terminal.

20. The wave separator according to claim 1, further comprising:

a matching circuit connected to the common terminal;

wherein

the matching circuit includes an inductor including a first end connected to the common terminal and a second end connected to ground, and a capacitor connected in series between an antenna and the common terminal.

21. The wave separator according to claim 15, wherein the multiplexer is applied to Band2 and Band4.

22. The wave separator according to claim 15, wherein the multiplexer is applied to Band2, Band4, and Band30.

23. The wave separator according to claim 15, wherein the multiplexer is applied to Band1 and Band3.

24. The wave separator according to claim 15, wherein the multiplexer is applied to Band1, Band3, and Band1.

25. The wave separator according to claim 1, wherein the wave separator is a hexplexer.