EP0836278B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Elastic surface wave filter device
Assignee: Murata Manufacturing Co Ltd
•
Filing: 1997-10-08
•
Granted: 2002-07-24
•
Expires: 2017-10-08
Abstract
No abstract record available.
Inventors
- 👤 Yutaka Tada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 22:57
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H9/42; H03H9/0023; H03H9/0028
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
451 words
An elastic surface acoustic wave filter apparatus (1; 11; 21; 31; 41; 51)
comprising: a first set of cascaded elastic surface acoustic wave filters (3b, 4; 34; 43b, 44))
including a first elastic surface acoustic wave filter (3b; 43b) having a
predetermined value of an input/output phase characteristic within a pass band
of said elastic surface acoustic wave filter apparatus (1; 11; 21; 31; 41; 51) and
a second elastic surface acoustic wave filter (4; 34; 44) having an input/output
phase characteristic that is different by about 180 degrees from said
predetermined value of the input/output phase characteristic of the first elastic
surface acoustic wave filter (3b; 43b) within the pass band of said elastic
surface acoustic wave filter apparatus (1; 11; 21; 31; 41; 51), said first and
second elastic surface acoustic wave filters (3b, 4; 34; 43b, 44) being
electrically connected to each other in a cascade arrangement such that said
first set of cascaded elastic surface acoustic wave filters (3b, 4; 34; 43b, 44) has
a pair of first input/output terminals (6, 7b) and a pair of second input/output
terminals (8, 9b, 18); and a second set of cascaded elastic surface acoustic wave filters (3a, 3c; 23c; 43a,
43c) including a third elastic surface acoustic wave filter (3a; 43a) having said
predetermined value of input/output phase characteristic within a pass band of
said elastic surface acoustic wave filter apparatus (1; 11; 21; 31; 41; 51) and a
fourth elastic surface acoustic wave filter (3c; 23c; 43c) having said
predetermined value of input/output phase characteristic within the pass band of
said elastic surface acoustic wave filter apparatus, said third and fourth elastic
surface acoustic wave filters (3a, 3c; 23c; 43a, 43c) being electrically connected
to each other in a cascade arrangement such that said second set of cascaded
elastic surface acoustic wave filters (3a, 3c; 23c; 43a, 43c) has a pair of third
input/output terminals (6, 7a) and a pair of fourth input/output terminals (8, 9a;
18); wherein said pair of first input/output terminals of said first set of cascaded elastic
surface acoustic wave filters (3b, 4; 34; 43b, 44) and said pair of third
input/output terminals of said second set of cascaded elastic surface acoustic
wave filters (3a, 3c; 23c; 43a, 43c) are electrically connected in parallel to
define an unbalanced input/output terminal (6) and a grounded terminal (7a,
7b), and said pair of second input/output terminals of said first set of cascaded
elastic surface acoustic wave filters (3b, 4) and said pair of fourth input/output
terminals of said second set of cascaded elastic surface acoustic wave filters
(3a, 3c; 23c, 43a, 43c) are electrically connected in series to define a pair of
balanced input/output terminals (9a, 9b).
Claim 2
Dependent Claim
29 words
The elastic surface acoustic wave filter apparatus according to claim 1, wherein
a series connection point (18) of said second input/output terminal and said
fourth input/output terminal is grounded.
Claim 3
Dependent Claim
148 words
The elastic surface acoustic wave filter apparatus according of claim 1 or claim
2, wherein each of said first and third elastic surface acoustic wave filter (3b,
3a; 43b, 43a) comprises an input IDT and a pair of output IDTs between which said
input IDT is interposed and each of said second and fourth elastic surface acoustic wave
filters (4, 3c; 44, 43c) comprises an output IDT and a pair of input IDTs
between which said output IDT, and said output IDT of the second elastic surface
acoustic wave filter (4; 44) is configured in the opposite orientation to said input IDT
of said first elastic surface acoustic wave filter (3b; 43b)
and said input IDTs of the second elastic
surface acoustic wave filter (4; 44) are configured in the same orientation as that of
said output IDTs of said first elastic surface acoustic wave filter (3b; 43b).
Claim 4
Dependent Claim
134 words
The elastic surface acoustic wave filter apparatus according to claim 1 or claim
2, wherein each of said first and third elastic surface acoustic wave filters
comprises an input IDT and a pair of output IDTs between which said input IDT and is interposed
each of said second and fourth elastic surface acoustic wave filters comprises
an output IDT and a pair of input IDTs between which said output IDT is interposed, and said
output IDT of the second elastic surface acoustic wave filter is configured in the
same orientation as that of said input IDT of said first elastic surface acoustic
wave filter and said input
IDTs of the second elastic surface acoustic wave filter are
configured in the opposite orientation to said output IDTs of said first elastic surface acoustic wave
filter.
Claim 5
Dependent Claim
130 words
The elastic surface acoustic wave filter apparatus according to claim 1 or claim
2, wherein each of said first and third elastic surface acoustic wave filters (3b,
3a) comprises an input IDT and a pair of output IDTs between which said input IDT is interposed
and each of said second and fourth elastic surface acoustic wave filters (3c, 34),
comprises an output IDT and a pair of input IDTs between which said output IDT is interposed,
and said second elastic surface acoustic wave filter (34) has a spacing between
an electrode finger of one of its input IDTs and an electrode finger of its output
IDT that is different by a multiple of any integer plus about 0.5 wavelength from
that of said first elastic surface acoustic wave filter (3b).
Claim 6
Dependent Claim
53 words
The elastic surface acoustic wave filter apparatus according to claim 3 or claim
4, wherein said pair of balanced input/output terminals (9a, 9b) are connected to
respective electrodes of said output IDTs of said second and fourth elastic
surface acoustic wave filters (4, 23c), respectively, which have the same
number of electrode fingers.
Claim 7
Dependent Claim
53 words
The elastic surface acoustic wave filter apparatus according to claim 3 or claim
4, wherein said input IDTs of said first and third elastic surface acoustic wave
filters (43b, 43a) and said output IDTs of said second and fourth elastic surface
acoustic wave filters (44, 43c) have an even number of electrode fingers.
Claim 8
Dependent Claim
150 words
The elastic surface acoustic wave filter apparatus according or claim 1 or claim
2, wherein each of said second and fourth elastic surface acoustic wave filters
(4, 3c; 44; 43c) comprises an input IDT and a pair of output IDTs between which
said input IDT is interposed and each of said first and third elastic surface acoustic wave
filters (3b, 3a; 43b, 43a) comprises an output IDT and a pair of input IDTs
between which said output IDT is interposed; and said input IDT of the second elastic surface
acoustic wave filter (4; 44) is configured in the opposite orientation to said output IDT
of said first elastic surface acoustic wave filter (3b; 43b)
and said output IDTs of the second elastic
surface acoustic wave filter (4; 44) are configured in the same orientation as that of
said input IDTs of said first elastic surface acoustic wave filter (3b; 43b).
Claim 9
Dependent Claim
134 words
The elastic surface acoustic wave filter apparatus according to claim 1 or claim
2, wherein each of said second and fourth elastic surface acoustic wave filters
comprises an input IDT and a pair of output IDTs between which said input IDT is interposed and
each of said first and third elastic surface acoustic wave filters comprises an
output IDT and a pair of input IDTs between which said output IDT is interposed, and said input
IDT of the second elastic surface acoustic wave filter is configured in the same
orientation as that of said output IDT of said first elastic surface acoustic wave
filter and said output IDTs of
the second elastic surface acoustic wave filter are configured in the opposite orientation
to said input IDTs of said first elastic surface acoustic wave filter.
Claim 10
Dependent Claim
130 words
The elastic surface acoustic wave filter apparatus according to claim 1 or claim
2, wherein each of said second and fourth elastic surface acoustic wave filters
(3c, 34) comprises an input IDT and a pair of output IDTs between which said input
IDT is interposed and each of said first and third elastic surface acoustic wave filters (3b, 3a)
comprises an output IDT and a pair of input IDTs between which said output IDT is interposed,
and said second elastic surface acoustic wave filter (34) has a spacing between
an electrode finger of its input IDT and an electrode finger of one of its output
IDTs that is different by a multiple of any integer plus about 0.5 wavelength from
that of said first elastic surface acoustic wave filter (3b).
Claim 11
Dependent Claim
53 words
The elastic surface acoustic wave filter apparatus according to claim 8 or claim
9, wherein said pair of balanced input/output terminals (9a, 9b) are connected to
respective electrodes of said input IDTs of said second and fourth elastic
surface acoustic wave filters (4, 23c), respectively, which have the same
number of electrode fingers.
Claim 12
Dependent Claim
53 words
The elastic surface acoustic wave filter apparatus according to claim 8 or claim
9, wherein said output IDTs of said first and third elastic surface acoustic wave
filters (43b, 43a) and said input IDTs of said second and fourth elastic surface
acoustic wave filters (44, 43c) have an even number of electrode fingers.
References Cited (Backward Citations)
US5365138A
Cited
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