EP0609555A2
Expired / Lapsed
EP
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Frequency selective component and method
Assignee: Motorola Solutions Inc
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Filing: 1993-12-23
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Granted: —
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Expires: 2013-12-23
Abstract
Abstract A frequency selective component (201, 301) and a method for making a frequency selective component (201, 301). The frequency selective component (201, 301) includes a substrate (255) having at least a first surface and an acoustic impedance transformer (218) coupled to the substrate (255). The acoustic impedance transformer (218) transforms an acoustic impedance of the substrate (255) to a second acoustic impedance. The frequency selective component (201, 301) further includes a mechanical resonator (203, 301) disposed on the acoustic impedance transformer (218). The frequency selective component (201, 301) provides a frequency selection function. <IMAGE>
Inventors
- 👤 Lawrence N. Dworsky
- 👤 Luke C.B. Mang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 00:33
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/15; H03H9/17; H03H9/171; H03H9/172; H03H9/175
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
58 words
A frequency selective component (201, 301) comprising: a substrate (255) having a first surface; acoustic impedance transformer means (218) coupled to said substrate (255) for transforming an acoustic impedance of said substrate (255) to a second acoustic impedance; and acoustic resonator means (203, 301) disposed atop said acoustic impedance transformer means (218) for providing a frequency selection function.
Claim 2
Dependent Claim
28 words
A frequency selective component (201, 301) as claimed in claim 1, wherein said substrate (255) comprises a cubic material and said first surface comprises a {100} oriented surface.
Claim 3
Dependent Claim
19 words
A frequency selective component (201, 301) as claimed in claim 1, wherein said substrate (255) comprises a III-V material.
Claim 4
Dependent Claim
17 words
A frequency selective component (201, 301) as claimed in claim 1, wherein said substrate (255) comprises silicon.
Claim 5
Dependent Claim
79 words
A frequency selective component (201, 301) as claimed in claim 1, wherein said acoustic impedance transformer means (218) comprises: first layers (250, 215) one-fourth of an acoustic wavelength thick (251, 216), said first layers (250, 215) having a first acoustic impedance; second layers (220) one-fourth of said acoustic wavelength thick (221), said second layers having a second acoustic impedance; and wherein said first (250, 215) and second (220) layers are alternately disposed to form an acoustic impedance transformer (218).
Claim 6
Dependent Claim
54 words
A frequency selective component (201, 301) as claimed in claim 5, wherein said acoustic impedance transformer means (218) transforms a third acoustic impedance characterizing an interface between said acoustic impedance transformer means (218) and said substrate (255) to a fourth acoustic impedance, said fourth acoustic impedance approaching an acoustic impedance of a clamped surface.
Claim 7
Dependent Claim
36 words
A frequency selective component (201, 301) as claimed in claim 1, wherein said acoustic resonator means (203, 301) comprises an acoustic resonator (203, 301) one fourth of a first acoustic wavelength in thickness (211; 320, 320').
Claim 8
Dependent Claim
143 words
A frequency selective component (201, 301) as claimed in claim 7, wherein said acoustic resonator (203, 301) comprises: a first electrode (305') disposed atop said acoustic impedance transformer means (218), said first electrode (305') providing a first electrical contact; a first layer of piezoelectric material (310') disposed atop said first electrode (305'); a second electrode (305'') disposed atop said first layer of piezoelectric material (310'), said second electrode (305'') providing a second electrical contact; a second layer of piezoelectric material (310) disposed atop said second electrode (305''); a third electrode (305) disposed atop said second layer of piezoelectric material (310), said third electrode (305) providing a third electrical contact; and wherein said first (305'), second (305'') and third (305) electrodes and said first (310') and second (310) layers of piezoelectric material have a combined thickness (320, 320') of one-fourth of an acoustic wavelength.
Claim 9
Dependent Claim
54 words
A frequency selective component (301) as claimed in claim 8, wherein the position of the second electrode (305'') within the acoustic resonator (301) is such that a first motional capacitance between said first (305') and second (305'') electrodes is approximately equal to a second motional capacitance between said second (305'') and third (305) electrodes.
Claim 10
Independent Claim
60 words
A method for making an acoustic resonator (201, 301), the method comprising steps of: (a) providing a substrate material (255) having a first acoustic impedance; (b) disposing an acoustic reflector (218) on the substrate material (255); and (c) coupling a piezoelectric resonator (203, 301) one fourth of a first acoustic wavelength thick (211; 320. 320') to the acoustic reflector (218).
References Cited (Backward Citations)
No citation records indexed.
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