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Surface acoustic wave filter with 21.4 MHz surface-mounted packaging fan-shaped structure

A sound surface filter, fan-shaped structure technology, applied in the direction of electrical components, impedance network, etc., to enhance the anti-interference effect, improve the effect of signal-to-noise ratio

Pending Publication Date: 2021-11-23
CHINA ELECTRONICS TECH GRP NO 26 RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After consulting domestic and foreign literature, it has not been found that thick-sheet LiNO 3 (Niobium niobate) 128°Y-X cut fan-shaped structure design 21.4MHz, surface mount package SMD1965 SAW device

Method used

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  • Surface acoustic wave filter with 21.4 MHz surface-mounted packaging fan-shaped structure
  • Surface acoustic wave filter with 21.4 MHz surface-mounted packaging fan-shaped structure
  • Surface acoustic wave filter with 21.4 MHz surface-mounted packaging fan-shaped structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In this embodiment, a SAW filter with a 21.4MHz surface-mount package fan-shaped structure is proposed, such as figure 1 , including the use of 128° niobium niobate cutting type, the size of the crystal garden substrate is Φ (diameter) 100mm × 0.75 (thickness) mm, and the roughness is 120#. The input and output interdigital transducers designed and manufactured on this crystal garden , shielding strips, sound-absorbing glue.

[0022] Such as figure 2 , the peripheral circuit designed by the device of the present invention, L1 and L2 are the series inductance and resistance of the circuit, and C1 and C2 are the associated capacitance of the circuit.

[0023] In this embodiment, the structure of the transducer I is shown in Table 1. The substrate material is 128°-LN niobate niobate, the film material is AL, the film thickness is 500nm, and the number of transducer segments is three. The number of cascaded devices is 3-1-3, and the duty cycle (in one cycle, the ratio of...

Embodiment 2

[0027] The index of the filter prepared according to the embodiment is shown in Table 2, and Table 3 further illustrates the properties of the transducer with structures such as 128°-LN niobate in Example 1, the film material is AL, and the film thickness is 500nm. .

[0028] Table 1 filter index

[0029]

[0030] Table 3 Substrate material characteristic parameters

[0031]

[0032] Figure 4 For the overall structure of the sound surface filter of the present invention, the sound-absorbing glue 1 is arranged on the end face of the input transducer, and the output transducer and the output transducer are interdigitated transducer 3 as shown in the figure, which is a fan-shaped fork with a narrow top and a wide bottom. Finger transducers, a solid shielding strip 4 with a wide top and a narrow bottom is arranged in the middle of the two forked transducers. The end faces of the input and output interdigital transducers are provided with sound-absorbing glue 2, and the in...

Embodiment 3

[0034] In this embodiment, when gluing the SAW filter, a rectangular gluing area is selected when gluing the outside of the input transducer and the output transducer, and the isosceles trapezoidal transducer is not glued after gluing Partially form a right-angled trapezoidal structure, and test the SAW filter after gluing, when large ripples appear at the low end of the SAW filter frequency response diagram, apply glue to the narrower end of the shielding strip; If large ripples appear at the high end of the response diagram, apply glue to the wider end of the shielding strip.

[0035] Such as image 3 , giving a schematic diagram of the present invention and the traditional gluing method. In the traditional method, gluing is generally applied to the left and right end faces of the SAW filter, and the gluing method is to apply gluing along the two end faces, while the present invention adopts Half-covering method, that is, as shown in the figure, the gluing area is a rectang...

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Abstract

The invention belongs to the technical field of surface acoustic waves, and particularly relates to a surface acoustic wave filter with a 21.4 MHz surface-mounted packaging fan-shaped structure. The surface acoustic wave filter comprises an input transducer, a shielding strip and an output transducer, the shielding strip is arranged between the input transducer and the output transducer, and the two end faces of the surface acoustic wave filter are coated with sound absorption glue. The shielding strip is solid, and the coating material is an aluminum structure with a narrow upper part and a wide lower part; The invention provides a high-reliability surface acoustic wave filter which has the advantages of short-band radio station, frequency of 21.4 MHz, relative bandwidth of about 4%-25%, high rectangularity, low sidelobe, low delay, power resistance and the like. The device solves the problem of broadband filtering in the communication field, realizes low-sidelobe signal purification, improves the signal-to-noise ratio, and enhances the anti-interference effect.

Description

technical field [0001] The invention belongs to the field of acoustic surface technology, and in particular relates to a 21.4MHz surface-mount package fan-shaped SAW filter. Background technique [0002] Now, whether in military or civilian fields, shortwave radio stations, wireless transmitters, and receivers are widely used in different bandwidths at 21.4MHz, and the market’s frequency signal bandwidth ranges from 4% to 25%. SAW filters with good ripple and small group delay fluctuation are in great demand. Filters are now designed at this frequency point, and crystal filters are generally used, but the volume of crystal filters is relatively large. The design of the traditional SAW filter generally adopts the pin-type shell, and the volume is also relatively large. But the broadband of signal bandwidth 4% to about 25%, high rectangularity, low sidelobe, low delay time resistance power, adopt the 21.4MHz SAW filter of high reliability of surface-mounted package to have no...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H9/64H03H3/08H03H9/02
CPCH03H9/64H03H3/08H03H9/02559
Inventor 张显洪蒋道军张晟
Owner CHINA ELECTRONICS TECH GRP NO 26 RES INST