Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Elliptical surface acoustic wave filter

A surface acoustic wave and filter technology, applied in the field of filters, can solve the problems of limitation, deterioration of out-of-band suppression, and reduction of filter bandwidth, etc., to achieve the effect of increasing out-of-band suppression

Active Publication Date: 2020-04-17
天通瑞宏科技有限公司
View PDF6 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

image 3 The frequency response of the filter structure shown is Figure 4 As shown, it can be seen from the figure that this method reduces the width of the filter bandwidth is limited, and as the bandwidth is reduced, the out-of-band rejection is severely deteriorated

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Elliptical surface acoustic wave filter
  • Elliptical surface acoustic wave filter
  • Elliptical surface acoustic wave filter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0030] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the preferred embodiments of the present invention will be described below in conjunction with specific examples, but this should not be construed as a limitation of this patent.

[0031] The elliptic filter, also known as the Cauer filter, is a filter with ripples in the passband and stopband. Compared with other types of filters, elliptic filters have the smallest passband and stopband fluctuations under the condition of the same order. It has the same fluctuation in the passband and stopband, which is different from the Butterworth filter which is flat in the passband and stopband, and the passband is flat, the stopband is rippled or the stopband is flat, the passband is rippled Chebyshev filter.

[0032] The low-pass prototype transfer function of the elliptic filter is,

[0033]

[0034] where R n is the nth-order Jacobian elliptic function, ω o...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses an elliptical surface acoustic wave filter. The elliptic surface acoustic wave filter comprises at least four resonance units, a first resonance unit and a second resonance unit are connected in series, and a third resonance unit and a fourth resonance unit are connected in parallel between a reference potential point and a series point of the first resonance unit and the second resonance unit; the resonant frequencies of the third resonant unit and the fourth resonant unit are different; the circuit structures of the four (first to fourth) resonance units are the same;a circuit structure formed by all the resonance units satisfies a transfer function Gn(omega) of the elliptic filter. According to the elliptic surface acoustic wave filter, any relative filter bandwidth can be realized on a piezoelectric substrate with a high electromechanical coupling coefficient.

Description

technical field [0001] The invention relates to the technical field of filters, in particular to an elliptical surface acoustic wave filter. Background technique [0002] Traditional low-loss surface acoustic wave filters mostly use trapezoidal structures, such as figure 1 As shown, the filter of this ladder structure only includes two kinds of resonators, that is, the series arm resonant unit and the parallel arm resonant unit. Including two kinds of resonators Zs and Zp, first define the resonance frequency and anti-resonance frequency of the series resonator as frs and fap respectively, and the resonance frequency and anti-resonance frequency of the parallel resonator as frp and fap respectively. When fap≈frs, a band-pass filter whose center frequency is fap≈frs can be formed. In addition, the filter has two transmission zero points of f=fas and f=frp, which determine the passband edge of the filter. Its frequency response is as figure 2 As shown, the structure can a...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H03H9/64H03H9/145H03H9/02
CPCH03H9/64H03H9/145H03H9/02535
Inventor 王华磊周一峰廖庆嵩吴长春沈旭铭
Owner 天通瑞宏科技有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com