Filter, duplexer, high-frequency front-end circuit and communication device

A technology of filters and acoustic resonators, which is applied in the fields of high-frequency front-end circuits and communication devices, duplexers, and filters. loss of characteristics, the effect of increasing design flexibility

Active Publication Date: 2020-05-26
ROFS MICROSYST TIANJIN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitation of the Q value of LTCC, its performance in insertion loss, out-of-band rejection and roll-off is average; at the same time, due to the existence of sidewall inductance (lead-Inductor), LTCC has poor far-band rejection characteristics

Method used

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  • Filter, duplexer, high-frequency front-end circuit and communication device
  • Filter, duplexer, high-frequency front-end circuit and communication device
  • Filter, duplexer, high-frequency front-end circuit and communication device

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Embodiment Construction

[0049] Figure 1a is the electrical symbol of a piezoelectric acoustic resonator, Figure 1b is its equivalent electrical model diagram, without considering the loss item, the electrical model is simplified to a resonant circuit composed of Lm, Cm and C0. According to the resonance condition, there are two resonant frequency points in the resonant circuit: one is fs when the impedance value of the resonant circuit reaches a minimum value, and fs is defined as the series resonant frequency point of the resonator; the other is when the impedance value of the resonant circuit When fp reaches the maximum value, fp is defined as the parallel resonant frequency of the resonator. in,

[0050]

[0051] And, fs is smaller than fp; at the same time, the effective electromechanical coupling coefficient Kt of the resonator is defined 2 eff (hereinafter abbreviated as Kt 2 ), which can be represented by fs and fp:

[0052]

[0053] figure 2 is the relationship between the reson...

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Abstract

The invention relates to the technical field of filters, and in particular relates to a filter, a duplexer, a high-frequency front-end circuit and a communication device. The filter comprises a firstseries branch and a plurality of parallel branches which are located between the input end and the output end of the filter; one end of the parallel branch is located on the first series branch, and the other end of the parallel branch is grounded; the filter further comprises at least one second series branch located between the input end and the output end of the filter, and the second series branch comprises an inductor; for a whole formed by the first series branch and the second series branch, at least one acoustic wave resonator exists in the whole, and the acoustic wave resonator is connected with the inductor in the series branch where the acoustic wave resonator is located in series. According to the filter provided by the technical scheme, the roll-off characteristic of the filter is improved; the insertion loss characteristic near the series resonance frequency point of the resonator is reduced; and the far-band suppression characteristic of the filter is improved.

Description

technical field [0001] The present invention relates to the technical field of filters, in particular to a filter, a duplexer, a high-frequency front-end circuit and a communication device. Background technique [0002] With the development of wireless communication applications, people have higher and higher requirements for data transmission rate. Corresponding to the data transmission rate is the high utilization rate of spectrum resources and the complexity of spectrum. The complexity of the communication protocol puts forward strict requirements on the various performances of the RF system. In the RF front-end module, the RF filter plays a vital role. It can filter out-of-band interference and noise to meet the requirements of the RF system and The requirements of the communication protocol for the signal-to-noise ratio. [0003] RF filters are mainly used in wireless communication systems, for example, RF front-ends of base stations, mobile phones, computers, satellit...

Claims

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Application Information

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IPC IPC(8): H03H9/70H03H9/54
CPCH03H9/54H03H9/706
Inventor 庞慰边子鹏
Owner ROFS MICROSYST TIANJIN CO LTD
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