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A surface wave device

A surface wave device and filter technology, applied in electrical components, impedance networks, etc., can solve the problem of not considering the attenuation of low frequency bands, and achieve the effect of large attenuation

Active Publication Date: 2013-01-09
TAIYO YUDEN KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, in the surface wave filter of Patent Document 1, the amount of attenuation on the low-band side of the passband is not considered.
Therefore, according to the system using the surface wave filter of Patent Document 1, the amount of attenuation on the low-band side of the pass band becomes a problem

Method used

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  • A surface wave device
  • A surface wave device
  • A surface wave device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] image 3 It is a figure showing the structure of the surface wave device 30 of Example 1.

[0041] refer to image 3The surface wave device 30 includes a filter circuit 12, a first inductor L1, a second inductor L2, and a third inductor L3. The filter circuit 12 is connected between the antenna terminal 11 and the transmission signal terminal Tx. The first inductor L1 is connected in parallel with the filter circuit 12 between the antenna terminal 11 and the transmission signal terminal Tx. The second inductor L2 is connected in series with the first inductor L1 between the antenna terminal 11 and the transmission signal terminal Tx. The third inductor L3 is connected between the node between the first inductor L1 and the second inductor L2 and the ground GND. The first and third inductors L1 and L3 are used for impedance matching on the antenna terminal 11 side. The second and third inductors L2 and L3 are used for impedance matching on the transmission signal ter...

Embodiment 2

[0051] The structure of the surface wave device of embodiment 2 is to put image 3 The filter circuit 12 in is set as the DMS (Double Mode Surface Acoustic Wave) filter, and other structures are the same as image 3 Same as shown. Below, use the same image 3 The same reference numerals are used for description, and the description of each part is omitted.

[0052] Figure 6 and Figure 7 It is a graph showing the simulation results of the frequency characteristics of the surface wave device 30 of the second embodiment. In the simulation of Embodiment 2, the center frequency of the filter circuit 12 was set to 1880 Mhz. The inductance values ​​L1 to L3 of the first, second and third inductors L1 to L3 are set such that Lant is 10.0 nH and Ltx is 50.0 nH.

[0053] Figure 6 The solid line 50 and dashed lines 52 and 54 in (a) are simulation results of frequency characteristics based on combinations of inductance values ​​L1-L3 of the first, second and third inductors L1-L...

Embodiment 3

[0061] The structure of the surface wave device of embodiment 3 is that the filter circuit 12 is set as the same DMS filter as that of embodiment 2, and other structures are the same as image 3 Same as shown. Below, use the same image 3 The same reference numerals are used for description, and the description of each part is omitted.

[0062] Figure 8 It is a graph showing the simulation results of the frequency characteristics of the surface wave device 30 of the third embodiment. In the simulation of Embodiment 3, the center frequency of the filter circuit 12 was set to 1733 Mhz.

[0063] The inductance values ​​L1 to L3 of the first, second and third inductors L1 to L3 are set such that Lant is 6.00 nH and Ltx is 15.2 nH.

[0064] Figure 8 The solid line 60 and the dotted line 62 in Table 3 are the results of simulation of the frequency characteristics based on the combinations of inductance values ​​L1-L3 of the first, second and third inductors L1-L3 shown in Tab...

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Abstract

The invention discloses a surface wave device, which can ensure attenuation on both a high frequency band side and a low frequency band side of a frequency band are high. The surface wave device (30) in the invention comprises the following components: a first filter circuit (12), which is connected between a first terminal (11) and a second terminal (Tx); a first inductor (L1), which is connected with the first filter circuit (12) in parallel and then connected between the first terminal (11) and the second terminal (Tx); a second inductor (L2), which is connected with the first inductor (L1) and then connected between the first terminal (11) and the second terminal (Tx); and a third inductor (L3), which is connected between ground GND and node between the first terminal (11) and the second inductor (L2).

Description

technical field [0001] The present invention relates to surface wave devices. Background technique [0002] In recent years, along with the demand for miniaturization and weight reduction of mobile communication terminals such as mobile phones, miniaturization and weight reduction of components mounted on mobile communication terminals are also required. In addition, components having multiple functions are also required. Under such circumstances, a duplexer including a filter having a large amount of attenuation in frequency bands other than the pass band and a plurality of filter circuits has been developed. [0003] Patent Document 1 describes a surface wave filter in which an inductance element is provided between a common input and output terminal and the ground. Thereby, the steepness near the high frequency band side of the pass band can be improved. [0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2002-76838 [0005] However, in the surface...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03H9/64H03H9/72
Inventor 李铁
Owner TAIYO YUDEN KK