Broadband and low-fluctuation band-pass LC filter

An LC filter and low fluctuation technology, applied in the field of filters, can solve the problems of increased insertion loss, difficulty in realization, and inability to guarantee various parameters of SAW filters, and achieve high rectangularity and low insertion loss. Effect

CN104883152AActive Publication Date: 2015-09-02北京中科飞鸿科技股份有限公司
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-09-02

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Abstract

The invention provides a broadband and low-fluctuation band-pass LC filter. According to the filter, ordinary inductors are replaced by winding magnetic rings with small temperature drift, good stability, and high Q value, and 0805 packaging capacitors are employed so that the stability of electrical parameters is guaranteed, and the electrical performance index of the filter is greatly increased. Penetrating holes are arranged at four corners around a PCB so that input, output, and grounding signals can all be perfectly transmitted to the PCB and components. Besides, a transfer function expansion equation of the filter is designed based on the design principle of in-band fluctuation, standing waves, and optimal dimension, and the capacitors and the winding magnetic rings are arranged strictly according to the equation so that the filter is advantaged by small packaging, large bandwidth, low insertion loss, high rectangular degree, high stop-band suppression, low standing wave, and low in-band fluctuation.
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Description

technical field

[0001] The invention relates to the field of filters, in particular to a wide-band, low-fluctuation band-pass LC filter. Background technique

[0002] With the development of radio frequency technology, the requirements for filter frequency indicators are becoming increasingly stringent. Some commonly used communication equipment transmit and receive channels need to use filters with larger bandwidths to meet the increasing amount of information transmission and wide frequency bandwidth. But at the same time, the requirements for volume are becoming more and more stringent, and the volume must be developed towards "miniaturization".

[0003] Generally speaking, it is not easy to realize a "broadband" filter with "good rectangular coefficient" in the 21.4MHz frequency band. Under the existing technology, it can only be realized with a surface acoustic wave filter, but With the increase of the frequency bandwidth, the insertion loss of the surface acoustic wav...

Examples

Embodiment Construction

[0029] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0030] Embodiments of the present invention provide a wide-band, low-fluctuation band-pass LC filter, such as figure 1 As shown, it includes a base 1, a PCB board 2, a capacitor 4, a winding magnetic ring 5 and four pins 3, the PCB board 2 is arranged on the base 1, and the PCB board 2 is 0.5 mm thick, 7.5 mm wide, and long 17.5mm, the outside of the winding magnetic ring 5 is covered with an outer winding enameled wire 6, and the capacitor 4 and the winding magnetic ring 5 are fixed on the PCB by soldering; at the four corners of the PCB board 2 Each has a small hole, the pin 3 passes through the small hole, and one end of the pin 3 is welded on the PCB board 2; the upper part of the filter is packaged with a nickel metal shell, and the lower base 1 is a The sur...