Variable inductor

Abstract

The invention discloses a variable inductor, which comprises a substrate, a core, an inductor body and a pair of electrodes of the inductor body, wherein the inductor body is printed on the substrate, the substrate is provided with a hole, and the core is inserted into the hole and moves along the length direction of the hole. Continuous variability of inductance of high-frequency microwave is realized by changing position of the core.

Description

Technical field [0001] The invention relates to a variable inductor, in particular to a variable inductor that can be used in various high-frequency and microwave circuits. Background technique [0002] In the electronic device family, the existence of adjustable inductors makes the production of electronic circuits more flexible and convenient. In electronic circuits below several hundred MHz, tunable inductors have been widely used, such as matching circuits and tuning circuits. However, when the operating frequency is higher, such as above several thousand MHz, the existing lumped parameter adjustable inductors can no longer reflect the characteristics of the inductance, the frequency characteristics become worse, the Q value becomes smaller, and the efficiency of the use of the inductor is lost. [0003] Therefore, the applicant submitted a patent application for a tunable inductor on May 10, 2004, with the authorization number: ZL 200410027166.9, but it is difficult for the t...

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Problems solved by technology

However, when the frequency of use is higher, such as above several thousand MHz, the existing centralized parameter adjustable inductors can no longer reflect the characteristics of the inductor, the frequency characteristics deteriorate, the Q value becomes smaller, and the efficiency of the inductor has been lost.

[0003] Therefore, the applicant submitted a patent application for an adjustable inductor on May 10, 2004, the authorization number: ZL 200410027166.9, but it is difficult to achieve a higher Q value for the adjustable inductor; Submitted a patent application for a segmented adjustable inductor on May 12, the authorization number: ZL200610156510.3, but the segmented adjustable inductor has a large volume and a long path for the RF signal to pass, which will increase unnecessary signal insertion loss

The applicant submitted a patent application for an electric parameter adjustment system and device on July 28, 2008, application number: 200810144258.3. Although the electric adjustment device overcomes the previous weakness, its inductance cannot be continuously changed

[0004] In addition, the inductance of the existing adjustable inductor is made of copper enameled wire, with a magnetic core in the middle. The problem is that it is large in size and it is difficult to meet the miniaturization requirements of radio frequency circuits. We know that the circuits of radio frequency systems generally need Shielded metal box, the larger the volume (height) of the device, the larger the space it occupies, the greater the processing cost of the shielding box; since the inductor is a copper wire wound inductor, not a radio frequency microstrip line, its radio frequency characteristics cannot be determined. High, its self-resonant frequency is several GHz, but its working frequency is difficult to achieve above 2GHz. In addition, in order to maintain the airtightness and fixity of the coil, the bracket is generally filled with resin, and the bracket of the coil cannot withstand high temperature. Suitable for manual soldering and wave soldering, not suitable for reflow automatic soldering

If high-temperature materials are used for filling, the cost of filling is very high; in addition, the processing of copper wire winding is complicated, and mass production requires many machines to work at the same time, which is time-consuming and labor-intensive.

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