JPH10303603A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the dielectric filter thin although it has the same electric characteristics by making elliptic the shape of an inductor wound with an insulation-coated copper wire mounted on a wiring board and reducing its height. SOLUTION: This dielectric filter 10 has a coaxial resonator 4, a capacitor 5, and an inductor 1 mounted on the wiring board 3. This inductor 1 is wound elliptically with a polyester-coated copper wire and has a height (h) of up to 1.35 mm. The thickness of 0.4 mm of the wiring board 3 and the thickness of 0.15 mm of the case which are usually used are added to the height (h) of 1.35 mm of the inductor 1 and then the dielectric filter 10 is 1.9 mm high, so a product of <=2 mm is actualized and contact between the case and inductor 1 can be avoided. Here, a circularly sectioned coil is pressed to lower height and may be used as the inductor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric filter used in the field of mobile communication and the like.

[0002]

2. Description of the Related Art In recent years, portable telephones or mobile communication utilizing a microwave band have become popular. Since these devices are required to be small and lightweight, dielectric filters used in communication devices are also required to be small and lightweight, and there is a current requirement for products having a height of 2 mm or less.

FIG. 2 is an external perspective view of a conventional dielectric filter. As shown in FIG. 2, a conventional dielectric filter is composed of a coaxial resonator 4, a capacitor 5, and a copper wire covered with polyester on a wiring board 3 in which a component mounting portion of the wiring is subjected to solder plating. It is configured by mounting the wound inductor 2 and the like.

[0004]

However, in the current inductor, the height of the inductor itself is so high that contact with a case covering components mounted on a wiring board is inevitable. Had an adverse effect.

[0005] Accordingly, an object of the present invention is to provide a thin dielectric filter which has the same electrical characteristics as a conventional product and is thin.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a dielectric filter comprising a coaxial resonator, a capacitor and an inductor formed by winding an insulated copper wire on a wiring board. Is elliptical, and the height of the inductor is reduced. The inductor may be an inductor having a low profile by crushing a coil having a circular cross section.

According to the present invention, the elliptical shape of the inductor makes it possible to reduce the size and thickness of the dielectric filter, thereby meeting the requirements for products having a height of 2 mm or less.

[0008]

Embodiments of the present invention will be described below.

FIG. 1 is an external perspective view of a dielectric filter according to an embodiment of the present invention. In FIG. 1, a dielectric filter 10 has a coaxial resonator 4, a capacitor 5, and an inductor 1 mounted on a wiring board 3. or,
The inductor 1 was formed by winding a polyester-coated copper wire in an elliptical shape and setting the height h to a maximum of 1.35 mm.

In the dielectric filter of the present invention, in order to avoid contact with the case and keep the height of the dielectric filter at 2 mm or less, the thickness of the wiring board conventionally used is 0.4 mm, The height of the inductor, including 0.15 mm, was MAX 1.35 mm. As a result, the height of the dielectric filter can be set to 1.9 mm,
mm or less, and contact between the case and the inductor could be avoided.

Incidentally, as a result of comparing and evaluating 100 electric characteristics of the dielectric filter according to the present invention and 100 electric characteristics of the conventional dielectric filter, completely equivalent characteristics were shown.

[0012]

As described above, according to the present invention,
By making the shape of the inductor elliptical, it is possible to provide a thin dielectric filter whose electrical characteristics are the same as those of the conventional product.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a dielectric filter according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a conventional dielectric filter.

[Explanation of symbols]

 1, 2 Inductor 3 Wiring board 4 Coaxial resonator 5 Capacitor 6 Terminal pin 10 Dielectric filter h Height

Claims (1)

[Claims] 1. A dielectric filter comprising a coaxial resonator, a capacitor, and an inductor formed by winding an insulated copper wire on a wiring board, wherein the shape of the inductor is made elliptical. Dielectric filter.