JP2009295730A - Inductor for high frequency - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the increase of loss due to proximity effect at a high frequency. <P>SOLUTION: An inductor for high frequency is a solenoid coil having four or more turns, and an average winding pitch in its end parts (1b, 2b, 1c, and 2c) is made wider than that in its center parts (1a and 2a). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high frequency inductor, and more particularly, to a high frequency inductor having a structure capable of suppressing an increase in loss due to a proximity effect at a high frequency.

Conventionally, a high-frequency inductance element including a circular coil in which a round wire is wound in a circular solenoid is known (for example, see Patent Document 1).
Japanese Patent Application Laid-Open No. 08-078237

The above-described conventional high-frequency inductance element has a problem that when the frequency becomes 1 GHz or higher, the loss increases to a degree that cannot be ignored due to the proximity effect. In addition, there is a problem that the resistance value increases so as not to be ignored due to the skin effect. Further, when mounted on a substrate, there is a problem that it cannot be adsorbed by a mounter because it is a circular coil. Furthermore, in order to withstand solder reflow, there has been a problem that the temperature index of the insulating coating of the round wire must be increased.
Accordingly, an object of the present invention is to provide a high frequency inductor capable of suppressing an increase in loss due to a proximity effect at a high frequency. Another object of the present invention is to provide a high frequency inductor capable of suppressing an increase in resistance value due to a skin effect at a high frequency. Another object of the present invention is to provide a high frequency inductor that can be attracted by a mounter when mounted on a substrate. It is another object of the present invention to provide a high frequency inductor that can withstand solder reflow even if the temperature index of the insulation coating of the electric wire is lowered.

In the first aspect, the present invention is a solenoid coil having four or more turns, and the average of the end portions (1b, 2b, 1c, 2c) rather than the average winding pitch of the central portion (1a, 2a). Provided is a high-frequency inductor (1, 2) characterized by having a large winding pitch.
Losses due to proximity effects at high frequencies occur predominantly in the wire at the end of the solenoid coil. This is because in the central part of the solenoid coil, the magnetic fields generated by the currents on both sides sandwiching the central part cancel each other, so the leakage magnetic field that cuts the electric wire in the central part is weakened and the loss is reduced, but at the end of the solenoid coil This is because the magnetic fields do not cancel each other, so that the leakage magnetic field concentrates on the electric wire at the end and the loss increases.
Therefore, in the high-frequency inductor (1, 2) according to the first aspect, the average of the end portions (1b, 2b, 1c, 2c) is larger than the average winding pitch of the central portion (1a, 2a) of the solenoid coil. The typical winding pitch was increased. Thereby, since it can relieve | moderate that a magnetic field concentrates on the electric wire of an edge part (1b, 2b, 1c, 2c), the increase in the loss by the proximity effect in a high frequency can be suppressed.

In a second aspect, the present invention provides a high frequency inductor (1, 2) characterized in that, in the high frequency inductor according to the first aspect, the electric wire is a square wire.
In the high-frequency inductors (1, 2) according to the second aspect, square lines are used. However, when the square lines are compared with the round lines, the circumference of the surface of the square lines is longer than the circumference of the surface of the round lines. Become. That is, the cross-sectional area near the surface is increased. Therefore, an increase in resistance value due to the skin effect at high frequencies can be suppressed.

In a third aspect, the present invention provides a high-frequency inductor (1, 2) characterized in that, in the high-frequency inductor (1, 2) according to the first or second aspect, the electric wire is a silver wire or a silver-plated wire. 2).
In the high frequency inductors (1, 2) according to the third aspect, since the silver wire or the silver plated wire is used, the high frequency resistance can be reduced.

In a fourth aspect, the present invention relates to the high frequency inductor (1, 2) according to any one of the first to third aspects, wherein the high frequency inductor (1, 2) is a square coil. I will provide a.
In the high-frequency inductors (1, 2) according to the fourth aspect, since a square coil is used, a planar portion can be adsorbed by a mounter when mounted on a substrate.

In a fifth aspect, the present invention provides a high-frequency inductor (1, 2) according to any one of the first to fourth aspects, wherein legs (1d, 2d, 1e, 2e) projecting downward are provided at both ends. Provided is a high-frequency inductor (1, 2) characterized by comprising:
In the high frequency inductor (1, 2) according to the fifth aspect, since the leg portions (1d, 2d, 1e, 2e) protrude downward, the leg portions (1d, 2d, 1e, 2e) are removed by solder reflow. When soldering to the board, even if the solder temperature is directly applied to the legs (1d, 2d, 1e, 2e), the solder temperature is not directly applied to the main body. Therefore, even if the temperature index of the insulation coating of the electric wire is lowered, it can withstand solder reflow.

  According to the high frequency inductor of the present invention, it is possible to suppress an increase in loss due to a proximity effect at a high frequency. In addition, an increase in resistance value due to a skin effect at a high frequency can be suppressed. Moreover, when mounting on a board | substrate, it can adsorb | suck with a mounter. Further, it can withstand solder reflow even if the temperature index of the insulation coating of the wire is lowered.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings. Note that the present invention is not limited thereby.

  FIG. 1 is a front view illustrating the high-frequency inductor 1 according to the first embodiment. FIG. 2 is a left side view of the same.

The high-frequency inductor 1 is a solenoid coil obtained by winding an insulation-coated silver-plated copper square wire in a square shape with 9.25 turns.
When the coil length of the high-frequency inductor 1 is equally divided into eight sections, the central two sections are defined as the central section 1a, and the three sections on both sides of the central section 1a are defined as the end sections 1b and 1c. The average winding pitch of the end portions 1b and 1c is larger than the average winding pitch.
In addition, the lower sides of the extreme ends of the high-frequency inductor 1 protrude downward and form leg portions 1d and 1e for soldering to the substrate. The lower surfaces of the leg portions 1d and 1e are peeled off from the insulating coating and solder plated.

  As an example of the dimensions, the square line has a square cross section of 0.08 mm × 0.08 mm. The square shape is a 1 mm × 1 mm square. The coil length is 1.7 mm. The average winding pitch of the central portion 1a is 0.1 mm, and the average winding pitch of the end portions 1b and 1c is 0.21 mm. The leg portions 1d and 1e protrude downward by 0.1 mm from the lower surface of the coil body.

According to the high frequency inductor 1 of the first embodiment, the following effects can be obtained.
(1) Since the average winding pitch of the end portions 1b and 1c is larger than the average winding pitch of the central portion 1a and the magnetic field can be reduced from concentrating on the end portions (1b and 1c), The increase in loss due to the proximity effect can be suppressed.
(2) Since the cross-sectional area in the vicinity of the surface of the square line is larger than that of the round line, an increase in resistance value due to the skin effect at high frequency can be suppressed.
(3) Since a silver-plated wire is used, high frequency resistance can be reduced.
(4) Since the upper surface is flat, the upper surface can be adsorbed by a mounter when mounted on a substrate.
(5) Since the leg portions 1d and 1e protrude downward, when the leg portions 1d and 1e are soldered to the substrate by solder reflow, the leg portions 1d and 1e are attached to the main body even if the solder temperature is directly applied to the legs. Does not add solder temperature directly. Therefore, even if the temperature index of the insulating coating of the square wire is lowered, it can withstand solder reflow.

  FIG. 3 is a front view illustrating the high-frequency inductor 2 according to the second embodiment. FIG. 4 is a left side view of the same.

The high-frequency inductor 2 is a solenoid coil obtained by winding an insulating coated silver square wire in a square shape with 9.25 turns.
When the coil length of the high-frequency inductor 2 is equally divided into eight sections, the central two sections are defined as the central section 2a, and the three sections on both sides of the central section 2a are defined as the end sections 2b and 2c. The average winding pitch of the end portions 2b and 2c is larger than the average winding pitch.
In addition, the lower sides of the extreme ends of the high-frequency inductor 2 protrude downward and form leg portions 2d and 2e for soldering to the substrate. The lower surfaces of the leg portions 2d and 2e are peeled off from the insulation coating and solder plated.

  As an example of the dimensions, the square line has a square cross section of 0.08 mm × 0.08 mm. The square shape is a 1 mm × 1 mm square. The coil length is 1.2 mm. The average winding pitch of the central portion 2a is 0.2 mm, and the average winding pitch of the end portions 2b and 2c is 0.14 mm. The leg portions 2d and 2e protrude downward by 0.1 mm from the lower surface of the coil body.

  According to the high-frequency inductor 2 of the second embodiment, in addition to the effect of the high-frequency inductor 2 of the first embodiment, the mechanical strength of the end portions 2b and 2c is improved. It becomes strong against vibration.

  If the number of turns is 4 or more, the present invention can be implemented.

  The high frequency inductor of the present invention can be used for a high frequency circuit of, for example, about 1 GHz or more.

1 is a front view showing a high frequency inductor according to Embodiment 1. FIG. FIG. 3 is a left side view illustrating the high frequency inductor according to the first embodiment. 6 is a front view showing a high frequency inductor according to Embodiment 2. FIG. 6 is a left side view showing a high frequency inductor according to Embodiment 2. FIG.

Explanation of symbols

1, 2 Inductors for high frequency 1a, 2a Central part 1b, 1c, 2b, 2c End part 1d, 1e, 2d, 2e Leg part

Claims (5)

The solenoid coil has four or more turns, and the average winding pitch of the end portions (1b, 2b, 1c, 2c) is larger than the average winding pitch of the central portion (1a, 2a). Inductors for high frequency (1, 2). The high frequency inductor according to claim 1, wherein the electric wire is a square wire. The high frequency inductor (1, 2) according to claim 1 or 2, wherein the electric wire is a silver wire or a silver plated wire. The high frequency inductor (1, 2) according to any one of claims 1 to 3, wherein the high frequency inductor (1, 2) is a square coil. The high frequency inductor (1, 2) according to any one of claims 1 to 4, characterized by having legs (1d, 2d, 1e, 2e) projecting downward at both ends. (1,2).

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