A magnetoelectric adjustable inductor based on passive regulation

Abstract

The present invention relates to a magnetoelectric adjustable inductor based on a passive adjustment method, comprising: a magnetic core and a coil, wherein the magnetic core is composed of a piezomagnetic layer and a piezoelectric layer glued together, the coil is wound on the magnetic core, the magnetic core is placed in a suitable bias magnetic field, and a control electrode is led out on the piezoelectric layer; the present invention has the characteristics of convenient application, miniaturization, and extremely low power consumption.

Description

Technical Field

[0001] The present invention relates to a tunable electronic component, and more particularly to a variable inductance device based on a passive adjustment method. Background Art

[0002] Ultrasonic inductors are basic electronic devices and are widely used in common electronic circuits. The rapid development of electronic circuit technologies such as wireless communication technology has brought about a large demand for adjustable inductors. Many experts and scholars at home and abroad have proposed adjustable inductors with various principles and structures, all of which are committed to developing adjustable inductors with large adjustable range, high quality factor, low energy consumption and low cost.

[0003] Controllable magnetoelectric inductor is a new type of variable inductor that is different from traditional mechanical or current adjustable inductors. It uses the piezomagnetic effect and piezoelectric effect of stress or strain coupling to achieve voltage control of inductance. The polarized piezoelectric material will deform under the action of external voltage; this deformation is coupled to the piezomagnetic material, causing its initial magnetic permeability to change. Recently, a Chinese patent (ZL201310744355.7) and a document (X. Fang, N. Zhang and ZL Wang, Appl. Phys. Lett. 93, 102503 (2008)) have proposed a variety of magnetoelectric controllable toroidal inductor structural designs based on this principle.

[0004] The control of the piezoelectric phase in this traditional adjustable magnetoelectric inductor requires a very high voltage, which is extremely unfavorable for the miniaturization of the device, and the high-voltage drive circuit also increases the complexity of the device application. This patent proposes a new type of magnetoelectric adjustable inductor based on passive adjustment, which has the characteristics of miniaturization and convenient application. Summary of the invention

[0005] In view of the defects of the current magnetoelectric inductor, the technical problem to be solved by the present invention is to propose a new type of magnetoelectric adjustable inductor based on passive adjustment method. The present invention has the characteristics of convenient application, miniaturization, and extremely low power consumption.

[0006] The technical method of the present invention to solve the above technical problems is as follows:

[0007] The present invention provides a magnetoelectric adjustable inductor based on passive adjustment, comprising a magnetic core and a coil, wherein the magnetic core is composed of a piezomagnetic layer and a piezoelectric layer glued together, the coil is wound on the magnetic core, the magnetic core is placed in a suitable bias magnetic field, and a control electrode is led out on the piezoelectric layer.

[0008] The mechanical parameters of the piezoelectric layer are affected by its electrical boundary conditions. When the upper and lower electrodes of the piezoelectric layer are open circuited, its compliance coefficient is s D ; When the upper and lower electrodes of the piezoelectric layer are short-circuited, its compliance coefficient is s EIf an external resistor R is connected in series with the piezoelectric layer control electrode c , then its compliance coefficient is [s D ,s E ] between s(R c ). The average magnetic permeability of the magnetic inductor core is

[0009]

[0010] In the following table, m and p represent the piezomagnetic layer and the piezoelectric layer respectively, and n is the volume fraction of the piezomagnetic layer; d 33 , μ T 、s H are the piezomagnetic constant of the piezomagnetic layer, the magnetic permeability under free conditions and the compliance coefficient under constant magnetic field conditions, is the electromechanical coupling coefficient of the piezomagnetic layer. According to the above formula, when the external resistor R c By adjusting the inductance of the magneto-electric inductor, the change of the inductance of the magneto-electric inductor can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a structural diagram of a novel magnetoelectric adjustable inductor based on passive adjustment method of the present invention, wherein 1 is a piezomagnetic layer, 2 is a piezoelectric layer, 3 is a winding coil, 4 is a bias magnetic field, 5 is a control electrode, and 6 is a control resistor. DETAILED DESCRIPTION

[0012] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0013] like Figure 1 As shown, a magnetoelectric adjustable inductor based on passive adjustment method includes a piezomagnetic layer 1 magnetized in the length direction (external bias magnetic field 4), a piezoelectric layer 2 polarized in the thickness direction, a coil 3, a control electrode 5 and a control resistor 6.

[0014] Each necessary specific implementation detail and method is described in detail below. Except for those explicitly described as equivalent or alternative implementation schemes, the various implementation detail schemes disclosed below can be selectively applied or combined in one embodiment even if they are not directly related or synergistic in terms of functionality.

[0015] A pair of electrodes are made in the thickness direction of the piezoelectric layer, and the piezoelectric layer is pre-polarized with high voltage in the thickness direction. The piezoelectric layer and the piezoelectric layer are bonded by epoxy resin and aligned to form a magnetic electromagnetic core. Then the enameled wire is evenly wound on the magnetic electromagnetic core, and the first and last wire ends are used as the pins of the inductor. The electrodes of the piezoelectric layer are welded or bonded to lead out the control electrode through a wire or FPC to achieve a series connection with an external control resistor.

[0016] The piezomagnetic layer material can be nickel-based alloy (nickel, nickel-cobalt alloy, nickel-cobalt-chromium alloy), iron-based alloy (iron-nickel alloy, iron-aluminum alloy, iron-cobalt-vanadium alloy, iron-based amorphous alloy) and ferrite magnetostrictive material (nickel-cobalt and nickel-cobalt-copper ferrite), etc.

[0017] The piezoelectric layer material can be lead zirconate titanate piezoelectric ceramics, lead magnesium niobate-lead titanate piezoelectric ceramics or single crystals, lead magnesium niobate-lead zirconate titanate piezoelectric ceramics or single crystals, lead zinc niobate-lead titanate piezoelectric ceramics or single crystals, and potassium sodium niobate-based lead-free piezoelectric ceramics, sodium bismuth titanate-based lead-free piezoelectric ceramics, barium titanate piezoelectric ceramics, etc. When the external control resistor R c When the control electrode is open, the compliance coefficient of the piezoelectric layer is s D ; When the external control resistor R c = 0 (i.e. the control electrode is short-circuited), the compliance coefficient of the piezoelectric layer is s E For piezoelectric materials, there exists s D =(1-k 2 )s E The relationship between k and piezoelectric material is shown in Figure 2, where k is the electromechanical coupling coefficient of the piezoelectric material. If a piezoelectric layer material with a high k value and its working mode (33 mode or 31 mode) are selected, a larger adjustable range can be achieved.

[0018] The attached example shows a sandwich long sheet composite structure of the piezomagnetic / piezoelectric layer. However, the piezomagnetic / piezoelectric composite core can be selected as a symmetrical or asymmetrical structure according to the specific situation, the number of layers can be double or multi-layer, and the shape can also be selected as a long strip or ring sheet, rod, etc. The polarization direction of the piezoelectric layer can be selected in the thickness direction or the length direction; the direction of the external bias magnetic field determines the magnetization direction of the piezomagnetic layer, which is generally selected as the direction of the easy magnetization axis of the structure, as shown in the attached figure. Figure 1 The length direction of .

[0019] The above is only a preferred embodiment of the present invention. It should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, which are also considered to be within the protection scope of the present invention.

Claims

1. A magnetoelectric adjustable inductor based on passive regulation, characterized in that: The invention comprises a composite magnetic core and a coil. The composite magnetic core is formed by gluing a piezomagnetic layer and a piezoelectric layer. The coil is wound on the composite magnetic core. The composite magnetic core is placed in a suitable bias magnetic field. A control electrode is led out on the piezoelectric layer. The control electrode is used to connect to an external resistor.

2. The magnetoelectric adjustable inductor based on passive adjustment method according to claim 1, characterized in that: The piezomagnetic layer and the piezoelectric layer are bonded with epoxy resin and aligned to form a composite magnetic core. The coil is then evenly wound on the composite magnetic core. The first and tail wire ends serve as pins of the inductor. The electrodes of the piezoelectric layer are welded or bonded to lead out the control electrode through a wire or FPC to achieve a series connection with an external resistor.

3. The magnetoelectric adjustable inductor based on passive adjustment method according to claim 1, characterized in that: The material of the piezomagnetic layer is any one of the following materials: nickel-based alloy, nickel or iron-based alloy.

4. The magnetoelectric adjustable inductor based on passive adjustment method according to claim 3 is characterized in that: The nickel-based alloy is a nickel-cobalt alloy, a nickel-cobalt-chromium alloy, an iron-nickel alloy, a nickel-cobalt or a nickel-cobalt-copper ferrite, and the iron-based alloy is an iron-nickel alloy, an iron-aluminum alloy, an iron-cobalt-vanadium alloy, an iron-based amorphous alloy or a ferrite magnetostrictive material.

5. The magnetoelectric adjustable inductor based on passive adjustment method according to claim 1, characterized in that: The piezoelectric layer material is any one of the following materials: lead zirconate titanate piezoelectric ceramics, lead magnesium niobate-lead titanate piezoelectric ceramics or single crystals, lead magnesium niobate-lead zirconate titanate piezoelectric ceramics or single crystals, lead zinc niobate-lead titanate piezoelectric ceramics or single crystals, potassium sodium niobate-based lead-free piezoelectric ceramics, sodium bismuth titanate-based lead-free piezoelectric ceramics, and barium titanate piezoelectric ceramics.

6. The magnetoelectric adjustable inductor based on passive adjustment method according to claim 1, characterized in that: The composite magnetic core composed of the piezomagnetic layer and the piezoelectric layer is selected to be a symmetrical or asymmetrical structure according to the specific situation, with double or multiple layers, and the shape is selected to be a long strip, annular sheet or rod; the polarization direction of the piezoelectric layer is selected in the thickness direction or the length direction; the direction of the bias magnetic field determines the magnetization direction of the piezomagnetic layer, which is selected as the direction of the easy magnetization axis of the structure.

Images