JP2522478Y2 - Printed wiring board - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board having a high-frequency blocking circuit suitable for high-frequency applications such as communication equipment.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram showing a configuration example of a general voltage controlled oscillator. In this figure, 1 is an oscillation transistor, and 2 is a buffer amplification transistor. The emitter current of the buffer amplification transistor 2 flows into the oscillation transistor 1 as it is as a collector current. The resonance circuit 3 is connected to the collector of the oscillation transistor 1. Frequency control voltage V _CTL for the cathode to control the resonance frequency of the variable capacitance diode 3a in the resonant circuit 3 is supplied through a high frequency blocking inductor L _1. Also, it is interposed a high frequency blocking inductor L ₂ also between the emitter of the buffer amplifier transistor 2 and the collector of the oscillation transistor 1, the oscillation transistor 1 and the buffer amplifier transistor 2 and the high-frequency separating I have. By performing such connection through the high frequency blocking inductors L ₁ and L _2, the oscillating transistors 1 and the resonant circuit 3 is cut off from the other circuit high frequency stabilization of the oscillation frequency is made. Here, in particular the impedance of the high frequency blocking inductor L ₂ has a large effect on the Q of the resonance of the resonant circuit 3,
The characteristics of the voltage controlled oscillator as a whole, such as the C / N (carrier / noise) ratio, are affected. Therefore, the high-frequency blocking inductor used in this type of application needs to have a sufficiently high impedance and a sufficiently high self-resonant frequency with respect to the oscillation frequency. In the case of a voltage controlled oscillator used in a mobile communication device or the like, a chip inductor having a winding core encapsulated in a mold resin, a laminated chip inductor made of a magnetic material such as ferrite, or the like is used as a high-frequency blocking inductor. Further, as shown in FIG.
A pattern inductor or the like in which the microstrip line 20 is directly patterned on the surface of the zero is used as a high-frequency blocking inductor. In the case of a pattern inductor, the length D of the microstrip line 20 is determined so as to satisfy the condition D <λ / 4 when the wavelength of a signal to be handled is λ. In addition, with one end of the microstrip line short-circuited, the input impedance Zin viewed from the other end.
And the characteristic impedance Z of the microstrip line
₀ is given by the following equations. Zin = jZ ₀ tan βD, Z ₀ = (L / C) ^{1/2 In the} above equation, L is the inductance per unit length of the microstrip line, and C is the capacitance per unit length. Β is a phase constant representing a phase rotation corresponding to a unit length, and is given by β = 2π / λ. According to the above formula, by increasing the characteristic impedance Z _0, it is possible to increase the input impedance Zin of the microstrip line. However, between the microstrip lines and the ground conductor plane for distributed capacitance is present, to increase the characteristic impedance Z ₀ is limited. Therefore, in order to obtain the required input impedance Zin, it is necessary to make the length D of the microstrip line sufficiently long.

[0003]

The above-described chip inductor or pattern inductor has been effective as a high-frequency blocking inductor when the operating frequency is relatively low. However, in the case of a communication device that handles high frequencies higher than the quasi-microwave band, a high-frequency blocking inductor having a small inductance and a high self-resonant frequency is required. Therefore, it is impossible to use a commercially available chip inductor as this kind of high-frequency blocking inductor. Also, in the case of a pattern inductor, in the high frequency band, the microstrip line
And the capacitance 20b between the microstrip line 20 and the ground conductor surface 30.
Since the self-resonant frequency is lowered, it is not suitable as a high-frequency blocking inductor applied to this kind of application. The present invention has been made in view of the above circumstances, and has a high-frequency blocking inductor circuit that has a high self-resonant frequency, has a sufficiently large impedance for high frequencies, and can be used for a high-frequency circuit in a quasi-microwave band or higher. It is an object to provide a printed wiring board having the same.

[0004]

A printed wiring according to the present invention.
The board is made up of multiple layers of insulating material, each of
Provide a ground conductor on at least one of the joining surfaces of the edge layer.
Girder printed wiring board, provided on said surface and said joining surface.
Brass provided through the wiring pattern and the insulating layer
The cross-sectional shape electrically connected to the India through hole
The stepped wiring forms a high-frequency blocking inductor
I have.

[0005]

According to the above arrangement, the wiring perpendicular to the ground conductor surface of the printed wiring board has a small distributed capacitance and a large characteristic impedance per unit length. Therefore, a printed wiring board having a high-frequency blocking inductor circuit having a self-resonant frequency and an impedance suitable for the operating frequency can be realized by adjusting the combination of the wiring parallel to and perpendicular to the ground conductor surface.

[0006]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a cross-sectional structure of a multilayer printed wiring board on which a high-frequency blocking inductor according to an embodiment of the present invention is formed. The multilayer printed wiring board is formed by laminating an insulating layer of four layers, and the conductor pattern is printed on a bonding surface of the insulating layer surface and the respective insulating layers. Here, one face at least of the junction surface of the insulating layer table <br/> surface or the insulating layer
A ground conductor is provided to form a ground circuit surface . The wiring patterns 111 to 117 in FIG. 1 form a part of such a conductor pattern between the insulating layers. 101-
Reference numeral 108 denotes a blind through hole penetrating each insulating layer, and electrically connects the wiring patterns 111 to 117. The high-frequency blocking inductor according to the present embodiment is constituted by step-like wirings formed by these wiring patterns 111 to 117 and blind through holes 101 to 108 interposed between the signal terminals Port1 and Port2. According to such a configuration, since the capacitance between the wiring formed by the blind through-hole and the ground plane is small, the characteristic impedance Zo can be increased. Therefore, inductors with blind through holes are insulated
Compared with a pattern inductor formed on a plane parallel to the layer surface, a high-quality inductor having a large impedance per fixed length is obtained. The number of through-holes, the number of through-holes, the length of the wiring patterns 111 to 117, and the like are adjusted according to the frequency used. That is, when the operating frequency is low, the required inductance is large, so the number of through-hole stages is increased as shown in FIG. 1, and when the operating frequency is high, a small inductor is required. And reduce the number of through-hole steps.

[0007]

As described above, according to the present invention, there is an effect that a high-frequency blocking inductor having a high self-resonant frequency and a sufficiently large impedance for high frequencies is realized. Further, since the high frequency blocking inductor according the present invention uses a vertical wiring surface of the insulating layer, requires a small space requirement on the insulating layer, there is an effect that contributes to the miniaturization of the high frequency circuit.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a high-frequency blocking inductor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a voltage controlled oscillator.

FIG. 4 is a plan view and a cross-sectional view illustrating a configuration of a conventional pattern inductor.

[Explanation of symbols]

 101 to 108: wiring pattern, 111 to 117: blind through hole.

Claims (1)

(57) [Scope of request for utility model registration] A plurality of insulating layers, each having a surface
Or ground to at least one of the bonding surfaces of each insulating layer
A printed wiring board provided with a conductor, wherein:
The wiring pattern provided on the mating surface and the insulating layer
Cross section electrically connected to girder blind through hole
The stepped wiring forms a high-frequency blocking inductor.
A printed wiring board characterized by being formed.