JP2007208013A - High-frequency circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency circuit board which is capable of using its inner pattern not as a ground conductor but as a power feeding conductor of a power supply voltage or the other optional voltage while the inner pattern keeps to hold a shield effect. <P>SOLUTION: Grounding conductors 4 and 5 are arranged on the front surface 1 and the rear surface 3 of a dielectric substrate, and the grounding conductors 4 and 5 are connected to each other through a through-hole 6. The inner pattern 2 of a solid pattern formed between the front surface 1 and the rear surface 3 of the dielectric substrate is put into a state that points located inside its outer peripheral edge by a distance of λ/4 (λ is the wavelength of operating frequency) are turned into short-circuit states, a shielding effect can be obtained in an inner region beyond the points without grounding the inner pattern 2, and the region is used as an element mounting region. A hole 21 larger than the grounding through-hole 6 is formed at the inner pattern 2 and prevented from coming into contact with the grounding through-hole 6, a power supply voltage or the other optional voltage is applied to the inner pattern 2, and the voltage of the inner pattern 2 is applied to a device located on the front surface 1 or the rear surface 3 of the dielectric substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency circuit board, and particularly relates to a shield structure for the high-frequency circuit board.

  As shown in FIG. 4, the high-frequency circuit board is composed of a dielectric substrate 1 on the front surface, a solid pattern 2 on the inner layer, and a dielectric substrate 3 on the back surface. A shield structure is employed in which a shield case 7 is attached to shield the high-frequency circuit on the substrate from electromagnetic waves propagating in the external space and the substrate. The ground conductors 4 and 5 on the front and back surfaces arranged on the outer periphery are connected together with a solid pattern 2 on the inner layer by a conductor via a grounding through hole 6.

As prior art documents related to the present invention, a multilayer high-frequency circuit board for a module including semiconductor elements in the microwave band and the millimeter wave band, and particularly a high-frequency circuit board in which deterioration of characteristics of the high-frequency circuit due to unnecessary coupling is reduced is described below. Patent Document 1 and the like.
JP-A-9-321501

  In the above-described conventional high-frequency circuit board having a shield structure, the solid pattern 2 in the inner layer is also a ground conductor, and a power supply voltage or an arbitrary voltage cannot be applied to the solid pattern 2. The present invention makes it possible to use the solid pattern 2 on the inner layer of the high-frequency circuit board as a power supply voltage or a power supply conductor of any other voltage, not as a ground conductor, while maintaining the shielding effect, The purpose is to reduce the size of the substrate and stabilize the circuit operation.

  The high-frequency circuit board according to the present invention is (1) a multi-layer high-frequency circuit board having a solid pattern in an inner layer, and the wavelength of an electromagnetic wave of a high-frequency electric signal used on the high-frequency circuit board from the outer peripheral edge of the solid pattern. The inner region is used as an element mounting region by a quarter length, and a voltage different from the ground voltage is applied to the solid pattern.

  (2) The solid pattern does not come into contact with the conductor of the through-hole at the location of the solid pattern through which the conductor of the through-hole connecting the ground conductor provided on the front and back surfaces of the high-frequency circuit board passes. It is characterized in that a hole larger than the through hole is formed.

  (3) The pattern on the front or back surface of the high-frequency circuit board and the solid pattern on the inner layer are connected by an inner via, and applied to the solid pattern on an element mounted on the front or back surface of the high-frequency circuit board. It has the structure which provides a voltage, It is characterized by the above-mentioned.

  (4) The solid pattern of the inner layer is composed of a solid pattern of a plurality of layers, and has a configuration in which different voltages are applied to the solid patterns.

  (5) The solid pattern of the inner layer and the ground conductor are connected via a capacitor.

  According to the present invention, from the outer peripheral edge of the solid pattern of the inner layer, the inner region is set as the element mounting region by a length that is a quarter of the wavelength of the electromagnetic wave of the high-frequency electric signal used on the high-frequency circuit board. Thus, even when a power supply voltage or any other voltage is applied to the solid pattern of the inner layer without connecting the solid pattern of the inner layer to the ground conductor, λ / 4 (λ: frequency used) Therefore, a good shielding effect can be obtained, so that the solid pattern can be used as a power supply conductor for a power supply voltage or any other voltage while maintaining the shielding effect.

  This eliminates the need to route the bias voltage feed line applied to the elements disposed on the front or back surface of the high-frequency circuit board on the front or back surface of the high-frequency circuit board, thereby reducing the size of the circuit board and routing the feed line. It is possible to suppress noise generated by.

  FIG. 1 shows a basic configuration of a high-frequency circuit board according to the present invention. FIG. 2A shows the front and back surfaces of a high-frequency circuit board, and a ground conductor 4 or 5 is disposed on the outer periphery of the dielectric substrate 1 or 3 on the front or back surface, and a grounding through hole is provided in the ground conductor 4 or 5. 6 is shown.

  FIG. 5B shows the inner layer pattern of the high-frequency circuit board. As shown in the figure, the inner layer solid pattern 2 is not in contact with the conductor of the above-described grounding through hole 6. A hole 21 having a larger diameter is formed. Hereinafter, the solid pattern of the inner layer is referred to as an inner layer pattern.

  FIG. 6C shows a state when the high-frequency circuit board is cut at the cutting position AA ′ shown in FIGS. 6A and 6B, that is, when the ground through hole 6 is not cut. A cross-sectional view is shown. FIG. 6D shows a state when the high-frequency circuit board is cut at the cutting position BB ′ shown in FIGS. 6A and 6B, that is, when it is cut at a location where the grounding through hole 6 exists. A cross-sectional view is shown.

  As shown in FIG. 1D, the inner layer pattern 2 of the high-frequency circuit board according to the present invention has a larger hole 21 around the grounding through hole 6, so that the inner layer pattern 2 is It is not connected to the ground conductors 4 and 5 on the front and back surfaces. The ground conductors 4 and 5 on the front and back surfaces are arranged on the outer periphery of the dielectric substrates 1 and 3 and are connected through the through holes 6 as in the conventional case. Since the inner layer pattern 2 is not connected to the conductor of the grounding through hole 6, a power supply voltage or any other voltage can be applied to the inner layer pattern 2.

  The high-frequency circuit board according to the present invention uses a choke structure for the inner layer pattern 2 in order to have a shielding effect. The choke structure is a structure that shields electromagnetic waves only at a specific frequency. The principle of the present invention will be described below with reference to FIG. FIG. 2 corresponds to FIG. 1 (b) and (d) described above.

  In FIG. 2, the end C point of the inner layer pattern 2 is a point where the impedance of the high frequency circuit is infinite (open), and is away from the C point by λ / 4 (λ is the wavelength of the electromagnetic wave of the high frequency electric signal used). Further, at point D (broken line portion), a short circuit state occurs. Therefore, even if the D point is not connected and shielded by the ground conductor, the inner layer pattern 2 can obtain a good shielding effect in the region inside the D point.

  Here, assuming that the dielectric constant εr of the dielectric substrate is 3.6 and the thickness is 0.4 mm, λ / 4 = 44.9 mm when the frequency f of the high-frequency electrical signal used is f = 1 GHz, respectively. Λ / 4 = 4.4 mm when f = 10 GHz, λ / 4 = 1.4 mm when f = 30 GHz, and λ / 4 = 0.8 mm when f = 50 GHz. Therefore, the high-frequency circuit board according to the present invention can be suitably applied to a circuit board used in a high frequency band of several gigahertz or more.

  FIG. 3 is an embodiment of the present invention, and shows a configuration example in which various modifications are made to the basic configuration shown in FIG. In the first embodiment shown in FIG. 3A, a voltage different from the ground voltage is applied to the inner layer pattern 2, and the pattern of the dielectric substrate 1 on the surface and the inner layer pattern 2 are connected by the inner via 8, An embodiment is shown in which a voltage applied to the inner layer pattern 2 is applied to an element 9 such as a device or a component arranged on the surface of the high-frequency circuit board.

  By using this configuration, it is not necessary to draw a bias voltage feeding line to be applied to the element 9 such as a device or a component disposed on the front or back surface of the high-frequency circuit board on the front or back surface of the high-frequency circuit board. As well as reducing the size of the circuit board, it is possible to suppress noise generated by routing the power supply line, and to obtain a circuit board with stable circuit operation.

  In the second embodiment shown in FIG. 3B, a dielectric substrate 10 is further added to the basic structure shown in FIG. 1D, and a second inner layer pattern 11 is provided on the dielectric substrate 10. This is an example. Since the first inner layer pattern 2 and the second inner layer pattern 11 are independent of each other, different voltages can be applied to each. By using this configuration, a plurality of different voltages can be applied to devices and components on the front or back surface of the high-frequency circuit board.

  The third embodiment shown in FIG. 3 (c) is an embodiment in which a capacitor 12 for connecting the inner layer pattern 2 and the ground conductor 4 via the inner via 8 is added to the basic configuration shown in FIG. 1 (d). It is. By using this configuration, the capacitor 12 acts as a bypass capacitor, and the noise caused by the low frequency generated in the inner layer pattern 2 is absorbed by the capacitor 12, thereby reducing the influence of the noise and making the voltage of the inner layer pattern 2 more stable. Can be maintained in a state.

  Further, the inner layer pattern 2 acts as a patch antenna structure and may oscillate due to resonance. However, by connecting the inner layer pattern 2 to the ground conductor 4 via the capacitor 12 and guiding a high frequency component causing oscillation to the ground conductor. Such an oscillation phenomenon can be prevented.

It is a figure which shows the basic composition of the high frequency circuit board by this invention. It is principle explanatory drawing of the high frequency circuit board by this invention. It is a figure which shows the Example of this invention. It is a figure which shows the shield structure of the conventional high frequency circuit board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,3 Dielectric board | substrate 2 Inner layer pattern 21 Hole of inner layer pattern 4,5 Ground conductor 6 Grounding through hole 7 Shield case 8 Inner via 9 Element such as device or component 10 Dielectric substrate 11 Inner layer pattern 12 Capacitor

Claims (5)

In a high-frequency circuit board with a multilayer structure having a solid pattern in the inner layer,
From the outer peripheral edge of the solid pattern, the inner region is an element mounting region corresponding to the length of one quarter of the wavelength of the electromagnetic wave of the high-frequency electric signal used on the high-frequency circuit board. A high frequency circuit board characterized by having a configuration for applying different voltages.   A hole larger than the through-hole so that the solid pattern does not come into contact with the conductor of the through-hole at the location of the solid pattern through which the conductor of the through-hole connecting the ground conductor provided on the front and back surfaces of the high-frequency circuit board passes. The high-frequency circuit board according to claim 1, wherein:   A configuration in which a pattern on the front or back surface of the high-frequency circuit board and the solid pattern on the inner layer are connected by an inner via, and a voltage applied to the solid pattern is applied to an element mounted on the front or back surface of the high-frequency circuit board. The high-frequency circuit board according to claim 1, comprising:   4. The high-frequency circuit board according to claim 1, wherein the solid pattern of the inner layer includes a solid pattern of a plurality of layers, and a different voltage is applied to each of the solid patterns. 5.   5. The high frequency circuit board according to claim 2, wherein the solid pattern of the inner layer and the ground conductor are connected via a capacitor.

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