JPH0514052A - High frequency circuit module with filter - Google Patents

Abstract

PURPOSE:To attain shield between a high frequency circuit section and a filter section without increasing lamination number of a multi-layer board with respect to the high frequency circuit module with filter. CONSTITUTION:A shield layer 3 is provided to plural layers in the inside of a multi-layer board 2 and the shield layers 3 formed separately are interconnected by a blind throughhole 8. A high frequency circuit section is mounted to the upper side of the shield layer and a filter section is mounted (built in) to the lower side of the shield layer. Furthermore, a shield cap 1 is covered onto the high frequency circuit section and the shield cap 1 and the shield layer 3 are connected to shield the surround of the high frequency circuit section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency circuit module with a filter, more specifically, a VC with a filter.
The present invention relates to a high frequency circuit module with a filter including a high frequency circuit unit such as O (voltage controlled oscillator) and a filter unit.

[0002]

2. Description of the Related Art FIGS. 3 to 5 are views showing an example previously proposed by the present inventor, FIG. 3 is an exploded perspective view of an oscillator module with a filter, FIG. 4 is a circuit example of a VCO with a filter, and FIG. 5
FIG. 5 is a sectional view of an oscillator module with a filter having the circuit configuration of FIG. 4.

In the figure, 1 is a shield cap, 2 is a multilayer substrate, 3 is a shield layer (GND layer), 4 is a component mounting surface, 5
Is a mounting component (discrete component), 6 is a layer on which the oscillator is mounted, and 7 is a layer on which the filter is mounted.

Further, C _{1 to} C ₁₃ are capacitors, and L _{1 to} L
Reference numeral ₅ is a coil, R _{1 to} R ₆ are resistors, Tr ₁ and Tr ₂ are transistors, Tc is a control terminal, V _D is a variable capacitance diode, OUT is an output terminal, and Vcc is a power supply.

The present inventor has previously proposed a circuit block with a filter (Japanese Patent Application No. 2-149345) using a multi-layer substrate, and FIGS. 3 to 5 are views showing examples thereof. Figure 3
Shows an oscillator module with a filter in which an oscillating unit and a filter unit are mounted on a multilayer substrate.

In such an oscillator module with a filter, it is necessary to electromagnetically shield the oscillating portion and the filter portion. Therefore, the configuration shown in FIG. 3 is used. As shown in the figure, a multilayer substrate 2 is used as a substrate, and a shield layer (GND layer) 3 is formed on the inner layer of the multilayer substrate 2. The shield layer 3 is formed as a thick film conductor pattern by printing a thick film conductor on the entire surface of one inner layer, and is used as a GND layer.

Then, one side of the shield layer 3 is a layer 6 on which an oscillating portion is mounted, and the other side of the shield layer 3 is
It is the layer 7 on which the filter part is mounted. Since the surface layer of the layer 6 on which the oscillator is mounted is the component mounting surface 4, the mounting component (transistor or the like) 5 is mounted on the component mounting surface 4.

With such a structure, the oscillating portion and the filter portion are mounted on the multilayer substrate 2, but the periphery of the oscillating portion needs to be completely shielded, so that the upper portion of the multilayer substrate 2 (on the component mounting surface 4 side). Then, the shield cap 1 is covered and electrically connected to the shield layer 3.

When the shield cap 1 is placed on the multilayer substrate 2, the oscillating portion is covered with the shield cap 1 and the shield layer 3, so that the oscillating portion can be completely shielded.

A specific example of the oscillator module with a filter as described above will be described below with reference to FIGS. In this example, a VCO (voltage controlled oscillator) is used as an oscillator, a filter is added to this VCO, and a VC with a filter is added.
This is an example of O. A band pass filter (BPF) was used as the filter.

As shown in FIG. 4, a VCO with a filter is provided.
Is composed of an oscillation unit, a buffer unit, and a bandpass filter unit. A control terminal Tc is provided on the input side of the oscillation section, and an output terminal OUT is provided on the output side of the bandpass filter section.

The oscillating unit is composed of a transistor Tr ₁ , capacitors C _{1 to} C ₆ , resistors R _{1 to} R ₃ , a coil L ₁ and a variable capacitance diode V _D , and a buffer unit is a transistor Tr ₂ and a capacitor C ₇ to. C ₉ , C ₁₃ , resistances R _{4 to} R
₆ and coil L ₂ .

The bandpass filter section is composed of capacitors C _{10 to} C ₁₂ and coils L _{3 to} L ₅ , and
Respectively _{L 3 C 10, L 4 C} 12, L 5 C 11 constitute an LC resonant circuit.

The cross section of an oscillator with filter (VCO with filter) module in which the circuit of the VCO with filter of FIG. 4 is mounted on a multilayer substrate is configured as shown in FIG. 5, for example. In addition, in FIG. 5, one cross section of the multilayer substrate is illustrated, and the shield cap is omitted. The transistors and resistors are mounted as discrete parts.

In the cross section shown in the drawing, a shield layer (GND layer) 3 is provided on one layer inside the multi-layer substrate 2, and an oscillating section and a buffer section are mounted on the upper side (upper side in the figure) of this shield layer 3 and The bandpass filter part is mounted on the side.

[0016] In the upper shield layer 3, the coil L ₁ of the oscillator, the coil L ₂ and the like of the buffer unit is formed using a thick film conductor pattern, are then incorporated in the multilayer substrate. Also, the capacitors C _{1 to} C ₆ of the oscillator and the capacitor C of the buffer
₇ , C ₉ and C ₁₃ are also formed using a thick film conductor pattern and are built in the multilayer substrate 2.

Transistors other than the above, Tr ₁ , Tr ₂ ,
Components such as resistors R _{1 to} R ₆ and variable capacitance diode V _D are
It is mounted on the component mounting surface 4 as a discrete component and connected to a predetermined wiring pattern.

Below the shield layer (GND layer) 3, the coils L ₃ to of the bandpass filter portion (BPF portion) are provided.
L ₅ and capacitors C _{10 to} C ₁₂ are formed using a thick film conductor pattern and are built in the multilayer substrate 2.

In the cross section of FIG. 5, only the coil L ₃ and the capacitor C ₁₀ are shown, but other coils and capacitors are similarly incorporated. In addition, the bandpass filter section is formed below the buffer section as much as possible so as not to be affected by the oscillation section.

[0020]

The above-mentioned problems have the following problems. (1) In the oscillator module with a filter, since it is necessary to shield the oscillating unit and the filter unit, the oscillating unit is arranged on one side and the filter unit is arranged on the other side with the shield layer as a boundary. When such layer setting is performed, the number of layers of the multilayer substrate increases (the multilayer substrate cannot be effectively used).

(2) In the oscillator module with a filter shown in FIG. 5, the bandpass filter section is formed below the buffer section so as not to be influenced by the oscillation section. Therefore, the portions indicated by A and B in FIG. 5 become dead spaces.

(3) In particular, when a coil having a high Q is required, it is necessary to use a helical coil having a large number of turns, for example. In order to incorporate such a helical coil in the multilayer substrate 2, the number of layers of the multilayer substrate 2 must be increased. In particular, the above coil is required in the coil of L ₁ of the oscillation section and L _{3 to} L ₅ of the filter section. Therefore, even if the number of layers of the multi-layer substrate increases, the module becomes thicker and the dead space shown by A and B in FIG. 5 further increases.

(4) When the number of layers of the multi-layer substrate constituting the module increases, the number of times of printing or lamination increases in the structural process, which is troublesome. As a result, the cost of the module increases. Further, it becomes difficult to miniaturize the module.
When the substrate becomes thicker, if the substrate is made of ceramics, degreasing firing is performed for manufacturing, but degreasing takes a very long time, resulting in an increase in cost.

(5) When the number of layers of the multilayer substrate increases, for example, since the substrate is thick, it becomes difficult to insert the lead frame in the SIOP structure module. Further, when the surface mount component is used, the mounting height becomes high. The present invention confronts such a problem, without increasing the number of stacked multilayer substrates,
It is an object of the present invention to provide a shield between the oscillator and the filter.

[0025]

FIG. 1 is a principle diagram of the present invention. In the figure, the same reference numerals as those in FIG. 3 indicate the same elements. Also,
Reference numeral 8 denotes a blind through hole (a through hole whose inside is filled with a conductor). The present invention has the following configuration to solve the above problems.

(1) The shield layer 3 is set on the inner layer of the multilayer substrate 2, and the high frequency circuit section is mounted on one side of the multilayer substrate 2 with the shield layer as a boundary, and the filter section is on the other side. And the surroundings of the oscillating portion by covering the multilayer substrate surface on which the high frequency circuit portion is mounted with the shield cap 1 and electrically connecting the shield cap 1 and the shield layer 3 to each other. In the high frequency circuit module with a filter, the shield layer 3 is set over a plurality of layers inside the multilayer substrate 2. (2) In the above configuration (1), the high frequency circuit section includes an oscillation section.

[0027]

The operation of the present invention based on the above construction will be described with reference to FIG. The shield layer 3 is provided on the inner layer of the multilayer substrate 2.
When setting, instead of setting it on one layer as in the conventional case, it is set by dividing into a plurality of layers (for example, two layers), and a blind through hole (through hole whose inside is filled with a conductor) 8 is provided between them. Connecting.

Then, with the shield layer as a boundary, the high frequency circuit section is mounted on the upper side of the figure, and the filter section is mounted on the lower side. In this case, the filter unit is entirely built in the multilayer substrate, but the high frequency circuit unit is mounted using discrete components and built-in components.

A shield cap 1 is placed on the upper part of the multilayer substrate 2 on which the high frequency circuit section and the filter section are mounted so as to cover the high frequency circuit section.
And the shield layer 3 are electrically connected. With this configuration, the dead space as in the conventional example can be effectively utilized, and the high frequency circuit section and the filter section can be mounted on the multilayer substrate having a small number of layers.

The high-frequency circuit section is shielded by the shield cap 1 and the shield layer 3 around the entire circumference. Therefore, the filter section is not affected by the noise from the high frequency circuit section.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. (Description of Embodiments) FIG. 2 is a sectional view of an oscillator module with a filter according to an embodiment of the present invention. In the figure,
The same reference numerals as those in FIGS. 3 to 5 denote the same components. 3A is a first shield pattern (GND pattern), 3B is a second shield pattern (GND pattern) 2-1 to 2-
Reference numeral 6 denotes the first to sixth layers of the multilayer substrate.

The oscillator module with a filter of this embodiment is a diagram in which the circuit of the VCO with a filter shown in FIG. 4 is mounted on a multilayer substrate. Note that FIG. 2 shows a cross section of the multilayer substrate, and the shield cap is not shown.

As shown, the multilayer substrate 2 is connected to the first layer 2-
A six-layer structure including the first to sixth layers 2-6 was adopted. A shield layer (GND layer) is set inside the multilayer substrate 2. In this example, the first shield pattern (GND pattern) 3A formed on the first layer 2-1 and the fourth layer 2 are formed. -4
The second shield pattern (GND pattern) 3B formed above constitutes a shield layer.

That is, the first shield pattern 3A is set on the first layer 2-1 and the second shield pattern 3B is set on the fourth layer 2-4. In this case, the first shield pattern 3A and the second shield pattern 3B are formed such that one ends thereof extend to a position where they are slightly overlapped when viewed from the stacking direction, and a blind through hole (the inside is Connection is made by through holes 8 filled with conductors.

The first shield pattern 3A and the second shield pattern 3A
The oscillation part and the buffer part are mounted on the upper side of the shield layer composed of the shield pattern 3B and the filter part is mounted on the lower side.

A more specific description is as follows.
In the cross section of the drawing, a bandpass filter section (BPF section) is mounted (built-in) on the first layer 2-1 to the third layer 2-3 located below the second shield pattern 3B.

The oscillating section and the buffer section are the second layer 2-2 to the sixth layer located above the first shield pattern 3A.
The layer 2-6 and the fifth layer 2-5 to the sixth layer 2-6 located above the second shield pattern 3B are mounted.

As the mounting arrangement of the oscillating section and the buffer section, the buffer section is arranged above the second shield pattern 3B, and the oscillating section is arranged above the first shield pattern 3A.

The sixth layer 2-6 is used as the component mounting surface 4 for mounting components such as transistors (discrete components). Furthermore, above the multilayer substrate 2 (upper side in the figure)
The shield cap 1 (see FIG. 1) from above, and the shield cap and the first and second shield patterns 3A,
By electrically connecting to 3B, the periphery of the oscillation unit and the buffer unit is shielded.

The band pass filter section must be connected to the buffer section, and the connection method is as follows. For example, a doughnut-shaped blank (a portion without a conductor) is provided in a part of the second shield pattern 3B, and a through-hole electrode is provided inside the blank so as not to contact the second shield pattern 3B. When connecting the bandpass filter section and the buffer section, they are connected via the through-hole electrodes.

(Other Embodiments) The embodiments have been described above, but the present invention can be implemented as follows. (1) As the filter high frequency circuit, the VCO shown in FIG. 4 is used.
The present invention is not limited to circuits and high-frequency oscillators, but can be applied to various circuits such as high-frequency amplifiers and transmitters. Further, it can be applied to the use of mounting various oscillation elements such as a crystal oscillator in the high frequency circuit section.

(2) The shield layers may be set over two layers, but it is also possible to set over a plurality of layers. (3) The oscillator module with a filter may be configured as an insertion component or may be configured as an SMD (surface mount component).

[0043]

As described above, the present invention has the following effects. (1) Since the shield layer is set over a plurality of layers in the multilayer substrate, it is possible to appropriately arrange the built-in components while preventing a dead space in the multilayer substrate. As a result, the number of laminated layers of the multilayer substrate can be smaller than that in the conventional example.

(2) Since the number of laminated layers of the multi-layered substrate is small, the printing process and the laminating process for producing the multi-layered substrate are reduced, and the labor and degreasing process are not required. As a result, the cost of the product can be reduced. (3) If the number of laminated layers of the multilayer substrate is small, the substrate becomes thin accordingly. As a result, the oscillator module with a filter can be made thinner, and the conventional mounting problems are eliminated.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a sectional view of an oscillator module with a filter according to an embodiment of the present invention.

FIG. 3 is an exploded perspective view of a conventionally proposed oscillator module with a filter.

FIG. 4 is a circuit example of a VCO with a filter.

5 is a cross-sectional view of an oscillator module with a filter having the circuit configuration of FIG.

[Explanation of symbols]

1 Shield cap 2 Multi-layer board 3 Shield layer (GND layer) 4 Component mounting surface 5 Mounted parts 6 Layer mounting the oscillator 7 Layer in which the filter part is mounted 8 blind through holes

Claims (2)

[Claims] 1. A multi-layer substrate (2) is provided with a shield layer (3) as an inner layer, and a high-frequency circuit section is mounted on one side of the multi-layer substrate (2) with the shield layer (3) as a boundary. On the other side, a filter section is built in and mounted, and a shield cap (1) is covered so as to cover the surface of the multilayer substrate on which the high-frequency circuit section is mounted, and the shield cap (1) and the shield layer (3 ) And a high frequency circuit module with a filter which shields the periphery of the high frequency circuit part by electrically connecting the shield layer (3) to a plurality of layers inside the multilayer substrate (2). High-frequency circuit module with a filter characterized by: 2. The high frequency circuit module with a filter according to claim 1, wherein the high frequency circuit section includes an oscillating section.