JP2001217560A - High frequency module incorporating oscilation circuit and communication machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency circuit module incorporating oscillation circuit which prevents the deterioration of a characteristic due to the vibration of a metallic case, and to provide a communication machine using it. SOLUTION: Electronic parts are loaded on a substrate and an oscillation circuit is constituted. The metallic case fitted on the substrate is constituted of sidewalls following the outer periphery of the substrate of the vicinity of the outer periphery and a top face parallel to the substrate. The adjacent sidewalls are jointed by solder.

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 having a built-in oscillation circuit, such as a voltage-controlled oscillator and a PLL module, and a communication device using the same.

[0002]

2. Description of the Related Art A high frequency circuit module such as a voltage controlled oscillator or a PLL module has chip components such as a chip resistor, a chip capacitor, and an FET mounted on a substrate, and a power input terminal, a control voltage input terminal, and a signal on an end surface of the substrate. Various terminal electrodes such as an output terminal and a ground terminal are provided, and a cover-shaped metal case is mounted on the upper part of the substrate.

[0003]

However, in a conventional high-frequency circuit module having such a built-in oscillation circuit, a metal plate is punched out in a five-sided development view of a rectangular parallelepiped and bent to form a high-frequency circuit. Manufactures metal cases for circuit modules.

However, in a metal case having such a structure, the top surface of the case is easily deformed by external stress. This is shown in FIG. Arrows in the figure are external forces. When an external force is applied to the metal case in this way, the butted portions of the adjacent side walls are shifted, and the entire metal case is easily distorted. As a result, the positional relationship between the microstrip line or component formed on the substrate and the top surface of the metal case will change due to the vibration of external force, and as a result, the phase noise and spurious characteristics of the oscillation circuit will deteriorate. There was a problem.

An object of the present invention is to provide a high-frequency circuit module with a built-in oscillation circuit, which prevents deterioration of characteristics due to deformation and vibration of a metal case, and a communication device using the same.

[0006]

A high frequency circuit module with a built-in oscillation circuit according to the present invention comprises an electronic component mounted on a substrate to form an oscillation circuit, and a metal case mounted on the substrate.
A top surface portion that is substantially parallel to the substrate and a side wall portion that is continuous with the top surface portion along the outer periphery or near the outer periphery of the substrate, and the adjacent side wall portions are welded to each other.

With this structure, the butted portions of the adjacent side walls are joined, so that even if an external force is applied to the top surface of the metal case, the metal case is not easily deformed and the rigidity of the metal case is increased. As a result, deterioration of the phase noise and spurious characteristics of the oscillator due to the vibration of the metal case can be prevented.

Further, the high-frequency circuit module with a built-in oscillation circuit according to the present invention is a high-frequency circuit module with a built-in oscillation circuit, wherein an electronic component is mounted on a substrate to form an oscillation circuit and a metal case is mounted on the substrate. By drawing the plate, the metal case is composed of a top surface portion substantially parallel to the substrate and a side wall portion along the outer periphery or near the outer periphery of the substrate, and adjacent side wall portions, and the side wall portion and the top surface portion Is a continuum.

According to this structure, the adjacent side walls are integrated with each other, and the side wall portion and the top surface portion are integrated with each other.
Even if an external force is applied to the top surface of the metal case, the metal case is not easily deformed, and the rigidity of the metal case increases. As a result, deterioration of the phase noise and spurious characteristics of the oscillator due to the vibration of the metal case can be prevented.

[0010] A communication device according to the present invention is configured by mounting the high-frequency circuit module with a built-in oscillation circuit on a circuit board.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a PLL module according to a first embodiment will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the PLL module. Here, reference numeral 1 denotes a substrate made of a dielectric ceramic, which forms a microstrip line by forming a ground electrode on substantially the entire lower surface thereof and forming a line of a predetermined pattern on the upper surface thereof. Various terminal electrodes 2 such as a power terminal, a data input terminal, a signal output terminal, and a ground terminal are formed in concave portions on four end surfaces of the substrate 1. Further, on the upper surface of the substrate 1, various electronic components such as a chip resistor, a chip capacitor, and a PLL integrated circuit chip are mounted.

In FIG. 1, reference numeral 4 denotes a metal case, which is formed by punching and bending a metal plate as described later. The metal case 4 includes a top surface having substantially the same size as or slightly smaller than the substrate 1 and four side walls (side wall A, side wall B, side wall C, and side wall D) continuous with the top surface. Protrusions 5 projecting downward on the side walls B and D
When the metal case 4 is attached to the upper part of the substrate 1, the protrusion 5 comes into contact with or comes close to the concave portion of the predetermined terminal electrode forming portion.

FIG. 2 is a view showing a state before the metal case 4 is bent. In this way, a metal plate is punched out in a developed shape of the metal case 4 and a position shown by a broken line in the figure is bent downward by 90 ° to form a cover shape. Thereafter, the adjacent side walls are soldered at the butted portions.

FIG. 3 shows a state where the side wall A and the side wall B abut against each other. In this way, the portion where two adjacent side walls A and B abutted by bending the metal plate are soldered. Between the side walls B and C,
The same applies between the side walls C and D and between the side walls D and A. This structure greatly increases the rigidity of the entire metal case.

In the example shown in FIG. 3, the adjacent side wall portions are welded using solder as a bonding material, but the metal plates may be directly welded.

The metal case 4 constructed as described above
Is placed on the top of the substrate 1 shown in FIG.
Is soldered to a terminal electrode 2 as a predetermined ground terminal on the end face of the substrate 1. Thus, a PLL module covered by the metal case 4 is configured.

Since the length of the side wall A and the side wall C hanging from the top surface is shorter than the length of the side wall B and the side wall D hanging from the top surface, the metal case 4 In the attached state, the lower end sides of the side walls A and C are separated from the upper part of the terminal electrode 2 on the substrate side by a predetermined distance. Therefore, these terminal electrodes do not short-circuit to the ground via the metal case.

With such a mounting structure of the metal case, the side wall of the metal case in which the projection 5 is not formed rises from the substrate. However, since the rigidity of the entire metal case 4 is high, stress from the outside is increased. Even if it is applied, the vibration of the top surface of the metal case is suppressed. As a result, the positional relationship between the microstrip line or the electronic component formed on the substrate and the top surface can always be kept constant, and the phase noise and spurious characteristics of the oscillator do not deteriorate.

FIG. 4 is a block diagram of the PLL module. Here, the PLL divides the oscillation signal of the VCO at a division ratio according to the control data, detects a phase difference between the signal and a reference frequency signal, and outputs a detection signal. The loop filter is a low-pass filter or the like, and converts a detection signal output from the PLL into a control voltage signal for the VCO. The VCO is a voltage controlled oscillator that oscillates at an oscillation frequency according to the input control voltage. This VCO is composed of a main line provided with a reflection amplification circuit at an end, a sub line connected to a variable capacitance element, and a dielectric resonator coupled to both the main and sub lines.

In the embodiment described above, the PLL module is taken as an example. However, as in the case of the VCO in FIG. 4, a main / sub line and a reflection amplifier circuit are provided on a substrate, and both main and sub lines are provided. Regarding the voltage controlled oscillator in which the dielectric resonator to be coupled is arranged, the metal case may be configured in the same manner as that shown in FIGS. Further, the present invention can be similarly applied to other high frequency circuit modules with a built-in oscillation circuit.

FIG. 5 is a partial perspective view of a metal case used in the high-frequency circuit module with a built-in oscillation circuit according to the second embodiment before drawing. In this example, a metal plate is punched out as shown in FIG. 5A, and drawing is performed so that the area shown by the broken line in the figure becomes the top surface. FIG. 5B is a partial perspective view of the metal case after drawing. In this way, the top surface and the side walls A and B are made into a continuous body by drawing the metal plate. Similarly, regarding the positions of other adjacent side wall portions, the side wall portion and the top surface portion are set as a continuous body. According to this structure, it is not necessary to perform a welding process between adjacent side walls by soldering or welding after bending.

Next, the configuration of the communication device will be described with reference to FIG. In the figure, ANT is a transmitting / receiving antenna, DPX is a duplexer, BPFa, BPFb, and BPFc are band-pass filters, AMPa and AMPb are amplifier circuits, MIXa and MIXb are mixers, and TCX.
O is an oscillator, and PLL is a PLL module that generates a predetermined local signal using TCXO as a reference frequency signal. The VCO is a voltage controlled oscillator that modulates the oscillation frequency with a signal corresponding to a transmission signal (transmission data).

The MIXa modulates a frequency signal output from the PLL with a modulation signal, the BPFa passes only a transmission frequency band, and the AMPa amplifies the power and transmits the amplified signal from the ANT via the DPX. BPFb allows only the reception frequency band of the signal output from the DPX to pass, and AMP
b amplifies it. The MIXb mixes the frequency signal output from the BPFc with the received signal and outputs an intermediate frequency signal IF.

In the PLL module shown in FIG.
A module having the structure shown in FIGS. 1 to 4 is used. Also,
A module having the above-described metal case is used for the voltage controlled oscillator VCO. These high-frequency modules with built-in oscillation circuits are mounted on a circuit board (motherboard) of a communication device.

The above communication device is a portable telephone for notifying an incoming call using a vibrator or the like. Even if the whole device is vibrated by a vibrator or the like, the characteristics of the high-frequency module with a built-in oscillation circuit do not change.
Thus, a small communication device having excellent communication characteristics in cellular wireless communication can be obtained.

[0026]

According to the first aspect of the present invention, the butted portions of the adjacent side walls are joined, so that even if an external force is applied to the top surface of the metal case, the metal case is not easily deformed. The rigidity of the metal case increases. As a result, deterioration of the phase noise and spurious characteristics of the oscillator due to the vibration of the metal case can be prevented.

According to the second aspect of the present invention, the adjacent side walls are integrated with each other, and the side wall portion and the top surface portion are integrated with each other. The case is not easily deformed, and the rigidity of the metal case is increased. As a result, deterioration of the phase noise and spurious characteristics of the oscillator due to the vibration of the metal case can be prevented. Also,
It becomes unnecessary to perform a welding process between adjacent side walls by soldering or welding after bending.

According to the third aspect of the present invention, there is no deterioration in the phase noise and spurious characteristics of the oscillator, and the PDC, PH
A small communication device having excellent communication characteristics in cellular wireless communication such as S and GSM can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a PLL module according to a first embodiment.

FIG. 2 is a diagram showing a state before bending a metal case used in the PLL module;

FIG. 3 is a perspective view showing a configuration of a corner portion of the metal case.

FIG. 4 is a block diagram of the PLL module.

FIG. 5 is a diagram showing a configuration of a metal case of the high-frequency circuit module with a built-in oscillation circuit according to the second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a communication device.

FIG. 7 is a diagram showing a deformed state of a case in a conventional high-frequency circuit module.

[Explanation of symbols]

 1-substrate 2-terminal electrode 3-electronic component 4-metal case 5-projection

Claims (3)

[Claims] 1. A high-frequency circuit module with a built-in oscillation circuit in which an electronic component is mounted on a substrate to form an oscillation circuit and a metal case is mounted on the substrate, wherein the metal case is substantially parallel to the substrate. A high frequency circuit module with a built-in oscillation circuit, comprising: a top surface portion; and a side wall portion which is continuous with the top surface portion along the outer periphery or the vicinity of the outer periphery of the substrate, and the adjacent side wall portions are welded to each other. 2. A high-frequency circuit module with a built-in oscillation circuit comprising an electronic component mounted on a substrate to form an oscillation circuit and a metal case mounted on the substrate, wherein the metal case is drawn by drawing a metal plate. A top surface portion substantially parallel to the substrate, and a side wall portion along the outer periphery or near the outer periphery of the substrate, adjacent side wall portions, and the side wall portion and the top surface portion as a continuous body High frequency circuit module with built-in oscillation circuit. 3. A communication device comprising the high-frequency circuit module with a built-in oscillation circuit according to claim 1 mounted on a circuit board.