JPH07101815B2 - Ultra-high-frequency voltage controlled oscillator varactor diode mounting structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a varactor diode mounting structure for an ultra high frequency voltage controlled oscillator, and more particularly to a varactor diode mounting structure for an ultra high frequency voltage controlled oscillator with a high oscillation output (about 0.5 w or more) using a varactor diode. Regarding

2. Description of the Related Art Conventionally, in this type of ultra-high frequency voltage controlled oscillator, since the power consumed by the varactor diode is generally large, heat radiation to the outside is required. Since the heat of the varactor diode normally flows out to the cathode side, the cathode electrode is mounted on a metal chassis to obtain a good heat dissipation result, and one electrode of the varactor diode is used by being grounded at high frequency. When the cathode electrode is mounted on a metal chassis, the cathode electrode is directly grounded, and good results are obtained in terms of grounding. However, when there is only a single positive voltage, or when it is necessary to separate both electrodes of the varactor diode from the ground potential in terms of direct current in the circuit configuration, the cathode electrode of the varactor diode cannot be mounted directly on the metal chassis. The structure is as shown in the figure.

In FIG. 2, the cathode electrode of the varactor diode 1 is embedded in a diode mounting metal mount 12 and soldered, and the diode mounting metal mount 12 is insulated by an insulating mica plate 13 and an insulating material 14. It is attached to the metal chassis 8 and fixed to the metal chassis 8 with nuts 15. The varactor diode 1 is connected to the circuit board 3 by a conductor piece 16. Therefore, the high frequency grounding and heat dissipation of the cathode electrode of the varactor diode 1 are determined by the shape, the dielectric constant and the thermal resistance of the insulating mica plate 13. However, since the frequency band used is the microwave band, the material of the insulating mica plate 13 is also limited, and mica is usually used as the material.

The nut 15 is a cathode electrode of the varactor diode 1 in terms of potential, and the cathode electrode of the varactor diode 1 is directly exposed to the outside of the oscillator. in this case,
Since microwave leakage becomes a problem, it is necessary to select a radio wave absorber, usually an epoiron, as the insulating material 14.
More often, it is necessary to insert an epoiron between the insulating mica plate 13 and the nut 15.

In such a conventional ultra-high frequency voltage controlled oscillator, many mechanical parts having a complicated structure are used in the structure formed in order to obtain good results in the heat dissipation of the varactor diode 1 and the high frequency grounding, and the cost is increased. Not only that, but the high-frequency grounding capacity is determined by the thickness and size of the insulating mica plate 13. Therefore, in order to obtain the practically necessary capacity [several PF (picofarad) or more], make the shape larger. It has the drawback of having to. Further, in the conventional structure in which the diode mounting metal mount 12 in which the cathode electrode of the varactor diode 1 is embedded is guided to the outside of the oscillator, even if a radio wave absorber is used for the insulating material 14, a high frequency current to the outside is generated. Has the drawback that it often becomes a problem.

The object of the present invention is to eliminate the above-mentioned drawbacks of the conventional ones, and it is possible to reduce the number of parts, the structure is simple, the cost can be reduced, and the problem of microwave leakage does not occur. An object is to provide a varactor diode mounting structure for a voltage controlled oscillator.

Structure of the Invention A varactor diode mounting structure for an ultra high frequency voltage controlled oscillator according to the present invention is a varactor diode mounting structure for an ultra high frequency voltage controlled oscillator having a varactor diode, wherein a circuit pattern portion is provided on one of the upper and lower surfaces and a full conductor is provided on the other side. A first dielectric having respective parts, a second dielectric having full-surface conductors on both upper and lower surfaces, and a conductive good heat conductor provided so as to penetrate the first dielectric. The first dielectric and the second dielectric are adhered to each other on the entire surface conductor portions, and one electrode of the varactor diode is attached to the circuit pattern portion of the first dielectric. In addition, the second dielectric has a smaller thermal resistance and a larger dielectric constant than the first dielectric.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings.

1 (a) is a plan view showing an embodiment of the present invention, and FIG. 1 (b) is a sectional view taken along the line AA of FIG. 1 (a). In the figure, the cathode electrode of the varactor diode 1 is connected to the circuit pattern of the dielectric 4 whose upper surface is a circuit pattern and whose lower surface is a full conductor, and the dielectric 4 is a dielectric whose upper and lower surfaces are all conductive conductors. The entire surface of the conductor 6 is soldered or bonded with an adhesive, and the dielectric 6 is bonded and fixed to the metal chassis 8. Further, a conductive good heat conductor (for example, a copper conductor) 5 is provided so as to penetrate through the dielectric 4, and one side of the Teflon glass fiber circuit board passes through the connecting conductor piece 7 on the circuit pattern. A chip capacitor 2 grounded by a through hole 11 provided in 3 is provided, and a fine circuit wire 9 for connection further connects the circuit pattern and the capacitor capacitor 10.

When a Teflon glass fiber substrate is used as the dielectric 4, if an alumina ceramic substrate having a low thermal resistance and a high dielectric constant is selected as the dielectric 6, the heat of the varactor diode 1 has a lower thermal resistance than the dielectric 4. Heat conductor 5
It is conducted to the dielectric body 6 through and is radiated to the metal chassis 8.

Further, the high-frequency grounding of the varactor diode 1 is such that the dielectric 4 has a small permittivity, so that the varactor diode 1 is grounded to the dielectric 6 having a large permittivity through the good heat conductor 5 at a high frequency, and the grounding capacitance of the dielectric 6 is high. Several PF can be obtained by using an alumina ceramic substrate. If this ground capacity is insufficient, the chip capacitor 2 can add an arbitrary capacity.

Since the cathode electrode of the varactor diode 1 is connected to the outside as shown in FIG. 1 (b), microwave leakage becomes a problem. However, due to the inductance of the connection thin wire 9 and the capacitance of the Kantz-type capacitor 10. If the low-pass filter is formed, the connection fine line 9 is connected to the circuit pattern of the dielectric 4, so that microwave leakage to the outside is sufficiently improved. Further, if necessary, the solution can be solved by using a can-type capacitor containing an absorber as the can-type capacitor 10.

In this manner, the upper and lower surfaces are the circuit pattern portion, the multi-sided surface is the whole conductor portion of the dielectric 4, and the upper and lower surfaces are the whole surface conductor portion of the dielectric body 6 and the whole surface conductor portions are bonded together. ,
An ultra high frequency voltage controlled oscillator having a structure in which one electrode of the varactor diode 1 is connected to the circuit pattern portion is
Especially when the output is high (0.5w or more) and one side of the varactor diode 1 cannot be directly grounded, the structure is simple and small compared to the structure of the conventional example as shown in FIG. 2, and the number of parts is reduced. The cost is reduced and the problems due to microwave leakage are eliminated.

As a recent trend, a digital APC Loop (digital automatic phase control loop) is often used to improve the frequency stability of the voltage controlled oscillator. In this case, both electrodes of the varactor diode 1 should not be grounded. However, this embodiment is effective in such a case.

EFFECTS OF THE INVENTION As described above, according to the present invention, one surface of the upper and lower surfaces is the circuit pattern portion, and the first and second surfaces are the whole surface conductor portion.
The upper surface and the lower surface of both surfaces are bonded to the second dielectric material of the full-surface conductor portion at each of the full-area conductor portions, and one electrode of the varactor diode is connected to the circuit pattern portion of the first dielectric material, and By using a dielectric having a smaller thermal resistance and a larger permittivity than the first dielectric, the structure is simple and small, the number of parts can be reduced, the cost can be reduced, and microwave leakage can occur. The effect is that no problems will occur.

[Brief description of drawings]

1 (a) is a plan view showing an embodiment of the present invention, FIG. 1 (b) is a sectional view taken along the line AA of FIG. 1 (a), and FIG. 2 is a longitudinal sectional view showing a conventional example. is there. Explanation of symbols of main parts 1 ... Varactor diode 2 ... Chip capacitor 4 ... One side is a circuit pattern and the other side is a conductor of full conductor 5 ... Good heat conductor 6 ... Both sides are full conductor Dielectric 9 …… Thin wire for connection 10 …… Kanto type capacitor

Claims (1)

[Claims] 1. A varactor diode mounting structure for an ultra-high frequency voltage controlled oscillator having a varactor diode, comprising:
A first dielectric having a circuit pattern portion on one of the upper and lower surfaces and a full conductor portion on the other, a second dielectric having full conductor portions on both upper and lower surfaces, and penetrating the first dielectric. The first dielectric and the second dielectric are adhered to each other by the whole conductor portions, and the first dielectric is provided. One of the electrodes of the varactor diode is connected to the circuit pattern portion, and the second dielectric has a lower thermal resistance and a higher dielectric constant than the first dielectric. The varactor diode mounting structure for the ultra high frequency voltage controlled oscillator.