JP4095263B2 - High frequency package - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency package that accommodates high-frequency circuit components and the like.
[0002]
[Prior art]
The high-frequency package has a structure in which a region on which a circuit component is arranged on a base plate is surrounded by a rectangular frame having a predetermined height, and a line conductor penetrates from the outside to the inside of the frame. Then, the line conductor projecting inside the frame and the circuit component arranged on the base plate in the frame are connected by wire bonding or the like.
[0003]
As one of the high-frequency packages described above, there is a so-called metal wall package type in which a base plate and a frame part are formed of metal and an internal space surrounded by the frame is shielded.
[0004]
In the metal wall package type, a part of a metal frame is formed of a dielectric member such as ceramic, and a line conductor penetrates the part of the dielectric member. The line conductor portion located inside the metal frame is formed on the dielectric substrate.
[0005]
[Problems to be solved by the invention]
In a conventional high-frequency package, for example, a metal wall package type, a line conductor penetrates a part of a dielectric member provided in a part of a metal frame, and a line conductor part extending into the metal frame is on a dielectric substrate. Is provided. In this case, a coaxial line having a metal frame or a base plate as an outer conductor is formed in a portion penetrating the metal frame, and a microstrip line having a base plate as a ground conductor is formed inside the metal frame. The
[0006]
In the case of the high-frequency package having the above structure, for example, a dielectric member provided in a part of a metal frame and a dielectric substrate positioned inside the metal frame are integrally formed, and the same dielectric material is used. Yes. Therefore, the characteristic impedance of the coaxial line formed in the penetrating portion of the metal frame and the microstrip line formed inside the metal frame are different. For example, the characteristic impedance of the microstrip line is the coaxial line. And the electrical characteristics such as the voltage standing wave ratio are deteriorated.
[0007]
In this case, it is conceivable to increase the width of the line conductor located inside the metal frame and reduce the characteristic impedance of the microstrip line. However, when the line conductor is made to penetrate the dielectric member of the metal frame body, usually, a hole through which the line conductor passes is made in the dielectric member, and after passing the line conductor through this hole, the dielectric member is heated to A method of hermetically sealing the conductor is taken. Therefore, when the width of the tip end portion of the line conductor is wide, the hole formed in the dielectric member is also increased accordingly. As a result, when the dielectric member is heated and the line conductor is sealed, it is difficult to ensure airtightness between the line conductor and the dielectric member, which is narrower than the tip portion.
[0008]
An object of the present invention is to provide a high-frequency package that solves the above-described drawbacks and that provides a good voltage standing wave ratio and airtightness.
[0009]
[Means for Solving the Problems]
The present invention provides a base plate on which circuit components are arranged, a metal frame that surrounds a region of the base plate on which the circuit components are arranged at a predetermined height, and a part of which is formed of a dielectric member, and the metal A dielectric substrate provided on the base plate adjacent to the portion of the dielectric member on the inner side surrounded by the frame body, and extending through the dielectric member to the dielectric substrate; A high-frequency package comprising a strip-shaped line conductor having a uniform width that forms a coaxial line at a portion penetrating a body member and forms a microstrip line on the dielectric substrate, wherein a part of the metal frame is formed The relative dielectric constant of the dielectric substrate is made larger than that of the dielectric member to be formed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG.
[0011]
Reference numeral 11 denotes a metal base plate, and a rectangular metal frame 12, for example, is formed at a predetermined height so as to surround an area where circuit components are arranged on the metal base plate 11. For example, through holes 12a and 12b having a rectangular cross section are provided in a part of two opposite frame body sides 121 and 122 of the metal frame body 12, for example. The portions of the through holes 12a and 12b are sealed with dielectric members 13a and 13b having a predetermined relative dielectric constant, for example, glass. Further, inside the metal frame 12, adjacent to the dielectric members 13 a and 13 b constituting a part of the metal frame 12, the glass frame 12 is made of glass having a relative dielectric constant larger than that of the dielectric members 13 a and 13 b. Dielectric substrates 14 a and 14 b are provided on the base plate 11. The dielectric substrate 14a is not shown because of the drawing.
[0012]
For example, strip-like line conductors 15 a and 15 b made of Kovar material extend through the dielectric members 13 a and 13 b to the dielectric substrates 14 a and 14 b inside the metal frame 12. The line conductors 15a and 15b are connected to circuit components (not shown) arranged in the metal frame 12 by wire bonding, for example, using the width portions.
[0013]
In addition, after the wire conductors 15a and 15b and circuit components are wire-bonded, the upper opening of the metal frame 12 is sealed with a lid (not shown).
[0014]
Here, FIG. 2A shows a structure of the high-frequency package of FIG. 1 viewed from above. FIG. 2B shows a cross-sectional view of FIG. 2A taken along line aa. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.
[0015]
In the case of the configuration described above, the line conductors 15 a and 15 b constitute a coaxial line having the metal frame body 12 and the base plate 11 as outer conductors in a portion penetrating the frame body 12. Inside the metal frame 12, a microstrip line having the base plate 11 as a ground conductor is formed. In this case, the relative dielectric constants of the dielectric substrates 14a and 14b inside the metal frame 12 are made larger than the dielectric members 13a and 13b constituting a part of the metal frame 12. Therefore, the difference in characteristic impedance between the coaxial line in the metal frame 12 portion and the microstrip line inside the metal frame 12 is reduced, and the voltage standing wave ratio is reduced.
[0016]
For example, glass having a relative permittivity of 4.1 is used as the dielectric members 13a and 13b constituting a part of the metal frame 12, and the relative permittivity is 7.0 as the dielectric of the dielectric substrates 14a and 14b. In the case of using the above glass, the voltage standing wave ratio of the high frequency input / output terminal was reduced from 2.1 to 1.3 as compared with the case where a dielectric material having a relative dielectric constant of 4.1 was used for both.
[0017]
In the above embodiment, glass is used for the dielectric member in the metal frame portion and the dielectric substrate inside the metal frame. Compared to ceramic, glass has a wider range of relative permittivity and is suitable for the present invention.
[0018]
In addition, in the case of the above configuration, since the width of the line conductor is uniform, it is not necessary to enlarge the hole provided in the dielectric member of the metal frame portion during manufacturing, and the airtightness of the line conductor and the dielectric member is not required. Is secured.
[0019]
In the above embodiment, Kovar is used as the strip-shaped line conductor. In this case, since the coefficient of thermal expansion of Kovar is substantially the same as that of the glass of the dielectric material, airtightness between the strip-shaped line conductor and the dielectric member is ensured.
[0020]
【The invention's effect】
According to the present invention, a high frequency package capable of obtaining a good voltage standing wave ratio and airtightness is realized.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining an embodiment of the present invention.
2A and 2B are a top view and a cross-sectional view for explaining an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Base plate 12 ... Metal frame 13a, 13b ... Dielectric member 14a, 14b ... Dielectric board | substrate 15a, 15b ... Strip-shaped line conductor

Claims (4)

A base plate on which circuit components are arranged, a metal frame that surrounds a region in which the circuit components are arranged on the base plate at a predetermined height, and a part thereof is formed of a dielectric member; and the metal frame Inside the enclosed area, adjacent to the dielectric member portion, a dielectric substrate provided on the base plate, and extends through the dielectric member to the dielectric substrate and penetrates the dielectric member A dielectric line forming a part of the metal frame in a high-frequency package comprising a strip-shaped line conductor having a uniform width that forms a coaxial line on the dielectric substrate and forms a microstrip line on the dielectric substrate. A high frequency package characterized in that a relative permittivity of the dielectric substrate is made larger than a relative permittivity of a body member.   The high frequency package according to claim 1, wherein the dielectric member forming a part of the metal frame has a rectangular cross section in a plane perpendicular to the extending direction of the strip-shaped line conductor.   2. The high frequency package according to claim 1, wherein the dielectric member and the dielectric substrate forming part of the metal frame are made of a glass material.   The high-frequency package according to any one of claims 1 to 3, wherein a material forming the strip-shaped line conductor is Kovar.

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