JP3203744B2 - Coaxial microstrip line converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial microstrip line converter used, for example, as a coaxial connector.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional coaxial microstrip line converter. The coaxial microstrip line converter 30 includes a resin case 2 made of a cube. External terminals 4 and internal terminals 5 are provided in the resin case 2. External terminal 4
Is provided on the upper surface 2 a of the resin case 2. Also,
The external terminal 4 includes an inner side surface 3a of the concave portion 3 provided on the case upper surface 2a and one opposing side surface 2b
It extends from 2c to the bottom surface 2d. Internal terminal 5
Is provided at the center of the bottom surface 2 d of the case 2, and its tip extends to the other opposing side surfaces 2 e and 2 f of the case 2.

[0003] In the drawing, reference numeral 6 denotes a pipe-shaped center conductor erected on the internal terminal 5, the tip of which protrudes into the recess 3.

[0004]

By the way, in the coaxial microstrip line converter 30 constructed as described above, the external terminal 4 formed between the external terminal 4 and the internal terminal 5, especially on the inner side surface 3a of the concave portion. The structure is such that stray capacitance F is easily generated between the internal terminal 5 and the internal terminal 5. When such a stray capacitance F occurs, the capacitance component of the converter 30 increases by the amount of the stray capacitance F, and the characteristic impedance of the converter 30 fluctuates. When the characteristic impedance fluctuates, a reflected wave is generated and a voltage standing wave ratio (VSW
R) may deteriorate, and it may be difficult to transmit an incident signal accurately and without loss.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a coaxial microstrip line converter capable of transmitting an incident signal accurately without loss by improving impedance matching. And

[0006]

In order to achieve the above object, a coaxial microstrip line converter according to the present invention comprises:
The case and the case from the top to the side of the case.
And external terminals formed along the surface of contact in the case
When subjected sides from the bottom of the kicking installation surface for mounting and an internal terminals formed on the external terminals and spaced position
In both cases, the internal terminal is connected to the external terminal provided on the side of the case.
A central conductor provided to face the external terminal;
A flat terminal portion formed along the bottom surface of the base.
The internal coaxial microstrip line converter is characterized in that the internal terminal has a narrow portion at least in a part of the terminal portion .

[0007]

According to the above construction, the internal terminal has a narrow portion, and when a high-frequency signal flows, an inductance component is generated in this portion. Since this inductance component functions to cancel the stray capacitance generated between the internal terminal and the external terminal, the fluctuation of the characteristic impedance due to the stray capacitance can be suppressed . In addition,
According to the configuration, a flat plate is placed on the bottom of the case,
And a narrow portion is provided in the terminal portion.
To generate an inductance component,
Punching the flat plate member that constitutes the terminal part by pressing
The narrow width to obtain the inductance component
A part can be formed. Therefore, the inductor is
Simpler than machining to generate
Process and obtain an arbitrary inductance component
It is easy.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a bottom view thereof.

The basic structure of the coaxial microstrip line converter 1 is the same as that of the conventional example, and the same or similar parts are denoted by the same reference numerals. That is, the coaxial microstrip line converter 1 includes a resin case 2 formed of a substantially cube. Upper surface 2a of case 2
Is formed with a concave portion 3. The case 2 is provided with an external terminal 4 and an internal terminal 10, and these terminals 4 and 10 are provided separately from each other on the surface of the case 2.

That is, the external terminals 4 provided on the upper surface 2a of the case extend to the inner peripheral surface 3a of the concave portion, and also extend to one of the opposite side surfaces 2b and 2c of the resin case 2. Further, the tip of the side extension 4a reaches the case bottom 2d. On the other hand, the internal terminal 10
Is provided on the case bottom surface 2d, and its tip 10a,
Unlike the external terminal 4, the terminal 10 a reaches the other opposing side surfaces 2 e and 2 f of the case 2.

Further, the internal terminal 10 has a pipe-shaped center conductor 6. The center conductor 6 is provided upright at the center of the internal terminal 10, and its tip projects into the recess 3.

In FIG. 1, reference numeral 20 denotes a microstrip line to which the coaxial microstrip line converter 1 is connected, 21 denotes a hot line formed on the microstrip line 20, and 22 denotes a microstrip line 20. It is an earth line formed at Reference numeral 23 denotes a through hole, which is connected to a ground line (not shown) on the back surface by a conductor (not shown) formed on the inner peripheral surface.

Next, a configuration which is a feature of this embodiment will be described.
As shown in the bottom view of FIG. 2, the internal terminal 10 does not have the same width C over the entire length, and two narrow portions 8 each having a width D smaller than the width C are provided in the middle. Have been. By providing the narrow portion 8, an inductance component is generated therein, and the stray capacitance F generated inside the coaxial microstrip line converter 1 is compensated to prevent the fluctuation of the characteristic impedance. Hereinafter, this will be described.

In the coaxial microstrip line converter 1 as well, when a high-frequency signal is incident, a stray capacitance F is generated between the external terminal 4 and the internal terminal 10. As shown in the equivalent circuit diagram of FIG. 3, the stray capacitance F is inserted in parallel into the circuit, thereby increasing the original capacitance and further reducing the characteristic impedance of the converter 1. Become.

That is, usually, the characteristic impedance Z
₀ has the following relationship: Z ₀ = √ (L / C) Z ₀ : characteristic impedance L: inductance value per unit length C: capacitance value per unit length In this equation, when the capacitance value C increases due to the generation of the stray capacitance F, the characteristic impedance Z ₀ decreases accordingly. That is, the characteristic impedance at the point where the converter 1 is inserted becomes smaller than the characteristic impedance (normally 50Ω) in the transmission network.

However, the coaxial microstrip line converter 1 is provided with a narrow portion 8 at the internal terminal 10. When a high-frequency signal is incident on the converter 1 having such a structure, the narrow portion 8 is inductance L ₁ occurs. The inductance L ₁ will be connected in parallel to the transmission circuit, also rises L values in the above expression therefor. This increase in the inductance value cancels out the increase in the capacitance value due to the stray capacitance F, so that the characteristic impedance Z ₀ does not decrease. That is compensated stray capacitance F by the inductance value L ₁ which occurs narrow portion 8, the characteristic impedance Z ₀ does not vary in transducer 1, matching with the transmission network will be able to keep.

The stray capacitance F generated in the converter 1
Varies slightly depending on the shape and permittivity of the case 2 and the shapes of the terminals 4 and 10. Therefore, the shape and number of the narrow portions 8 that compensate for the stray capacitance F may be changed accordingly. That is, in the above-described embodiment, a total of two narrow portions 8 are formed.
The number of the narrow portions 8 is further increased, or conversely, is made single according to the value of the terminal 10, and further, the entire width of the terminal 10 is made smaller than a predetermined width, so that the entire internal terminal 10 becomes narrower.
It may be.

The voltage standing wave ratio (VSS) of the coaxial microstrip line converter 1 of this embodiment thus constructed
WR) is shown in FIG. 4, and the voltage standing wave ratio (VSWR) of the conventional coaxial microstrip line converter 30 is shown in FIG. As is clear from these figures, it is understood that the voltage standing wave ratio (VSWR) is improved (reduced) in the coaxial microstrip line converter of the present invention.

Further, in the present embodiment, the present invention is applied to the coaxial microstrip line converter 1. However, it is needless to say that the structure of the present invention can be applied to a coaxial coplanar converter. Absent.

[0020]

As described above, according to the present invention, a narrow portion is provided in an internal terminal, and a stray capacitance generated in a converter is compensated by an inductance component generated in the narrow portion. Therefore, the characteristic impedance in the converter does not decrease and the impedance matching is improved. Therefore, the coaxial microstrip line converter has low reflection, low voltage standing wave ratio (VSWR),
The incident signal can be transmitted accurately without loss. According to the present invention, the mounting surface is used for mounting.
A flat terminal portion is provided on the bottom of the case,
With a narrow part in the child part, an inductance component is generated.
Press the flat plate member that constitutes the terminal
By punching with
It is possible to form a narrow portion for obtaining a portion. Therefore, axial
For processing so that an inductance component is generated
Processing is simpler than in the case of
It is easy to obtain a conductance component.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the structure of a coaxial microstrip line converter according to one embodiment of the present invention.

FIG. 2 is a bottom view of the coaxial microstrip line converter of the embodiment.

FIG. 3 is an equivalent circuit diagram of a transmission network to which the coaxial microstrip line converter of the above embodiment is connected.

FIG. 4 is a diagram showing a voltage standing wave ratio (VSWR) of the coaxial microstrip line converter of the embodiment.

FIG. 5 is a diagram showing a voltage standing wave ratio (VSWR) of a conventional coaxial microstrip line converter.

FIG. 6 is a partially cutaway perspective view showing the structure of a conventional coaxial microstrip line converter.

[Explanation of symbols]

 2 Case 4 External terminal 8 Narrow section 10 Internal terminal

Claims (1)

(57) [Claims] 1. A case (2), an external terminal (4) formed along the surface of the case (2) from the upper surface to the side surface of the case (2), and a case in the case (2).
An internal terminal (10) formed at a position separated from the external terminal (4) from a bottom surface to a side surface, which is a mounting surface for mounting ;
And the internal terminal (10) is provided in the case
(2) facing the external terminal (4) provided on the side surface;
A central conductor (6) provided at the bottom of the case (2)
A coaxial microstrip line converter comprising a flat terminal formed along a surface , wherein the internal terminal (10) is narrow at least partially in the terminal. A coaxial microstrip line converter comprising a width portion (8).