JPH06275345A - High-frequency coaxial connector - Google Patents

Abstract

PURPOSE:To provide a high-frequency coaxial connector having electrically stable characteristics in the frequency from DC to 40GHz or higher, having no impedance mismatch and no leak of radio waves, and excellent mechanically. CONSTITUTION:A high-frequency coaxial connector is constituted of a central conductor, a dielectric layer, and an outer conductor, and a central conductor small-diameter section 6 is provided near the center section of the central conductor. An outer conductor inner diameter expansion section 7 is provided on the inner wall of the outer conductor at the position corresponding to it. An adhesive hardening type high-dielectric resin is filled and hardened in the space formed by the central conductor small-diameter section 6 and the outer conductor inner diameter expansion section 7. A high-dielectric resin layer 8 is provided to firmly bond the central conductor, dielectric layer, and outer conductor.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is used in microwaves, millimeter waves, especially in SHF band including Ku and Ka bands, and also in EHF band, and has stable electric characteristics and excellent mechanical characteristics. It relates to high frequency coaxial connectors.

SMA type connectors are from DC to 18 GHz
It has been widely used in the field of, but in order to use it in the short wavelength band of K band or more, it is used in higher frequency band by changing the specifications of the center conductor, dielectric and outer conductor. It is being made possible.

However, in the high frequency coaxial connector used in the microwave or millimeter wave, it is required that the voltage standing wave ratio (hereinafter referred to as VSWR) is small, there is no radio wave leakage, and the reproducibility is excellent. To be done.

[0004]

2. Description of the Related Art In a high frequency coaxial connector, how to reduce the VSWR of a conductor, to minimize radio wave leakage, and how to firmly support it is a problem, and it has been conventionally used. As a method, for example, Japanese Patent Publication Sho 5
As disclosed in Japanese Patent Laid-Open No. 2-6474, a method is used in which a hole is formed in an outer conductor and a dielectric, epoxy resin is injected into the hole, and the center conductor, the dielectric, and the outer conductor are joined.

However, according to this method, there is a drawback that radio wave leakage increases and VSWR increases in the Ku and Ka wave bands, and at present, improvement thereof is desired.

[0006]

In general, a coaxial connector ideally has a uniform cross section in the lengthwise direction, and discontinuity in the lengthwise direction causes a reflected wave and seriously affects the microwave. Therefore, it is necessary to eliminate the discontinuity inside the connector. However, if a connector is used if necessary, it is necessary to use the short discontinuity as described above to stably hold the center conductor and minimize reflection due to the discontinuity.

Here, the inventor of the present invention has a small VSWR, no radio wave leakage, excellent mechanical and electrical characteristics, and excellent moisture resistance and corrosion resistance.
It is an object of the present invention to provide a high frequency coaxial coaxial connector such as an SMA type which can be effectively and effectively used even in a super high frequency region of Hz or higher.

[0008]

A center conductor end portion of such a high frequency coaxial connector is made into a male and female turn, and by inserting the male terminal center conductor into the female terminal center conductor, both of them are elastic springs. It is firmly joined by force, and it is devised to avoid impedance mismatch due to discontinuity at the end of the connector.

However, when attachment / detachment of the turn connector is reversed, relative axial movement occurs between the central conductor and another connector member such as an insulating material. To prevent this, an insulator is used. Must be fixed to the center conductor. Also, the rotational movement of the insulator and outer conductor must be controlled so that the center conductor rotates and thus does not loosen.

In order to prevent such relative movement of the center conductor, the insulator and the outer conductor, in the present invention, a coaxial constriction portion is provided near the center portion of the center conductor of the connector, and it corresponds to this. An inner diameter enlarged portion is provided on the inner wall of the outer conductor at the position, the space defined by the both is filled with an adhesive high-dielectric substance to eliminate the electrical impedance mismatch in the connector, and both the dielectric and the outer conductor-
The present invention has been completed by finding that it can be safely used in a mechanically strongly bonded state even in a severe environment such as 65 ° to + 125 ° C.

That is, according to the present invention, in a high frequency coaxial connector comprising a central conductor, a dielectric layer and an outer conductor, a coaxial small diameter portion is provided in the vicinity of the central portion of the central conductor, and the inner wall of the outer conductor at a position corresponding to this portion. Has a coaxial inner diameter expansion part,
The space defined by the small-diameter portion and the enlarged inner-diameter portion is filled with an adhesive curable high-dielectric resin and cured to firmly bond the center conductor, the dielectric layer and the outer conductor, and at the same time, high-frequency coaxial with respect to high frequency. The present invention provides a high-frequency coaxial connector characterized by providing an impedance substantially matching the characteristic impedance of the connector.

Referring to the drawings, in FIG. 1, a central conductor 5 having a diameter d ₁ and an insulator layer 4 having a dielectric constant ε ₁ are shown.
And 23, and the outer conductor 11 having the inner diameter D ₁ constitutes a coaxial line having a constant characteristic impedance,
A concentric small-diameter portion 6 having a diameter d ₂ is provided near the center of the central conductor 5, and an inner diameter enlarged portion 7 having an inner diameter D ₂ larger than the inner diameter D ₁ is provided at a position corresponding to the outer conductor.
And a space defined by the small diameter portion and the enlarged inner diameter portion is filled with an adhesive curable dielectric resin having a dielectric constant greater than the dielectric constant ε ₁ of the insulating layer to form a coaxial portion having a short thickness L. By doing so, the central conductor 5, the insulator layer 4, and the outer conductor 11 are mechanically and firmly integrated.

In this system, the reflection coefficient of the system obtained by the theoretical analysis is

[Equation 1] (Wherein, Cd is step蓉量, f is the frequency, _{V O} light _{speed, Y O,} Y _H indicates the Adomitsutansu of each line) can be easily obtained from.

Since the characteristic impedance Z _O of the coaxial line is usually defined as 50Ω by the standard, if the diameter of the central conductor and the dielectric constant of the insulator are determined, the diameter D ₂ of the Teflon coating layer will be

[Equation 2] (Equations D and d represent the diameters of the small diameter portion and the enlarged inner diameter portion, respectively, and ε represents the dielectric constant of the insulator.)

[0015]

[Equation 1] Furthermore, the impedance Z _H of the small diameter part is set to 5 by theoretical calculation.
When the value is set to about 1Ω, the preferable result that the reflection coefficient is 0.01 or less is obtained. Therefore, the diameter d ₂ of the central conductor of the small-diameter portion is set in consideration of the diameter d ₁ of the normal diameter portion of the central conductor. If it is made a little smaller than this, the effect can be achieved. In consideration of mechanical strength and electrical performance, and considering that the dielectric constant of epoxy resin is 2.8,

[Equation 2] (In the formula, each symbol is as described above.) From the above, the coating diameter D ₂ of the epoxy resin can be easily obtained. The thickness L is determined in consideration of the mechanical strength and the influence of higher order mode generation.
The thickness L is determined in consideration of the mechanical strength and the influence of higher order mode generation.

As described above, one of the major features of the system used in the present invention is that the theoretical analysis is easy and the calculation result shows a good agreement with the actual measurement value.

The coaxial male connector 1 of the present invention shown in FIG. 1 is located inside a hollow metallic tubular outer conductor 3 having a hollow portion 2 and a hollow portion 2 and a space between the central conductor 5 and the hollow conductor 2. Insulators 4, 23 filled and extending coaxially with the tubular outer conductor 3.
And a metal rod-shaped central conductor 5 coaxially provided in the center of the hollow portion 2.

The central conductor 5 has a small-diameter portion 6 substantially at the center thereof, and the outer body has an inner-diameter enlarged portion 7 on its inner wall at a position corresponding thereto. An annular insulating layer 8 is provided so as to fill the space defined by the small diameter portion 6 and the enlarged inner diameter portion 7 of the outer conductor.

The tip portion of the outer conductor 3 forms a thin short-diameter portion 9, which ends in a small-section end portion 10 and a flange 11 at the other end. The cylindrical insulator 4 that fills the space between the hollow portion of the outer conductor 3 and the central conductor 5 ends at the end face 12 with the small end portion 10 and its cut end aligned.

The central conductor 5 projects from the end face 12 to become a small-section male end portion 13, and ends at a conical tip. A coupling nut 17 is rotatably fixed to the rear portion of the thin wall portion 9 of the outer conductor by a snap ring 15 in an annular groove 14 with the outer wall of the outer conductor, and has a thread 16 on the inner surface of the tip. The screw thread 16 and the end surface 12 are hollow portions 2
5 is formed.

The thin portion 9 of the outer conductor 3 ends in a step 18, and a cylindrical hollow portion 19 is formed between the outer conductor 3 and the coupling nut 17 so as to be slidable with the tip of a female coupling body (not shown). An annular washer 20 is provided on the base portion.

The joint of the connector 1 joins the respective central conductors and is inserted through the cavities 25 and 19 so that the face 12
And is joined via the washer 20 and screwed by the joining nut 17 to join with a female type coupling body (not shown).

The hollow portion 21 of the rear end portion of the outer conductor terminating in the flange 11 of the male connector 1 and the central conductor 5'extending rearward is further an insulator which is coaxial and has the same diameter and extends first and terminates in the plane 22. 23, the male connector 1 is a flange 1
The center conductor 5'is attached to another device by means of 1 and is used by being connected to the circuit of the other device.

FIG. 2 shows a female connector corresponding to the male connector shown in FIG. 1. The same parts as those of the male connector, and those having the same functions are designated by the same reference numerals. However, a lowercase letter a is added to this.
The female connector 1a has center conductors 5a, 5a 'of the same diameter which terminate in the female end portion 13a, a small diameter portion 6a in the center portion of the center conductor, and a correspondingly enlarged diameter portion in the outer conductor inner wall. 7a is formed, the space defined by the two is filled with a high dielectric constant insulator 8a, and the central conductor 5 is adjacent to this.
The hollow part between a and 5a 'and the outer conductor 3a is made into the insulator layer 4
Cylindrical insulators 4a and 23a, which are filled with a and 23a and extend further, are provided at the rear end portion.

The tip 1 of the thin small end 5a of the center conductor 13
3a has a hole for receiving the end portion 13 of the male connector center conductor 5, which is cut open in its length direction to elastically grasp the male tip 13 of the male connector to be inserted therein. It is like this.

The thin small end face portion 13a 'of the central conductor 13a and the end face of the insulator 4a end with the cut ends aligned to form an end face 12a. The outer conductor 3a has its inner diameter enlarged at a position where it contacts the end face 12a to form a hollow portion 25a together with the thin end face 12a, and has a thread portion 16a on the outer periphery thereof.

The female connector 1a has a thin outer conductor portion 3a '.
To the mating washer and the surface 12a to the mating mating surface is joined with a male coupling (not shown) which is screwed by a thread 16a by a coupling nut.

The female connector 1a is attached to another device by a flange 11a, and the center conductor 5a 'is used by being connected to a circuit of the other device. The equipment to which the male connector and the female connector are attached is connected to other equipment by a semi-rigid cable having a female connector or a male connector at its tip, or is connected to a high frequency device such as a terminator.

In assembling this connector, for both male and female, one cylindrical Teflon insulator is press-fitted from one of the center conductors, and this is fitted so that the small diameter part of the center conductor and the enlarged part of the inner wall of the outer conductor are aligned. Insert it into the conductor, and then inject a certain amount of adhesive high-dielectric resin, such as epoxy resin, into the space defined by the small diameter part of the center conductor and the enlarged diameter part of the inner wall of the outer conductor by the automatic metering device before it solidifies. When the other cylindrical Teflon insulator is inserted from the end and the adhesive high dielectric constant resin is solidified, the inner conductor and the outer conductor are adhered and firmly joined by the epoxy resin.

The present invention will be described below with reference to examples.

EXAMPLES In the high frequency coaxial connector shown in FIG.
Suppose d ₂ = 1.0φ, D ₂ = 4.4φ, L = 1 mm
A coaxial connector having a characteristic impedance of 51Ω was formed inside the MA connector to prepare the high-frequency coaxial connector of the present invention shown in FIGS. 1 and 2, and these were measured as a pair to obtain the results shown in FIG. This result shows that the residual reflection coefficient of the measurement system is about 0.
Although it contains 05, the calculation result shows a good tendency. The measurement was performed with a microwave network and an analyzer. For comparison, d ₂ = 0.95, d ₂ = 1.
As 05, husband _{Z O} s 49Omu, measures make sample 53Omu, and the results are shown in Figure 3.

[0031]

[Effect] With this high-frequency coaxial connector, the calculated values of the return loss and the like were well signed with the measured values, and the VSWR was about 1.05 or less at each frequency. This connector is easy and inexpensive to manufacture, and it excels not only in electrical performance but also in mechanical performance, and stainless steel, beryllium copper, etc. are used for the metal part, and it is used for the gasket, as is commonly used for metal parts. Vibration resistance, using silicon rubber, etc.
Impact resistance, corrosion resistance, moisture resistance and high temperature to low temperature, low temperature to high temperature heating-cooling cycle, for example, -65 ° C to +12.
It could be used even under severe conditions of 5 ° C.

[Brief description of drawings]

FIG. 1 is a sectional view of a male high-frequency coaxial connector of the present invention.

FIG. 2 is a sectional view of the female high-frequency coaxial connector of the present invention.

FIG. 3 is a graph showing a VSWR obtained by the high frequency coaxial connector of the present invention obtained in an example.

[Explanation of symbols]

1,1a: male and female connectors, 4,23,4a, a
4a: Dielectric material, 6, 6a: Small diameter part of central conductor, 7, 7a:
Expanded outer conductor inner diameter, 8, 8a: high dielectric resin layer

Claims (1)

[Claims] 1. A high frequency coaxial connector comprising a center conductor, a dielectric layer and an outer conductor, wherein a small diameter portion coaxial with the center conductor is provided, and a coaxial inner diameter is provided on an inner wall of the outer conductor at a position corresponding thereto. With an enlarged portion, the space defined by the small diameter portion and the inner diameter enlarged portion is filled with an adhesive curable high-dielectric resin and hardened, and the central conductor, the dielectric layer and the outer conductor are firmly joined together, The above-mentioned high-frequency coaxial connector, which provides an impedance that substantially matches the characteristic impedance of the high-frequency coaxial connector for high frequencies.