KR20060136198A - Coaxial to waveguide transition apparatus for embodying airline coaxial line - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a coaxial line-waveguide transition apparatus including an airline coaxial line.

2. The technical problem to be solved by the invention

The present invention uses only a general-purpose SMA connector and waveguide having a cutoff frequency of 26 GHz without additional processes and probe fabrication, and has excellent frequency characteristics, and can realize an airline coaxial line that can realize a compact, lightweight, and low-cost transition structure. Its purpose is to provide a track-waveguide transition device.

3. Summary of Solution to Invention

The present invention relates to a coaxial line-waveguide transition apparatus (structure), which uses a SMA (Sub Miniature A) connector to the coaxial line to transmit a signal between the coaxial line and the waveguide, the waveguide; A dielectric coaxial line consisting of a dielectric and an inner conductor of the SMA connector; A probe conductor penetrated into the waveguide among the inner conductors of the SMA connector; And an airline coaxial line existing between the dielectric coaxial line and the probe conductor and composed of air and an inner conductor of the SMA connector.

4. Important uses of the invention

The present invention is used in communication devices and components of the ultra-high frequency and microwave band.

Waveguide, Coaxial Line, SMA Connector, Airline Coaxial Line, Dielectric Coaxial Line

Description

Coaxial to waveguide transition apparatus for embodying airline coaxial line

1 is a perspective view of an embodiment of a coaxial line-waveguide transition apparatus including an airline coaxial line according to the present invention;

2 is a side view of the embodiment of FIG. 1;

3 is a graph illustrating an exemplary performance simulation of the coaxial line-waveguide transition device of FIG. 1.

* Explanation of symbols on the main parts of the drawing

101: waveguide

102: probe conductor among inner conductors of SMA connector

103: back short plane 104: air

105: inner conductor of SMA connector 106: Teflon dielectric of SMA connector

107: air line coaxial line 108: dielectric coaxial line

109: SMA connector 110: metal conductor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial line-waveguide transition apparatus including an airline coaxial line. The present invention relates to a coaxial line-waveguide transition apparatus of ultra-high frequency and microwave band using an airline coaxial line between a probe conductor and a coaxial line to improve frequency characteristics.

Important applications of circuits in the microwave and millimeter frequency bands are in the aerospace and military sectors. By the way, since the input and output ports of the module consisting of a circuit of the frequency of this band uses a waveguide or an SMA connector, a transition structure of the waveguide and the SMA connector is necessary for the electrical connection between the modules. In addition, the circuits used in these fields are exposed to strong mechanical vibrations and impacts, so mechanical stability is also very important.

In general, the transition structure of the coaxial line-waveguide at a frequency of 26 GHz or more corresponding to the cutoff frequency of the SMA connector is manufactured using a coaxial feedthrough having a cutoff frequency characteristic of 26 GHz or more. However, in this case, since the diameter of the inner conductor of the coaxial feedthrough is not suitable as a probe for the transition structure, a probe for transition must be additionally manufactured. Since the probe and the inner conductor have to be bonded, a process of digging a hole in the center of the probe is required, and an additional process such as bonding with conductive epoxy is necessary.

However, the error occurring during such an additional process affects the electrical properties of the transition structure, which makes it difficult to predict stable performance. In addition, there is a problem that the coaxial line-waveguide transition structure cannot be implemented at a light weight and low cost due to additional processes and probe fabrication.

The present invention has been proposed to solve the above problems, and can realize a small, lightweight, low-cost transition structure with excellent frequency characteristics by using only a general-purpose SMA connector and waveguide having a cutoff frequency of 26 GHz without additional processes and probe fabrication. It is an object of the present invention to provide a coaxial line-waveguide transition apparatus including an airline coaxial line.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The present invention for achieving the above object, in the coaxial line-waveguide transition apparatus (structure), in order to transmit a signal between the coaxial line and the waveguide, using the coaxial line SMA (Sub Miniature A) connector, The waveguide; A dielectric coaxial line consisting of a dielectric and an inner conductor of the SMA connector; A probe conductor penetrated into the waveguide among the inner conductors of the SMA connector; And an airline coaxial line existing between the dielectric coaxial line and the probe conductor, the air line consisting of air and an inner conductor of the SMA connector.

The present invention relates to a transition structure (coaxial line-waveguide transition device) used in communication equipment and components of the ultra-high frequency and microwave bands, and in particular, the frequency shift rate of the coaxial line-waveguide transition structure (device) using only a waveguide and an SMA connector. It is designed to have the characteristic of 26GHz or more (preferably 30GHz or more) which is the cutoff frequency of the SMA connector.

That is, the present invention relates to a coaxial line-waveguide transition structure (apparatus) of ultra-high frequency and microwave bands, and comprises only an SMA connector and a waveguide having a cutoff frequency of about 26 GHz, without using a separate probe, and having a frequency characteristic of 30 GHz or more. The transition structure (device) is designed to have

To this end, the present invention uses a general-purpose SMA connector with a cutoff frequency of 26 GHz as a coaxial line, and adds an airline coaxial line between the probe conductor and the coaxial line without using additional probes, thereby improving frequency characteristics. In addition, it is possible to realize a structurally simple, lightweight and low-cost transition structure (device).

According to the present invention, even at a frequency of 30 GHz or more, the transition structure between the SMA connector and the waveguide having a cutoff frequency of about 26 GHz can be made without a probe, and in particular, the transition structure made in this band has a bandwidth characteristic of 2 GHz or more in the band. Therefore, the transition structure produced by the present invention has the advantage that it can be manufactured in a small size, light weight, low cost compared to the transition using the existing K-type connector.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of one embodiment of a coaxial line-waveguide transition apparatus including an airline coaxial line according to the present invention, in particular showing a coaxial line-waveguide transition structure for a Ka-band circuit. 2 is a side view of the embodiment of FIG. 1. Hereinafter, for convenience of description, the description will be given with reference to FIGS. 1 and 2.

As shown in FIG. 1, the coaxial line-waveguide transition apparatus (structure) including the airline coaxial line 107 according to the present invention is configured to transmit signals between the coaxial line 107 and 108 and the waveguide 101. A sub-miniature A (SMA) connector (see 109 in FIG. 2) is used for the coaxial lines 107 and 108 and consists of a waveguide 101, a Teflon dielectric 106 and an inner conductor 105 of the SMA connector 109. A coaxial line 108, a probe conductor penetrating into the waveguide 101 of the inner conductor 105 of the SMA connector 109 (which is a conductor penetrating into the waveguide of the inner conductor of the SMA connector) 102, It exists between the dielectric coaxial line 108 and the probe conductor 102, and includes an airline coaxial line 107 composed of the air 104 and the inner conductor 105 of the SMA connector 109. do.

In a preferred embodiment of the present invention, the standard waveguide WR-34 is adopted as a design goal for the Ka-band circuit, and the frequency band of the TE ₁₀ mode of the standard waveguide WR-34 is from 21.7 GHz to 33 GHz.

The conductor (probe conductor) 102 of the portion of the inner conductor 105 of the SMA connector 109 penetrated into the waveguide 101 collects the signal transmitted to the waveguide 101 or is transmitted from the SMA connector 109. It serves as a probe for transmitting a signal, there is no need for a separate probe manufacturing and bonding process with the inner conductor 105. Therefore, it is less sensitive to mechanical shock and vibration, and the manufacturing cost can be reduced.

Referring to the conductor (probe conductor) 102 of the portion of the waveguide 101 of the SMA connector 109 penetrated into the waveguide 101 in the waveguide 101 of FIG. 2, the inner conductor of the SMA connector 109 is shown. The diameter "CD (diameter of the probe conductor)" of the conductor (probe conductor) 102 of the portion penetrated into the waveguide 101 is fixed to 1.92 mm, and the portion penetrated into the waveguide 101 is provided. "PL (length of probe conductor)" of conductor (probe conductor) 102 and the distance "BD" from the center of inner conductor 105 to back short plane 103 of waveguide 101 (The distance from the center of the inner conductor to the back shot plane) can be set as a variable and optimized using a three-dimensional electromagnetic analysis simulator.

Here, the distance "BD" from the center of the inner conductor 105 to the back short plane 103 of the waveguide 101 should form a length of λ / 4 to have an electrically high impedance. In addition, the length of λ / 4 of the WR-34 waveguide is small at about 1.53 mm in the Ka-band of 30 GHz. When the length of the WR-34 waveguide is structurally problematic, if the length of the WR-34 waveguide is "λ / 4 + λ", the same electrical characteristics are achieved. You can get it. In FIG. 2, the distance "BD" from the center of the inner conductor 105 to the back short plane 103 of the waveguide 101 is expressed by the length of λ / 4 + λ.

The airline coaxial line 107 is composed of air 104 and the inner conductor 105 of the SMA connector 109, and the characteristic impedance is the diameter of the inner conductor 105 ("CD") and the dielectric constant of the air 104. (ε) and the diameter of the machined hole ("AD"). At this time, in order to adjust the characteristic impedance to 50 Ohm, "AD" is set to 2.9 mm, and the length "AL" of the airline coaxial line 107 is sufficiently long to 4 mm considering the depth of the fixing screw of the SMA connector 109. Design. Accordingly, the signal transmitted from the waveguide 101 is collected by the probe conductor 102, and the collected signal passes through the air line coaxial line 107 having a characteristic impedance of 50 Ohm. At this time, the cutoff frequency of the air line coaxial line 107 is about 46 GHz, which is higher than the cutoff frequency of the dielectric coaxial line 108. Thus, the air line coaxial line 107 must be formed to avoid the phenomenon such as resonance due to the higher order mode.

Thereafter, the signal passing through the airline coaxial line 107 passes through the dielectric coaxial line 108. Here, the dielectric coaxial line 108 is a main component of the SMA connector 109, and the characteristic impedance is set to 50 Ohm by the diameter "SD" of the Teflon dielectric 106 and the diameter "CD" of the inner conductor 105. Lost

At this time, the Teflon dielectric 106 is designed to be included in the depth "SL" for the mechanical and electrical stable mounting on the metal conductor 110 of the body of the transition structure, where "SL" is about 1mm is suitable.

In addition, the length of the dielectric coaxial line 108 needs to be performed in three-dimensional electromagnetic field analysis simulation in consideration of the length included in the body of the SMA connector 109 to predict more accurate electrical characteristics.

3 shows the electrical characteristics of the coaxial line-waveguide transition device (structure) of the present invention. This characteristic is the result of the three-dimensional electromagnetic field analysis simulation of FIG.

As shown in FIG. 3, it can be seen that the reflection loss is 20 dB or more from the frequency of 28.9 GHz to 31.3 GHz, and the insertion loss exhibits a low loss characteristic of about 0.1 dB.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention has an electrical low loss characteristic at a frequency of 26 GHz or more using only an SMA connector having a cutoff frequency of about 26 GHz without additional probes, and uses only a low-cost general purpose SMA connector without a probe. Simple, compact, lightweight and inexpensive coaxial line-waveguide transition structure can be produced.

In addition, since the present invention does not require an additional process such as adhesion of the probe, it is very stable mechanically, and there is an excellent effect that there is little risk of damage to mechanical shock and vibration.

Claims (6)

In the coaxial line-waveguide transition apparatus (structure), In order to transmit signals between the coaxial line and the waveguide, a sub miniature A (SMA) connector is used as the coaxial line, The waveguide; A dielectric coaxial line consisting of a dielectric and an inner conductor of the SMA connector; A probe conductor penetrated into the waveguide among the inner conductors of the SMA connector; And An air line coaxial line existing between the dielectric coaxial line and the probe conductor and composed of air and an inner conductor of the SMA connector. Coaxial line-waveguide transition apparatus including an air line coaxial line comprising a. The method of claim 1, The probe conductor, Collects the signal transmitted to the waveguide, or serves as a probe for transmitting a signal transmitted from the SMA connector, the conductor of the portion of the inner conductor of the SMA connector penetrated into the waveguide, electrical and mechanically stable characteristics Coaxial line-waveguide transition apparatus comprising an air line coaxial line, characterized in that to provide. The method of claim 1, The air line coaxial line, Designed to avoid resonance due to higher order mode, the length of the air line coaxial line is a coaxial line-waveguide transition apparatus including an air line coaxial line, characterized in that designed in consideration of the depth of the fixing screw of the SMA connector . The method of claim 3, wherein The characteristic impedance of the air line coaxial line, A coaxial line-waveguide transition apparatus comprising an airline coaxial line, characterized by the diameter of the inner conductor and the permittivity of the air and the diameter of the machined hole. The method according to any one of claims 1 to 4, The distance from the center of the inner conductor to the back shot plane of the waveguide is A coaxial line-waveguide transition apparatus comprising an airline coaxial line, characterized by forming a length of "λ / 4" or "λ / 4 + λ" to have an electrically high impedance. The method of claim 5, The length of the air line coaxial line is 4mm, The diameter of the processed hole is 2.9mm, Coaxial line-waveguide transition apparatus including an airline coaxial line, characterized in that the diameter of the inner conductor is 1.92mm.

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