JP7077137B2 - Transmission lines and connectors - Google Patents

Description

The present invention relates to a transmission line and a connector, and more particularly to a transmission line capable of transmitting a wide band radio wave with low loss, and a connector connected to the transmission line.

Conventionally, waveguides, coaxial cables, planar waveguides, and the like have been known as various transmission lines used in the configuration of communication networks.

The waveguide is a structure used for radio wave transmission. As the waveguide, for example, a square waveguide and a circular waveguide are known. For example, Patent Document 1 discloses a waveguide in which a gap is formed in each of the upper side wall and the lower side wall of the waveguide. This gap is formed to transmit radio waves in a predetermined transmission mode represented by an integer value starting from 0, which is called a mode number.

Coaxial cables are generally used as transmission lines for high-frequency signals (radio waves). A coaxial cable with an elongated hole called a slot for leaking radio waves is called a Leaky Coaxial cable (LCX) and is used as a transmission line for wireless communication.

As the planar waveguide, for example, a microstrip line, a coplanar line, a slot line, and the like are known. For example, Patent Document 2 discloses a Coplanar line in which leakage to the parallel plate mode is suppressed by a metal via embedded in a dielectric substrate.

Japanese Unexamined Patent Publication No. 2001-189610 Japanese Unexamined Patent Publication No. 2000-269707

With the spread of smartphones and the introduction of the Internet of Things (IoT), the amount of data flowing through communication networks is increasing dramatically. In order to improve the communication speed, the frequency of radio waves transmitted on the transmission line is also increasing regardless of the communication format of wired communication or wireless communication.

Although the waveguide has an advantage that it can be transmitted with low loss, it cannot transmit radio waves having a frequency lower than the cutoff frequency, and the frequency band of the transmitted radio waves is limited.

Coaxial cables are suitable for high-frequency signal transmission, but are not suitable for long-distance transmission due to the large loss due to the internal dielectric. Coaxial cables capable of transmitting high frequency signals in the gigahertz band exist, but are very expensive. In addition, although leaky coaxial cables used for wireless communication have a proven track record in transmitting high frequency signals in the megahertz band, leaky coaxial cables capable of transmitting and leaking high frequency signals in the gigahertz band are very expensive.

Further, both the techniques of Patent Documents 1 and 2 are techniques for realizing a configuration in which one of a plurality of transmission modes is suppressed, and are not techniques for realizing a configuration in which a plurality of transmission modes are compatible with each other.

The present invention provides a transmission line capable of transmitting radio waves in a wide band with low loss by realizing transmission of radio waves in a plurality of transmission modes, and a connector connected to the transmission line.

The transmission line according to the present invention has a first waveguide along the axial direction, a tubular first waveguide member that receives an input of a first signal, and a first waveguide member at the position of the first slit. A second waveguide member that covers the inner space, forms a first gap between each opening edge of the first slit, and receives a second signal input, and a first waveguide member. A waveguide formed in a space interposed between the and the second waveguide member and surrounded by the first waveguide member and the second waveguide member, and the first waveguide member and the first gap. , And a first insulating member that constitutes a coplanar line formed by a surface in which the second waveguide member is connected.

According to the transmission line according to the present invention, radio wave transmission can be realized by a plurality of transmission modes of a waveguide mode and a coplanar mode. This makes it possible to transmit radio waves in a wide band with low loss.

The connector according to the present invention is a connector connected to a transmission line according to the present invention, and is electrically connected to a connector conductor portion electrically connected to a first waveguide member and a first waveguide member. It has a first conductor line to be connected and a second conductor line electrically connected to the second waveguide member, and the connector conductor portion constitutes a housing along the outer peripheral surface of the transmission line. The housing includes a connector line portion in which one end is opened and one end of a transmission line is inserted from the open portion at one end.

In the connector line portion, each of the first conductor line and the second conductor line is formed in a layer on the first surface of the dielectric substrate, and between the first conductor line and the second conductor line. Can be mediated by a dielectric.

According to the present invention, by realizing the transmission of radio waves in a plurality of transmission modes, it is possible to provide a transmission line capable of transmitting radio waves in a wide band with low loss and a connector connected to the transmission line. ..

It is a perspective view of the transmission line which concerns on 1st Embodiment. It is an exploded perspective view of the transmission line which concerns on 1st Embodiment. FIG. 1 is a cross-sectional view taken along the line AA of the transmission line shown in FIG. 1, and FIG. 1B is a partially enlarged view of a region R1 shown in FIG. 1A. It is a top view of the first waveguide member 1 in the case of providing the discontinuity part in the coplanar line, (a) shows the top view in the case of providing the discontinuity part in the first waveguide member 1, (b). Shows a top view when a discontinuous portion is provided in the second waveguide member 2A. It is a graph which shows the radio wave leakage amount measured by changing the position and width of a slit in a waveguide mode. It is a perspective view of the connector which concerns on 1st Embodiment. It is an exploded perspective view of the connector which concerns on 1st Embodiment. It is sectional drawing which follows the B1-B1 line of the connector shown in FIG. It is sectional drawing which follows the B2-B2 line of the connector shown in FIG. It is a top view of the connector line part. It is a bottom view of the connector line part. 10 is an end view of the connector line portion seen from the direction of arrow C shown in FIG. 10, and FIG. 10B is a partially enlarged view of the region R2 shown in FIG. 10A. It is a graph which shows the frequency characteristic by the simulation of the transmission line and the connector which concerns on 1st Embodiment. It is a perspective view which shows the state which connected the transmission line and the connector which concerns on 1st Embodiment. 14 is a cross-sectional view taken along the line DD of the transmission line and the connector shown in FIG. 14, and FIG. 14B is a partially enlarged view of the region R3 shown in FIG. 14A. It is a schematic diagram explaining the operation of the coplanar mode. It is a perspective view of the transmission line which concerns on 2nd Embodiment. It is an exploded perspective view of the transmission line which concerns on 2nd Embodiment. It is sectional drawing which follows the EE line of the transmission line shown in FIG. It is a figure which shows the various transmission lines which concerns on another embodiment, and (a) to (c) schematically show the cross section perpendicular to the axial direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, the same reference numerals indicate the same or similar components, and thus duplicate description of the same or similar components will be omitted.

In the following description, both the coaxial cable and the coaxial tube are collectively referred to as a coaxial cable.

[First Embodiment]
(1) Structure of transmission line FIG. 1 is a perspective view of a transmission line according to the first embodiment. FIG. 2 is an exploded perspective view of the transmission line according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line AA of the transmission line shown in FIG. 1, and FIG. 3B is a partially enlarged view of the region R1 shown in FIG. 1A.

As shown in FIGS. 1 to 3, the transmission line 10A according to the first embodiment includes a first waveguide member 1, a second waveguide member 2A, and a first insulating member 4.

The first waveguide member 1 is a tubular member, and is composed of a bottom surface 1a, a side wall 1b, and an upper surface 1c. The upper surface 1c of the first waveguide member 1 is provided with a first slit 11 along the axial direction. A first signal (for example, GND) is input to the first waveguide member 1 extending along the axial direction via a connector 60 described later. The cross-sectional shape of the first waveguide member 1 may be, for example, an ellipse having a long axis and a short axis, in addition to the rectangular shape shown in the figure.

The second waveguide member 2A is a member that extends along the axial direction, and is arranged so as to cover the space in the first waveguide member 1 at the position of the first slit 11. A plurality of first gaps 31 are formed between the slits 11 and the opening edges 11a and 11b of the slit 11. In the illustrated example, the second waveguide member 2A has a protruding portion 22 fitted in the first slit 11 provided in the first waveguide member 1 and a strip-shaped portion 23 on both sides of the protruding portion 22. I am preparing for it all together. A second signal (SIG) is input to the second waveguide member via the connector 60 described later. As shown in FIG. 3, the width direction dimension of the first gap 31 along the lateral direction (hereinafter referred to as the width direction) of the transmission line 10A is W ₁ , and the transmission line 10A is fitted into the first slit 11. Assuming that the dimension in the width direction of the projecting portion 22 of the second waveguide member 2A of the portion is S ₁ , the dimension in the width direction of the first slit 11 is expressed as S ₁ + 2W ₁ .

For the first waveguide member 1 and the second waveguide member 2A, it is preferable to use a material having a high conductivity, and for example, a metal such as aluminum, copper, or brass can be used. The materials used for the first waveguide member 1 and the second waveguide member 2A may be the same or different. The first waveguide member 1 and the second waveguide member 2A can be manufactured by various manufacturing methods such as pressing, extrusion, and extraction.

The first insulating member 4 is a member that extends along the axial direction, and is interposed between the upper surface 1c of the first waveguide member 1 and the band-shaped portion 23 of the second waveguide member 2A. In the illustrated example, the first insulating member 4 is a substantially flat plate-shaped member. The first insulating member 4 may be a layered insulating layer. For the first insulating member 4, for example, a dielectric such as polyimide, Teflon (registered trademark), or alumina can be used. The first waveguide member 1 and the second waveguide member 2A need not be in electrical contact with each other, and the first insulating member 4 is not limited to the exemplified dielectric and may be, for example, an air layer. ..

The hollow space surrounded by the first waveguide member 1 and the second waveguide member 2A forms a waveguide in the waveguide mode. In a waveguide in waveguide mode, radio waves propagate in waveguide mode. The plane in which the upper surface 1c of the first waveguide member 1, the plurality of first gaps 31, and the projecting portion 22 of the second waveguide member 2A are connected constitutes a coplanar mode line. On a coplanar mode track, radio waves propagate in coplanar mode. In the following description, the waveguide mode waveguide is also referred to simply as a waveguide, and the coplanar mode line is also simply referred to as a coplanar line.

The impedance Z ₀ of the Coplanar line is _a function of the widthwise dimension S1 of the projecting portion 22 of the _second waveguide member 2A and the widthwise dimension W1 of the _first gap 31, and S1 /. It is expressed by a mathematical formula with (S ₁ + 2W ₁ ) as a variable. That is, the impedance of the coplanar line can be adjusted by the dimension S ₁ and the dimension W ₁ , and impedance matching with the coaxial cable is possible. Illustratively, dimensions S1 and W1 can be adjusted so that the impedance of the Coplanar line is, for example, _about 50Ω, which is _a typical impedance value for coaxial cables. The electromagnetic field distribution of the Coplanar line is similar to the electromagnetic field distribution of the coaxial cable, and the Coplanar line and the coaxial cable can be well matched. This enables transmission of radio waves in a wide band.

FIG. 4 is a top view of the first waveguide member 1 when a discontinuous portion is provided in the coplanar line. (A) shows a top view when a discontinuity portion is provided in the first waveguide member 1, and (b) shows a top view when a discontinuity portion is provided in the second waveguide member 2A.

The first slit 11 or the second waveguide member 2A may be provided with discontinuity portions 13 and 24 as shown in FIGS. 4A and 4B, in which the line width of the coplanar line is discontinuous. can. As a result, radio waves are radiated from the discontinuous portions 13 and 24, and the transmission line 10A can also be used as a transmission line for wireless communication. The amount of radio wave leakage in the waveguide mode can be adjusted by the position and width of the gap (gap 31 in this embodiment) between the first waveguide member 1 and the second waveguide member 2A. .. The amount of radio wave leakage can be determined according to the application of the transmission line 10A, that is, whether the radio wave is used for transmission or wireless communication.

The line width of the coplanar line can be changed, for example, by changing the width direction dimension of the first slit 11 or the width direction dimension of the projecting portion 22 of the second waveguide member 2A. .. The discontinuity portion 13 is formed by cutting out the opening edge 11a of the first slit 11 in a rectangular shape, for example. The discontinuous portion 24 is formed by recessing both side surfaces of the projecting portion 22 of the second waveguide member 2A into, for example, a rectangular shape. The dimension of the illustrated rectangular notch or recess with respect to the axial direction is preferably one wavelength (1λ) or less, where λ is the wavelength of the radio wave.

FIG. 5 is a graph showing the amount of radio wave leakage measured by changing the position and width of the gap in the waveguide mode. In the graph, the width of the gap is the dimension W1 of the _first gap 31 shown in FIG. 3 (b). The position of the gap is the separation distance L1 in the width direction between the center line C of the first waveguide member ₁ and the center of the first gap 31.

The discontinuous portions 13 and 24 can be provided at predetermined intervals along the axial direction. This makes it possible to give directivity to the radiated radio waves. Assuming that the wavelength of the radio wave is λ, the predetermined interval can be, for example, 1 / 2λ.

The discontinuity portions 13 and 24 can be formed by various aspects. The discontinuous portion 13 shown in FIG. 4A is formed by changing the width of the first slit 11 along the axial direction. The discontinuous portion 24 shown in FIG. 4B is formed by changing the width of the protruding portion 22 of the second waveguide member 2A along the axial direction.

(2) Connector Structure FIG. 6 is a perspective view of the connector according to the first embodiment. FIG. 7 is an exploded perspective view of the connector according to the first embodiment. FIG. 8 is a cross-sectional view taken along the line B1-B1 of the connector shown in FIG. FIG. 9 is a cross-sectional view taken along the line B2-B2 of the connector shown in FIG. Both the B1-B1 wire and the B2-B2 wire show a cross section passing through the inner conductor 82 of the connector connecting portion 8 described later.

As shown in FIGS. 6 to 9, the connector 60 according to the first embodiment is a connector connected to the transmission line 10A, and includes a connector conductor portion 6, a connector line portion 7, and a connector connection portion 8. To prepare for. The connector conductor portion 6 and the connector line portion 7 form a housing 9 along the outer peripheral surface of the transmission line 10A. In the present embodiment, one end of the housing 9 is open, and as will be described later, one end of the transmission line 10A can be inserted from the open portion 90 of the housing 9. That is, in the present embodiment, the dimension of the end face in the open portion 90 of the housing 9 is slightly larger than the dimension of the end face at one end of the transmission line 10A.

The connector conductor portion 6, the connector line portion 7, and the connector connection portion 8 constituting the connector 60 convert the radio wave input from the coaxial cable so as to excite the coplanar line in the coplanar mode, and transmit the waveguide. Is converted to be excited in the waveguide mode.

The connector conductor portion 6 constitutes the bottom surface and the side wall of the housing 9. At the time of connection with the transmission line 10A, the connector conductor portion 6 is electrically connected to the first waveguide member 1 of the transmission line 10A. In the present embodiment, the connector conductor portion 6 is provided with a back short 61 at the other end with respect to the open portion 90 at one end. The back short 61 is also called a rear metal, and is a metal arranged at the rear in the transmission direction of radio waves. It is preferable to use a material having high conductivity for the connector conductor portion 6, and for example, a metal such as aluminum, copper, or brass can be used.

The connector line portion 7 is a planar member constituting the upper surface of the housing 9. The connector line portion 7 will be described in detail later with reference to FIGS. 10 to 12, but the first conductor line 71 (GND), the second conductor line 72 (SIG), the dielectric substrate 73, and the dielectric 74. It comprises a third conductor line (GND) 75 and a conductive via 76. When connected to the transmission line 10A, the first conductor line 71 is electrically connected to the first waveguide member 1 of the transmission line 10A, and the second conductor line 72 is the second conductor of the transmission line 10A. It is electrically connected to the waveguide 2A. For example, the first signal is input to the first conductor line 71 and the third conductor line 75, and the second signal is input to the second conductor line 72 via the connector connection portion 8.

The connector connection portion 8 is a structure including an outer conductor 81, an inner conductor 82, and a dielectric 83. The outer conductor 81 is electrically connected to the first conductor line 71 of the connector line portion 7, and the inner conductor 82 is electrically connected to the second conductor line 72 of the connector line portion 7. The inner conductor 82 is also called a probe. The dielectric 83 is interposed between the outer conductor 81 and the inner conductor 82, and electrically insulates the outer conductor 81 and the inner conductor 82. For the connector connection portion 8, for example, a known coaxial connector can be used.

The outer conductor 81 is electrically connected to the outer conductor of the coaxial cable (not shown), and the inner conductor 82 is electrically connected to the inner conductor of the coaxial cable. In this embodiment, as shown in FIG. 9, the outer conductor 81 of the connector connecting portion 8 is electrically connected to the first conductor line 71 and the third conductor line 75 via the conductive via 76. .. As a result, the first signal from the outer conductor of the coaxial cable is input to the first conductor line 71 and the third conductor line 75.

FIG. 10 is a top view of the connector line portion. FIG. 11 is a bottom view of the connector line portion. 12 is an end view of the connector line portion seen from the direction of arrow C shown in FIG. 10, and FIG. 12B is a partially enlarged view of the region R2 shown in FIG. 10A.

As shown in FIG. 11, the first conductor line 71 is layered on one surface of the dielectric substrate 73 on the side in contact with the transmission line 10A (in this embodiment, the surface on the inner surface side of the housing 9). Is formed in. The second conductor line 72 is also formed in a layered manner on one surface of the dielectric substrate 73 on the side in contact with the transmission line 10A. A dielectric 74 is interposed between the first conductor line 71 and the second conductor line 72, and electrically insulates the first conductor line 71 and the second conductor line 72.

Generally, in the Coplanar line, the conductor to which the signal line SIG is input and the conductor to which the ground signal line GND is input are arranged in the same plane. Therefore, in the connector connected to the transmission line 10A, if the conductor line connected to the coplanar line as a signal line is arranged on the outer surface of the connector (outer surface of the housing 9), the signal is sent to the grounded connector panel or the like. There is a risk of a short circuit with the conductor line to which the wire is connected, and if a short circuit occurs, radio waves cannot be transmitted. In the present embodiment, the reason why the first conductor line 71 and the second conductor line 72 connected to the coplanar line of the transmission line 10A are arranged on the same surface on the inner surface side of the housing 9 is the connector. This is to avoid a short circuit of the signal due to contact with a panel or the like.

Further, in the present embodiment, most of the surface of one surface of the connector line portion 7 on the side in contact with the transmission line 10A is the first conductor line 71. The first signal is input to the first conductor line 71, and the first signal is also input to the connector conductor portion 6 arranged on the lower surface of the connector line portion 7. That is, in the connector 60, the surface of the housing 9 on the inner surface side is covered with conductors on the upper surface, the bottom surface, and the four surfaces of both side walls, whereby the transmission characteristics of radio waves in the waveguide mode are improved. ..

As shown in FIG. 10, the third conductor line 75 is layered on the other surface of the dielectric substrate 73 on the side not in contact with the transmission line 10A (in this embodiment, the surface on the outer surface side of the housing 9). Is formed in. In this embodiment, as shown in FIG. 10, the third conductor line 75 is formed in a U shape. As a result, an exposed region exp where the dielectric substrate 73 is exposed is formed on the other surface of the connector line portion 7. The exposed region exp corresponds to a region on one surface of the connector line portion 7 where the second conductor line 72 is formed. By forming the exposed region exp, it is possible to reduce the possibility that unnecessary radio waves propagate due to the difference in the electromagnetic field distribution from the coplanar mode.

As shown in FIGS. 10 and 11, the conductive via 76 penetrates the dielectric substrate 73, and the first conductor line 71 formed on one surface and the third conductor line 71 formed on the other surface. Is electrically connected to the conductor line 75 of the above. The inner peripheral surface of the conductive via 76 is coated with a conductive metal. The inner conductor 82 of the connector connecting portion 8 is inserted into the through hole 79 shown in FIGS. 10 and 11. In the present embodiment, the inner conductor 82 of the connector connecting portion 8 is inserted into the through hole 79, so that the inner conductor 82 is electrically connected to the second conductor line 72 on the other surface of the dielectric substrate 73. ing. As a result, the second signal from the inner conductor of the coaxial cable is input to the second conductor line 72.

The connector line portion 7 can be manufactured by, for example, a known printed wiring technique. For example, as the dielectric substrate 73, a known printed circuit board, flexible substrate, or the like made of glass epoxy or the like can be used. By applying a known printed wiring technique to such a printed circuit board or a flexible substrate, a first conductor line 71, a second conductor line 72, a dielectric 74, a third conductor line 75, and a conductive via can be applied. 76 can be produced respectively. For the first conductor line 71, the second conductor line 72, and the third conductor line 75, it is preferable to use a material having high conductivity, and for example, a metal such as aluminum or copper can be used.

The second conductor line 72 of the connector line portion 7 is preferably formed so that the width dimension is tapered along the line. Preferably, in consideration of the transmission characteristics, the widthwise dimension S2 of the _second conductor line ₇₂ is preferably increased in a tapered shape while maintaining the ratio to the widthwise dimension W2 of the dielectric 74. .. When the dimension S2 in the width direction of the _second conductor line 72 is increased, the connection with the transmission line 10A becomes easy. By increasing the dimension S2 in a tapered shape without suddenly changing the dimension _S2 along the line, it is possible to prevent the leakage of radio waves from the place where the dimension changes suddenly on the line and suppress the deterioration of the transmission characteristics. can do.

Further, it is preferable to provide a low-pass filter on the second conductor line 72 of the connector line portion 7. By providing the low-pass filter, the propagation mode can be divided into a waveguide mode and a coplanar mode according to the frequency of the radio wave to be transmitted, and the radio wave can be transmitted. The low-pass filter can be formed, for example, by alternately arranging a component having a large impedance and a component having a low impedance on a line. That is, the dimension _W2 in the width direction of the dielectric 74 is changed along the line. Here, the dimension W ₂ acts as a gap with respect to the waveguide mode, causing radio wave leakage. Therefore, it is desirable that the width direction dimension S2 + 2W ₂ of the _second conductor line 72 and the two dielectrics 74 is about 1/4 of the width direction dimension of the waveguide.

In the example shown in FIG. 11, a C-L-C-LC type low-pass filter is exemplifiedly provided on the line indicated by reference numeral 77 of the second conductor line 72. Here, C means a capacitor component, and L means an inductance component. The capacitor component C and the inductance component L can be expressed using the widthwise dimension S2 of the _second conductor line 72 _mounted on the dielectric substrate 73 and the widthwise dimension W2 of the dielectric 74. can. The capacitor component C can be formed by increasing the ratio of S ₂ / (S ₂ + 2W ₂ ) on the line to be mounted. The inductance component L can be formed by reducing the ratio of S ₂ / (S ₂ + 2W ₂ ) on the mounted line.

Illustratively, as shown in FIG. 11, in the section of the line forming the low-pass filter 77, the capacitor component C and the inductance component L are formed as follows.

For the capacitor component C, it is desirable to make the dimension W ₂ as small as possible, but the reduction of the dimension W ₂ leads to manufacturing difficulty. In the present embodiment, the line width S2 is made thicker _than the line before the low-pass filter 77, the second conductor line 72 is formed concave in a plan view, and the first conductor line 71 is flat. It is formed in a convex shape visually. As a result, the distance between the lines constituting the capacitor component C is lengthened, and the required value of the capacitor component C is obtained.

Regarding the inductance component L, although it is necessary to increase the dimension W ₂ , it is better not to increase the dimension W ₂ as much as possible because it leads to the leakage of radio waves in the waveguide mode. In the present embodiment, the line width S ₂ is narrower than that of the line before the low-pass filter 77, thereby suppressing the expansion of the required dimension W ₂ . As a result, the required value of the inductance component L is obtained while suppressing the leakage of radio waves in the waveguide mode.

Returning to FIGS. 8 and 9, it is preferable to provide a high-pass filter on the inner conductor 82 of the connector connection portion 8. By providing the high-pass filter, it is possible to reduce the deterioration of the transmission characteristics due to the interconnection between the waveguide mode and the coplanar mode. In particular, it is possible to reduce the deterioration of the transmission characteristics in the coplanar mode.

The high-pass filter can be formed by various embodiments. Although not shown, the high-pass filter can be formed, for example, by partially reducing the diameter of the inner conductor 82. Alternatively, the high-pass filter can be formed, for example, by loading a dielectric (not shown) on the inner conductor 82. Alternatively, for example, a high-pass filter may be formed by embedding a capacitor of a chip component in the inner conductor 82.

FIG. 13 is a graph showing frequency characteristics by simulation of a transmission line and a connector according to the first embodiment.

The coplanar mode is a quasi-TEM mode, and can theoretically transmit radio waves having a frequency from 0 to infinity. Therefore, the coplanar line can transmit not only radio waves having a frequency operating in the coplanar mode but also radio waves having a frequency operating in the waveguide mode.

According to the transmission line 10A and the connector 60 according to the present embodiment, it is possible to divide the propagation mode into a waveguide mode or a coplanar mode and transmit the radio wave according to the frequency of the radio wave to be transmitted. This can be realized by providing a low-pass filter 77 on the second conductor line 72 of the connector line portion 7 constituting the coplanar line.

When the low-pass filter 77 is not provided, the radio wave is transmitted in the coplanar mode and the waveguide mode at a frequency higher than the cutoff frequency. By providing the low-pass filter 77, it is possible to reduce the deterioration of the transmission characteristics due to the mutual coupling between the waveguide mode and the coplanar mode, and it is possible to set either of the modes that can be transmitted according to the frequency of the radio wave.

When the low-pass filter 77 is provided, in the coplanar line, radio waves below the cutoff frequency of the low-pass filter 77 pass through the low-pass filter 77 and propagate in the coplanar line in the coplanar mode. Above the cutoff frequency, the radio waves cannot propagate on the coplanar line in the coplanar mode, causing reflection of the radio waves. On the other hand, in the waveguide, the radio wave below the cutoff frequency cannot be transmitted in the waveguide mode, and the radio wave is reflected in the waveguide. Above the cutoff frequency, radio waves propagate through the waveguide in waveguide mode. The cutoff frequency of the waveguide is determined by the shape of the waveguide. For example, when the cross-sectional shape of the waveguide is rectangular and the wavelength of the radio wave is λ, the cutoff frequency is a frequency at which the dimension of the long side of the waveguide is λ / 2 or more.

In the simulation shown in FIG. 13, the cutoff frequency of the waveguide is about 5 GHz, and the cutoff frequency of the low-pass filter is about 3 GHz. Referring to the graph shown in FIG. 13, in the frequency band of DC (DC) to about 3 GHz, the radio wave propagates in the coplanar line in the coplanar mode, and in the frequency band of about 5 GHz to about 6 GHz, the radio wave is in the waveguide. Is shown to propagate in waveguide mode. In the frequency band of about 3 GHz to about 5 GHz in the graph, the transmission characteristics are suppressed by the cutoff frequency of the low-pass filter and the cutoff frequency of the waveguide. Specifically, in the frequency band of about 3 GHz or higher, the transmission characteristics are suppressed by the cutoff frequency of the low-pass filter, and in the frequency band up to about 5 GHz, the transmission characteristics are suppressed by the cutoff frequency of the waveguide. There is.

(3) Connection of Transmission Line and Connector FIG. 14 is a perspective view showing a state in which the transmission line and the connector according to the first embodiment are connected. 15 is a cross-sectional view taken along the line DD of the transmission line and the connector shown in FIG. 14, and FIG. 15B is a partially enlarged view of the region R3 shown in FIG. 14A.

One end of the housing 9 of the connector 60 composed of the connector conductor portion 6 and the connector line portion 7 is open, and one end of the transmission line 10A is inserted into the open portion 90 of the housing 9. At this time, the second conductor line 72 arranged on the inner surface of the connector line portion 7 is electrically connected to the second waveguide member 2A of the transmission line 10A. Further, the first conductor line 71 arranged on the inner surface of the connector line portion 7 is electrically connected to the first waveguide member 1 of the transmission line 10A. The first waveguide member 1 is also electrically connected to the connector conductor portion 6.

For the electrical connection or conduction between the members, for example, conductive bolts 95 and nuts 96 illustrated in the figure, conductive adhesives, conductive spring materials, and other conductive connecting members may be used. can. Good fit can be obtained by using bolts 95 and nuts 96 for connection.

In the illustrated example, the conduction between the second conductor line 72, which is the signal line of the second signal (SIG), and the second waveguide member 2A is a conductive bolt on the upper surface of the transmission line 10A and the connector 60. It is done via 95. Conduction between the connector conductor portion 6 to which the first signal (GND) is connected and the first waveguide member 1 is performed at the bottom surface or the side wall of the transmission line 10A and the connector 60 via the conductive bolt 95.

Therefore, in the illustrated example, the first signal (GND) is the first waveguide member 1 of the transmission line 10A, the connector conductor portion 6 of the connector 60, the first conductor line 71, and the third conductor line 75. And the conductive via 76 and the outer conductor 81 of the connector connecting portion 8 are input. Further, the second signal (SIG) is input to the second waveguide member 2A of the transmission line 10A, the second conductor line 72 of the connector 60, and the inner conductor 82 of the connector connection portion 8.

As described above, according to the transmission line 10A and the connector 60 according to the first embodiment, radio wave transmission can be realized by a plurality of transmission modes of the waveguide mode and the coplanar mode. This makes it possible to transmit radio waves in a wide band with low loss.

FIG. 16 shows a schematic diagram illustrating the operation of the coplanar mode. In (a), the electric field generated in the general coplanar mode is illustrated by an arrow, and in (b), the electric field generated when the conductor is configured in a multilayer structure in the coplanar mode is illustrated by an arrow. There is. In FIGS. 16A and 16B, the three conductors shown in the center and left and right are arranged on a substrate such as a dielectric substrate. The signal line SIG is input to the conductor shown in the center, and the ground signal line GND is input to the conductors shown on the left and right.

[Second Embodiment]
FIG. 17 is a perspective view of the transmission line according to the second embodiment. FIG. 18 is an exploded perspective view of the transmission line according to the second embodiment. FIG. 19 is a cross-sectional view taken along the line EE of the transmission line shown in FIG. Hereinafter, the differences from the transmission line 10A according to the first embodiment will be described.

As shown in FIGS. 17 to 19, the transmission line 10B according to the second embodiment includes a first waveguide member 1, a second waveguide member 2B, and an insulator 41. In the transmission line 10B according to the second embodiment, the shapes of the second waveguide member 2B and the insulator 41 are the second waveguide member 2A and the first insulation of the transmission line 10A according to the first embodiment. It is different from the shape of the object 41.

Referring to FIGS. 3 and 19 in comparison, the second waveguide member 2B shown in FIG. 19 does not have the band-shaped portion 23 of the second waveguide member 2A shown in FIG. 3, and is axially oriented. It is a generally flat member that extends along it. Further, the insulator 41 shown in FIG. 19 is a member that extends along the axial direction, and although it is interposed between the first waveguide member 1 and the second waveguide member 2B, the shape of the member is Is not a flat plate as shown in FIG. 3, but is generally a rod.

The second waveguide member 2B is arranged so as to cover the space in the first waveguide member 1 at the position of the first slit 11, and is arranged with the opening edges 11a and 11b of the first slit 11. A plurality of first gaps 31 are formed between them. The insulator 41 is inserted into the first gap 31 and intervenes so as to close the first gap 31, and electrically insulates the first waveguide member 1 and the second waveguide member 2B. There is.

The hollow space surrounded by the first waveguide member 1 and the second waveguide member 2B forms a waveguide in the waveguide mode. The plane on which the upper surface 1c of the first waveguide member 1, the plurality of first gaps 31, and the second waveguide member 2B are connected constitutes a coplanar mode line.

When connected to the connector 60, the conduction between the second conductor line 72, which is the signal line of the second signal (SIG), and the second waveguide member 2B is, for example, on the upper surface of the transmission line 10B and the connector 60, for example. This is done via the conductive bolt 95.

As described above, according to the transmission line 10B according to the second embodiment, the same effect as that of the transmission line 10A according to the first embodiment is obtained.

[Other embodiments]
In each of the transmission lines 10A and 10B of the above-described embodiment, the coplanar line is formed at one location on the upper surface 1c, but the position and number of the coplanar lines are not limited to this. For example, in the transmission lines 10A and 10B, a coplanar line may be further provided on the bottom surface 1a or the side wall 1b of the first waveguide member 1.

20 is a diagram showing various transmission lines 10C to 10E according to other embodiments, and FIGS. 20A to 20C schematically show cross sections perpendicular to the axial direction. Hereinafter, various transmission lines exemplified in FIGS. 20 (a) to 20 (c) will be described.

[Third Embodiment]
In the transmission line 10C according to the third embodiment shown in FIG. 20A, coplanar lines are provided at two locations, the upper surface 1c and the bottom surface 1a of the first waveguide member 1. That is, the illustrated transmission line 10C has a configuration in which the coplanar line is further provided on the bottom surface 1a of the first waveguide member 1 in the transmission line 10B according to the second embodiment shown in FIG.

19 and 20 (a) are compared and referred to. A second slit along the axial direction is provided on the bottom surface 1a of the first waveguide member 1. Then, a third waveguide member 2C having the same shape as the second waveguide member 2B is arranged so as to cover the space in the first waveguide member 1 at the position of the second slit. A plurality of second gaps 32 are formed between the two slits and the opening edge. A plurality of second insulators 42 are interposed between the first waveguide member 1 and the third waveguide member 2C. For example, a second signal is input to the third waveguide member 2C. The hollow space surrounded by the first waveguide member 1, the second waveguide member 2B, and the third waveguide member 2C forms a waveguide in the waveguide mode. The plane on which the upper surface 1c of the first waveguide member 1, the plurality of first gaps 31, and the second waveguide member 2B are connected constitutes a coplanar mode line. The plane on which the bottom surface 1a of the first waveguide member 1, the plurality of second gaps 32, and the third waveguide member 2C are connected constitutes a further coplanar mode line.

It can be connected to the connector 60 in various ways. For example, in the connector 60, instead of the planar conductor constituting the bottom surface of the connector conductor portion 6, the connector 60 has the same configuration as the connector line portion 7 and the connector connection portion 8 arranged on the upper surface side of the connector 60. Place on the bottom of the. As a result, a radio wave as an input signal from the coaxial cable can be connected to the coplanar line further provided on the bottom surface of the transmission line 10C.

The position where the third waveguide member 2C is provided is not limited to the illustrated embodiment. For example, the third waveguide member 2C may be provided on the side wall 1b of the first waveguide member 1 or may be provided on both side walls 1b. Alternatively, the third waveguide member 2C may be provided on both the bottom surface 1a and the side wall 1b, or may be provided on the top surface 1c, the bottom surface 1a, and both side walls 1b.

[Fourth Embodiment]
In the transmission line 10D according to the fourth embodiment shown in FIG. 20B, coplanar lines are provided side by side on the upper surface 1c of the first waveguide member 1. That is, in the illustrated transmission line 10D, in the transmission line 10B according to the second embodiment shown in FIG. 19, the second waveguide member 2B is divided into a plurality of fourth waveguide members 2D, and a plurality of divided members are divided. A plurality of fourth waveguide members 2D are arranged in parallel with a third gap 33 sandwiched between the waveguide members 2D and 2D.

Refer to FIG. 19 in comparison with FIG. 20 (b). The plurality of fourth waveguide members 2D are arranged in parallel with each other on the upper surface 1c of the first waveguide member 1 in which the second waveguide member 2B is arranged. As a result, a third gap 33 is formed between the fourth waveguide member 2D. A third insulator 43 is interposed in the third gap 33. For example, a second signal is input to the plurality of fourth waveguide members 2D. The hollow space surrounded by the first waveguide member 1 and the plurality of fourth waveguide members 2D forms a waveguide in the waveguide mode. The plane in which the upper surface 1c of the first waveguide member 1, the plurality of first gaps 31, and the plurality of fourth waveguide members 2D are connected constitutes two coplanar mode lines provided side by side. ..

The number of the fourth waveguide member 2D and the number of the third gap 33 are not limited to the illustrated embodiment. For example, the number of the fourth waveguide member 2D may be three or more, and in this case, two or more of the third gap 33 are also formed.

[Fifth Embodiment]
In the transmission line 10E according to the fifth embodiment shown in FIG. 20 (c), a coplanar line is provided in two layers on the upper surface 1c of the first waveguide member 1. That is, the illustrated transmission line 10E has a configuration having a coplanar line having a multi-layer structure, and in the transmission line 10B according to the second embodiment shown in FIG. 19, the second waveguide member 2B is connected to a plurality of fifth guides. It is configured to be divided into wave members 2E, and a plurality of divided waveguide members 2E are arranged in the stacking direction.

19 and 20 (c) are compared and referred to. The plurality of fifth waveguide members 2E are arranged in parallel with each other in the stacking direction on the upper surface 1c of the first waveguide member 1 in which the second waveguide member 2B is arranged. A conductive connecting member 98 is provided between the plurality of fifth waveguide members 2E. For example, a second signal is input to the plurality of fifth waveguide members 2E. The hollow space surrounded by the first waveguide member 1 and the plurality of fifth waveguide members 2E forms a waveguide in the waveguide mode. The plurality of laminated fifth waveguide members 2E are integrated via a conductive connecting member 98, and the upper surface 1c of the first waveguide member 1, the plurality of first gaps 31, and the laminated layers. The plane in which the plurality of fifth waveguide members 2E connected to each other constitutes one coplanar mode line.

The number of the fifth waveguide member 2E and the number of the conductive connecting member 98 are not limited to the illustrated embodiment. For example, the number of the fifth waveguide member 2E may be three or more, and in this case, two or more conductive connecting members 98 are also provided.

In the example shown in FIG. 20 (c), the upper surface 1c of the first waveguide member 1 is divided into a plurality of planes, but it may be integrated without being divided. Similarly, the insulator 41 is also divided into a plurality of members and inserted into the plurality of first gaps 31 formed side by side in the stacking direction, but the insulator 41 divided in the stacking direction is It may be an integrated one.

[Other forms]
Although the present invention has been described above by the specific embodiment, the present invention is not limited to the above-described embodiment.

In the first to fourth embodiments described above, the conductor serving as the waveguide member in the coplanar mode does not have a multi-layer structure, but the conductor may have a multi-layer structure. For example, in the transmission line 10 (10A to 10D), each of the first waveguide member 1 and the second waveguide member 2 (2A to 2D), which are conductors constituting the plane of the coplanar line, has a multilayer structure. It may be configured with. That is, as shown in FIG. 16B, the conductor is configured in a multilayer structure in the Coplanar line. As a result, in the coplanar mode, the electric field concentrated between the conductors of the coplanar line can be alleviated and the conductor loss can be reduced.

In the above-described embodiment, the second waveguide member 2 is manufactured by a method such as pressing, extrusion, and extraction using a material such as a metal having high conductivity, but the second waveguide member 2 is manufactured. The method of doing so is not limited to this. As another manufacturing method, the second waveguide member 2 may be manufactured by a layer structure in which a conductor foil is attached to a plate-shaped or tape-shaped dielectric such as a flexible substrate.

In the first and second embodiments described above, the coplanar line is formed by a plane formed by a first waveguide member 1, a second waveguide member 2A, 2B, and a plurality of first gaps 31. However, the positional relationship between the second waveguide members 2A and 2B and the first waveguide member 1 is not limited to this. The second waveguide members 2A and 2B do not have to be exactly in the same plane as the first waveguide member 1, and are located at a predetermined distance in the vertical direction from the surface of the first waveguide member 1. You may. The third embodiment to the fifth embodiment are the same as those of the first and second embodiments.

In the above-described embodiment, the first waveguide member 1 and the second waveguide member 2 are the outer conductor and the inner conductor of the coaxial cable (or coaxial tube), respectively, via the connector connection portion 8 of the connector 60, respectively. Although they are connected, the connection mode between the first waveguide member 1 and the second waveguide member 2 and the coaxial cable (or coaxial tube) is not limited to this. The first waveguide member 1 and the second waveguide member 2 are each connected to the outer conductor and the inner conductor of the coaxial cable (or coaxial tube) by, for example, individual electric wires, without passing through the connector connection portion 8, respectively. You may.

In the first and second embodiments described above, the connector conductor portion 6 is provided with a back short 61 at the other end with respect to the open portion 90 at one end, but the back short 61 has an arbitrary configuration. For example, the connector conductor portion 6 may have the back short 61 omitted. As a result, the transmission line can transmit the radio wave in the direction opposite to the transmission direction of the radio wave, and can transmit the radio wave in both directions along the axial direction. Further, for example, a radio wave absorber may be loaded on at least one of the front side and the rear side of the back short 61 along the axial direction. In the case of the connector conductor portion 6 omitting the back short 61, the radio wave absorber may be loaded on the open portion 90 at one end of the connector conductor portion 6 or may be loaded on the other end of the connector conductor portion 6. As a result, when the signal of the coaxial cable is converted to the coplanar mode, a part of the radio wave leaks into the space of the waveguide under the connector connection portion 8 via the connector connection portion 8, and the transmission characteristic is improved. It is possible to reduce deterioration. The third embodiment to the fifth embodiment are the same as those of the first and second embodiments.

In the above-described embodiment, the first signal and the second signal from the coaxial cable are input to each part of the connector line part 7 via the connector connection part 8, but the first signal and the second signal are input to the connector line part. The mode to be input to 7 is not limited to this. The first signal and the second signal from the coaxial cable may be input to the connector line portion 7 by, for example, individual electric wires or wiring.

In the above-described embodiment, one end of the transmission line 10 is inserted into the open portion 90 of the housing 9 of the connector 60, but the connection mode between the connector 60 and the transmission line 10 is not limited to this. One end of the connector 60 may be inserted into the open portion 90 of the transmission line 10 by reversing the magnitude relationship between the dimension of the end face of the connector 60 in the open portion 90 of the housing 9 and the dimension of the end face of the transmission line 10. In this case, the connector 60 may be arranged with the front and back of the connector line portion 7 reversed.

A protective material can be provided around the transmission line 10 in the axial direction. As the protective material, a material having a small dielectric loss is desirable.

In the above-described embodiment, one of the second conductor lines 72 is formed in the connector line portion 7, but the number of the second conductor lines 72 is not limited to this. For example, the second conductor line 72 may be branched into two or more lines from the connector connection portion 8 to form a plurality of lines. For example, the radio wave input as the second signal may be orthogonally branched at the connector connection portion 8, and the orthogonal components of the orthogonally branched radio waves may be divided into different conductor lines and supplied to the connector line portion 7. Orthogonally branched radio waves are, for example, carrier waves and modulated waves.

In the above-described embodiment, the low-pass filter 77 is formed in the connector line portion 7, but the connector line portion 7 may function as an electronic circuit by further providing an electronic component in the connector line portion 7. Examples of exemplary electronic components provided in the connector line section 7 include an amplifier for signal amplification, a mixer for signal modulation, an oscillator, and the like. For example, a communication system using leaked waves can be configured as described below. First, a plurality of frequencies flow through the coaxial cable, which is the input source of radio waves. Then, the coplanar mode transmission is set to the intermediate frequency IF, the local signal LO is output from the oscillator arranged in the connector line portion 7, and the RF signal modulated by the mixer arranged in the connector line portion 7 is transmitted in the waveguide mode. Can be made to.

1 First waveguide member 1a (first waveguide member 1) bottom surface 1b (first waveguide member 1) side wall 1c (first waveguide member 1) top surface 2 (2A, 2B, 2C) , 2D, 2E) 2nd waveguide 4 1st insulating member 6 Connector conductor 7 Connector line 8 Connector connection 9 Housing 10 (10A, 10B, 10C, 10D, 10E) Transmission line 11 1st Slits 11a, 11b Opening edge 13 Discontinuous portion 22 (of the first waveguide member 1) Protruding portion 23 (of the second waveguide member 2A) Band-shaped portion 24 (of the second waveguide member 2A) Discontinuity 31, 32, 33 Gap 41, 42, 43 Insulation 60 Connector 61 Back short 71 First conductor line (GND)
72 Second conductor line (SIG)
73 Dielectric Substrate 74 Dielectric 75 Third Conductor Line (GND)
76 Conductive via 77 Low-pass filter 79 Through hole 81 Outer conductor 82 (of connector connection 8) Inner conductor 83 (of connector connection 8) Dielectric 90 (of connector connection 8) Open portion 95 (of housing 9) Conductive connector (bolt)
96 Conductive connecting member (nut)
98 Conductive connecting member

Claims (17)

A tubular first waveguide having a first slit along the axial direction and receiving a first signal input.
It covers the space in the first waveguide member at the position of the first slit, forms a first gap with each opening edge of the first slit, and inputs a second signal. With the second waveguide member that receives
A waveguide formed in a space interposed between the first waveguide member and the second waveguide member and surrounded by the first waveguide member and the second waveguide member, and the above-mentioned A first insulating member constituting a first waveguide member, the first gap, and a coplanar line formed by a surface on which the second waveguide member is connected.
A transmission line. The transmission line according to claim 1, wherein the first slit or the second waveguide is provided with a discontinuous portion in which the line width of the coplanar line is discontinuous. The transmission line according to claim 2, wherein the discontinuous portions are provided at predetermined intervals along the axial direction. The transmission line according to any one of claims 1 to 3, wherein the second waveguide has a layer structure of a dielectric layer and a conductor layer formed on the surface of the dielectric layer. The first waveguide further comprises a second slit along the axial direction.
It covers the space in the first waveguide member at the position of the second slit, forms a second gap with each opening edge of the second slit, and inputs a second signal. With the third waveguide member that receives
A space interposed between the first waveguide member and the third waveguide member and surrounded by the first waveguide member, the second waveguide member, and the third waveguide member. A second insulating member constituting the waveguide formed by the above, the first waveguide member, the second gap, and the coplanar line formed by the surface on which the third waveguide member is connected.
The transmission line according to any one of claims 1 to 4, further comprising. The second waveguide is composed of a plurality of fourth waveguides arranged in parallel with each other with a third gap on the surface on which the second waveguide is arranged.
The transmission line according to any one of claims 1 to 4, wherein a third insulating member is interposed in the third gap. The second waveguide is composed of a plurality of fifth waveguides arranged in parallel with each other in the stacking direction on the surface on which the second waveguide is arranged.
The transmission line according to any one of claims 1 to 4, wherein a conductive connecting member electrically connected to each other is interposed between the plurality of fifth waveguide members. A connector connected to the transmission line according to any one of claims 1 to 7.
A connector conductor portion electrically connected to the first waveguide member,
It has a first conductor line electrically connected to the first waveguide member and a second conductor line electrically connected to the second waveguide member, and the connector conductor portion is used as described above. A connector comprising a housing along the outer peripheral surface of a transmission line, the housing having a connector line portion in which one end is opened and one end of the transmission line is inserted from the open portion of one end. In the connector line portion, each of the first conductor line and the second conductor line is formed in a layer on the first surface of the dielectric substrate, and the first conductor line and the second conductor are formed. The connector according to claim 8, wherein a dielectric is interposed between the line and the line. The connector line portion is
A third conductor line formed in a layer on the second surface of the dielectric substrate, and
A first conductive via that penetrates the dielectric substrate and electrically connects the first conductor line and the third conductor line.
9. The connector according to claim 9. An exposed region on which the dielectric substrate is exposed is formed on the second surface of the dielectric substrate, and the second conductor line is formed on the first surface of the dielectric substrate in the exposed region. The connector according to claim 9 or 10, which corresponds to the area covered. The connector according to any one of claims 8 to 11 , wherein the second conductor line has a low-pass filter formed on the line. It has an outer conductor electrically connected to the first conductor line and an inner conductor electrically connected to the second conductor line, and the outer conductor becomes an outer conductor of a coaxial cable or a coaxial tube. The connector according to any one of claims 8 to 12 , further comprising a connector connection that is electrically connected and the inner conductor is electrically connected to the coaxial cable or the inner conductor of the coaxial tube. The connector according to claim 13 , wherein a high-pass filter is formed on the inner conductor of the connector connection portion. The connector according to any one of claims 8 to 14 , wherein the housing includes a radio wave absorber at at least one of an open portion at one end and the other end. The connector according to any one of claims 8 to 15 , wherein the other end of the housing is further opened, and one end of the transmission line is inserted from the open portion of the other end. The connector according to any one of claims 8 to 16 , wherein the housing has a side wall further opened and one end of the transmission line is inserted from the open portion of the side wall.

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