Patent Description:
<FIG> is an exploded view of a configuration <NUM> of mounting a coaxial RF connector <NUM> of the edge mount, end launch to a substrate <NUM> disclosed in a patent document No. <NUM>. The connector <NUM> has a base plate <NUM> through which a threaded end <NUM> protrudes, and the end <NUM> is formed to receive a corresponding male SMA connector. In the connector <NUM>, a central conductor <NUM>, and four mounting protrusions <NUM>, <NUM>, <NUM>, and <NUM> extend from the base plate <NUM>. A quasi-coaxial transmission line <NUM> formed on the substrate <NUM> has a strip of metal <NUM> formed on a top face of a dielectric material layer <NUM>, and a metal layer <NUM> covering the dielectric material layer <NUM> and the strip of metal <NUM>. The quasi-coaxial transmission line <NUM> extends to a position near an end of the substrate <NUM> (stops short of the end) to avoid an unintended connection between the strip of metal <NUM> and the base plate <NUM>. The strip of metal <NUM> is exposed because the metal layer <NUM> is disposed not from the end of the substrate <NUM>.

With this arrangement, lower portions of the mounting protrusions <NUM>, <NUM> of the connector <NUM> are mounted at positions indicated by dotted lines <NUM>, <NUM> of a grounding surface <NUM> of the substrate <NUM>, and the central conductor <NUM> of the connector <NUM> is pressed against a position indicated by a dotted line <NUM> of the strip of metal <NUM>. However, because the central conductor <NUM> and the strip of metal <NUM> have unshielded portions where an unwanted signal coupling can occur, a conductive shielding cover <NUM> is provided over the portions. The shielding cover <NUM> is fixed to areas, depicted in dotted lines <NUM> and <NUM>, through soldering or the like.

[Patent Document <NUM>] <CIT>. <CIT> describes a method to design and assemble a connector for the transition between a coaxial cable and a microstrip line, particularly for the one that features the attenuation or even elimination of a resonant response caused by the excitation of the first higher-order mode of the conventional coaxial connector from the frequency response of the transition. <CIT> describes a means for connecting an electroconductive circuit mounted on a printed circuit board to an outside circuit in such a manner that an operator can test fully and align the electroconductive circuit mounted on the printed circuit board prior to the final assembly of the printed circuit board within a circuit box wherein the printed circuit board is installed for operation. Printed circuit boards are used to modulate or otherwise modify the output of an outside circuit, particularly those producing signals in the radio frequency range. <CIT> describes an adaptor to connect a coaxial cable to microstrip lines. <CIT> describes an adaptor for connecting a coaxial line with a planar line carried on a substrate with a ground plane wherein the adapter consists of a coaxial connector with an internal conductor connecting the coaxial line with the planar line through a face with a through-hole of constant diameter.

However, the prior art technology uses the shielding cover, which is a separate part with respect to the coaxial connector, to shield portions between the substrate and the coaxial connector, making it difficult to make the electric potentials of the base plate and the shielding cover of the coaxial connector to be identical. As a result, propagation characteristics of a signal between the substrate and the coaxial connector may be degraded.

The present disclosure provides a coaxial connector as well as a substrate with a coaxial connector capable of avoiding a degradation in propagation characteristics of a signal.

A coaxial connector according to claims <NUM>-<NUM> is provided. Further, a substrate with a coaxial connector according to claims <NUM>-<NUM> is provided.

According to the technologies of the present disclosure, a coaxial connector and a substrate with a coaxial connector capable of avoiding a degradation of propagation characteristics of a signal can be provided.

<FIG> and <FIG> relate to coaxial connectors that do not have all the features defined in independent claim <NUM>. Nevertheless, said coaxial connectors are considered useful for understanding the present invention.

In each embodiment, directions of parallel, perpendicular, orthogonal, horizontal, vertical, upward/downward, left/right, and the like are allowed to deviate from the exact directions to an extent not to impair the advantageous effects of the present invention. A X-axis direction, a Y-axis direction, and a Z-axis direction denote a direction parallel to an X-axis, a direction parallel to a Y-axis, and a direction parallel to a Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. An XY-plane, a YZ-plane, and a ZX-plane denote a virtual plane parallel to the X-axis direction and the Y-axis direction, a virtual plane parallel to the Y-axis direction and the Z-axis direction, and a virtual plane parallel to the Z-axis direction and the X-axis direction, respectively.

According to each of the present embodiments, a coaxial connector and a substrate with a coaxial connector are used to propagate a signal in a high frequency band (e.g., <NUM>-<NUM>), e.g., microwaves or millimeter waves. Such a high frequency band includes a <NUM>-<NUM> UHF band, a <NUM>-<NUM> SHF band, and a <NUM>-<NUM> EHF band. Examples of a high-frequency device formed on a substrate with a coaxial connector according to each of the present embodiments include a planar antenna, a planar waveguide (a planar transmission line), and the like.

According to each of the present embodiments, a coaxial connector and a substrate with a coaxial connector may be used in, for example, a <NUM> mobile communication system, a wireless communication standard such as Bluetooth, or a wireless local area network (LAN) standard such as IEEE <NUM>. A coaxial connector and a substrate with a coaxial connector according to each of the present embodiments, in a case of being used in a vehicle, may be used in an on-vehicle radar system for radar irradiation or in a V2X communication system for inter-vehicle communication, roadside-to-vehicle communication, or the like.

Next, a substrate with a coaxial connector in one comparative example will be described for comparison with a coaxial connector and a substrate with a coaxial connector according to each of the present embodiments.

<FIG> is a partially magnified plan view depicting a substrate with a coaxial connector in one comparative example. <FIG> is a partial cross-sectional view of the substrate with the coaxial connector in the comparative example. <FIG> and <FIG> depict a configuration in which a coaxial connector <NUM> is attached to an edge of a substrate <NUM>.

In <FIG> and <FIG> , the substrate <NUM> includes a plate-like dielectric layer <NUM>, a power supply line <NUM> provided on one side of the dielectric layer <NUM>, and a ground conductor <NUM> opposing the power supply line <NUM> via the dielectric layer <NUM>. A transmission line <NUM> is formed on the substrate <NUM>.

The transmission line <NUM> is a microstrip line having a structure that includes the dielectric layer <NUM>, the power supply line <NUM> formed on a first principal surface <NUM> of the dielectric layer <NUM>, and the ground conductor <NUM> formed on a second principal surface <NUM> of the dielectric layer <NUM>. The power supply line <NUM> is a planar conductor pattern whose surface is parallel to an XY plane and is formed on the first principal surface <NUM>. The ground conductor <NUM> is a conductor pattern whose surface is parallel to the XY plane and is a conductor pattern formed on the second principal surface <NUM>.

The coaxial connector <NUM> includes a base <NUM>, a coaxial structure <NUM> provided in the base <NUM>, and a pair of protrusions <NUM> projecting from the base <NUM>.

The coaxial structure <NUM> has a configuration in which the dielectric <NUM> is between a central conductor <NUM> and an outer conductor <NUM>. One end of the coaxial structure <NUM> is provided with a connecting section <NUM> to which an end of a coaxial cable, not depicted, is connected. The central conductor <NUM> has a contact portion 154a that extends from the other end opposite to the connecting section <NUM>. The contact portion 154a is in contact with the power supply line <NUM> formed on the first principal surface <NUM> of the substrate <NUM> that is inserted toward the base <NUM> between the contact portion 154a and the pair of protrusions <NUM>. The pair of protrusions <NUM> protrude from the X-axis ends of the base <NUM> toward the substrate <NUM>, i.e., in the direction opposite to the Y-axis direction.

The coaxial connector <NUM> is attached to the substrate <NUM> with the contact portion 154a conductively in contact with the power supply line <NUM>. This way of attaching the coaxial connector <NUM> to the substrate <NUM> allows for transmission of a high frequency signal between the transmission line <NUM> formed on the substrate <NUM> and a coaxial cable not depicted whose one end is connected to the connecting section <NUM> of the coaxial connector <NUM>.

However, an outer edge portion <NUM> located at an edge of the substrate <NUM> may often have slopes <NUM> and <NUM> formed by chamfering. The slope <NUM> is a portion of the outer edge portion <NUM> at which the first principal surface <NUM> side is chamfered, and the power supply line <NUM> is not formed. The slope <NUM> is a portion of the outer edge portion <NUM> at which the second principal surface <NUM> side is chamfered, and the ground conductor <NUM> is not formed. Thus, the outer edge portion <NUM> between the transmission line <NUM> and the coaxial connector <NUM> has the slopes <NUM> and <NUM> formed from chamfering of the dielectric layer <NUM> used in the transmission line <NUM>, and the ground conductor <NUM> is not formed at the portion of the outer edge portion <NUM> where the second principal surface <NUM> side is chamfered. Therefore, the characteristic impedance of the outer edge portion <NUM> differs significantly between the transmission line <NUM> and the coaxial connector <NUM>. Therefore, there is an unshielded portion adjacent to the outer edge portion <NUM> where unwanted signal radiation may occur. Thus, characteristic impedance discontinuity occurring due to the outer edge portion <NUM> between the transmission line <NUM> and the coaxial connector <NUM> may be increased and propagation characteristics of a signal between the substrate <NUM> and the coaxial connector <NUM> may be degraded.

<FIG> is a diagram illustrating a characteristic impedance of a signal path of a substrate with a coaxial connector in the comparative example. For example, suppose that each of a characteristic impedance of the transmission line <NUM> formed on the substrate <NUM>, a characteristic impedance of the coaxial connector <NUM>, and a characteristic impedance of a coaxial cable connected to the coaxial connector <NUM> is 50Ω. In this case, as described above, at least the contact portion 154a is not shielded, and also, an impedance section Z2 having a characteristic impedance different from <NUM>Ω is generated between the transmission line <NUM> and the coaxial connector <NUM>. When the impedance section Z2 where the characteristic impedance is discontinuous is present between the substrate <NUM> and the coaxial connector <NUM>, multiple reflections of a signal that is transmitted may occur, resulting in degradation in the propagation characteristics of the signal (e.g., an increase in the transmission loss).

On the other hand, according to the present embodiments, a coaxial connector and a substrate with a coaxial connector have configurations that can avoid degradation in the signal propagation characteristics between the substrate and the coaxial connector. Now, a configurations of coaxial connectors and substrates with coaxial connectors according to the present embodiments will be described in detail.

<FIG> is a partial magnified perspective view depicting a coaxial connector and a substrate with the coaxial connector according to a first embodiment. <FIG> is a partially magnified plan view depicting the substrate with the coaxial connector according to the first embodiment. <FIG> is a partial cross-sectional view of the substrate with the coaxial connector according to the first embodiment. <FIG> depict a configuration in which the coaxial connector 51A is attached to an edge of the substrate <NUM>.

In <FIG> , the substrate <NUM> includes a plate-like dielectric layer <NUM>, a power supply line <NUM> provided on one side of the dielectric layer <NUM>, and a ground conductor <NUM> opposite to the power supply line <NUM> via the dielectric layer <NUM>. A transmission line <NUM> is formed in the substrate <NUM>.

The transmission line <NUM> is a microstrip line having a structure including the dielectric layer <NUM>, the power supply line <NUM> formed on a first principal surface <NUM> of the dielectric layer <NUM>, and the ground conductor <NUM> formed on a second principal surface <NUM> of the dielectric layer <NUM>.

The dielectric layer <NUM> has the first principal surface <NUM> and the second principal surface <NUM> opposite to the first principal surface <NUM>. <FIG> and <FIG> depict the power supply line <NUM> provided on the first principal surface <NUM> side of the dielectric layer <NUM>. <FIG> depicts the ground conductor <NUM> disposed on the second principal surface <NUM> side of the dielectric layer <NUM>. The first principal surface <NUM> is an example of a first surface of the dielectric layer. The second principal surface <NUM> is an example of a second surface opposite the first surface of the dielectric layer.

The dielectric layer <NUM> is a plate-like or sheet-like substrate mainly containing dielectric. Both the first principal surface <NUM> and the second principal surface <NUM> are parallel to the XY plane. The dielectric layer <NUM> may be, for example, a dielectric substrate or a dielectric sheet. Examples of a material of the dielectric layer <NUM> include, but are not limited to, glasses such as quartz glass, soda-lime glass, alkalifree glass, aluminosilicate glass, borosilicate glass, alkaline borosilicate glass, and the like, ceramics, fluororesins such as polytetrafluoroethylene, liquid crystal polymers, cycloolefin polymers, polycarbonates, and the like.

The material of the dielectric layer <NUM> may be a transparent dielectric member through which visible light is transmitted, for example, to improve designability. A translucent dielectric member may be used instead of the transparent dielectric member. Transmittance with respect to visible light of the dielectric layer <NUM> is preferably greater than or equal to <NUM>%, more preferably greater than or equal to <NUM>%, yet more preferably greater than or equal to <NUM>%, especially preferably greater than or equal to <NUM>%, and most preferably greater than or equal to <NUM>%, in order to avoid blockage of visible light.

The power supply line <NUM> is a planar conductor pattern whose surface is parallel to the XY plane. The power supply line <NUM> is a conductor pattern formed on the first principal surface <NUM> and may be formed of a conductor sheet or a conductor substrate disposed on the first principal surface <NUM>. Examples of the material of the conductor used in the power supply line <NUM> include, but are not limited to, gold, silver, copper, platinum, aluminum, chromium, and the like. The power supply line <NUM> is an example of a signal line in contact with the dielectric layer <NUM>. For example, in the case where the transmission line <NUM> is a microstrip line, the power supply line <NUM> corresponds to a strip conductor.

The power supply line <NUM> may be formed on the first principal surface <NUM> side via an interlayer such as polyvinyl butyral or ethylene vinyl acetate, or an adhesive layer such as an optically clear adhesive (OCA). The power supply line <NUM> may be also in direct contact with the first principal surface <NUM>.

In the first embodiment, the power supply line <NUM> is a solid pattern of an area that has transmittance with respect to visible light lower than transmittance with respect to visible light of the dielectric layer <NUM>. For example, the entire power supply line <NUM> is made of an opaque planar conductor.

The power supply line <NUM> may be a conductor pattern having a mesh shape such that thus-formed lattice-like apertures improve designability. The mesh structure improves transmittance with respect to visible light and allows both designability and conductivity to be achieved. The power supply line <NUM> may be the same as or differ from the dielectric layer <NUM> in transmittance with respect to visible light.

The ground conductor <NUM> is a pattern of a conductor whose surface is parallel to the XY plane. The ground conductor <NUM> is a conductor pattern formed on the second principal surface <NUM> side and may be formed of a conductor sheet or a conductor substrate disposed on the second principal surface <NUM> side. Examples of the material of the ground conductor <NUM> include, but are not limited to, gold, silver, copper, platinum, aluminum, chromium, and the like. The ground conductor <NUM> is in contact with the dielectric layer <NUM>.

The ground conductor <NUM> may be formed on the second principal surface <NUM> side via an interlayer such as polyvinyl butyral or ethylene vinyl acetate, or an adhesive layer such as an optically clear adhesive (OCA). The ground conductor <NUM> may be also in direct contact with the second principal surface <NUM>.

The ground conductor <NUM> is a solid pattern of an area that has transmittance with respect to visible light lower than the transmission with respect to visible light of the dielectric layer <NUM>. For example, the entire ground conductor <NUM> is made of an opaque planar conductor.

The ground conductor <NUM> may be a pattern of a conductor having a mesh shape such that thus-formed lattice-like apertures improve designability. The mesh structure improves transmittance with respect to visible light and allows both designability and conductivity to be achieved. The ground conductor <NUM> may be the same as or differ from the dielectric layer <NUM> in transmittance with respect to visible light.

The coaxial connector 51A includes a base <NUM>, a coaxial structure <NUM> provided in the base <NUM>, and a protrusion <NUM> protruding from a base surface 53a of the base <NUM>.

In the first embodiment, the base <NUM> has the base surface 53a parallel to the ZX plane. The base surface 53a is a portion facing an end surface <NUM> of the substrate <NUM>. The end surface <NUM> is a portion in the Y-axis direction, which is perpendicular to the direction normal to the substrate <NUM> (in this case, the Z-axis direction).

The coaxial structure <NUM> has a configuration in which a dielectric <NUM> is between a central conductor <NUM> and an outer conductor <NUM>. One end of the coaxial structure <NUM> is provided with a connecting section <NUM>, to which an end of a coaxial cable, not depicted, is connected. The connecting section <NUM> may have, for example, a male threaded shape. The central conductor <NUM> has a contact portion 54a which extends from the other end of the coaxial structure <NUM> opposite to the connecting section <NUM>.

The contact portion 54a protrudes from the base surface 53a of the base <NUM>. The expression that "the contact portion 54a protrudes from the base surface 53a" means that the contact portion 54a protrudes toward the substrate <NUM> with respect to a ZX plane including the base surface 53a. In the first embodiment, the base surface 53a is coplanar with one end surface of the dielectric <NUM> included in the coaxial structure <NUM>. However, as long as the contact portion 54a protrudes from the base surface 53a, the base surface 53a may be at a position shifted along the Y-axis direction or the direction opposite thereto with respect to the end surface of the dielectric <NUM>.

When the substrate <NUM> is inserted between the contact portion 54a and the protrusion <NUM> toward the base surface 53a, the contact portion 54a is electrically in contact with the power supply line <NUM> formed on the first principal surface <NUM> of the inserted substrate <NUM> at a power supply end <NUM>. It is preferable that the contact portion 54a and the power supply line <NUM> be electrically connected through a conductive connection implemented by a conductive adhesive, a solder, or the like.

The protrusion <NUM> protrudes from the base surface 53a of the base <NUM>. The expression that "the protrusion <NUM> protrudes from the base surface 53a" means that the protrusion <NUM> protrudes toward the substrate <NUM> with respect to a ZX plane including the base surface 53a. One or more protrusions may be provided as the protrusion <NUM>.

The protrusion <NUM> is a conductor having the same electrical potential as the outer conductor <NUM> of the coaxial structure <NUM>, for example. Accordingly, when the substrate <NUM> is inserted between the contact portion 54a and the protrusion <NUM> toward the base surface 53a, the ground conductor <NUM> in contact with the protrusion <NUM> can have the same electrical potential as the electrical potential of the outer conductor <NUM>. The protrusion <NUM> may be a member integrally formed with the base <NUM> or a separate member connected to the base <NUM>.

The protrusion <NUM> may, for example, be a portion that supports, from the lower side (from the lower side with respect to the Z-axis direction), the substrate <NUM> inserted between the contact portion 54a and the protrusion <NUM> toward the base surface 53a. In this case, the protrusion <NUM> is a part of an attaching structure for attaching the coaxial connector 51A to an edge of substrate <NUM>.

It should be noted that the attaching structure for attaching the coaxial connector 51A to the edge of the substrate <NUM> may be any attaching structure as long as the advantageous effects of the present invention are not impaired. For example, as depicted in <FIG> , the attaching structure may be configured to tighten the substrate <NUM> to the protrusion <NUM> by bolts <NUM> and <NUM> inserted into through holes formed in the substrate <NUM>. Washers or a portion of the base <NUM> may be inserted between the first principal surface <NUM> and the bolts <NUM> and <NUM> to prevent direct contact between the bolts <NUM> and <NUM> and the substrate <NUM>.

The coaxial connector 51A is attached to the substrate <NUM> with the contact portion 54a electrically conductively in contact with the power supply line <NUM>. As a result of the coaxial connector 51A being attached to the substrate <NUM> in this manner, a high frequency signal can be transmitted between the transmission line <NUM> formed in the substrate <NUM> and a coaxial cable (not depicted) whose one end is connected to the connecting section <NUM> of the coaxial connector 51A.

However, as described above, an outer edge portion <NUM> located at an edge of the substrate <NUM> often has slopes <NUM> and <NUM> formed by chamfering. The first slope <NUM> is a portion of the outer edge portion <NUM>, in which the first principal surface <NUM> side is chamfered, and the power supply line <NUM> is not formed. The second slope <NUM> is a portion of the outer edge portion <NUM>, in which the second principal surface <NUM> is chamfered, and the ground conductor <NUM> is not formed.

The outer conductor <NUM> in the first embodiment has a protruding conductor 50a that protrudes from the base surface 53a and is not in contact with the substrate <NUM> inserted between the contact portion 54a and the protrusion <NUM>. The expression "the protruding conductor 50a that protrudes from the base surface 53a" means that the protruding conductor 50a protrudes toward the substrate <NUM> with respect to a ZX plane including the base surface 53a. In the first embodiment, there is a space along the direction normal to the substrate <NUM> between the protruding conductor 50a and the slope <NUM>.

By thus providing the protruding conductor 50a, at least the contact portion 54a can be shielded by the protruding conductor 50a. Therefore, discontinuity of characteristic impedance occurring due to the outer edge portion <NUM> between the transmission line <NUM> and the coaxial connector 51A is reduced, and it is possible to avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A. For example, multiple reflection of a signal transmitted between the substrate <NUM> and the coaxial connector 51A comes to be not likely to occur, and an increase in transmission loss can be avoided.

In the first embodiment, the protruding conductor 50a protrudes from the base surface 53a in such a manner that the contact portion 54a is positioned between the substrate <NUM>, inserted between the contact portion 54a and the protrusion <NUM>, and the protruding conductor 50a protruding from the base surface 53a. This prevents an unwanted signal from emitting in a direction opposite to the substrate <NUM> with respect to the contact portion 54a. For example, the protruding conductor 50a is an eave-like portion extending from the coaxial structure <NUM> in a direction parallel to an axial direction of the coaxial structure <NUM> and has the same electric potential as the electric potential of the outer conductor <NUM>.

When viewed in a direction normal to the substrate <NUM> with the substrate <NUM> inserted between the contact portion 54a and the protrusion <NUM>, the protruding conductor 50a preferably protrudes from the base surface 53a in such a manner that the protruding conductor 50a overlaps the outer edge portion <NUM>. Thereby, it is possible to further reduce discontinuity of characteristic impedance, occurring due to the outer edge portion <NUM>, between the transmission line <NUM> and the coaxial connector 51A, and it is possible to further avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A.

The protruding conductor 50a may protrude from the base surface 53a as far as a boundary between the power supply line <NUM> (power supply end <NUM>) and the outer edge portion <NUM>, or may protrude beyond the boundary, when viewed from a direction normal to the substrate <NUM>. Protruding of the protruding conductor 50a from the base surface 53a up to or beyond the boundary reduces discontinuity of characteristic impedance, occurring due to the outer edge portions <NUM>, between the transmission line <NUM> and the coaxial connector 51A, as compared to protruding of the protruding conductor 50a from the base surface 53a stopping short of the boundary. Thus, degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A can be further avoided.

It is preferable that, when viewed from a direction normal to the substrate <NUM> with the substrate <NUM> inserted between the contact portion 54a and the protrusion <NUM>, the protrusion <NUM> protrudes from the base surface 53a in such a manner that the protrusion <NUM> overlaps the contact portion 54a. Thereby, it is possible to further reduce discontinuity of the characteristic impedance, occurring due to the outer edge portion <NUM>, between the transmission line <NUM> and the coaxial connector 51A, and it is possible to further avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A.

The protrusion <NUM> may protrude from the base surface 53a as far as a distal end of the contact portion 54a or protrude beyond the distal end of the contact portion 54a, when viewed from a direction normal to the substrate <NUM>. The protrusion <NUM> protruding from the base surface 53a up to or beyond the distal end can reduce discontinuity of the characteristic impedance, occurring due to the outer edge portion <NUM>, between the transmission line <NUM> and the coaxial connector 51A, compared to protruding of the protrusion <NUM> from the base surface 53a stopping short of the distal end. Thus, degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A can be further avoided.

Furthermore, parallelism of the end surface <NUM> in relation to the base surface 53a is preferably <NUM> or less, and more preferably <NUM> or less, from the point of view of restricting a drop in propagation characteristics of signals between the substrate <NUM> and the coaxial connector 51A. Furthermore, a calculated average roughness Ra of the end surface <NUM> is preferably <NUM> or less, and more preferably <NUM> or less, from the point of view of restricting a drop in propagation characteristics of the signals between the substrate <NUM> and the coaxial connector 51A. This is to enable highly accurate management of a length dimension of a part of the contact portion 54a which is not in contact with the power supply line <NUM> in a state of contact between the end surface <NUM> and the base surface 53a. It is therefore possible to limit a reduction in the effects afforded by the protruding conductor 50a due to discrepancies in mounting dimensions, namely an effect of reducing discontinuity of characteristic impedance of the outer edge portion <NUM> between the transmission pathway <NUM> and the coaxial connector 51A, and an effect of shielding unwanted signal emission. Here, the calculated average roughness Ra is a value defined by JIS B <NUM>:<NUM>.

As depicted in <FIG> and <FIG> , an impedance adjusting portion <NUM> for implementing impedance matching may be provided at a portion of (at a location pathway along) the transmission line <NUM> such as a microstrip line. <FIG> depicts an example in which the impedance adjusting portion <NUM> is separated from the slope <NUM>, and <FIG> depicts an example in which the impedance adjusting portion <NUM> is in contact with the slope <NUM>.

By providing the impedance adjusting portion <NUM> at a portion of the transmission line <NUM>, the advantageous effects of reducing discontinuity in characteristic impedance occurring due to the outer edge portion <NUM> between the transmission line <NUM> and the coaxial connector 51A are improved than a case where the impedance adjusting portion <NUM> is not provided. Therefore, it is possible to further avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A.

For example, as depicted in <FIG> or <FIG> , the impedance adjusting portion <NUM> may be implemented by stubs branching from the power supply line <NUM> on the first principal surface <NUM> of the substrate <NUM>. The stubs are distribution-element circuits connected at locations pathway along the transmission line <NUM>. Patterns of the stubs are formed, for example, in the same manner as a pattern of the power supply line <NUM>. As depicted in <FIG> or <FIG> , by forming the stubs laterally symmetrical with respect to the longitudinal direction of the power supply line <NUM>, for example, influences of the stubs on directivity of an antenna conductor, not depicted, connected at the distal ends of the transmission line <NUM>, can be reduced.

The impedance adjusting portion <NUM> may include a matching circuit formed of a lumped-element circuit using a reactance element such as an inductor or a capacitor.

<FIG> is a diagram illustrating characteristic impedances of signal paths with respect to the substrate with the coaxial connector according to the first embodiment. For example, suppose that each of characteristic impedance of the transmission line <NUM> formed on the substrate <NUM>, characteristic impedance of the coaxial connector 51A, and characteristic impedance of a coaxial cable connected to the coaxial connector 51A is <NUM>Ω. By providing the impedance adjusting portion <NUM>, an impedance section Z1 can be formed between the transmission line <NUM> and the outer edge portion <NUM>. The impedance section Z1 being thus formed compensates for a change in characteristic impedance caused by the outer edge portion <NUM>. Therefore, it is possible to reduce discontinuity of characteristic impedance between the transmission line <NUM> and the coaxial connector 51A, and avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51A.

<FIG> is a partially magnified perspective view depicting a coaxial connector and a substrate with the coaxial connector view according to a second embodiment. <FIG> is a partial cross-sectional view of the substrate with the coaxial connector according to the second embodiment. <FIG> and <FIG> depict a configuration in which the coaxial connector 51B is attached to an edge of the substrate <NUM>. The descriptions of the structures and the advantageous effects of the second embodiment similar to those of the first embodiment will be omitted or simplified by reference to the descriptions hereinbefore. In the second embodiment, a protruding dielectric 55a is added to the first embodiment.

A dielectric <NUM> in the second embodiment has the protruding dielectric 55a protruding from a base surface 53a toward between a contact portion 54a and a protruding conductor 50a. The expression "the protruding dielectric 55a protruding from a base surface 53a" means that the protruding dielectric 55a protrudes toward the substrate <NUM> with respect to a ZX plane including the base surface 53a.

By providing the protruding dielectric 55a, discontinuity of characteristic impedance occurring due to an outer edge portions <NUM> between a transmission line <NUM> and a coaxial connector 51B is reduced, and degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51B is avoided. For example, multiple reflection of a signal transmitted between the substrate <NUM> and the coaxial connector 51B comes to be not likely to occur, and an increase in transmission loss can be avoided. In the second embodiment, the protruding dielectric 55a is an eave-like portion extending from a coaxial structure <NUM> in a direction parallel to an axial direction of the coaxial structure <NUM>.

In the second embodiment, the protruding dielectric 55a is in contact with at least one of the contact portion 54a and the protruding conductor 50a. Thus, discontinuity of characteristic impedance occurring due to the outer edge portion <NUM> between the transmission line <NUM> and the coaxial connector 51B is reduced, and it is possible to avoid degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51B. The protruding dielectric 55a may be in contact with a part of or the entirety of the contact portion 54a or in contact with a part of or the entirety of the protruding conductor 50a.

The protruding dielectric 55a may protrude from the base surface 53a as far as a boundary between a power supply line <NUM> (power supply end <NUM>) and the outer edge portion <NUM>, or may protrude beyond the boundary, when viewed from a direction normal to the substrate <NUM>. The protruding dielectric 55a protrudes from the base surface 53a to or beyond the boundary to reduce discontinuity of characteristic impedance occurring due to the outer edge portions <NUM> between the transmission line <NUM> and the coaxial connector 51B as compared to a configuration in which the protruding dielectric 55a protruding from the base surface 53a stops short of the boundary. That is, degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51B can be more surely avoided.

Examples of the material of the protruding dielectric 55a include, but are not limited to, glasses such as quartz glass, soda-lime glass, alkalifree glass, aluminosilicate glass, borosilicate glass, alkali borosilicate glass, and the like, fluororesins such as polytetrafluoroethylene, liquid crystal polymers, and the like.

<FIG> is a partial cross-sectional view of a coaxial connector and a substrate with the coaxial connector according to a third embodiment. <FIG> depicts a configuration in which the coaxial connector 51C is attached to an edge of the substrate <NUM>. Concerning the third embodiments, the descriptions of the structures and the advantageous effects similar to or the same as those of the above-described embodiments will be omitted or simplified by reference to the descriptions hereinbefore. The third embodiment adds dielectric members 58A and 58B to the second embodiment.

The dielectric member 58A is a generally triangular prismatic element having a side along a slope <NUM>, a side along a contact portion 54a, and a side along a base surface 53a. At least a portion of a space between the contact portion 54a and the slope <NUM> is filled with the dielectric member 58A. The dielectric member 58B is a generally triangular prismatic element having a side along a slope <NUM>, a side along a protrusion <NUM>, and a side along the base surface 53a. At least a portion of a space between the protrusion <NUM> and the slope <NUM> is filled with the dielectric member 58B.

By providing the dielectric members 58A and 58B, discontinuity of characteristic impedance occurring due to an outer edge portion <NUM> between a transmission line <NUM> and the coaxial connector 51C is reduced, and degradation in the propagation characteristics of a signal between the substrate <NUM> and the coaxial connector 51C is avoided. For example, multiple reflection of a signal transmitted between the substrate <NUM> and the coaxial connector 51C comes to be not likely to occur, and an increase in transmission loss is avoided.

A material of the dielectric member 58A may be similar to or have a higher dielectric constant than a dielectric constant of a dielectric layer <NUM>. Specific examples include, but are not limited to, glasses such as quartz glass, soda-lime glass, alkalifree glass, aluminosilicate glass, borosilicate glass, alkali borosilicate glass, and the like, ceramics, fluororesins such as polytetrafluoroethylene, liquid crystal polymers, cycloolefin polymers, polycarbonates, and the like.

<FIG> depict examples of configurations of protruding conductors and protruding dielectrics. Any of the configurations of <FIG> are applicable to each of the embodiments described above. Each of the protruding conductor 50a and the protruding dielectric 55a depicted in each of <FIG> protrudes from the base surface 53a to surround a portion of the outer peripheral surface of the contact portion 54a.

In each of <FIG> and <FIG> , each of the protruding conductor 50a and the protruding dielectric 55a has an eave shape obtained from a circular cylinder being approximately halved. In <FIG> , the protruding conductor 50a has an eave shape obtained from a square or rectangular cylinder being approximately halved, and the protruding dielectric 55a has an eave shape obtained from a circular cylinder being approximately halved. In <FIG> , each of the protruding conductor 50a and the protruding dielectric 55a has an eave shape obtained from a square or rectangular cylinder being approximately halved.

Although the coaxial connectors and the substrates with the coaxial connectors have been described with reference to the embodiments, the present invention is not limited to the embodiments described above. Various modifications or improvements, such as a combination or a substitution with some or all of the other embodiments, are possible within the scope of the present invention.

Claim 1:
A coaxial connector (51B, 51C) comprising:
a base surface (53a);
a coaxial structure (<NUM>) where a dielectric (<NUM>) is between a central conductor (<NUM>) and an outer conductor (<NUM>); and
a protrusion (<NUM>) protruding from the base surface,
wherein
the central conductor includes a contact portion (54a) protruding from the base surface,
the coaxial connector being configured such that in response to a substrate (<NUM>) being inserted toward the base surface between the contact portion and the protrusion, the contact portion comes into contact with a conductor pattern (<NUM>) formed on a surface of the substrate, and
the outer conductor includes a protruding conductor (50a) protruding from the base surface and not in contact with the substrate inserted between the contact portion and the protrusion
and wherein the dielectric includes a protruding dielectric (55a) protruding from the base surface toward between the contact portion and the protruding conductor.