Transmission line structure and antenna module

Abstract

In this transmission line structure (10), the shape of each of ground pads (13A, 13B) is a rectangular shape having a long side along a second direction substantially perpendicular to a first direction in which a transmission line (141) extends, and a short side along the first direction. The length of each ground pad (13A, 13B) in the first direction is shorter than the dimension of a connector (12A, 12B) in the first direction.

Description

Transmission line structure and antenna module

[0001] The present disclosure relates to a transmission line structure and an antenna module including the transmission line structure and an antenna substrate.

[0002] International Publication No. 2022 / 038879 (Patent Document 1) discloses an antenna module having a transmission line structure including a transmission line for transmitting a high-frequency signal and a ground electrode.

[0003] International Publication No. 2022 / 038879

[0004] A connector may be used when connecting a transmission line structure including a transmission line and a ground electrode to another substrate. When using a transmission line structure in which a connector is arranged, the transmission line structure may be bent for use depending on the application. However, in International Publication No. 2022 / 038879 (Patent Document 1), the connection portion of the connector in the transmission line structure including the transmission line and the ground electrode is not devised, and the thickness of the transmission line structure is also thick, so the transmission line structure is not suitable for use in a bent state.

[0005] An object of the present disclosure is to provide a transmission line structure that is suitable for use in a bent state.

[0006] A transmission line structure according to one embodiment of the present disclosure includes a flat dielectric substrate having a first main surface and a second main surface opposite the first main surface, a ground electrode disposed between the first main surface and the second main surface, a first transmission line disposed closer to the first main surface than the ground electrode and extending in a first direction, a ground pad disposed on the first main surface, a first signal pad connected to an end of the first transmission line on the first main surface, at least one interlayer connector disposed within the dielectric substrate and connected to the ground electrode and the ground pad, and a connector connected to the ground pad and the first signal pad on the first main surface. The ground pad is rectangular in shape with long sides extending along a second direction substantially perpendicular to the first direction and short sides extending along the first direction. The length of the ground pad in the first direction is shorter than the dimension of the connector in the first direction.

[0007] According to one embodiment of the present disclosure, the ground pad has a rectangular shape having a long side extending along a second direction substantially perpendicular to a first direction in which the first transmission line extends, and a short side extending along the first direction. The length of the ground pad in the first direction is shorter than the dimension of the connector in the first direction. That is, in the transmission-line structure, the length of the ground pad in the first direction in which the first transmission line extends is shorter than the dimension of the connector, and the contact area between the ground pad and the connector is small. This reduces the force applied to the connection between the ground pad and the connector when the transmission-line structure is bent, making it easier to bend the transmission-line structure.

[0008] 1 is a diagram showing an antenna module according to a first embodiment; 2 is a perspective view of a transmission-line structure according to a first embodiment; 3 is a plan view of a transmission-line structure according to a first embodiment; 4 is a cross-sectional view of a transmission-line structure according to a first embodiment; 5 is a diagram showing a connector according to a first embodiment; 6 is a plan view of a transmission-line structure according to a second embodiment; 7 is a cross-sectional view of a transmission-line structure according to a second embodiment; 8 is a plan view of a transmission-line structure according to a third embodiment; and 9 is a plan view of a transmission-line structure according to a fourth embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0010] 1 is a diagram showing an antenna module 100 according to a first embodiment. The antenna module 100 is used, for example, in mobile terminals such as mobile phones, smartphones, and tablets, and personal computers with communication functions. An example of the frequency band of radio waves used in the antenna module 100 according to the first embodiment is millimeter-wave radio waves with center frequencies of 28 GHz, 39 GHz, and 60 GHz, but radio waves in other frequency bands are also applicable.

[0011] The antenna module 100 includes an RFIC 110, an antenna device 190A having radiation electrodes 191A1 to 191A4, an antenna device 190B having radiation electrodes 191B1 to 191B4, a transmission-line structure 10, and connectors 12A and 12B. The RFIC 110 supplies a high-frequency signal. The antenna device 190A is connected to the transmission-line structure 10 via the connector 12A. The antenna device 190B is connected to the transmission-line structure 10 via the connector 12B. The RFIC 110 may have a SiP structure incorporating peripheral components such as a PMIC (power management IC).

[0012] Hereinafter, the antenna devices 190A and 190B will also be collectively referred to as "antenna device 190." The radiation electrodes 191A1 to 191A4 will also be collectively referred to as "radiating electrode 191A." The radiation electrodes 191B1 to 191B4 will also be collectively referred to as "radiating electrode 191B." The radiation electrodes 191A and 191B will also be collectively referred to as "radiating electrode 191."

[0013] The antenna device 190A is connected to the BBIC 200 via a connecting member 180. The antenna device 190B is connected to the antenna device 190A by a transmission line structure 10. The BBIC 200 is mounted on a motherboard 250 and constitutes a baseband signal processing circuit. The BBIC 200 is electrically connected to the RFIC 110.

[0014] The signals transmitted from the BIC 200 to the antenna module 100 are radiated from the antenna devices 190A and 190B. The signals received by the antenna devices 190A and 190B are processed by the BIC 200.

[0015] The motherboard 250 is a flat printed circuit board on which multiple components including the BBIC 200 are mounted. The motherboard 250 is formed, for example, from an MLB (multilayer board). A ground electrode 251 is arranged on the mounting surface of the motherboard 250. The ground electrode 251 is arranged so as to be attached widely over the entire mounting surface of the motherboard 250. The ground electrode 251 may be arranged only on a portion of the mounting surface of the motherboard 250. The ground electrode 251 may be arranged inside the mounting surface of the motherboard 250, rather than on the surface of the mounting surface.

[0016] The dielectric substrate constituting the antenna device 190 may be, for example, a low temperature co-fired ceramics (LTCC) multilayer substrate, a multilayer resin substrate formed by laminating multiple resin layers made of resins such as epoxy or polyimide, a multilayer resin substrate formed by laminating multiple resin layers made of liquid crystal polymer (LCP) having a lower dielectric constant, a multilayer resin substrate formed by laminating multiple resin layers made of fluorine-based resin or PET (Polyethylene Terephthalate), or a ceramic multilayer substrate other than LTCC. Note that the dielectric substrate constituting the antenna device 190 does not necessarily have a multilayer structure and may be a single-layer substrate.

[0017] The radiating electrode 191 is formed of a flat conductor such as copper or aluminum. The shape of the radiating electrode 191 is not limited to a rectangle, and may be a polygon, a circle, an ellipse, or a cross. The radiating electrode 191 is formed on the surface or an internal layer of a dielectric substrate.

[0018] In Figure 1, an array antenna is shown in which four radiation electrodes 191 are arranged in one direction, but it may be formed from a single radiation electrode 191, or may be configured with multiple radiation electrodes arranged one-dimensionally or two-dimensionally.

[0019] The ground electrode 170A is disposed inside the dielectric substrate of the antenna device 190A, facing the radiation electrode 191A. The ground electrode 170B is disposed inside the dielectric substrate of the antenna device 190B, facing the radiation electrode 191B.

[0020] A high-frequency signal from the RFIC 110 is supplied to the radiation electrode 191A of the antenna device 190A. The high-frequency signal from the RFIC 110 is supplied to the radiation electrode 191B of the antenna device 190B via the transmission line structure 10. When a high-frequency signal is supplied to the antenna device 190A, radio waves are radiated from the radiation electrode 191A, but no radio waves are radiated from the radiation electrode 191B. Conversely, when a high-frequency signal is supplied to the antenna device 190B, radio waves are radiated from the radiation electrode 191B, but no radio waves are radiated from the radiation electrode 191A. The antenna devices 190A and 190B radiate radio waves in different directions.

[0021] The connection member 180 is a flat cable having a plate shape. The connection member 180 is disposed so that the back surface of the connection member 180 is in contact with the mounting surface of the motherboard 250. The connection member 180 includes a ground electrode 181 therein. The connection member 180 includes a plurality of power supply lines therein. The connection member 180 has a dielectric substrate formed of ceramics such as LTCC or resin. The connection member 180 may be formed of a flexible material, or may be formed of a rigid material that does not deform. The power supply lines and the ground electrode 181 and other conductive members included in the connection member 180 are connected to the antenna device 190 and the motherboard 250 by a detachable connector or by solder.

[0022] Next, the transmission-line structure 10 will be described with reference to FIGS. 2 to 4. FIG. 2 is a perspective view of the transmission-line structure 10 according to the first embodiment. The transmission-line structure 10 in FIG. 2 is shown in a bent state. FIG. 2(A) is a diagram showing a state in which connectors 12A and 12B are attached to the transmission-line structure 10. FIG. 2(B) is a diagram showing a state in which the connectors 12A and 12B are detached from the transmission-line structure 10.

[0023] Fig. 3 is a plan view of the transmission-line structure 10 according to the first embodiment. The transmission-line structure 10 in Fig. 3 is shown in an extended state. Fig. 4 is a cross-sectional view of the transmission-line structure 10 according to the first embodiment. Fig. 4 is a partial cross-sectional view taken along line IV-IV in Fig. 3. Note that the cross-sectional view in Fig. 4 is schematically illustrated with the thickness in the layer direction increased compared to the actual product.

[0024] The transmission line structure 10 includes a dielectric substrate 11, connectors 12A and 12B, transmission lines 141 and 151, ground pads 13A and 13B, signal pad members 14A1 to 14A4, 14B1 to 14B4, 15A1 to 15A4, and 15B1 to 15B4, a ground electrode 161, a ground via 165, a signal via 155, and a protective member 20.

[0025] The dielectric substrate 11 has a flexible structure as shown in Fig. 2. The dielectric substrate 11 may be made of the same material as the material constituting the dielectric substrate constituting the antenna device 190 described above, as long as it has a flexible structure. As shown in Fig. 3, the dielectric substrate 11 is a flat-plate-shaped substrate having a second main surface opposite to the first main surface, where the side on which the connectors 12A and 12B are arranged is defined as a first main surface.

[0026] The ground electrode 161 is disposed between the first and second main surfaces of the dielectric substrate 11. The ground electrode 161 is electrically connected to a ground pad disposed on the first main surface by ground vias 165 serving as a plurality of interlayer connectors.

[0027] The transmission line 141 is disposed closer to the first main surface than the ground electrode 161, and extends in a first direction that is the direction of the longer sides of the dielectric substrate 11. Note that in Figures 3 and 4, the transmission line 141 is illustrated on the first main surface. The resist that is the protective member 20 shown in Figure 2 is not shown in Figures 3 and 4.

[0028] The transmission line 141 is a line for transmitting high-frequency signals, and includes four lines as shown in Figures 2 and 3. As shown in Figures 2 to 4, one end of the transmission line 141 functions as signal pad members 14A1 to 14A4 for electrical connection with the connector 12A. The other end of the transmission line 141 functions as signal pad members 14B1 to 14B4 for electrical connection with the connector 12B. The signal pad members 14A1 to 14A4 and the signal pad members 14B1 to 14B4 are collectively referred to as first signal pads.

[0029] The transmission line 151 is disposed closer to the second principal surface than the ground electrode 161, and extends in a first direction that is the direction of the long sides of the dielectric substrate 11. Like the transmission line 141, the transmission line 151 is a line for transmitting high-frequency signals, and includes four lines, which are not shown in any illustrations except for the cross-sectional view shown in FIG.

[0030] One end of the transmission line 151 is connected to signal pad members 15A1 to 15A4 for electrical connection with the connector 12A via a signal via 155 extending in the thickness direction of the dielectric substrate 11. The other end of the transmission line 151 is connected to signal pad members 15B1 to 15B4 for electrical connection with the connector 12B via a signal via 155 extending in the thickness direction of the dielectric substrate 11. The signal pad members 15A1 to 15A4 and the signal pad members 15B1 to 15B4 are collectively referred to as second signal pads.

[0031] The frequency band of the signal transmitted through transmission line 141 is higher than the frequency band of the signal transmitted through transmission line 151. This is because a signal with a higher frequency band experiences greater loss over distance than a signal with a lower frequency band, and therefore transmission line 141, whose signal frequency band is higher than that of transmission line 151, is arranged closer to connectors 12A and 12B to shorten the transmission distance. This makes it possible to reduce signal loss in transmission line 141.

[0032] The transmission line 141 is disposed on the first main surface of the dielectric substrate 11, which is the mounting surface of the connectors 12A and 12B. Unlike the transmission line 151, the transmission line 141 is thereby connected to the connectors 12A and 12B without passing through the signal via 155, which makes it easier to achieve impedance matching with components connected to the transmission line 141.

[0033] The transmission line structure 10 has a structure in which a single layer of ground electrode 161 is disposed between the transmission lines 141 and 151 in the thickness direction of the dielectric substrate 11. The transmission line structure 10 forms a stripline by sandwiching the ground electrode 161 between the transmission lines 141 and 151. In this way, the transmission line structure 10 can have a lower height in the thickness direction than a structure having multiple layers of ground electrodes because the ground electrode 161 is a single layer.

[0034] The connector 12A is electrically connected to the ground pad 13A, the first signal pads (signal pad members 14A1 to 14A4), and the second signal pads (signal pad members 15A1 to 15A4) on the first main surface side of the dielectric substrate 11. The connector 12A, which is not shown in FIG. 3, is located on the line indicated by the outer edge 120A.

[0035] The connector 12B is electrically connected to the ground pad 13B, the second signal pads (signal pad members 14B1 to 14B4), and the second signal pads (signal pad members 15B1 to 15B4) on the first main surface side of the dielectric substrate 11. The connector 12B, which is not shown in FIG. 3, is located on the line indicated by the outer edge 120B.

[0036] Ground pads 13A and 13B are rectangular in shape, with long sides aligned in a second direction substantially perpendicular to a first direction, which is the long side direction of dielectric substrate 11, and short sides aligned in the first direction. The lengths of ground pads 13A and 13B in the first direction are shorter than the dimensions of connectors 12A and 12B in the first direction. That is, in transmission-line structure 10, the lengths of ground pads 13A and 13B in the first direction, in which transmission lines 141 and 151 extend, are shorter than the dimensions of connectors 12A and 12B, and the contact areas between ground pads 13A and 13B and connectors 12A and 12B are small. This reduces the force applied to the connections between ground pads 13A and 13B and connectors 12A and 12B when transmission-line structure 10 is bent, making it easier to bend transmission-line structure 10.

[0037] Ground pad 13A is disposed between the first signal pads (signal pad members 14A1 to 14A4) and the second signal pads (signal pad members 15A1 to 15A4). Ground pad 13B is disposed between the first signal pads (signal pad members 14B1 to 14B4) and the second signal pads (signal pad members 15B1 to 15B4). This allows ground pads 13A and 13B to function as a shield between the first and second signal pads, preventing electromagnetic field coupling between the signal pads and improving isolation characteristics.

[0038] The extension portions 131 are arranged to extend from the long side of the ground pad 13A between the signal pad members 14A1 to 14A4 of the first signal pad in a direction toward the center of the dielectric substrate 11 in a plan view. Similarly, the extension portions 131 are arranged to extend from the long side of the ground pad 13B between the signal pad members 14B1 to 14B4 of the first signal pad in a direction toward the center of the dielectric substrate 11 in a plan view.

[0039] The extension portions 132 are arranged to extend from the long side of the ground pad 13A between the signal pad members 15A1 to 15A4 of the second signal pad in a direction away from the center in a plan view of the dielectric substrate 11. Similarly, the extension portions 132 are arranged to extend from the long side of the ground pad 13B between the signal pad members 15B1 to 15B4 of the second signal pad in a direction away from the center in a plan view of the dielectric substrate 11.

[0040] Ground pad 13A and extension member 131 and extension member 132 are integrally formed, but may be separate members and electrically connected. Ground pad 13B and extension member 131 and extension member 132 are integrally formed, but may be separate members and electrically connected.

[0041] The extensions 131 and 132 extending from the ground pads 13A and 13B can prevent impedance mismatch between the transmission lines 141 and 151 in the mounting portion of the connector 12A.

[0042] The extension portions 131 extending from the ground pads 13A and 13B can electrically isolate the signal pad members 14A1 to 14A4 and the signal pad members 14B1 to 14B4 from each other, thereby improving the isolation characteristics.

[0043] The extensions 132 extending from the ground pads 13A and 13B can suppress coupling between the signal pad members 15A1 to 15A4 and between the signal pad members 15B1 to 15B4, thereby improving isolation characteristics.

[0044] The lengths of the extensions 131 and 132 in the first direction are preferably equal to or less than the lengths of the first and second signal pads, thereby suppressing unwanted resonance between the extensions 131 and 132 and the signal pads.

[0045] The length of the ground pad 13A (13B) in the second direction (longer side direction) is longer than the length of the connector 12A (12B) in the second direction (longer side direction). This improves the mounting strength and mounting accuracy when mounting the connectors 12A and 12B. When mounting the connectors 12A and 12B, solder is applied to the symmetrically shaped ground pads 13A (13B). The mounting accuracy of the connectors 12A and 12B is improved by the self-alignment effect, in which the surface tension of the molten solder returns the connectors to the design center.

[0046] Next, the connectors 12A and 12B will be described. Fig. 5 shows the connectors 12A and 12B according to embodiment 1. Fig. 5(A) is a front view of the connectors 12A and 12B, and Fig. 5(B) is a plan view of the connectors 12A and 12B.

[0047] The connectors 12A and 12B are connectors for transmitting high-frequency signals from one substrate to another. The connectors 12A and 12B include a main body 121, a first conductor 122, and a second conductor 123. The main body 121 is made of an insulating material. The first conductor 122 and the second conductor 123 are made of conductive materials.

[0048] The first conductor portion 122 is electrically connected to the ground pads 13A and 13B, and the second conductor portion 123 is electrically connected to the first signal pad and the second signal pad.

[0049] As described above, in transmission-line structure 10 of the first embodiment, the lengths of ground pads 13A and 13B are shorter than the dimensions of connectors 12A and 12B in the first direction in which transmission lines 141 and 151 extend, and the contact areas between ground pads 13A and 13B and connectors 12A and 12B are small. This reduces the force applied to the connections between ground pads 13A and 13B and connectors 12A and 12B when transmission-line structure 10 is bent, making it easier to bend transmission-line structure 10.

[0050] [Embodiment 2] Next, a transmission-line structure 10A according to embodiment 2 will be described with reference to Figures 6 and 7. Figure 6 is a plan view of the transmission-line structure 10A according to embodiment 2. Figure 6(A) shows the entire transmission-line structure 10A, and Figure 6(B) shows an enlarged view of a portion of the transmission-line structure 10A.

[0051] The transmission-line structure 10A according to the second embodiment has some structural changes compared to the transmission-line structure 10 according to the first embodiment. Specifically, the transmission-line structure 10A differs from the transmission-line structure 10 in the shape of the extension portions extending from the ground pads 13A and 13B, the position of the transmission line 141 in the thickness direction of the dielectric substrate 11, the position of the ground via 165, and the inclusion of a signal via 145 connected to the transmission line 141.

[0052] Transmission line structure 10A is arranged such that extension portion 134 extends from the long sides of ground pads 13A and 13B to surround the entire periphery of the first signal pad. Transmission line structure 10A is arranged such that extension portion 135 extends from the long sides of ground pads 13A and 13B to surround the entire periphery of the second signal pad.

[0053] In this way, the extension parts 134 and 135 surround the entire outer periphery of each signal pad, thereby preventing external electromagnetic interference and improving electromagnetic compatibility (EMC). The extension part 134 can suppress the generation of unwanted waves from the transmission line 141, and the extension part 135 can also suppress the generation of unwanted waves from the transmission line 151.

[0054] In the transmission line structure 10A, the position of the transmission line 141 in the thickness direction of the dielectric substrate 11 is located closer to the ground electrode 161 than the position of the transmission line structure 10. This makes it possible to protect the transmission line 141 from the outside.

[0055] 6B and 7 , in the transmission line structure 10A, the ground vias 165 are electrically connected to the extension member 135 at a plurality of positions. Similarly, the ground vias 165 are electrically connected to the extension member 134 at a plurality of positions.

[0056] 6B and 7, the signal vias 155 arranged at the ends of the plurality of signal pad members 15A1-15A4 (15B1-15B4) in the second signal pad are positioned so as to overlap the extension portion 135 when viewed in a plan view from the normal direction of the ground pad 13A (13B). Similarly, the signal vias 145 arranged at the ends of the plurality of signal pad members 14A1-14A4 (14B1-14B4) in the first signal pad are positioned so as to overlap the extension portion 134 when viewed in a plan view from the normal direction of the ground pad 13A (13B).

[0057] Each of the signal pad members 14A1 to 14A4 (14B1 to 14B4) is electrically connected to the signal via 145 (155) via a signal line 157. The signal via 145 (155) is disposed at a position where it does not overlap with the extension portion 134 (135) in the thickness direction of the dielectric substrate 11.

[0058] 6B and 7, on the second signal pad side, at least some of the ground vias 165 are arranged at positions (positions indicated by dashed two-dot lines in FIG. 6B) that connect adjacent signal vias 155. Similarly, on the first signal pad side, at least some of the ground vias 165 are arranged at positions that connect adjacent signal vias 145.

[0059] In this way, the ground vias 165 are arranged in positions that surround the signal vias 145 and 155 in a lattice pattern. This makes it possible to suppress coupling between the signal pad members 14A1 to 14A4 and between the signal pad members 14B1 to 14B4, thereby improving isolation characteristics. The lattice-like arrangement of the ground vias 165 not only suppresses the generation of unwanted waves from the transmission line 141, but also suppresses the generation of unwanted waves from the transmission line 151.

[0060] Third Embodiment Next, a transmission-line structure 10B according to a third embodiment will be described with reference to Fig. 8. Fig. 8 is a plan view of the transmission-line structure 10B according to the third embodiment. Fig. 8 shows an enlarged portion of the transmission-line structure 10B.

[0061] The transmission line structure 10B of the third embodiment differs from the transmission line structure 10 of the first embodiment in that it does not have extension portions 131 and 132 and has additional signal pad members 14A5 and 15A5.

[0062] 8, the extension portions 131 and 132 may not be provided, and the number of signal pad members 14A1 to 14A5 (15A1 to 15A5) may be changed as needed. That is, the number of transmission lines 141 (151) connected to the signal pad members 14A1 to 14A5 (15A1 to 15A5) may be changed as needed.

[0063] [Fourth Embodiment] Next, a transmission-line structure 10C according to a fourth embodiment will be described with reference to Fig. 9. Fig. 9 is a plan view of the transmission-line structure 10C according to the fourth embodiment. Fig. 9 shows an enlarged view of a portion of the transmission-line structure 10C.

[0064] Transmission line structure 10C according to the fourth embodiment differs from transmission line structure 10B according to the third embodiment in the shape of the extension portions extending from ground pads 13A and 13B.

[0065] 9 , the transmission line structure 10C includes protrusions 136 and 137 that are disposed at both ends of the ground pad 13A (13B) in the second direction (longer side direction) and protrude in the first direction (short side direction). When viewed in a plan view from the normal direction of the ground pad 13A (13B), the shape including the ground pad 13A (13B) and the protrusions 136 and 137 is substantially H-shaped.

[0066] This increases the proportion of the ground pad 13A and the protrusions 136, 137 in the area of ​​the outer edge 120A where the connector 12A is disposed, thereby improving the mounting strength of the connector 12A. The ground pad 13A and the protrusions 136, 137 are symmetrical with respect to the first and second directions, which improves self-alignment. The transmission line structure 10C also improves the mounting strength and self-alignment on the connector 12B side.

[0067] The shape of the protrusions 136 and 137 may be any shape other than a substantially H-shape, as long as it is symmetrical with respect to the first direction and the second direction.

[0068] [Modifications] In the above-described embodiment, the ground pad 13A (13B) may be divided into multiple pieces as long as it has a rectangular shape. The ground pad 13A (13B) may also have a shape close to an ellipse with rounded corners of the rectangular shape.

[0069] In the above-described embodiment, the substrate connected to connectors 12A and 12B of transmission line structure 10 may be a substrate other than a substrate used for an antenna such as antenna devices 190A and 190B.

[0070] In the above embodiment, the case has been described in which connector 12A is disposed at ground pad 13A and connector 12B is disposed at ground pad 13B at both ends of transmission-line structure 10. However, transmission-line structure 10 may have a connector disposed at one end and a component other than a connector disposed at the other end. For example, transmission-line structure 10 may have a structure in which a connector is disposed at one end and a patch antenna is disposed at the other end. A signal may be transmitted to the patch antenna to radiate radio waves.

[0071] <Aspects> (1) A transmission line structure according to the present disclosure includes a flat dielectric substrate having a first main surface and a second main surface opposite the first main surface, a ground electrode disposed between the first and second main surfaces, a first transmission line disposed closer to the first main surface than the ground electrode and extending in a first direction, a ground pad disposed on the first main surface, a first signal pad connected on the first main surface to an end of the first transmission line, at least one interlayer connector disposed within the dielectric substrate and connected to the ground electrode and the ground pad, and a connector connected on the first main surface to the ground pad and the first signal pad. The ground pad is rectangular in shape, having a long side extending along a second direction substantially perpendicular to the first direction and a short side extending along the first direction. The length of the ground pad in the first direction is shorter than the dimension of the connector in the first direction.

[0072] According to the transmission line structure of the present disclosure, the force applied to the connection between the ground pad and the connector when the transmission line structure is bent can be reduced, making it easier to bend the transmission line structure.

[0073] (2) The transmission line structure according to (1), further comprising a second transmission line disposed closer to the second main surface than the ground electrode, wherein a frequency band of a signal transmitted to the first transmission line is higher than a frequency band of a signal transmitted to the second transmission line.

[0074] According to the transmission line structure of the present disclosure, since a signal with a high frequency band experiences greater loss over distance than a signal with a low frequency band, the first transmission line, whose signal has a higher frequency band than the second transmission line, can be arranged closer to the connector, thereby reducing signal loss.

[0075] (3) The transmission line structure according to (2), further comprising a second signal pad connected to an end of the second transmission line on the first main surface, and the ground pad is disposed between the first signal pad and the second signal pad.

[0076] According to the transmission line structure of the present disclosure, the ground pad functions as a shield between the first signal pad and the second signal pad, preventing electromagnetic field coupling between the signal pads and thereby improving isolation characteristics.

[0077] (4) The transmission line structure according to any one of (1) to (3), wherein the first transmission line is disposed on the first main surface.

[0078] According to the transmission line structure of the present disclosure, by directly joining the first transmission line and the connector, it is possible to easily achieve impedance matching with a member connected to the first transmission line.

[0079] (5) In the transmission line structure according to any one of (1) to (4), the length of the ground pad in the second direction is longer than the dimension of the connector in the second direction.

[0080] According to the transmission line structure of the present disclosure, it is possible to improve the mounting strength when mounting a connector, and also improve the mounting accuracy.

[0081] (6) The transmission line structure according to any one of (3) to (5), wherein each of the first signal pad and the second signal pad includes a plurality of signal pad members, and further includes a first extension portion extending from a long side of the ground pad to between the signal pad members in each signal pad.

[0082] According to the transmission line structure of the present disclosure, the first extension member portion can prevent impedance mismatch between the first transmission line and the second transmission line in the mounting portion of the connector and can improve isolation characteristics.

[0083] (7) The transmission line structure according to any one of (3) to (5), further comprising a second elongated member portion connected to the ground pad and arranged to surround the entire outer periphery of each signal pad.

[0084] The transmission line structure of the present disclosure can prevent external electromagnetic interference and improve electromagnetic compatibility (EMC).

[0085] (8) In the transmission line structure according to (7), at least one interlayer connector includes a plurality of interlayer connectors. Each of the first signal pad and the second signal pad includes a plurality of signal pad members. Each of the plurality of interlayer connectors is connected to the second elongated member portion at a plurality of positions on the first main surface side. A signal via disposed at an end of the plurality of signal pad members in each signal pad is disposed in a position overlapping with the second elongated member portion when viewed in a plan view from the normal direction of the ground pad. At least a portion of the plurality of interlayer connectors is disposed in a position connecting each of adjacent signal vias.

[0086] The transmission line structure of the present disclosure can electrically isolate each signal pad member, thereby improving isolation characteristics. By arranging the interlayer connectors in a grid pattern, it is possible to suppress the generation of unwanted waves from the first transmission line and also suppress the generation of unwanted waves from the second transmission line.

[0087] (9) The transmission line structure according to any one of (1) to (8), further comprising protrusions arranged at both ends of the ground pad in the second direction and protruding in the first direction.

[0088] According to the transmission line structure of the present disclosure, it is possible to improve the mounting strength of the connector and also improve self-alignment.

[0089] (10) The transmission line structure according to (9), wherein the shape including the ground pad and the protrusion is substantially H-shaped when viewed in a plan view from the normal direction of the ground pad.

[0090] According to the transmission line structure of the present disclosure, it is possible to improve the mounting strength of the connector and also improve self-alignment.

[0091] (11) An antenna module according to the present disclosure includes the transmission line structure according to any one of (1) to (10) above, and an antenna substrate having a radiation electrode connected to the transmission line structure via a connector provided on the transmission line structure.

[0092] According to the antenna module of the present disclosure, the transmission line structure can be easily bent.

[0093] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0094] 10, 10A, 10B, 10C Transmission line structure, 11 Dielectric substrate, 12A, 12B Connector, 13A, 13B Ground pad, 14A1 to 14A4, 14B1 to 14B5, 15A1 to 15A4, 15B1 to 15B4 Signal pad member, 20 Protective member, 100 Antenna module, 120A, 120B Outer edge, 121 Main body portion, 122 First conductor portion, 123 Second conductor portion, 131, 132, 134, 135 Extension portion, 136, 137 Protrusion portion, 141, 151 Transmission line, 145, 155 Signal via, 157 Signal line, 161, 170A, 170B, 181, 251 Ground electrode, 165 Ground via, 180 Connection member, 190, 190A, 190B Antenna device, 191, 191A1 to 191A4, 191B to 191B4 Radiation electrode, 250 Motherboard.

Claims

1. A transmission line structure comprising: a flat dielectric substrate having a first main surface and a second main surface opposite the first main surface; a ground electrode arranged between the first main surface and the second main surface; a first transmission line arranged on the first main surface side of the ground electrode and extending in a first direction; a ground pad arranged on the first main surface; a first signal pad connected to an end of the first transmission line on the first main surface; at least one interlayer connector arranged within the dielectric substrate and connected to the ground electrode and the ground pad; and a connector connected to the ground pad and the first signal pad on the first main surface side, wherein the ground pad has a rectangular shape with long sides along a second direction substantially perpendicular to the first direction and short sides along the first direction, and the length of the ground pad in the first direction is shorter than the dimension of the connector in the first direction.

2. The transmission line structure according to claim 1, further comprising a second transmission line arranged closer to the second principal surface than the ground electrode, wherein the frequency band of signals transmitted to the first transmission line is higher than the frequency band of signals transmitted to the second transmission line.

3. The transmission line structure of claim 2, further comprising a second signal pad connected to an end of the second transmission line on the first main surface, and the ground pad is disposed between the first signal pad and the second signal pad.

4. The transmission line structure according to any one of claims 1 to 3, wherein the first transmission line is disposed on the first main surface.

5. The transmission line structure according to any one of claims 1 to 4, wherein the length of the ground pad in the second direction is longer than the dimension of the connector in the second direction.

6. The transmission line structure of claim 3, wherein each of the first signal pad and the second signal pad includes a plurality of signal pad members, and further comprises a first extension portion extending from a long side of the ground pad to between the signal pad members in each signal pad.

7. The transmission line structure of claim 3, further comprising a second elongated member portion connected to the ground pad and surrounding the entire periphery of each signal pad.

8. The transmission line structure according to claim 7, wherein the at least one interlayer connector includes a plurality of interlayer connectors, wherein each of the first signal pad and the second signal pad includes a plurality of signal pad members, wherein each of the plurality of interlayer connectors is connected to the second elongated member portion at a plurality of positions on the first main surface side, wherein signal vias arranged at ends of the plurality of signal pad members in each signal pad are arranged at positions overlapping with the second elongated member portion when viewed in a plane normal to the ground pad, and wherein at least a portion of the plurality of interlayer connectors are arranged at positions connecting each of the adjacent signal vias.

9. The transmission line structure according to any one of claims 1 to 8, further comprising protrusions arranged at both ends of the ground pad in the second direction and protruding in the first direction.

10. The transmission line structure according to claim 9, wherein the shape including the ground pad and the protrusion is substantially H-shaped when viewed in a plan view from the normal direction of the ground pad.

11. An antenna module comprising: a transmission line structure according to any one of claims 1 to 10; and an antenna substrate having a radiation electrode, connected via the connector provided on the transmission line structure.

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