Dielectric substrate and antenna module

Abstract

This dielectric substrate includes an antenna part, and a power supply path that is connected to the antenna part and supplies power to the antenna part. The antenna part comprises: a plurality of dielectric layers that have an opening; a plurality of via conductors that are formed around the openings; and a plurality of conductor layers that are provided between the plurality of dielectric layers, have an opening, and electrically connect the plurality of via conductors. The power supply path comprises: a plurality of dielectric layers; a plurality of via conductors; and a plurality of conductor layers that are provided between the plurality of dielectric layers, have an opening, and electrically connect the plurality of via conductors. In at least one of the antenna part and the power supply path, a dielectric layer located at a boundary between the antenna part and the power supply path is formed in a core layer having a dielectric constant different from that of the dielectric layer.

Description

Dielectric substrate and antenna module

[0001] The present disclosure relates to a dielectric substrate and an antenna module.

[0002] Patent Document 1 describes a stacked aperture antenna.

[0003] Patent No. 3420474

[0004] The dielectric substrate of the present disclosure includes an antenna unit and a power feed path connected to the antenna unit and supplying power to the antenna unit, wherein the antenna unit includes a plurality of dielectric layers each having an opening, a plurality of via conductors formed around the opening, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and the power feed path includes a plurality of the dielectric layers, a plurality of the via conductors, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and at least one of the antenna unit and the power feed path has a dielectric layer located at the boundary between the antenna unit and the power feed path formed of a core layer having a dielectric constant different from that of the dielectric layer.

[0005] The antenna module of the present disclosure includes an antenna unit, a power supply path connected to the antenna unit and supplying power to the antenna unit, and an integrated circuit that transmits and receives radio waves via the antenna unit, wherein the antenna unit includes a plurality of dielectric layers each having an opening, a plurality of via conductors formed around the opening, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and the power supply path includes a plurality of the dielectric layers, a plurality of the via conductors, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and at least one of the antenna unit and the power supply path has a dielectric layer located at the boundary between the antenna unit and the power supply path, which is formed of a core layer with a dielectric constant different from that of the dielectric layer.

[0006] Fig. 1 is a diagram showing a configuration example of a dielectric substrate according to a first embodiment. Fig. 2 is a diagram for explaining a layered structure of the dielectric substrate according to the first embodiment. Fig. 3 is a diagram showing a configuration example of a dielectric substrate according to a second embodiment. Fig. 4 is a diagram showing a configuration example of an antenna module according to a third embodiment.

[0007] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0008] In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. The direction parallel to the X axis in a horizontal plane is defined as the X-axis direction, the direction parallel to the Y axis in the horizontal plane perpendicular to the X axis is defined as the Y-axis direction, and the direction parallel to the Z axis perpendicular to the horizontal plane is defined as the Z-axis direction. Furthermore, the plane including the X axis and Y axis will be referred to as the XY plane as appropriate, the plane including the X axis and Z axis will be referred to as the XZ plane as appropriate, and the plane including the Y axis and Z axis will be referred to as the YZ plane as appropriate. The XY plane is parallel to the horizontal plane. The XY plane, XZ plane, and YZ plane are perpendicular to each other.

[0009] [First embodiment] (Dielectric substrate) A configuration example of a dielectric substrate according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a configuration example of a dielectric substrate according to a first embodiment.

[0010] As shown in Fig. 1, the dielectric substrate 1 includes an antenna section 10 and a power feed line 20. The antenna section 10 and the power feed line 20 are integrally configured. In the example shown in Fig. 1, only one antenna section 10 is shown, but the antenna sections 10 may be provided in an array on the power feed line 20.

[0011] The antenna portion 10 includes a dielectric layer 11 , an opening 12 , a plurality of via conductors 13 , and a slot 14 .

[0012] The dielectric layer 11 extends in the XY plane. A plurality of the dielectric layers 11 are stacked in the Z-axis direction. The dielectric layer 11 is formed of a dielectric material. The dielectric layer 11 is a dielectric film. The dielectric layer 11 is, for example, a dielectric film formed of an olefin resin-based film material. The relative dielectric constant of the dielectric layer 11 is, for example, 2.7, but is not limited to this. The thickness of the dielectric layer 11 is, for example, 56 μm, but is not limited to this. Specifically, as will be described later, a conductor layer formed of a conductive material is provided between the dielectric layers 11.

[0013] The openings 12 are provided across the plurality of dielectric layers 11. The dielectric layers 11 in which the openings 12 are provided are called main conductor layers. Electromagnetic waves are emitted from the openings 12.

[0014] The plurality of via conductors 13 are formed along the stacking direction of each dielectric layer 11. The plurality of via conductors 13 are formed around the opening 12. The plurality of via conductors 13 are configured to surround the opening 12. The plurality of via conductors 13 are formed of a conductive material. The plurality of via conductors 13 are electromagnetically connected to each other by a conductor layer. It is preferable that the maximum spacing between the plurality of via conductors 13 be, for example, about ¼ of the wavelength of the radio waves used by the antenna unit 10 for communication, so as to prevent electromagnetic wave leakage.

[0015] The slot 14 is provided at a position where it contacts at least the power supply line 20 .

[0016] The power feed line 20 includes a dielectric layer 21, a plurality of via conductors 22, a core layer 23, and a slot 24. The power feed line 20 transmits electromagnetic waves in the stacking direction of the dielectric layer 21 (the Z-axis direction).

[0017] The dielectric layers 21 are stacked in the Z-axis direction. The dielectric layers 21 are formed of a dielectric material. The dielectric layers 21 are formed of, for example, the same dielectric material as the dielectric layers 11. The dielectric layers 21 are dielectric films. The relative dielectric constant of the dielectric layers 21 is, for example, 2.7, but is not limited to this. The thickness of the dielectric layers 21 is, for example, 56 μm, but is not limited to this. Specifically, as will be described later, a conductor layer formed of a conductive material is provided between the dielectric layers 21.

[0018] The via conductors 22 are formed along the lamination direction of the dielectric layers 21. The via conductors 22 are electromagnetically connected to the corresponding via conductors 13.

[0019] The core layer 23 is provided at a position where it contacts at least the antenna section 10. The core layer 23 is formed of a dielectric material. The core layer 23 has higher rigidity than the dielectric layer 21. The dielectric substrate 1 can ensure sufficient rigidity by having the core layer 23. The core layer 23 is formed of a dielectric material different from that of the dielectric layer 21. The core layer 23 is formed of, for example, a material containing PPE (polyphenylene ether) glass cloth. The dielectric constant of the core layer 23 is different from that of the dielectric layer 21. The dielectric constant of the core layer 23 is, for example, 3.6, but is not limited to this. The thickness of the core layer 23 is, for example, 50 μm, but is not limited to this.

[0020] Depending on the design, the dielectric constant of the core layer 23 may be larger or smaller than the dielectric constant of the dielectric layer 21. For example, the dielectric constant of the core layer 23 is a value outside the range of manufacturing variations in the dielectric constant of the dielectric layer 21. For example, the dielectric constant of the core layer 23 is a value that deviates by ±10% or more from the set value of the dielectric constant of the dielectric layer 21.

[0021] The slot 24 is provided at a position where it contacts at least the antenna section 10 .

[0022] The antenna section 10 and the power feed line 20 are electromagnetically connected via the slot 14 and the slot 24 .

[0023] (Layer Structure) The layer structure of the dielectric substrate according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the layer structure of the dielectric substrate according to the first embodiment.

[0024] As shown in Fig. 2, the antenna unit 10 has a structure in which a dielectric layer 11-1, a dielectric layer 11-2, and a dielectric layer 11-3 are stacked in the Z-axis direction. Although Fig. 2 shows three dielectric layers 11 stacked, the present disclosure is not limited to this. The number of stacked dielectric layers 11 in the antenna unit 10 may be two, or may be four or more.

[0025] The antenna unit 10 includes conductor layers 15-1, 15-2, 15-3, and 15-4. The conductor layers 15-1 to 15-4 are formed of a conductive material extending in the XY plane. The conductor layers 15-1 to 15-4 are formed of, for example, copper, but are not limited to this. The thickness of the conductor layers 15-1 to 15-4 is, for example, 20 μm, but is not limited to this. When it is not necessary to distinguish between the conductor layers 15-1 to 15-4, they will be collectively referred to as conductor layer 15.

[0026] The conductor layer 15-1 is provided on the lower surface of the dielectric layer 11-1. The conductor layer 15-2 is provided between the dielectric layers 11-1 and 11-2. The conductor layer 15-3 is provided between the dielectric layers 11-2 and 11-3. The conductor layer 15-4 is formed on the upper surface of the dielectric layer 11-3.

[0027] That is, the conductor layer 15 is provided between the dielectric layers 11. The conductor layer 15 electrically connects the plurality of via conductors 13 formed along the lamination direction of the dielectric layers 11.

[0028] The power feed line 20 has a structure in which a dielectric layer 21-1, a dielectric layer 21-2, and a dielectric layer 21-3 are stacked in the Z-axis direction. Although Fig. 2 shows three dielectric layers 21 stacked, the present disclosure is not limited to this. In the power feed line, the number of stacked dielectric layers 21 may be two, or may be four or more.

[0029] The power supply path 20 includes conductor layers 25-1, 25-2, 25-3, and 25-4. The conductor layers 25-1 to 25-4 are formed of a conductive material extending in the XY plane. The conductor layers 25-1 to 25-4 are formed of, for example, copper, but are not limited to this. The thickness of the conductor layers 25-1 to 25-4 is, for example, 20 μm, but is not limited to this. When it is not necessary to distinguish between the conductor layers 25-1 to 25-4, they will be collectively referred to as conductor layer 25.

[0030] The conductor layer 25-1 is provided on the lower surface of the dielectric layer 21-1. The conductor layer 25-2 is provided between the dielectric layer 21-1 and the dielectric layer 21-2. The conductor layer 25-3 is provided between the dielectric layer 21-2 and the dielectric layer 21-3. The conductor layer 25-4 is formed on the upper surface of the dielectric layer 21-3.

[0031] That is, the conductor layer 25 is provided between the dielectric layers 21. The conductor layer 25 electrically connects the plurality of via conductors 22 formed along the stacking direction of the dielectric layers 21.

[0032] The core layer 23 is provided on the conductor layer 25-4. The core layer 23 is provided at the boundary between the antenna unit 10 and the power feed line 20. The core layer 23 only needs to be provided at least at the boundary between the antenna unit 10 and the power feed line 20. For example, one or two of the dielectric layers 21-1 to 21-3 may be replaced with the core layer 23. That is, a plurality of core layers 23 may be provided in the power feed line 20.

[0033] Here, a problem associated with the embodiment will be described. Generally, an antenna-embedded substrate including the antenna unit 10 and the power feed path 20 has a problem in that the operating band is limited.

[0034] Normally, a reflected wave occurs at the boundary between the antenna unit 10 and the power feed line 20 that supplies electromagnetic waves to the antenna unit 10 because there is a change in the physical structure at the boundary. Explained in terms of an electrical circuit, this is because the characteristic impedance of the power feed line and the input impedance of the antenna unit are different, causing a reflected wave to occur at the boundary between the antenna unit 10 and the power feed line 20 that supplies electromagnetic waves to the antenna unit.

[0035] The reflected wave generated at the boundary between the antenna unit 10 and the power feed line 20 can be canceled out by a new reflected wave from the reflection point by adding a structure for suppressing the reflected wave. However, while the original reflected wave can be completely canceled out at certain frequencies, it cannot be canceled out at other frequencies due to a phase shift. The greater the difference between the frequency of the original reflected wave and the new reflected wave, the greater the influence of the original reflected wave. The greater the difference between the characteristic impedance of the power feed line 20 and the input impedance of the antenna unit 10, the more significant the influence of the original reflected wave becomes, resulting in a narrower operating band.

[0036] Therefore, by providing a core layer 23 having a dielectric constant different from that of the dielectric layer 11 and the dielectric layer 21 between the antenna section 10 and the power supply line 20 in the dielectric substrate 1, it is possible to obtain an antenna that operates over a wide band, for example, in the sub-terahertz wave band (100 GHz to 300 GHz band).

[0037] Generally, when the medium is made of a dielectric and electromagnetic waves are transmitted through the power feed line 20, the characteristic impedance changes as the dielectric constant of the power feed line changes. Therefore, a core layer 23 is provided at the boundary between the antenna unit 10 and the power feed line 20 to bring the characteristic impedance of the power feed line 20 closer to the input impedance of the antenna unit 10. This makes it possible to suppress reflections that occur at the boundary between the antenna unit 10 and the power feed line 20, thereby widening the operating band.

[0038] In other words, by providing a core layer 23 with an impedance intermediate between the input impedance of the antenna unit 10 and the characteristic impedance of the power feed line 20 at the boundary between different impedance circuits, such as the antenna unit 10 and the power feed line 20, the change in impedance can be made smooth, thereby widening the bandwidth in which reflected waves are suppressed. The magnitude relationship of the impedances should satisfy the following equation (1) or (2): Power feed line 20 > core layer 23 > antenna unit 10 (1) Power feed line 20 < core layer 23 < antenna unit 10 (2)

[0039] In the first embodiment, when the core layer 23 is formed in the power feed line 20, the characteristic impedance of the portion where the core layer 23 and the plurality of via conductors 22 are provided is different from the characteristic impedance of the portion where the dielectric layer 21 and the plurality of via conductors 22 are provided. Specifically, the characteristic impedance of the portion where the core layer 23 and the plurality of via conductors 22 are provided is between the input impedance of the antenna unit 10 and the characteristic impedance of the portion where the dielectric layer 21 and the plurality of via conductors 22 are provided. This makes it possible to make the change in impedance of the path from the antenna unit 10 to the power feed line 20 smooth.

[0040] This embodiment can provide advantageous effects particularly in the sub-terahertz wave band (100 GHz to 300 GHz band). The reason for this is explained below. Generally, the thickness of a dielectric layer of a printed circuit board is several hundred μm or less. At a frequency of about 1 GHz, the wavelength is about 300 mm, and the thickness of the dielectric layer of a printed circuit board is sufficiently smaller than the wavelength. For this reason, the length of the dielectric layer as a line can be ignored, and therefore changes in the characteristic impedance do not affect the reflection characteristics.

[0041] However, at a frequency of 300 GHz, the wavelength is 1 mm. In this case, the thickness of the dielectric layer of the printed circuit board is on the order of a fraction of the wavelength, so changes in impedance affect the reflection characteristics. Therefore, by smoothing the change in impedance from the power feed line 20 to the antenna unit 10, it is possible to suppress the generation of reflected waves and widen the operating band.

[0042] That is, in this embodiment, a core layer 23 can be provided at the boundary between the antenna section 10 and the power supply path 20 based on the thicknesses of the dielectric layer 11 and the dielectric layer 21 and the wavelength of the radio waves used for communication.

[0043] The frequency of the radio waves used for communication by the antenna unit 10 is not limited to the sub-terahertz wave band (100 GHz to 300 GHz band). The frequency of the radio waves used for communication by the antenna unit 10 may be, for example, a microwave band (e.g., 3 GHz to 30 GHz band), a quasi-millimeter wave band (e.g., 20 GHz to 30 GHz band), or a millimeter wave band (30 GHz to 300 GHz).

[0044] As described above, in the first embodiment, the core layer is provided in the power feed path at the boundary with the antenna unit, thereby enabling the first embodiment to widen the operating band.

[0045] Second Embodiment (Dielectric Substrate) A configuration example of a dielectric substrate according to a second embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing a configuration example of a dielectric substrate according to the second embodiment.

[0046] As shown in FIG. 3, the dielectric substrate 1A includes an antenna section 10A and a feed path 20A.

[0047] The antenna section 10A differs from the antenna section 10 shown in FIG. 1 in that a core layer 16 is provided at the boundary with the power feed line 20A.

[0048] The core layer 16 is provided at a position where it contacts at least the power feed path 20A. The core layer 16 is formed of a dielectric material. The core layer 16 has higher rigidity than the dielectric layer 11. The dielectric substrate 1A can ensure sufficient rigidity by having the core layer 16. The core layer 16 is formed of a dielectric material different from that of the dielectric layer 11. The core layer 16 is formed of, for example, a material containing PPE-based glass cloth. The dielectric constant of the core layer 16 is different from that of the dielectric layer 11. The dielectric constant of the core layer 16 is, for example, 3.6, but is not limited to this. The thickness of the core layer 16 is, for example, 50 μm, but is not limited to this.

[0049] 1 in that the power feed line 20A does not have a core layer 23. The power feed line 20A transmits electromagnetic waves in the in-plane direction of the dielectric layer 21. A slot 24 is formed in the dielectric layer 21 disposed on the upper surface of the power feed line 20A.

[0050] 2 except that the core layer 16 is provided in the antenna unit 10A and the core layer 23 is not provided in the power feed line 20A, so a detailed description thereof will be omitted. For example, the core layer 16 may be provided at least at the boundary between the antenna unit 10A and the power feed line 20A. For example, a plurality of core layers 16A may be provided in the antenna unit 10A.

[0051] In the second embodiment, when the core layer 16 is provided in the antenna unit 10A, the input impedance of the antenna unit 10A is approximately equal to the characteristic impedance of the power feed line 20A. In other words, the reflection coefficient at the boundary between the antenna unit 10A and the power feed line 20A is −10 dB or less.

[0052] As described above, in the second embodiment, the core layer is provided at the boundary with the power feed line in the antenna section, which allows the second embodiment to widen the operating band.

[0053] Third Embodiment A configuration example of an antenna module according to a third embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing a configuration example of an antenna module according to the third embodiment.

[0054] 4, the antenna module 100 includes an antenna unit 10, a power supply path 20, and a control unit 30. The control unit 30 is a type of integrated circuit.

[0055] The antenna module 100 according to the third embodiment transmits and receives radio waves in the sub-terahertz wave band (100 GHz to 300 GHz band). The antenna module 100 may transmit and receive radio waves in the microwave band (e.g., 3 GHz to 30 GHz band), quasi-millimeter wave band (e.g., 20 GHz to 30 GHz band), or millimeter wave band (30 GHz to 300 GHz).

[0056] The control unit 30 includes, but is not limited to, a central processing unit (CPU), a system-on-a-chip (SoC), a micro control unit (MCU), a field-programmable gate array (FPGA), and a coprocessor, for example. The control unit 30 may also be realized by a control integrated circuit (IC).

[0057] The control unit 30 controls the antenna unit 10. The control unit 30 controls the antenna unit 10 to transmit radio waves to an external device. The control unit 30 controls the antenna unit 10 to receive radio waves from the external device. In other words, the control unit 30 performs at least one of transmitting and receiving radio waves via the antenna unit 10. When multiple antenna units 10 are arranged in an array on the power feed path 20, the control unit 30 controls the multiple antenna units 10 to transmit radio waves to the external device. In this case, the control unit 30 controls the multiple antenna units 10 to receive radio waves from the external device. In other words, the control unit 30 causes the antenna module 100 to operate as an antenna.

[0058] Specifically, the control unit 30 can realize an antenna that transmits and receives radio waves in the sub-terahertz wave band (100 GHz to 300 GHz band) by controlling the antenna unit 10. In other words, the control unit 30 transmits or receives radio waves in the sub-terahertz wave band (100 GHz to 300 GHz) via the antenna unit 10. The control unit 30 can control the antenna unit 10 to realize, for example, an antenna for the microwave band (e.g., 3 to 30 GHz band), an antenna for the quasi-millimeter wave band (e.g., 20 GHz to 30 GHz band), or an antenna for the millimeter wave band (30 GHz to 300 GHz).

[0059] As described above, in the third embodiment, the control unit controls the antenna unit, thereby realizing an antenna that transmits and receives radio waves having frequencies in the sub-terahertz wave band (100 GHz to 300 GHz band).

[0060] The present disclosure can also be configured as follows: (1) A dielectric substrate including: an antenna unit; and a power feed line connected to the antenna unit and supplying power to the antenna unit, wherein the antenna unit includes: a plurality of dielectric layers each having an opening, a plurality of via conductors formed around the opening, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening, and electrically connecting the plurality of via conductors, and the power feed line includes: a plurality of the dielectric layers, a plurality of the via conductors, and a plurality of the conductor layers provided between the plurality of dielectric layers, each having the opening, and electrically connecting the plurality of via conductors, and at least one of the antenna unit and the power feed line is configured such that the dielectric layer located at the boundary between the antenna unit and the power feed line is formed of a core layer having a dielectric constant different from that of the dielectric layer. (2) The dielectric substrate according to (1), wherein the dielectric constant of the core layer is greater than the dielectric constant of the dielectric layer. (3) The dielectric substrate according to (1) or (2), wherein the core layer is provided in the power feed path, and a characteristic impedance of a portion of the power feed path where the core layer and the plurality of via conductors are provided is different from a characteristic impedance of a portion of the power feed path where the dielectric layer and the plurality of via conductors are provided. (4) The dielectric substrate according to (3), wherein a characteristic impedance of a portion of the power feed path where the core layer and the plurality of via conductors are provided is between an input impedance of the antenna unit and a characteristic impedance of a portion of the power feed path where the dielectric layer and the plurality of via conductors are provided. (5) The dielectric substrate according to (1) or (2), wherein the core layer is provided in the antenna unit, and wherein the characteristic impedance of the power feed path and the input impedance of the antenna unit are approximately equal. (6) The dielectric substrate according to any one of (1) to (5), wherein the core layer is formed of a material different from that of the dielectric layer. (7) The dielectric substrate according to (6), wherein the core layer has higher rigidity than the dielectric layer.(8) The dielectric substrate according to any one of (1) to (7), wherein at least one of the antenna section and the power feed line has a plurality of dielectric layers formed of the core layer. (9) The dielectric substrate according to any one of (1) to (8), wherein the antenna section is configured to transmit and receive radio waves in a sub-terahertz wave band. (10) An antenna module including: an antenna unit, a power feed path connected to the antenna unit and supplying power to the antenna unit, and an integrated circuit that transmits and receives radio waves via the antenna unit, wherein the antenna unit includes: a plurality of dielectric layers each having an opening, a plurality of via conductors formed around the opening, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and the power feed path includes: a plurality of the dielectric layers, a plurality of the via conductors, and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors, and wherein at least one of the antenna unit and the power feed path is formed such that the dielectric layer located at the boundary between the antenna unit and the power feed path is formed of a core layer having a dielectric constant different from that of the dielectric layer. (11) The antenna module according to (10), wherein the integrated circuit transmits or receives radio waves in the sub-terahertz wave band via the antenna unit.

[0061] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0062] REFERENCE SIGNS LIST 1, 1A Dielectric substrate 10, 10A Antenna section 20, 20A Power feed path 11, 21 Dielectric layer 12 Opening 13, 22 Via conductor 14, 24 Slot 15, 25 Conductor layer 16, 23 Core layer

Claims

1. A dielectric substrate comprising: an antenna unit; and a power feed path connected to the antenna unit and supplying power to the antenna unit, wherein the antenna unit comprises: a plurality of dielectric layers each having an opening; a plurality of via conductors formed around the opening; and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors; and the power feed path comprises: a plurality of the dielectric layers; a plurality of the via conductors; and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors; and wherein, in at least one of the antenna unit and the power feed path, the dielectric layer located at the boundary between the antenna unit and the power feed path is formed of a core layer having a dielectric constant different from that of the dielectric layer.

2. The dielectric substrate according to claim 1, wherein the dielectric constant of the core layer is greater than the dielectric constant of the dielectric layer.

3. The dielectric substrate according to claim 1, wherein the core layer is provided in the power feed path, and the characteristic impedance of a portion of the power feed path where the core layer and the plurality of via conductors are provided is different from the characteristic impedance of a portion of the power feed path where the dielectric layer and the plurality of via conductors are provided.

4. A dielectric substrate as described in claim 3, wherein the characteristic impedance of the portion of the power feed path where the core layer and the plurality of via conductors are provided is between the input impedance of the antenna part and the characteristic impedance of the portion of the power feed path where the dielectric layer and the plurality of via conductors are provided.

5. The dielectric substrate according to claim 1, wherein the core layer is provided in the antenna section, and the characteristic impedance of the feed path and the input impedance of the antenna section are approximately equal.

6. The dielectric substrate according to any one of claims 1 to 5, wherein the core layer is formed of a material different from that of the dielectric layer.

7. The dielectric substrate according to claim 6, wherein the core layer has higher rigidity than the dielectric layer.

8. The dielectric substrate according to claim 1, wherein at least one of the antenna section and the power feed line has a plurality of dielectric layers formed of the core layer.

9. The dielectric substrate according to claim 1, wherein the antenna section is configured to transmit and receive radio waves in the sub-terahertz wave band.

10. An antenna module comprising: an antenna unit; a power feed path connected to the antenna unit and supplying power to the antenna unit; and an integrated circuit that transmits and receives radio waves via the antenna unit, wherein the antenna unit comprises: a plurality of dielectric layers each having an opening; a plurality of via conductors formed around the opening; and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors; and the power feed path comprises: a plurality of the dielectric layers; a plurality of the via conductors; and a plurality of conductor layers provided between the plurality of dielectric layers, each having the opening and electrically connecting the plurality of via conductors; and wherein at least one of the antenna unit and the power feed path has a dielectric layer located at the boundary between the antenna unit and the power feed path formed of a core layer having a dielectric constant different from that of the dielectric layer.

11. The antenna module according to claim 10, wherein the integrated circuit transmits or receives radio waves in the sub-terahertz wave band via the antenna section.

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