JP2022102717A - High frequency board and antenna module - Google Patents

Abstract

To provide a high frequency board that embeds a log-periodic antenna inside the high frequency board and suppresses an increase in the placement area, is suitable for miniaturization, and can realize good antenna characteristics.SOLUTION: A high frequency board 10 includes a plurality of conductor patterns and a plurality of via conductors, and includes one or a plurality of log periodic antennas embedded inside the high frequency board 10. The plurality of log periodic antennas include, for example, a log periodic antenna 31 to 34 for vertical polarization, and a log -periodic antenna 41 to 44 for horizontal polarization, and can share both vertical polarization and horizontal polarization. Further, a ground conductor 11 is provided in a region that does not overlap with the plurality of log periodic antennas in a plan view.SELECTED DRAWING: Figure 1

Description

The present invention relates to a high-frequency substrate in which a dielectric layer and a conductor layer are alternately laminated to form a log-periodic antenna.

Conventionally, a log periodic antenna has been known as an antenna capable of expanding the usable frequency band. For example, Patent Document 1 discloses an antenna device in which a log-periodic antenna using a conductor pattern is configured on the surface of a dielectric substrate. Generally, a log-periodic antenna requires a large arrangement area for providing a large number of radiation elements. Therefore, for example, in Patent Document 1, the arrangement area of a log-periodic antenna is obtained by forming a radiation element in a meander shape or a V shape. Measures are shown to reduce the number.

Japanese Unexamined Patent Publication No. 11-168323

In recent years, in order to comply with various standards of wireless communication, it is common to adopt a configuration in which a large number of antenna elements are arranged in an array. Further, from the viewpoint of reducing the size and weight of the antenna device, it has been proposed to arrange a plurality of antenna elements using a dielectric substrate. However, assuming the adoption of a log-periodic antenna in order to share different frequency bands, a structure like the above-mentioned Patent Document 1 increases the arrangement area for forming a complicated antenna shape, and the antenna device has a large size. It is inevitable that it will change. Further, in recent years, an antenna device capable of sharing horizontal polarization and vertical polarization as different polarizations has been demanded, but in a planar configuration as in Patent Document 1, an antenna device capable of corresponding to different polarizations has been realized. It is difficult.

The present invention has been made to solve the above-mentioned problems, and a log-periodic antenna is configured inside a high-frequency substrate, and while maintaining good antenna characteristics, it is possible to suppress an increase in the arrangement area and reduce the size. It realizes a high frequency substrate.

In order to solve the above problems, the high-frequency substrate of the present invention is a high-frequency substrate in which a dielectric layer and a conductor layer are alternately laminated, and a plurality of conductor patterns formed on the conductor layer and the dielectric layer are formed. It is characterized by comprising one or a plurality of logarithmic period antennas configured by using a plurality of via conductors penetrating the above-mentioned one or a plurality of logarithmic period antennas, and the one or a plurality of logarithmic period antennas are embedded inside the high frequency substrate.

According to the high-frequency substrate of the present invention, since one or a plurality of log-periodic antennas are embedded inside the high-frequency substrate and configured by using a plurality of conductor patterns and a plurality of via conductors, the wavelength of the surrounding dielectric layer is shortened. The effect makes it possible to construct a log-periodic antenna in a compact size, and by using a conductor pattern in the plane direction and a via conductor in the thickness direction, it is possible to realize a log-periodic antenna having not only a plane shape but also various three-dimensional shapes. can.

In the present invention, in addition to one or more log-periodic antennas, one layer or one layer arranged in a region that does not overlap with the region where one or more log-periodic antennas are arranged in a plan view from the thickness direction of the high-frequency substrate. Multiple layers of ground conductors can be provided. Further, it is possible to provide a feeding structure for feeding a high frequency signal to each of one or a plurality of log periodic antennas.

The plurality of log-periodic antennas of the present invention may be composed of a log-periodic antenna for horizontal polarization and a log-periodic antenna for vertical polarization, and may be arranged in a first direction orthogonal to the thickness direction of the high-frequency substrate. As a result, when realizing a high-frequency substrate that can share both horizontal and vertical polarization, a complex three-dimensional shape can be easily constructed by appropriately combining the conductor pattern and the via conductor according to the stretching direction, and the wavelength. Combined with the shortening effect, miniaturization is possible.

In the present invention, the number of log-periodic antennas for horizontal polarization and the number of log-periodic antennas for vertical polarization may be the same, and two or more of each may be provided. In this case, one layer or a plurality of ground conductors arranged in a region that does not overlap with the region where the plurality of logarithmic period antennas are arranged in the plan view seen from the thickness direction of the high-frequency substrate, and the plan view seen from the thickness direction. An opening capable of accommodating an electronic component in the central region and a plurality of feeding paths included in the feeding structure and electrically connecting the electronic component and each of the plurality of logarithmic period antennas are provided on a high-frequency substrate. Further, only the horizontally polarized logarithmic period antenna can be arranged in the region overlapping the opening in the plan view from the thickness direction. Further, a plurality of log periodic antennas can be arranged symmetrically with respect to the central position in the first direction. With the above arrangement, the log-periodic antenna for vertical polarization, which requires a size in the thickness direction, can be prevented from overlapping with openings and electronic components, and the space of the high-frequency board is effective while maintaining good antenna performance. It can be used.

The logarithmic period antenna for horizontal polarization of the present invention is configured to include a plurality of pairs of horizontal radiating elements paired on the signal side and the ground side, and a plurality of pairs of horizontal radiating elements are configured by using a plurality of conductor patterns. In addition to arranging them side by side in the second direction orthogonal to the first direction in the thickness direction, the logarithmic period antenna for vertical polarization of the present invention has a plurality of pairs of vertical radiating elements paired on the signal side and the ground side. A plurality of pairs of vertical radiating elements can be configured by using a plurality of via conductors, and can be arranged side by side in the second direction. Each structure is a three-dimensional structure in which a plurality of conductor patterns and a plurality of via conductors are combined, and can be easily embedded inside a high-frequency substrate.

In the present invention, each of at least two horizontally polarized log-periodic antennas has a extending direction from the base end of a plurality of pairs of horizontal radiation elements to each tip on the signal side and the ground side so as to coincide with the first direction. May be. In this case, each of at least two log-periodic antennas for horizontally polarized waves in the vicinity of the central position in the first direction has a extending direction in the plane of the conductor layer and each tip is separated from the ground conductor from the first direction. It may be inclined in the direction. This suppresses the influence of interference with the surroundings in the vicinity of the center and the vicinity of the outer edge of the plurality of log periodic antennas for horizontal polarization, and is effective in improving the antenna gain.

In the present invention, in each of at least two log-periodic antennas for vertical polarization, the extension direction of each of the plurality of pairs of vertical radiating elements is the thickness direction, and a plurality of pairs constituting each of the plurality of pairs of vertical radiating elements. The signal-side via conductor and the plurality of ground-side via conductors may be arranged so as to face each other in the first direction, and their arrangement directions may be aligned with the second direction. In this case, each of at least two log-periodic antennas for vertical polarization in the vicinity of the central position has a plurality of pairs of vertically radiating elements whose extension directions coincide with each other in the thickness direction, and a plurality of signal-side via conductors and a plurality of signals. The ground-side via conductors are arranged so as to face each other in the first direction, and the respective arrangement directions are set so as to be inclined so as to be separated from the plurality of via conductors on the opposite side as they approach the ground conductor from the second direction. May be good. This suppresses the influence of interference with the surroundings in the vicinity of the center and the vicinity of the outer edge of the plurality of log periodic antennas for vertical polarization, and is effective in improving the antenna gain.

In the high frequency substrate of the present invention, electronic components can be placed in the openings. Examples of the electronic component placed in the opening include an IC chip. For example, the log periodic antenna can be fed from a predetermined terminal of the IC chip via a feeding path formed in the conductor layer of the high frequency substrate.

According to the present invention, one or a plurality of log-periodic antennas can be embedded inside a high-frequency substrate, and a complex log-periodic antenna shape can be formed by utilizing a plurality of conductor patterns and a plurality of via conductors, so that a wavelength shortening effect can be obtained. As a result, the high-frequency substrate can be miniaturized without increasing the arrangement area, and the frequency band can be widened to easily cope with different polarizations, and a high-frequency substrate with good antenna performance can be realized.

It is a top view of the whole high frequency substrate 10 of 1st Embodiment seen from above in the Z direction. It is a schematic sectional view of the high frequency substrate 10 of FIG. 1 as seen from the arrow A direction along the X direction. It is a schematic sectional view of the high frequency substrate 10 of FIG. 1 as seen from the arrow B direction along the Y direction. It is a perspective view which shows the structure of the log periodic antenna 41 for horizontal polarization which is constructed in the high frequency substrate 10. It is sectional drawing which shows the structure of the log periodic antenna 41 for horizontal polarization of FIG. It is a perspective view which shows the structure of the log periodic antenna 31 for vertical polarization which is constructed in the high frequency substrate 10. It is sectional drawing which shows the structure of the log periodic antenna 31 for vertical polarization of FIG. It is a top view which looked at the whole of the high frequency substrate 10 of 2nd Embodiment from above in the Z direction. FIG. 8 is an enlarged view showing the planar shape of the log periodic antenna 42a for horizontal polarization in FIG. 8. FIG. 8 is an enlarged view showing the planar shape of the log periodic antenna 32a for vertical flat polarization in FIG. 8.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, as an example of the embodiment to which the technical idea of the present invention is applied, two embodiments having different antenna shapes configured on the high frequency substrate will be described.

[First Embodiment]
A first embodiment, which is an example of the high frequency substrate of the present invention, will be described with reference to FIGS. 1 to 7. In FIGS. 1 to 7, for convenience of explanation, the X direction, the Y direction, and the Z direction, which are orthogonal to each other, are indicated by arrows. FIG. 1 is a plan view of the entire high-frequency substrate 10 of the first embodiment as viewed from above in the Z direction. 2 is a schematic cross-sectional view of the high frequency substrate 10 of FIG. 1 viewed from the direction of arrow A along the X direction, and FIG. 3 is a schematic cross-sectional view of the high frequency substrate 10 of FIG. 1 in the direction of arrow B along the Y direction. It is a schematic sectional view seen from. 4 and 5 are perspective views and sectional views showing the structure of the log-periodic antenna 41 for horizontal polarization configured on the high-frequency substrate 10, and FIGS. 6 and 7 are configured on the high-frequency substrate 10. It is a perspective view and the side view which shows the structure of the log periodic antenna 31 for vertical polarization.

The high-frequency substrate 10 of the first embodiment is a dielectric substrate made of a dielectric material having a predetermined dielectric constant, has a multilayer structure in which dielectric layers and conductor layers are alternately laminated, and is along the X direction. It is a rectangular plate-shaped member having a short side, a long side along the Y direction, and a predetermined thickness along the Z direction. In FIG. 1, the entire high-frequency substrate 10 is transmitted and shown in a plan view seen from above in the Z direction, and the RF region A1 including the multi-layered ground conductor 11 and the high-frequency circuit, and a plurality of log-periodic antennas 31 to 31. The antenna region A2 including 34, 41 to 44 is arranged respectively. That is, the RF region A1 and the antenna region A2 are region-divided at the boundary position XB in the X direction (second direction of the present invention) and face each other in the X direction.

In the antenna region A1, four vertically polarized log-periodic antennas 31 to 34 and four horizontally polarized log-periodic antennas 41 to 44 are embedded inside the dielectric substrate 10. They are arranged side by side in the Y direction (the first direction of the present invention). Here, the log-periodic antenna is an antenna that can secure a wide frequency band and sharp radiation directivity by regularly arranging pairs of radiation elements having different lengths. The four vertically polarized log-periodic antennas 31 to 34 radiate vertically polarized waves, and the four horizontally polarized log-periodic antennas 41 to 44 each radiate horizontally polarized waves. In the first embodiment, the case where the number of log-periodic antennas for vertical polarization and the number of log-periodic antennas for horizontal polarization are four each is shown, but from the viewpoint of antenna characteristics, the number of both is increased or decreased while keeping them the same. be able to. As will be described later, the structure may be such that at least one of a log periodic antenna for vertical polarization and a log periodic antenna for horizontal polarization is embedded inside the high frequency substrate 10.

As shown in FIG. 1, the arrangement of the eight log-periodic antennas 31 to 34 and 41 to 44 is symmetrical with respect to the central position YC in the Y direction. That is, in the vicinity of the central position YC, two horizontally polarized log-periodic antennas 42 and 43 are adjacent to each other, and from there, vertically polarized log-periodic antennas 32 and 33 and horizontally polarized log-periodic antennas 32 and 43 are adjacent to each other. The antennas 41 and 44 and the log periodic antennas 31 and 34 for vertical polarization are arranged in this order. The reason for adopting such an order will be described later. Further, in the first embodiment, eight log periodic antennas 31 to 34 and 41 to 44 are arranged at unequal intervals in the X direction. Generally, when a plurality of antennas are arranged side by side, they are often set at equal intervals according to the wavelength used, but even when the antenna intervals are set to be shifted to some extent in the arrangement of the first embodiment, the antenna performance is improved. It is possible to secure it.

Hereinafter, the cross-sectional structure of the high frequency substrate 10 of FIG. 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view of the high-frequency substrate 10 of FIG. 1 as viewed from the direction of arrow A along the X direction, and FIG. 3 is a cross-sectional view of the high-frequency substrate 10 of FIG. 1 as viewed from the direction of arrow B along the Y direction. It is a figure. In FIGS. 2 and 3, in order to clarify the structure of the RF region A1, the eight log-periodic antennas 31 to 34 and 41 to 42 are not shown. As shown in FIGS. 2 and 3, a plurality of conductor layers L including a lower surface 10a and an upper surface 10b facing in the Z direction are formed on the high frequency substrate 10, and each conductor layer L is various. Conductor pattern is formed. Further, the high-frequency substrate 10 is formed with a plurality of via conductors V extending through each dielectric layer in the Z direction, which is the thickness direction. The above-mentioned multi-layered ground conductor 11 (FIG. 1) is formed on the plurality of conductor layers L, and the ground conductors 11 facing each other in the Z direction are electrically connected to each other via the plurality of via conductors V.

Further, as shown in FIGS. 2 and 3, an opening 10c is formed in the central region on the side of the surface 10a of the high-frequency substrate 10, and the IC chip 20 is placed in the opening 10c. The IC chip 20 includes a plurality of terminals 20a, and each terminal 20a is connected to a plurality of pads (not shown) of a predetermined conductor layer L facing the opening 10c. The IC chip 20 is connected to each of the eight log-periodic antennas 31 to 34 and 41 to 44 from the predetermined eight terminals 20a via a feeding path (not shown) formed in the plurality of conductor layers L. It has the role of supplying power to the antenna. Further, in the RF region A1 in the vicinity of the IC chip 20, an RF circuit necessary for the operation of the IC chip 20 is configured. Further, as shown in FIG. 3, a reflector 12 is arranged on the upper part of the IC chip 20 in the antenna region A2. The reflector 12 is connected to the ground conductor 11 and functions as a shield plate for preventing interference between the IC chip 20 and the eight log periodic antennas 31 to 34 and 41 to 44. As can be seen from FIG. 1, the reflector 12 is arranged directly under the pair of log periodic antennas 42 and 43 for horizontal polarization.

Next, the structure of the log periodic antenna 41 for horizontal polarization will be described with reference to FIGS. 4 and 5. The basic structure of the other horizontally polarized log periodic antennas 42 to 44 is the same as that of the horizontally polarized log periodic antenna 41. As shown in FIG. 4, the log-periodic antenna 41 for horizontal polarization has signal-side connecting conductors 50a and 50b, ground-side connecting conductors 60a and 60b, signal-side and ground-side via conductors Va and Vb, and signal-side connecting conductors Va and Vb. It is configured to include three horizontal radiating elements 51, 52, 53 and three horizontal radiating elements 61, 62, 63 on the ground side. FIG. 4 shows the boundary position XB (see FIG. 1), and shows only the structure of the log-periodic antenna 41 for horizontal polarization in the antenna region A2.

In the above configuration, the pair of signal-side connecting conductors 50a and ground-side connecting conductors 60a are formed in the same conductor layer La (FIG. 5) and extend in the X direction from their respective ends Ea and Eb. The signal-side connecting conductor 50b is formed in the conductor layer Lb (FIG. 5) directly below, is connected to the signal-side connecting conductor 50a via the via conductor Va, and extends in the opposite direction to the signal-side connecting conductor 50a in the X direction. The ground-side connecting conductor 60b is formed on the conductor layer Lc (FIG. 5) directly above, is connected to the ground-side connecting conductor 60a via the via conductor Vb, and extends in the opposite direction to the ground-side connecting conductor 60a in the X direction. Therefore, as shown in FIG. 5, among the three continuous conductor layers La, Lb, and Lc, a pair of signal-side connecting conductors 50a and ground-side connecting conductors 60a arranged in the central conductor layer La are sandwiched between them. The signal side connecting conductor 50b is arranged at the lower part, and the ground side connecting conductor 60b is arranged at the upper part. Although not shown in FIG. 4, the end Ea of the signal-side connecting conductor 50a is connected to the feeding path 13 (FIG. 5) leading to the predetermined terminal 20a of the IC chip 20, and the end of the ground-side connecting conductor 50b. Eb is connected to a predetermined ground conductor 11.

In the signal side connecting conductor 50b and the ground side connecting conductor 60b, a pair of horizontal radiating elements 51 and 61, a pair of horizontal radiating elements 52 and 62, and a pair of a pair of horizontal radiating elements 51 and 61 forming a total of three pairs on the signal side and the ground side. The horizontal radiating elements 53 and 63 are connected to each other and extend from the base end to the tip end on both sides in the Y direction. A pair of horizontal radiating elements 51, 61, a pair of horizontal radiating elements 52, 62, and a pair of horizontal radiating elements 53, 63 arranged side by side in the X direction are arranged in the Y direction as they approach the boundary position XB. The length is long, and the stretching directions in the Y direction along the arrangement direction are staggered. Further, although the positions in the Y direction of each pair on the signal side and the ground side are common, the positions in the Z direction are different between the signal side and the ground side as described with reference to FIG.

As described above, the log periodic antenna 41 for horizontal polarization provided with three types of horizontally radiating elements having different lengths can radiate radio waves of horizontally polarized waves in a wide frequency band mainly along the X direction. However, due to the presence of the plurality of ground conductors 11, the radiation directivity of the log periodic antenna 41 for horizontal polarization becomes stronger mainly in the direction toward the side surface of the high frequency substrate 10 on the antenna region A2 side along the X direction. It becomes relatively weak in the direction facing the RF region A1 side. Further, the radiation directivity of the entire horizontally polarized wave of the high frequency substrate 10 is determined by the directivity obtained by synthesizing the four log periodic antennas 41 to 44 for horizontally polarized waves.

Next, the structure of the log periodic antenna 31 for vertical polarization will be described with reference to FIGS. 6 and 7. The basic structure of the other log-periodic antennas for vertical polarization 32 to 34 is the same as that of the log-periodic antenna 31 for vertical polarization. As shown in FIG. 6, the log-periodic antenna 31 for vertical polarization includes the signal-side connecting conductors 70a and 70b, the ground-side connecting conductors 80a and 80b, and the four vertical radiation elements 71, 72, 73 and 74 on the signal side. And four horizontal radiating elements 81, 82, 83, 84 on the ground side. Also in FIG. 6, only the structure of the log periodic antenna 31 for vertical polarization in the antenna region A2 on one side from the boundary position XB is shown.

In the above configuration, the pair of signal-side connecting conductors 70a and the ground-side connecting conductor 80a extend in the X direction from their respective ends Ed and Ee, and are folded back at the opposite ends to form a pair of signal-side connecting conductors. The 70b and the ground-side connecting conductor 80b extend in the opposite direction in the X direction. In this case, the signal-side connecting conductors 70a and 70b are formed in the conductor layer Ld (FIG. 5), and the ground-side connecting conductors 80a and 80b are formed in the conductor layer Le (FIG. 5) slightly below the conductor layer Ld. The pair of signal-side connecting conductors 70a and the ground-side connecting conductor 80a are arranged to face each other in the Z direction, but the pair of signal-side connecting conductors 70b and the ground-side connecting conductor 80b are spaced apart from each other in the Y direction. They are arranged facing each other in the Z direction. Further, although not shown in FIG. 6, the end Ed of the signal-side connecting conductor 70a is connected to the feeding path 13 (FIG. 7) leading to the predetermined terminal 20a of the IC chip 20, and the end of the ground-side connecting conductor 80b. Ee is connected to a predetermined ground conductor 11.

The signal side connecting conductor 70b and the ground side connecting conductor 80b on the folded side include a pair of vertical radiating elements 71 and 81 forming a total of four pairs on the signal side and the ground side, and a pair of vertical radiating elements 72 and 82. A pair of vertical radiating elements 73, 83 and a pair of vertical radiating elements 74, 84 are connected and extend vertically from the base end to the tip end in the Z direction. A pair of vertical radiating elements 71, 81, a pair of vertical radiating elements 72, 82, a pair of vertical radiating elements 73, 83, and a pair of vertical radiating elements 74, 84 arranged side by side in the X direction. The length in the Z direction becomes longer as it approaches the boundary position XB, and the extending directions in the Z direction along the alignment direction are staggered. Further, the positions in the X direction of each pair on the signal side and the ground side are common, but as described above, the positions in the Y direction are different between the signal side and the ground side.

As described above, the log periodic antenna 31 for vertical polarization provided with three types of vertically radiating elements having different lengths can radiate radio waves of vertically polarized waves having a wide frequency band mainly along the X direction. However, due to the presence of the plurality of ground conductors 11, the log-periodic antenna 31 for vertical polarization also has radiation directivity along the X direction, which has the same tendency as the log-periodic antenna 41 for horizontal polarization described above. Further, the radiation directivity of the entire vertical polarization of the high frequency substrate 10 is determined by the directivity obtained by synthesizing the four log periodic antennas 31 to 34 for vertical polarization.

Next, returning to FIG. 1, the arrangement order of the eight log periodic antennas 31 to 34 and 41 to 44 in the Y direction is mainly due to the arrangement in the Z direction described with reference to FIGS. 5 and 7. Originally, when horizontal polarization and vertical polarization can be shared, the number of horizontally polarized log-periodic antennas and the number of vertically polarized log-periodic antennas are the same and alternate from the viewpoint of antenna characteristics. Arranging them is a common arrangement. However, since the IC chip 20 in the opening 10c and the reflector 12 (FIG. 1) above the IC chip 20 exist just below the vicinity of the central position YC, as shown in FIG. 7, vertical extending to both sides in the Z direction. It is difficult to arrange the log periodic antennas 31 to 34 for polarization. Therefore, in the present embodiment, as shown in FIG. 5, two horizontally polarized log periodic antennas 42 and 43 capable of sufficiently reducing the thickness in the Z direction are arranged in the vicinity YC of the central position. , It is possible to avoid obstructing the arrangement of the IC chip 20 and the reflector 12. On the other hand, the log-periodic antennas 41 to 44 for horizontal polarization and the log-periodic antennas 31 to 34 for vertical polarization are arranged symmetrically on the left side and the right side of FIG. 1 with respect to the central position YC, and both are kept the same number. Therefore, it is possible to maintain good antenna performance while effectively utilizing the space without increasing the size of the high-frequency substrate 10.

In the above first embodiment, an example in which eight log-periodic antennas 31 to 34 and 41 to 44 are configured on the high-frequency substrate 10 has been described, but the present invention is not limited to this, and at least one log-periodic antenna is used for high frequency. The present invention can be applied even when a configuration embedded inside the substrate 10 is adopted. That is, in the conventional configuration, it is common to arrange the main part of the planar log periodic antenna on the surface of the substrate (see, for example, Patent Document 1). On the other hand, the high-frequency substrate according to the present invention forms a log-periodic antenna by combining conductor patterns of a plurality of conductor layers L and a plurality of via conductors V, and a dielectric material having a relatively high dielectric constant is around the antenna. Since it exists, there is an advantage that the log-periodic antenna can be compactly configured due to the wavelength shortening effect. In the conventional configuration, if a log-periodic antenna having the same antenna characteristics as the present invention is configured, an increase in the size of the substrate is unavoidable. Therefore, the effect of downsizing the high-frequency substrate by applying the present invention is clear.

In the first embodiment, the structure in which the IC chip 20 is placed in the opening 10c of the high-frequency substrate 10 is shown, but instead of the IC chip 20, various electronic components having a predetermined function are placed in the opening 10c. can do. Further, when power is supplied to the eight log periodic antennas 31 to 34 and 41 to 44 from the outside, a structure is adopted in which only the respective power supply terminals are provided and electronic parts such as the opening 10c and the IC chip 20 are not provided. May be. When such a structure is used, it is necessary to form a feeding structure including a feeding path from the feeding terminal provided in the exposed portion of the high frequency substrate 10 to the end portions Ea, Eb, Ed, and Ee shown in FIGS. 4 to 7. ..

[Second Embodiment]
Next, a second embodiment, which is an example of the high frequency substrate of the present invention, will be described with reference to FIGS. 8 to 10. Since most of the basic configurations and effects of the second embodiment are the same as those of the first embodiment, the differences from the first embodiment will be mainly described below. FIG. 8 is a plan view of the entire high-frequency substrate 10 of the second embodiment as viewed from above in the Z direction, and is a diagram corresponding to FIG. 1 of the first embodiment. The cross-sectional views of the high-frequency substrate 10 of FIG. 8 are the same as those of FIGS. 2 and 3.

As shown in FIG. 8, the high frequency substrate 10 of the second embodiment differs from the first embodiment in that the two log periodic antennas 32, 33 for vertical polarization and the two log periodic antennas for horizontal polarization shown in FIG. The periodic antennas 42 and 43 are replaced with two log-periodic antennas for vertical polarization 32a and 33a and two log-periodic antennas for horizontal polarization 42a and 43a having different planar shapes when viewed from the Z direction. .. Here, FIGS. 9 and 10 are enlarged views showing the planar shapes of the log-periodic antenna 42a for horizontal polarization and the log-periodic antenna 32a for vertical polarization of FIG. Regarding the other log-periodic antenna 42b for horizontal polarization and the log-periodic antenna 32b for vertical polarization, FIGS. 9 and 10 may be considered in a symmetrical arrangement with respect to the Y direction.

The horizontally polarized log periodic antenna 42a shown in FIG. 9 has almost the same three-dimensional structure as the components of the horizontally polarized log periodic antenna 42 described with reference to FIGS. 4 and 5, but the horizontal radiation element. The number and the stretching direction are different. That is, in the log periodic antenna 42a for horizontal polarization, a total of eight horizontal radiating elements 51 to 54 and 61 to 64 form four pairs on the signal side and the ground side, and the extending direction from the base end to the tip end of each. Is inclined from the Y direction. Specifically, the direction in which the tips of the eight horizontal radiating elements 51 to 54 and 61 to 64 on both sides are separated from the boundary position XB based on the positions of the signal side connecting conductor 50a and the ground side connecting conductor 60a (ground conductor). It is inclined toward (direction away from 11), and it is arranged symmetrically on both sides. The changes in length and the staggered arrangement of the eight horizontal radiating elements 51 to 54 and 61 to 64 are the same as in the first embodiment.

Further, the log-periodic antenna 32a for vertical polarization shown in FIG. 10 has almost the same three-dimensional structure as the constituent members of the log-periodic antenna 32 for vertical polarization described with reference to FIGS. 6 and 7, but is vertical. The arrangement direction of the radiating elements is different. That is, in the log-periodic antenna 32a for vertical polarization, the more the extension direction of the signal-side connecting conductor 70b and the arrangement direction of the four vertical radiation elements 71 to 74 connected to the signal-side connecting conductor 70b are closer to the boundary position XB (ground conductor). (The closer it is to 11), the more it is inclined in the direction away from the central signal-side connecting conductor 70a. Similarly, the closer the extension direction of the ground side connecting conductor 80b and the arrangement direction of the four vertical radiating elements 81 to 84 connected to the ground side connecting conductor 80b are to the boundary position XB (the closer to the ground conductor 11), the closer to the center ground side. It is inclined in a direction away from the connecting conductor 80a. The arrangement is symmetrical on both sides with respect to the central signal-side connecting conductor 70a and the ground-side connecting conductor 80a. The changes in the lengths of the eight vertical radiation elements 71 to 74 and 81 to 84 in the Z direction and the staggered arrangement are the same as in the case of the first embodiment.

As shown in FIG. 8, the planar shapes shown in FIGS. 9 and 10 include two log-periodic antennas 42a and 43a for horizontal polarization sandwiching a central position in the Y direction, and two vertically polarized antennas on both sides thereof. It is applied only to the log-periodic antennas 32a and 33a, and the other two log-periodic antennas 41 and 44 for horizontal polarization and the two log-periodic antennas 31 and 34 for vertical polarization are the first embodiment. It has the same planar shape as. When arranging multiple log-periodic antennas side by side, the log-periodic antenna near the center of the arrangement direction is more affected by interference with the surrounding log-periodic antennas and ground than the log-periodic antenna near the outer edge of the arrangement direction. As a result, the antenna gain tends to decrease. As a result of the verification by the inventors, it was found that it is effective to adopt the configurations of FIGS. 8 to 10 of the second embodiment in order to improve this point. As a result of the simulation, by adopting the configuration of the second embodiment, the log-periodic antennas 42a and 43a for horizontal polarization and the log-periodic antennas 32a and 33a for vertical polarization having the planar shapes of FIGS. 9 and 10 are oriented in the X direction. It was possible to confirm the improvement effect of the antenna gain along the line by about 2 to 3 dB.

In FIGS. 8 to 10, in the log periodic antennas 42a and 43a for horizontal polarization, the extending directions of the horizontal radiating elements 51 to 64 and 61 to 64 are inclined by about 30 ° as compared with the first embodiment, and Regarding the log periodic antennas 32a and 33a for vertical polarization, an example is shown in which the arrangement directions of the vertical radiation elements 71 to 74 and 81 to 84 are inclined by about 5 ° as compared with the first embodiment, but the respective inclinations are shown. The angle can be appropriately changed according to the desired antenna performance.

When manufacturing the high-frequency substrates 10 of the first and second embodiments, for example, a plurality of ceramic green sheets for low-temperature firing formed by the doctor blade method are prepared, and a plurality of ceramic green sheets are punched for each ceramic green sheet. Make a beer hall. Then, each via hole is filled with the conductive paste by screen printing to form a plurality of via conductors, and the surface of each ceramic green sheet is coated with the conductive paste by screen printing to form a plurality of via conductors. Form a conductor pattern. The plurality of conductor patterns and the plurality of via conductors thus formed can form a basic structure such as a plurality of log periodic antennas and a ground conductor. Next, a plurality of ceramic green sheets are laminated in order, heated and pressed, and the obtained laminate is degreased and fired to obtain a high frequency substrate 10.

Although the contents of the present invention have been specifically described above based on the first and second embodiments, the present invention is not limited to the above-described embodiments, and changes may be made without departing from the gist thereof. can. That is, the structure of the wiring board 10 described with reference to FIGS. 1 to 10 widely applies the present invention to various wiring boards using other structures and materials as long as the effects of the present invention can be obtained. be able to. In particular, the number and shape of the log-periodic antennas 41 to 44 for horizontal polarization and the log-periodic antennas 31 to 34 for vertical polarization, other design items, the arrangement and shape of the ground conductor 11, etc. As long as the action and effect of the present invention can be obtained, various changes can be made.

10 ... High frequency substrate 10a, 10b ... Surface 10c ... Opening 11 ... Ground conductor 12 ... Reflector 13 ... Feeding path 20 ... IC chips 31, 32, 33, 34 ... Verpendicular polarization logarithmic period antennas 41, 42, 43, 44 ... Logistic period antenna for horizontal polarization 51, 52, 53, 61, 62, 63 ... Horizontal radiating elements 71, 72, 73, 74, 81, 82, 83, 84 ... Vertical radiating elements 50a, 50b, 70a, 70b ... Signal side connecting conductors 60a, 60b, 80a, 80b ... Ground side connecting conductor L ... Conductor layer V ... Via conductor A1 ... RF region A2 ... Antenna region

Claims (13)

A high-frequency substrate in which dielectric layers and conductor layers are alternately laminated.
It comprises one or more log-periodic antennas configured with a plurality of conductor patterns formed on the conductor layer and a plurality of via conductors penetrating the dielectric layer.
A high-frequency substrate characterized in that the one or a plurality of log-periodic antennas are embedded inside the high-frequency substrate. It is characterized in that a one-layer or a plurality of layers of ground conductors arranged in a region that does not overlap with a region in which the one or a plurality of log periodic antennas are arranged in a plan view from the thickness direction of the high-frequency substrate is provided. The high frequency substrate according to claim 1. The high-frequency substrate according to claim 2, wherein a feeding structure for feeding a high-frequency signal is provided for each of the one or a plurality of log-periodic antennas. The plurality of log-periodic antennas are composed of a horizontally polarized log-periodic antenna and a vertically-polarized log-periodic antenna, and are arranged side by side in a first direction orthogonal to the thickness direction of the dielectric substrate. The high frequency substrate according to claim 3, which is characterized. The high-frequency substrate according to claim 4, wherein the number of the log-periodic antennas for horizontal polarization and the number of log-periodic antennas for vertical polarization are the same, and each is 2 or more. A layer or a plurality of ground conductors arranged in a region that does not overlap with a region in which the plurality of log periodic antennas are arranged in a plan view from the thickness direction of the high frequency substrate.
An opening that can accommodate electronic components in the central region in a plan view from the thickness direction,
A plurality of feeding paths included in the feeding structure and electrically connecting between the electronic component and each of the plurality of log periodic antennas.
Further prepare
The high-frequency substrate according to claim 5, wherein only the log-periodic antenna for horizontal polarization is arranged in a region overlapping the opening in a plan view from the thickness direction. The high frequency substrate according to claim 6, wherein the plurality of log periodic antennas are arranged symmetrically with respect to the central position in the first direction. The log periodic antenna for horizontal polarization includes a plurality of pairs of horizontal radiating elements paired on the signal side and the ground side.
The plurality of pairs of horizontal radiating elements are configured by using the plurality of conductor patterns, and are arranged side by side in the thickness direction and the second direction orthogonal to the first direction.
The log periodic antenna for vertical polarization includes a plurality of pairs of vertical radiation elements paired on the signal side and the ground side.
The plurality of pairs of vertical radiating elements are configured by using the plurality of via conductors and are arranged side by side in the second direction.
The high frequency substrate according to claim 7. Each of the at least two horizontally polarized log periodic antennas has the first direction extending from the base end of the plurality of pairs of horizontal radiation elements to the respective tips on the signal side and the ground side. The high frequency substrate according to claim 8. Each of the at least two log-periodic antennas for horizontal polarization in the vicinity of the central position in the first direction has the extension direction in the plane of the conductor layer and the tips thereof from the first direction to the ground. The high-frequency substrate according to claim 9, wherein the high-frequency substrate is inclined in a direction away from the conductor. In each of the at least two vertically polarized log periodic antennas, the extension direction of each of the plurality of pairs of vertical radiation elements is the thickness direction, and the plurality of pairs constituting each of the plurality of pairs of vertical radiation elements. The high frequency according to claim 8, wherein the signal-side via conductor and the plurality of ground-side via conductors are arranged to face each other in the first direction, and their respective arrangement directions are in the second direction. substrate. In each of the at least two log-periodic antennas for vertical polarization in the vicinity of the central position, the extension direction of the plurality of pairs of vertical radiation elements is the thickness direction, and the plurality of signal-side via conductors and the said. The plurality of ground-side via conductors are arranged so as to face each other in the first direction, and the more the respective arrangement directions are closer to the ground conductor from the second direction, the farther away from the plurality of ground-side via conductors. The high frequency substrate according to claim 11, characterized in that the direction is inclined to. The antenna module according to any one of claims 6 to 12, wherein the electronic component is placed in the opening.

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