antenna chip
Patent Information
- Application Number
- JP2026509349
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-08-30
- Publication Date
- 2026-09-07
Smart Images
Figure 2026530234000001_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to an antenna chip. [Background technology]
[0002] In recent years, with the increasing demand for higher data transfer speeds and wider bandwidths, millimeter-wave frequencies from 30 to 500 GHz have become a major candidate for future wireless communication system development. To achieve high data transmission speeds and large-capacity networks, integrated circuit designs at higher frequencies are necessary. This design has led to the successful development of integrated circuit chips containing power amplifiers (PAs), low-noise amplifiers (LNAs), mixers, filters, and other components at various frequencies up to 500 GHz. Simultaneously, the development of on-chip antennas, or antenna chips, for radiating amplified signals has also been observed.
[0003] Generally, integrated circuit chips are characterized by measuring the chip's output signal using a probing station with a three-point probe (Non-Patent Literature 1). During this measurement, the input and output, each having a signal pad and two ground pads, are connected to a vector network analyzer (VNA) via the three-point probe. The central signal probe of the three-point probe contacts the signal pad of the chip. The first and second ground probes on the outside of the three-point probe contact the first and second ground pads of the chip, respectively. For antenna chip characterization, the output-side three-point probe is replaced with a probe antenna positioned some distance from the antenna chip to collect the output signal radiated from the antenna chip. [Prior art documents] [Non-patent literature]
[0004] [Non-Patent Document 1] Banan, B., Shokraneh, F., Berini, P., & Liboiron-Ladouceur, O. (2017). "Electrical performance analysis of a CPW capable of transmitting microwave and optical signals." International Journal of Microwave and Wireless Technologies, 9(8), 1679-1686. doi:10.1017 / S1759078717000575 [Overview of the project] [Problems that the invention aims to solve]
[0005] In the characterization of an antenna chip, the radiation pattern of the output signal is measured. To measure the radiation pattern, the angle of the probe antenna relative to the antenna chip is sequentially changed, and the antenna gain at each angle is measured using a VNA with the probe antenna. One solution to achieve this angle change is to rotate the antenna chip. In this case, the antenna chip rotates relative to the three-point probe, because the three-point probe is usually configured to be immobile.
[0006] When the antenna tip is rotated relative to the three-point probe, if the rotation angle becomes large, the shape of the antenna tip's ground pad may prevent the ground probe of the three-point probe from making contact with the ground pad.
[0007] The objective of the present invention is to provide an antenna tip that can connect to a connection target, such as a three-point probe, even when the rotation angle relative to the connection target is large. [Means for solving the problem]
[0008] The antenna patch according to the present invention comprises a substrate having a first main surface, a first ground pad and a second ground pad formed on the first main surface and arranged in a first direction perpendicular to the thickness direction of the substrate with a gap between them, wherein the gap includes a first gap and a second gap extending from the first gap in a second direction perpendicular to the thickness direction and different from the first direction, a signal pad formed on the first main surface and located within the first gap, and a first antenna patch formed on the first main surface, located outside the gap, and constituting at least a part of the antenna. The antenna comprises a signal line formed on the first main surface, extending from the signal pad in the second direction and passing through the second gap, configured to transmit an electrical signal input to the signal pad to the first antenna patch, wherein the first boundary between the first ground pad and the first gap has the shape of a portion of a circular or regular n-gon (where n is an even number of 6 or more) contour line concentric with the signal pad, and the second boundary between the second ground pad and the first gap has the shape of a portion of a circular or regular m-gon (where m is an even number of 6 or more) contour line concentric with the signal pad.
[0009] With the above configuration, the antenna chip can be connected to the target object even if the rotation angle of the antenna chip relative to the target object is increased. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a plan view of an antenna chip according to an embodiment of the present invention. [Figure 2] Figure 2 is a bottom view of the antenna chip shown in Figure 1. [Figure 3] Figure 3 is an enlarged plan view of a portion of the antenna chip shown in Figure 1. [Figure 4] Figure 4 is a perspective view of a portion of the antenna chip shown in Figure 1. [Figure 5] Figure 5 is a diagram showing the configuration used when measuring the radiation pattern of an antenna chip. [Figure 6]FIG. 6 is a configuration diagram for measuring the radiation pattern of an antenna chip after rotation. [Figure 7] FIG. 7 is a diagram showing respective radiation pattern simulations of two different types of antennas (Antenna_1 and Antenna_2). [Figure 8] FIG. 8 is a diagram showing an antenna chip according to a comparative example. [Figure 9] FIG. 9 is a graph showing simulation results of impedance matching between the signal pad side (Port 1) and the coplanar waveguide side (Port 2) in a frequency range from 150 GHz to 350 GHz. [Figure 10] FIG. 10 is a graph showing S-parameters of the simulated signal pad and transition to a coplanar waveguide feed. [Figure 11] FIG. 11 is a graph showing simulation results of characteristic impedance matching between the signal pad side (Port 1) and the coplanar waveguide side (Port 2), and shows results for different substrate materials in a frequency range from 150 GHz to 350 GHz. [Figure 12] FIG. 12 is a schematic plan view of an antenna chip according to a modification of an embodiment of the present invention. [Figure 13] FIG. 13 is an enlarged plan view of an antenna chip according to a modification of an embodiment of the present invention. [Figure 14] FIG. 14 is a schematic enlarged plan view of an antenna chip according to a modification of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0011] Hereinafter, embodiments of the present invention and modifications thereof will be described with reference to the drawings. In each drawing, the same or similar elements are denoted by the same reference numerals. Among a plurality of identical elements, only some of the elements are denoted by reference numerals. In the drawings, some features are simplified and / or exaggerated for ease of understanding.
[0012] As shown in Figs. 1 to 4, the antenna chip 10 according to the present embodiment includes a substrate 20, ground pads 30 and 40, a signal pad 50, a signal line 60, antenna patches 71 and 72, a ground plane 80, and a plurality of vias 91 to 94.
[0013] The substrate 20 includes a first main surface 21 and a second main surface 22 that is the back surface of the first main surface 21. The main surface is a surface having the largest area among the respective surfaces of the substrate 20. On the first main surface 21, the ground pads 30 and 40, the signal pad 50, the signal line 60, and the antenna patch 71 are formed. On the second main surface 22, the antenna patch 72 and the ground plane 80 are formed.
[0014] The ground pads 30 and 40 are formed in a square shape. The ground pads 30 and 40 are arranged so as to be aligned in a first direction orthogonal to the thickness direction of the substrate 20 with a gap G therebetween. The gap G extends in a second direction orthogonal to the thickness direction and different from the first direction. Here, the second direction is orthogonal to the first direction. The gap G is defined by the ground pads 30 and 40, and separates the ground pads 30 and 40 from each other. The gap G includes gaps G1 to G3.
[0015] The circular signal pad 50 is disposed in the gap G1. The gap G1 is formed in an enlarged concentric shape with the signal pad 50. A boundary B1 between the gap G1 and the ground pad 30 has a shape of a first arc of a large-diameter circle that is concentric with the signal pad 50 and has a larger diameter than the signal pad 50. A boundary B2 between the gap G1 and the ground pad 40 has a shape of a second arc of the large-diameter circle opposite to the first arc. The second arc is an arc opposite to the first arc across the center of the large-diameter circle. A width w1 of a region between the signal pad 50 and the boundary B1 is constant. A width w1 of a region between the signal pad 50 and the boundary B2 is also constant.
[0016] Gap G2 extends from gap G1 in a second direction. A linear signal line 60 extends from signal pad 50 in a second direction and passes through gap G2. The end of signal line 60 on the second direction side is connected to antenna patch 71 located outside gap G. The signal pad 50, signal line 60, and antenna patch 71 are integrally formed as a single conductive layer. The single conductive layer, ground pad 30, and ground pad 40 are formed apart from each other on the first main surface 21.
[0017] Gap G3 extends from gap G1 in the direction opposite to the second direction. No conductors for transmitting electrical signals, such as the signal pad 50 and signal line 60, which will be described later, are placed in gap G3.
[0018] Parts of the ground pads 30 and 40 aligned in the first direction with a gap G1 between them are referred to as pad areas 31 and 41, respectively. Parts of the ground pads 30 and 40 aligned in the first direction with a gap G2 between them are referred to as pad areas 32 and 42, respectively. Parts of the ground pads 30 and 40 aligned in the first direction with a gap G3 between them are referred to as pad areas 33 and 43, respectively.
[0019] A portion 35 on the boundary B1 side of pad region 31, a portion 45 on the boundary B2 side of pad region 32, and the signal pad 50 located between them constitute a coplanar waveguide CPW2. Portions 35 and 45 are arranged side by side in the first direction with a gap G1 between them. Pad regions 32 and 42 and the signal line 60 located between them constitute a coplanar waveguide CPW1.
[0020] The ground plane 80 formed on the second main surface 22 of the substrate 20 includes a rectangular portion 81 that covers the coplanar waveguide CPW1 from the second main surface 22 side, and a pair of rectangular portions 82 and 83 extending from both ends of the rectangular portion 81 in the first direction in opposite directions in the second direction. The ground plane 80 has a shape that does not cover the coplanar waveguide CPW2 from the second main surface 22 side, that is, a shape that avoids the coplanar waveguide CPW2.
[0021] The antenna patch 72 formed on the second main surface 22 of the substrate 20 extends in a second direction from the ground plane 80. The antenna patch 72 and the ground plane 80 are integrally formed as a single conductive layer. The antenna patch 72 and the aforementioned antenna patch 71 constitute an antipodal Vivaldi antenna.
[0022] Multiple vias 91-94 penetrate the substrate 20. Multiple vias 91 and 92 electrically connect the ground pad 30 to the ground plane 80. Multiple vias 93 and 94 electrically connect the ground pad 40 to the ground plane 80.
[0023] Viewed from the thickness direction of the substrate 20, the multiple vias 91 are aligned in a first direction at positions overlapping with the pad area 32 of the ground pad 30, and the multiple vias 92 are aligned in a second direction at positions overlapping with the area of the pad area 31 excluding a portion 35. The multiple vias 91 electrically connect the pad area 32 and the rectangular portion 81 of the ground plane 80. The multiple vias 92 electrically connect the pad area 31 and the rectangular portion 82 of the ground plane 80.
[0024] Viewed from the thickness direction of the substrate 20, the multiple vias 93 are aligned in a first direction at positions overlapping with the pad area 42 of the ground pad 40, and the multiple vias 94 are aligned in a second direction at positions overlapping with the area of the pad area 41 excluding a portion 45. The multiple vias 93 electrically connect the pad area 42 and the rectangular portion 81 of the ground plane 80. The multiple vias 94 electrically connect the pad area 41 and the rectangular portion 83 of the ground plane 80.
[0025] Vias 91-94 limit the region of electromagnetic waves caused by electrical signals propagating along signal line 60. An additional role of vias 91-94 in the millimeter-wave band is to limit electromagnetic wave leakage through the substrate 20 and absorb undesirable substrate resonance modes and various parasitic effects that often occur during the operation of the millimeter-wave antenna chip 10.
[0026] This section describes a method for measuring the radiation pattern of the radiated signal emitted by the antenna 70 of the antenna chip 10. First, a three-point probe 952 is connected to the antenna chip 10, which is positioned at the basic position (rotation angle position of 0 degrees) as shown in Figure 5. Through this connection, the signal probe 952A, ground probe 952B, and ground probe 952C of the three-point probe 952 make contact with the signal pad 50, ground pad 30, and ground pad 40 of the antenna chip 10, respectively. This contact grounds the ground pads 30 and 40, the ground plane 80 connected to them via vias 91 to 94, and the antenna patch 72 connected to the ground plane 80. The VNA 951 inputs an electrical signal for radiation pattern measurement to the signal pad 50 via the signal probe 952A. The input electrical signal is transmitted to the antenna patch 71 via the signal pad 50 of the coplanar waveguide CPW2 and the signal line 60 of the coplanar waveguide CPW1. Antenna 70, including antenna patches 71 and 72, radiates electrical signals transmitted to antenna patch 71 in the form of electromagnetic waves such as millimeter waves. The electromagnetic waves are radiated in a radiation pattern PT. VNA951 collects these electromagnetic waves with a probe antenna 953 whose measurement area is region R, and measures the antenna gain based on these electromagnetic waves.
[0027] Subsequently, as shown in Figure 6, the antenna tip 10 is rotated and the three-point probe 952 is reconnected. The rotation center of the antenna tip 10 is the center of the signal pad 50. The position and orientation of the three-point probe 952 do not change even when the antenna tip 10 is rotated. After that, the antenna gain is measured using the same procedure as in Figure 5. The antenna tip 10 is rotated multiple times, and the antenna gain is measured each time it is rotated. The antenna tip 10 may also be rotated by an angle between the rotation angle shown in Figure 5 and the rotation angle shown in Figure 6.
[0028] The position of the probe antenna 953 is changed according to the rotation angle of the antenna tip 10. The relative position of the probe antenna 953 to the antenna tip 10 may be determined based on the characteristics of the probe antenna 953.
[0029] The contact position of the signal probe 952A is at the center of the signal pad 50. Therefore, when the antenna tip 10 rotates, the contact position of the signal probe 952A remains at the center of the signal pad 50 and does not change. The contact positions of the ground probes 952B and 952C change. Here, the boundaries B1 and B2 that define the ground pads 30 and 40, respectively, are concentric with the signal pad 50 and have a larger diameter arc shape than the signal pad 50, as described above. Therefore, even if the rotation angle of the antenna tip 10 increases, the contact between the ground probes 952B and 952C and the ground pads 30 and 40 is maintained. Here, the antenna tip 10 can be rotated over a wide range of ±70 to 75 degrees, totaling 140 to 150 degrees. This makes it possible to precisely measure the radiation pattern over a total range of 140 to 150 degrees in small steps of rotation angle.
[0030] Figure 7 shows a simulation of signals (electromagnetic waves) radiated from two antipodal Vivaldi antennas tuned to peak gain at 265 GHz. Figure 7 shows the radiation pattern in the XY plane (antenna plane). Hereafter, the antenna in the simulation on the left of Figure 7 will be referred to as Antenna 1, and the antenna in the simulation on the right will be referred to as Antenna 2.
[0031] The simulated maximum antenna gain for antenna_1 is approximately 10.2 dBi, while the simulated maximum antenna gain for antenna_2 is approximately 10.3 dBi. According to the simulation, when both antennas have similar gains at the same frequency of 265 GHz, the shape of the radiation pattern changes, resulting in different gains at the same radiation angle. For example, at 60 and 120 degrees, both antennas show similar gains of approximately 7.5 dBi. Further changing the angle to 30 and 150 degrees yields different simulation results, with antenna_1 gaining approximately 1-2 dBi and antenna_2 gaining approximately 5 dBi. In this case, it can be concluded that antenna_2 has a wider bandwidth than antenna_1. While 5 dBi is twice the peak gain, it is still considered usable at 265 GHz. Therefore, to confirm the simulation results and wideband characteristics of the fabricated antenna_2, measurements at larger angles are necessary. In the comparative example shown in Figure 8, the shapes of the signal pad 991, ground pads 992, and 993 prevent the ground probe 952B or 952C from contacting the ground pad 992 or 993 when measuring at large angles such as 30 degrees and 150 degrees. This can cause changes in impedance and other parameters, resulting in inaccurate measurements. However, with the above structure of the antenna tip 10 (particularly the arc shape of boundaries B1 and B2), contact between the ground probes 952B and 952C and the ground pads 30 and 40 is ensured, enabling accurate measurements.
[0032] To reduce signal input loss (insertion loss), the input impedance of the antenna tip 10 may be adjusted to 50Ω. Additionally, the coplanar waveguides CPW1 and CPW2 may have matching impedances to avoid significant signal reflection and mismatch.
[0033] In this embodiment, first the shapes of the conductive (metal) layers (pads 30, 40, 50, and signal line 60) and waveguides CPW1 and CPW2 are designed, and then the indium phosphide substrate 20 (ε) is designed, which is a standard parameter for high-frequency circuits for wireless communication applications. r = 12.3), substrate thickness t SUB = 55 μm, metal layer thickness t M = 4 μm, via radius R VIA = Adjust 30μm to exhibit a characteristic impedance of Z0 = 50Ω. Dielectric constant ε r While the base remains the same, the impedance changes significantly when the thickness of the substrate 20 and the metal layer changes, so this needs to be taken into consideration in the initial design of the pads.
[0034] In this embodiment, the coplanar waveguide CPW2 can be considered as a coplanar waveguide without a back-surface ground plane, and the coplanar waveguide CPW1 can be considered as a coplanar waveguide with a back-surface ground plane 80. The impedance is adjusted by the shape of the ground plane 80. Generally, the impedance of a coplanar waveguide can be calculated using equation (1). In equation (1), ε eff is the effective permittivity, K(k) is the elliptic integral, and K(k') is the complement of K(k).
number
[0035] The effective dielectric constant can be calculated using equation (2). In equation (2), K is the complete elliptic integral of the first kind, and k, k1, k', and k1' are equal. In equations (3) to (5), s is the line width (2*R1, s in Figure 3), w is the gap width (w1, w2 in Figure 3), and h is the substrate thickness (t SUB )
number
number
number
number
[0036] In this embodiment, an InP substrate (ε) with a thickness of 55 μm is used. r In the case of = 12.3), a characteristic impedance of 50Ω was achieved with R = 20μm, w1 = 30μm, s = 9μm, and w2 = 10μm.
[0037] Next, we will describe the results of an electromagnetic wave simulation based on a portion of the structure of the antenna chip 10 shown in Figure 4. The signal input was applied to the pad cross-section within the central plane of the signal pad 50 (Port 1). The output signal was collected together with the ground from the coplanar waveguide CPW1 (Port 2).
[0038] Figure 9 shows the simulation results of impedance-to-frequency measurements for the coplanar waveguides CPW1 and CPW2 with the dimensions (R, w1, s, w2, etc.) mentioned above. As can be seen, both Port1 (input) and Port2 (output) obtain stable characteristic impedance values of approximately 50Ω over a wide frequency range from 150GHz to 350GHz, allowing for stable measurement of the characteristics of the antenna chip 10 at various frequencies. Due to operation over a wide frequency range, assuming that the substrate material and substrate thickness do not change, the coplanar waveguides CPW1 and CPW2, once designed, can be used in various devices.
[0039] Figure 10 shows the S-parameters extracted from the above simulation. The signal transmission parameters (S21 and S12) show insertion losses of 1 dB or less in the frequency range of 150–350 GHz. The parameters S11 and S22 show values of -15 dB or less in the frequency range of 150–350 GHz. Therefore, it can be concluded that the system's return loss is acceptable in antenna designs that typically require values of -10 dB or less. Furthermore, the designed coplanar waveguides CPW1 and CPW2 can function as input and output signal pads when the antenna functions as a transceiver.
[0040] According to the present embodiment, the circular signal pad 50 and the ground pads 30, 40 that are concentric with the signal pad 50 and have contours of large-diameter circular arcs (boundaries B1, B2) allow the dimensions (R, w1, etc.) of the waveguide in the plane including the contact points between the three-point probe 952 and the pads 30 to 50 to be kept the same even when the measurement angle is considerably large. This reduces several mismatches and impedance inconsistencies.
[0041] The material of the substrate 20 may be replaced with another material different from indium phosphide. Table 1 shows the approximate dimensions of the coplanar waveguides CPW1 and CPW2 extracted from simulation results when the substrate material is Si, SiN, GaAs, GaN, InP, and Ge.
Table 1
[0042] Substrate thickness t SUB Assuming that is the same, the dielectric constant of the material is the main parameter that affects the above dimensions. Although many parameters can be arbitrarily selected, in general, low dielectric constant materials require larger signal pads 50 and signal lines 60 (R and s) than materials with a high dielectric constant ε r , and the spacing (w1 and w2) between the conductive layers of the coplanar waveguides CPW1 and CPW2 decreases as ε r decreases. The size of the signal pad 50 needs to be large enough to enable contact with the signal probe 952A.
[0043] Figure 11 shows the characteristic impedance values of the structure of Figure 4 having the dimensions in Table 1 for each material. As shown in Figure 11, stable impedance values around 50Ω are obtained in all cases, indicating that the coplanar waveguides CPW1 and CPW2 can be easily adjusted for various substrates to exhibit a desired impedance value different from 50Ω for specific applications. The material of the substrate may also be a polymer or the like.
[0044] The specific configuration of the antenna chip is not limited to the structure described above. For example, a processing circuit may be provided, located between the signal line 60 and the antenna patch 71, and configured to process the electrical signal transmitted from the signal line 60 to the antenna patch 71. The processing circuit may include one or any combination of a power amplifier, a low-noise amplifier, a mixer, and a filter. The antenna 70 can also be changed to any antenna. In the antenna chip 10, the antenna 70 consists of two antenna patches 71 and 72, but the antenna may consist of a single antenna patch.
[0045] Figure 12 shows an antenna chip 100 equipped with a processing circuit 190 and in which the antenna 70 is replaced with a Vivaldi antenna 170 consisting of a single antenna patch. In Figure 12, the processing circuit 190 is depicted as a simplified block. In the case of antenna chip 100, the electrical signal transmitted from the signal line 60 to the Vivaldi antenna 170 is the electrical signal after processing (e.g., after amplification) by the processing circuit 190. In Figure 12, the ground plane 80 does not cover the processing circuit 190 from the second main surface 22 side, but a ground plane that further covers the processing circuit 190 may be provided.
[0046] The shapes of boundaries B1 and B2 can also be changed to any shape. Boundary B1 may have the shape of a part of the contour line of a regular n-gon (where n is an even number greater than or equal to 6) concentric with the signal pad, and boundary B2 may have the shape of a part of the contour line of a regular m-gon (where m is an even number greater than or equal to 6) concentric with the signal pad. n and m may be the same or different. Even with such shapes, the connection between the three-point probe and the antenna tip is ensured when the rotation angle of the antenna tip relative to the three-point probe is increased.
[0047] The signal pad 50 may be a regular n-gon, and boundaries B1 and B2 may be part of the contour line of the concentrically expanded shape of the signal pad 50. By matching the shapes of the signal pad 50 and boundaries B1 and B2 in this way, the contour line of the signal pad 50 and boundaries B1 and B2 can be made parallel, and some of the discrepancies and impedance mismatches described above when the antenna tip is rotated can be reduced to some extent. Figure 13 shows the signal pad 50 and ground pads 30 and 40 (boundaries B1 and B2) when n=8.
[0048] The antenna chip may be connected to a device other than the 3-point probe 952.
[0049] As shown in Figure 13, a resistor 290 having first and second terminals connected to ground pads 30 and 40, respectively, may be provided. In Figure 13, the resistor 290 is depicted by a circuit symbol. The resistor 290 is a centrifugal resistor that dissipates excess energy from ground pads 30 and 40. Depending on the design, during the operation of the antenna chip, especially at high frequencies, the shape of ground pads 30 and 40 may cause resonance to occur in the gap between the signal pad 50 and ground pads 30 and 40, gradually accumulating electric fields and power in the pad areas, affecting the measurement characteristics and performance of the antenna chip. To remove this excess energy, the resistor 290 is connected to ground pads 30 and 40. Here, the resistor 290 is connected to pad areas 33 and 43. The resistor 290 has a higher resistivity than ground pads 30 and 40. The resistor 290 improves the performance of the antenna chip by reducing the S11 characteristics.
[0050] Although the present invention has been described above with reference to embodiments and modifications, the present invention is not limited to the above embodiments and modifications. For example, the present invention includes various modifications to the above embodiments and modifications that can be understood by those skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above embodiments and modifications can be combined as appropriate to the extent that they do not contradict each other. [Explanation of symbols]
[0051] 10...Antenna chip, 20...Substrate, 21...First main surface, 22...Second main surface, 30...Ground pad, 31~33...Pad area, 35...Part, 40...Ground pad, 41~43...Pad area, 45...Part, 50...Signal pad, 60...Signal line, 70...Antenna, 71~72...Antenna patch, 80...Ground plane, 81~83...Rectangular section, 91~94...Via, 100...Antenna chip, 170...Vivaldi antenna, 190...Processing circuit, 290...Resistor, 952...3-point probe, 952A...Signal probe, 952B~952C...Ground probe, 953...Probe antenna, 991...Signal pad, 992~993...Ground pad, B1~B2...Boundary, CPW1~CPW2...Coplanar waveguide, G...Gap, G1~G3...Gap, PT...Radiation pattern, R...Area.
Claims
1. A substrate having a first main surface, A first ground pad and a second ground pad are formed on the first main surface and are arranged in a first direction perpendicular to the thickness direction of the substrate with a gap between them, wherein the gap includes a first gap and a second gap extending from the first gap in a second direction perpendicular to the thickness direction and different from the first direction, A signal pad formed on the first main surface and located within the first gap, A first antenna patch formed on the first main surface, located outside the gap, and constituting at least a part of the antenna, The device comprises a signal line formed on the first main surface, extending from the signal pad in the second direction and passing through the second gap, and configured to transmit an electrical signal input to the signal pad to the first antenna patch, The first boundary between the first ground pad and the first gap has the shape of a part of a circular or regular n-gon (where n is an even number of 6 or more) contour line concentric with the signal pad. The second boundary between the second ground pad and the first gap has the shape of a part of the contour line of a circular or regular m-sided polygon (where m is an even number of 6 or more) concentric with the signal pad. Antenna chip.
2. The signal pad is circular, The first boundary has the shape of a first circular arc that is concentric with the signal pad and has a larger diameter than the signal pad, The second boundary has the shape of a second arc of the large-diameter circle that is opposite to the first arc. The antenna chip according to claim 1.
3. The substrate further comprises a ground plane formed on the second main surface, which is the back surface of the first main surface, The ground plane is formed in a shape that covers the first coplanar waveguide from the second main surface side, which includes a signal line passing through the second gap and parts of the first and second ground pads, respectively, arranged in the first direction with a gap between them. The antenna chip according to claim 1.
4. The ground plane is formed in a shape that avoids the second coplanar waveguide, which includes the signal pad and parts of the first and second ground pads, respectively, arranged in the first direction with a first gap between them, when viewed from the thickness direction. The antenna chip according to claim 3.
5. One or more first vias penetrate the substrate and electrically connect the ground plane and the first ground pad, The system further comprises one or more second vias that penetrate the substrate and electrically connect the ground plane and the second ground pad. The antenna chip according to claim 3.
6. The second main surface further comprises a second antenna patch formed thereon and electrically connected to the ground plane, The first antenna patch and the second antenna patch constitute an antipodal Vivaldi antenna. The antenna chip according to claim 3.
7. The system further comprises a processing circuit located between the signal line and the first antenna patch, configured to process the electrical signal transmitted from the signal line to the first antenna patch. The antenna chip according to claim 1.
8. The system further comprises resistors having a first end and a second end connected to the first ground pad and the second ground pad, respectively. The antenna chip according to claim 1.