Composite antenna unit and array antenna thereof

Abstract

The present invention relates to a composite antenna unit and an array antenna thereof. The antenna of the present invention is a three-layer structure composed of a patch antenna and a slot antenna. The first layer is a patch antenna with a resonance condition of half a wavelength, the second layer is a slot antenna with a resonance condition of half a wavelength, and the third layer is a transmission line and a feeding point position. The entire composite antenna unit is coupled to achieve a resonance condition, and a signal is fed from the transmission line to the slot antenna in a coupled form, and the slot antenna signal is coupled once more to the patch antenna. The composite array antenna has good antenna gain performance, and greatly improves the antenna bandwidth compared to a single patch antenna or a single slot antenna.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to a composite antenna unit and a composite array antenna. Background Art

[0002] With the advancement of mobile communication technology, mobile phones, PADs, laptops, and other electronic products have become indispensable in our lives. These products have been upgraded to include antenna systems to enhance their communication capabilities. As the required transmission speeds and throughput increase significantly, the frequencies used for signal transmission are also increasing. Devices or technologies with higher transmission speeds and throughput tend to utilize frequencies in the GHz band, or millimeter wave region. Therefore, millimeter waves will be the primary next-generation communication technology, now known as 5G systems.

[0003] 5G is a global research and development focus. Millimeter-wave antennas, with their high carrier frequency and wide bandwidth, are crucial for achieving 5G's ultra-high data rates. Millimeter-wave antenna design requires high directivity and high gain, but current technologies, such as single patch antennas and slot antennas, suffer from narrow bandwidth.

[0004] In addition, the conventional FR4 (Flame Retardant 4) substrate generally operates at frequencies below 10 GHz and is not suitable for high-frequency antenna design due to excessive loss. Summary of the Invention

[0005] The present invention aims to provide a device with wide bandwidth coverage to improve the problem of narrow bandwidth. The invention uses a combined patch antenna and slot antenna structure to improve the problem of excessively narrow bandwidth of a single patch antenna or a single slot antenna.

[0006] Another object of the present invention is to provide a 1×4 array antenna with a combined patch antenna and slot antenna architecture using an LCP (liquid crystal polymer) material as a substrate. LCP (liquid crystal polymer) material has the characteristics of low loss, low water absorption, and plasticity, providing excellent properties for antenna design.

[0007] On the one hand, the present invention provides a composite antenna unit, comprising: a first substrate having an upper surface and a lower surface opposite to the upper surface; a patch antenna disposed on the upper surface of the first substrate, and the patch antenna has a resonance condition of half a wavelength; a second substrate having an upper surface and a lower surface opposite to the upper surface, and having a blind hole serving as a feeding point; a slot antenna formed by a metal layer having a slit disposed between the upper surface of the second substrate and the lower surface of the first substrate, and the slot antenna has a resonance condition of half a wavelength; a transmission line disposed on the lower surface of the second substrate, the transmission line corresponding to the blind hole, and used to couple a signal to feed into the slot antenna; the entire composite antenna unit uses coupling to achieve a resonance condition, wherein a signal is fed by the transmission line to the slot antenna in a coupled manner, and the slot antenna signal is further coupled to the patch antenna.

[0008] In one embodiment of the present invention, the slot of the slot antenna and the transmission line are perpendicular to each other.

[0009] In one embodiment of the present invention, the patch antenna is composed of two patch antenna units with half-wavelength resonance conditions and a line segment connecting the patch antenna units, wherein the position of the line segment is aligned with one end edge of the slot of the slot antenna.

[0010] In one embodiment of the present invention, the patch antenna unit may be a patch antenna with a similar geometric shape such as square, rectangular, circular, elliptical, triangular, sector, ring or ring sector.

[0011] In one embodiment of the present invention, the position where the transmission line feed is coupled to the slot antenna is 0.26 wavelengths away from the center of the slot.

[0012] In one embodiment of the present invention, the first substrate and the second substrate are liquid crystal polymer material substrates.

[0013] On the other hand, the present invention provides a composite array antenna, comprising a 1×4 array antenna implemented by any one of the composite antenna units described above.

[0014] In one embodiment of the present invention, the overall thickness of the 1×4 array antenna is 400 um, and the operating frequency band is 27.4 GHz to 30 GHz.

[0015] In one embodiment of the present invention, the 1×4 array antenna includes a feeding network. The feeding network is a one-to-four feeding network and is located on the same layer as the transmission line.

[0016] In one embodiment of the present invention, the metal layer used to form the slot antenna is used as a reference ground. A plurality of blind vias are formed through the second substrate to connect the metal layer to the feed network layer. A metal surface is provided on the same layer of the feed network as an extension of the reference ground.

[0017] The advantage of this invention lies in the use of a combined patch antenna and slot antenna within the antenna unit architecture. The resonant condition for the patch and slot antennas is half-wavelength resonance. This composite patch and slot antenna architecture can improve the narrow bandwidth of a single patch or slot antenna. The antenna exhibits excellent antenna gain and significantly increases antenna bandwidth compared to a single patch or slot antenna.

[0018] This invention also proposes designing a 1×4 27.4-30 GHz array antenna using a combination of patch and slot antennas. The frequency bands are provided by the patch antenna, the slot antenna, and the path between the patch and slot antennas, respectively. This increases the bandwidth, compensating for the insufficient bandwidth of single patch and slot antennas. The antenna substrate is made of liquid crystal polymer (LCP), which boasts low loss and low water absorption, providing excellent antenna design characteristics. The antenna has a center frequency of 28.89 GHz, a bandwidth of 8.78%, and good return loss. The array antenna achieves a gain of 10.7 dBi. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the exploded three-dimensional structure of the composite antenna unit provided by an embodiment of the present invention.

[0021] Figure 2 A schematic diagram of the combined structure and stacking structure of the composite antenna unit provided in an embodiment of the present invention.

[0022] Figure 3 A schematic diagram comparing the patch antenna, slot antenna, and S-parameters of the composite antenna unit provided in an embodiment of the present invention.

[0023] Figure 4 Schematic diagram of current distribution in three modes of the composite antenna unit provided by an embodiment of the present invention.

[0024] Figure 5 A schematic diagram of the real impedance of the combined structure of the composite antenna unit provided in an embodiment of the present invention.

[0025] Figure 6 A schematic diagram of the combined structure and stacked structure of the composite antenna units in an array manner provided by an embodiment of the present invention.

[0026] Figure 7 A schematic diagram of the frequency response of an array of composite antenna units provided by an embodiment of the present invention.

[0027] Figure 8 A schematic diagram of 3D radiation patterns of antenna gain in three modes of an array of composite antenna units provided in an embodiment of the present invention.

[0028] Description of main component symbols:

[0029] 100 is a composite antenna unit; 110 is a patch antenna; 111 and 112 are patch antenna units; 113 is a line segment; 120 is a first substrate; 121 is an upper surface; 122 is a lower surface; 130 is a slot antenna; 131 is a metal layer; 132 is a slit; 140 is a second substrate; 141 is an upper surface; 142 is a lower surface; 143 is a blind hole; 150 is a transmission line; 201 is a first mode; 202 is a second mode; 203 is a third mode; 300 is a composite array antenna; 310 is a feed network; 320 is a blind hole; 330 is a metal surface. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The accompanying drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention. Therefore, only components related to the present invention are marked in these drawings, and the components shown are not drawn based on the number, shape, size ratio, etc. during implementation. The specifications and dimensions during actual implementation are actually a selective design, and the component layout may be more complex.

[0031] The following descriptions of the various embodiments refer to the accompanying drawings and are used to illustrate specific embodiments of the present invention. Directional terms mentioned in the present invention, such as "upper" and "lower", refer only to the directions in the accompanying drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, rather than to limit the present invention. In addition, in the specification, unless explicitly described as relative, the word "comprising" will be understood to mean including the components stated, but not excluding any other components.

[0032] See also Figure 1 and Figure 2The present invention discloses a composite antenna unit 100, for example, comprising: a first substrate 120 having an upper surface 121 and a lower surface 122 opposite to the upper surface 121; a patch antenna 110 disposed on the upper surface 121 of the first substrate 120, and the resonance condition of the patch antenna 110 is half a wavelength; a second substrate 140 having an upper surface 141 and a lower surface 142 opposite to the upper surface 141, and having a blind hole 143 as a feeding point; a The slot antenna 130 is formed by a metal layer 131 disposed between the upper surface 141 of the second substrate 140 and the lower surface 122 of the first substrate 120, having a slit 132. The resonant condition of the slot antenna 130 is half a wavelength. A transmission line 150 is disposed on the lower surface 142 of the second substrate 140, corresponding to the blind via 143, for coupling and feeding into the slot antenna 130. The slit 132 and the transmission line 150 are perpendicular to each other. The entire composite antenna unit 100 achieves resonance through coupling. Signals fed through the transmission line 150 are coupled to the slot antenna 130, which then couples the signal from the slot antenna 130 to the patch antenna 110.

[0033] In this embodiment, the patch antenna 110 comprises two patch antenna elements 111 and 112 that resonate at half the wavelength, and a line segment 113 connecting the patch antenna elements 111 and 112. The line segment 113 is aligned with one edge of the slot 132 of the slot antenna 130. In addition to the rectangular shape shown in the drawings of this embodiment, the patch antenna elements 111 and 112 may also have a similar geometric shape, such as a square, rectangular, circular, elliptical, triangular, sector-shaped, annular, or annular sector-shaped.

[0034] In this embodiment, the position where the transmission line 150 is fed into and coupled with the slot antenna 130 is 0.26 wavelengths away from the center of the slot 132 .

[0035] The first substrate 120 and the second substrate 140 can be made of an epoxy resin, a polyoxylene resin, a fluorine-based resin, or a liquid crystal polymer. Liquid crystal polymers are the most suitable substrate material for current applications. Liquid crystal polymers have low loss, low water absorption, and plasticity, making them suitable for high-frequency antenna design.

[0036] The composite antenna unit 100 of this embodiment combines a patch antenna 110 and a slot antenna 130, forming a three-layer structure with a thickness of 400 μm. The first layer is the patch antenna 110, which resonates at half a wavelength. The second layer is the slot antenna 130, which resonates at half a wavelength. The third layer is the transmission line 150. The antenna achieves resonance using coupling. Signals are fed from the third layer and coupled to the second layer. The second layer's signals are then coupled back to the first layer.

[0037] See also Figure 3 From this frequency response graph, we can see that at 28 GHz, the composite antenna unit 100 design, which combines patch antenna 110 and slot antenna 130, exhibits three modes. This compares to the single frequency response mode (A) of a single patch antenna or the single frequency response mode (B) of a single slot antenna. The present invention significantly improves bandwidth by combining patch antenna 110 and slot antenna 130, increasing the number of frequency response modes (C) within the frequency band from one to three.

[0038] See also Figure 4 and Figure 5 The three modes of the composite antenna unit 100 can be used to determine the resonance position of the current distribution diagram. The first mode 201 (such as Figure 5 (a) is provided by the patch antenna 110 of the first layer (at a frequency of 27.45 GHz), the second mode 202 (as shown in FIG. Figure 5 (b) is provided by the slot antenna 130 of the second layer (at a frequency of 28.80 GHz), the third mode 203 (as shown in FIG. Figure 5 (c) shows a coupling path provided between the patch antenna element 111 of the patch antenna 110 of the first layer and the slot 132 of the slot antenna 130 of the second layer (at a frequency of 30.02 GHz).

[0039] See also Figure 4 From the frequency response diagram, it can be seen that at 28 GHz, the real impedance of the composite antenna unit 100, which uses a combination of the patch antenna 110 and the slot antenna 130, is approximately 50 ohms in the antenna band. This indicates that the antenna impedance and the feed impedance have good impedance matching, which can reduce the reflection of energy in the antenna line.

[0040] See also Figure 6Another embodiment of the composite antenna of the present invention increases antenna gain by designing the antenna in an array configuration. The composite array antenna 300 of this embodiment includes a 1×4 array antenna implemented by the composite antenna unit 100 described above. The 1×4 array antenna is constructed using LCP material and has an overall thickness of 400 μm. The antenna structure described above for the composite antenna unit 100 comprises the first and second layers, with a third layer including a feed network 310. The operating frequency band is 27.4 GHz to 30 GHz.

[0041] The feeding network 310 of the 1×4 array antenna in this embodiment is a one-to-four feeding network 310 , and is located on the third layer together with the transmission line 150 .

[0042] In practice, the metal layer 131 used to form the slot antenna 130 serves as the reference ground (ground plane). Therefore, multiple blind vias 320 are formed in the second substrate 140, connecting the metal layer 130 to the third layer where the feed network 310 resides. A metal surface 330 is provided on this third layer, serving as an extension of the reference ground. The feed method is transformed from three-dimensional to planar, and the feed point can be designed differently based on the requirements of the feed adapter.

[0043] The antenna is connected to a feed network 310 using a 1×4 pattern. Considering the feed measurement requirements, the feed point and the reference ground must be designed on the same plane. The reference ground is connected from the second layer to the third layer via a blind via 320. A metal surface 330 connected to the blind via 320 is added to the third layer as an extension of the reference ground to meet the actual antenna measurement requirements.

[0044] The antenna of the combined array antenna 300 of this embodiment uses liquid crystal polymer (LCP) material as a substrate. The LCP material has low loss and is not easily deformed due to its low water absorption.

[0045] See Figure 7 , is a frequency response diagram of the 1×4 mode combined array antenna 300 of the present invention. There are three modes in the antenna frequency band, so the bandwidth is increased, as mentioned above. The center frequency of the antenna is 28.69 GHz, the bandwidth is 8.78% and it has good return loss. The array antenna gain can reach 10.7 dBi. Figure 8 As shown ((a) 27.68GHz, (b) 28.89GHz, (a) 29.66GHz).

[0046] In summary, one embodiment of the present invention utilizes a combined patch antenna and slot antenna within the antenna unit architecture. The resonant condition for the patch and slot antennas is half-wavelength resonance. This combined patch and slot antenna architecture improves the limited bandwidth of a single patch or slot antenna. The antenna exhibits excellent antenna gain and significantly improves antenna bandwidth compared to a single patch or slot antenna.

[0047] Another embodiment of the present invention proposes a 1×4 27.4-30 GHz array antenna designed using a combination of patch antennas and slot antennas. The frequency bands are provided by the patch antennas, the slot antennas, and the path between the patch and slot antennas, respectively. This increases the bandwidth, compensating for the insufficient bandwidth of single patch and slot antennas. The antenna uses a liquid crystal polymer (LCP) substrate, which features low loss and low water absorption, providing excellent design characteristics. The antenna has a center frequency of 28.69 GHz, a bandwidth of 8.78%, and good return loss. The array antenna can achieve a gain of 10.7 dBi.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A composite antenna unit, characterized in that: include: A first substrate having an upper surface and a lower surface opposite to the upper surface; A patch antenna is disposed on the upper surface of the first substrate, and the resonance condition of the patch antenna is half wavelength; the patch antenna is composed of two patch antenna units with half wavelength resonance condition and a connecting line segment connecting the patch antenna units; A second substrate having an upper surface and a lower surface opposite to the upper surface, and having a blind hole as a feeding point; A slot antenna, formed by a metal layer disposed between the upper surface of the second substrate and the lower surface of the first substrate having a slit, and the resonance condition of the slot antenna is half a wavelength; wherein the position of the connecting line segment of the patch antenna is aligned with an edge of one end of the slit of the slot antenna; A transmission line is disposed on the lower surface of the second substrate, and the transmission line corresponds to the blind hole and is used for coupling a signal to be fed into the slot antenna; The entire composite antenna unit uses coupling to achieve resonance conditions. The signal is fed from the transmission line and coupled to the slot antenna. The slot antenna signal is then coupled to the patch antenna.

2. The composite antenna unit according to claim 1, characterized in that: The slot of the slot antenna and the direction of the transmission line are perpendicular to each other.

3. The composite antenna unit according to claim 1, wherein: The patch antenna unit may be a patch antenna with a similar geometric shape such as square, rectangular, circular, elliptical, triangular, sector, ring or ring sector.

4. The composite antenna unit according to claim 1, wherein: The position where the transmission line feeds into and couples with the slot antenna is 0.26 wavelengths away from the center of the slot.

5. The composite antenna unit according to claim 1, wherein: The first substrate and the second substrate are liquid crystal polymer material substrates.

6. A composite array antenna, characterized in that: A 1×4 array antenna implemented by the composite antenna unit according to any one of claims 1-5.

7. The composite array antenna according to claim 6, wherein: The overall thickness of the 1×4 array antenna is 400um and the operating frequency band is 27.4GHz to 30GHz.

8. The composite array antenna according to claim 6, wherein: The 1×4 array antenna includes a feeding network, which is a one-to-four feeding network and is in the same layer as the transmission line.

9. The composite array antenna according to claim 8, wherein: The metal layer used to form the slot antenna is used as a reference ground, and a plurality of blind holes are formed by the second substrate, and the metal layer is connected to the feeding network layer. The same layer of the feeding network is provided with a metal surface as an extension of the reference ground.

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