Four-frequency-band highly-integrated microwave and millimeter wave common-caliber antenna

Abstract

The invention provides a four-frequency-band highly-integrated microwave and millimeter wave common-caliber antenna which comprises a first metal structure layer, a first dielectric substrate, a second metal structure layer, a second dielectric substrate, a metal large ground layer, a feed dielectric substrate and a feed metal structure layer. The first metal structure layer comprises two rectangular metal patches which are symmetrically arranged, and a metal structure group is arranged between the two rectangular metal patches; rectangular grooves are respectively etched on the two symmetrically arranged rectangular metal patches, metal blind holes are respectively arranged in the rectangular grooves, and the diameters of the metal blind holes in different rectangular grooves are different. The overall section of the antenna is greatly reduced, the overall size is compact, the antenna is more suitable for the terminal equipment integration environment, the common problem that multiple antennas are mutually restrained in an existing microwave and millimeter wave common-aperture antenna is overcome, and the effects of microwave bandwidth improvement and unit mutual coupling remarkable weakening are additionally achieved.

Description

Technical Field

[0001] The present invention relates to the field of microwave and millimeter-wave technologies, and in particular to a four-band highly integrated microwave and millimeter-wave common-aperture antenna. Background Art

[0002] Internet of Things (IoT) terminal devices highly pursue miniaturization and thinness, and the internal space is already very crowded. Moreover, the 5G-A communication requirements not only further increase the number of radio frequency components and antennas but also raise the requirements for antenna performance, which need to support stable connection and high-speed transmission of 1 million devices. Generally speaking, the newly added antennas in 5G-A need to meet the following three key performance requirements: ① covering multiple newly added frequency bands, especially the n78, n79 bands in the Sub-6 GHz band preferentially deployed and the n257, n258, and n260 (37 - 40 GHz) bands in the millimeter-wave band; ② microwave antennas need to meet the low-profile requirement to conform to the development trend of device thinness and support the application of multiple-input multiple-output (MIMO) technology to improve the channel capacity; ③ millimeter-wave antennas need to have beam scanning capabilities to support large-angle stable connection. Obviously, if the antennas for each frequency band are assembled separately, the space-constrained wireless terminal devices will be difficult to bear. The design concept of microwave / millimeter-wave common-aperture antennas effectively integrates the sub-antennas in two spectral ranges, reduces the occupied space, and becomes an important development direction for future terminal antennas.

[0003] Currently, there are mainly three implementation methods for microwave / millimeter-wave common-aperture antennas that have been reported. The first is the stacked arrangement of high- and low-frequency antennas. This type of common-aperture antenna has a relatively high profile, and an air layer needs to be loaded between the antennas to enhance the isolation between frequency bands, making it almost impossible to achieve integrated integration. The second is the embedded layout, that is, embedding millimeter-wave antennas with slightly smaller sizes into large-size microwave antennas. Although this design concept can enable independent design of each sub-antenna, it will inevitably damage the structure of the microwave antenna, resulting in varying degrees of deterioration of the microwave antenna performance compared to its independent operation. The third is the structure reuse-based compatible design, usually reusing part of the structure of one antenna as another antenna or part of it, such as feed structure reuse, edge redundant structure reuse, independent parasitic structure reuse, etc. The implementation of this scheme is often based on the mutual compatibility of dual-band antennas, that is, there is a "dual-band constraint". The sub-antenna structures are closely related, and there are one or more problems such as performance deterioration, difficulty in beamforming for millimeter waves, low flexibility of dual-band frequencies, and difficulty in integration.

[0004] In addition, existing common-aperture antenna solutions can often only achieve dual-band common-aperture integration. The few triple-band / four-band common-aperture antennas are all based on a given dual-band / triple-band antenna structure and then combined with general microwave / millimeter-wave antenna design schemes to complete the integrated construction, resulting in further exacerbation of the aforementioned "constraint" problem. The frequencies of the sub-antennas are almost completely fixed, making it difficult to adapt to diverse frequency and performance requirements in the actual application of terminal devices, and the coverage rate of high-demand frequency bands in 5G-A is insufficient.

[0005] Considering the above key issues, it is necessary to explore a multi-band common-aperture antenna design solution with high integration, high design flexibility, high 5G-A frequency band coverage, and no loss of sub-antenna performance. Summary of the Invention

[0006] The present invention provides a compact and highly integrated four-band microwave and millimeter-wave common-aperture antenna. Based on the design strategy of simultaneous multiplexing of multiple structures, it highly integrates the practical frequency bands required for multiple 5G-A communication needs. Moreover, each sub-antenna promotes each other but realizes relatively independent design and control based on strategies such as orthogonal polarization and orthogonal regulation. Finally, it achieves a microwave / millimeter-wave common-aperture antenna with high multi-band integration, no deterioration of sub-antenna performance, beamforming ability of the millimeter-wave antenna, and high degrees of freedom of the overall solution.

[0007] To achieve the above object, the present invention provides a four-band highly integrated microwave and millimeter-wave common-aperture antenna, which includes a first metal structure layer, a first dielectric substrate, a second metal structure layer, a second dielectric substrate, a metal ground layer, a feeding dielectric substrate, and a feeding metal structure layer;

[0008] The first metal structure layer includes: two symmetrically arranged rectangular metal patches, and a metal structure group is provided between the two rectangular metal patches; rectangular slots are respectively etched on the two symmetrically arranged rectangular metal patches, and metal blind holes are respectively provided in the rectangular slots, and the diameters of the metal blind holes in different rectangular slots are different.

[0009] Further, grounding metal vias are provided on one side of the two symmetrically arranged rectangular metal patches close to the metal structure group; feeding probes are provided on one side of the two symmetrically arranged rectangular metal patches far from the metal structure group.

[0010] Further, the central part of the first metal structure layer is composed of a group of rectangular metal structures with 12 center-loaded grounding vias. The rectangular metal structures form a millimeter-wave antenna array and at the same time serve as a decoupling structure for the microwave MIMO antenna.

[0011] Further, multiple groups of dielectric blocks are respectively provided in the rectangular slots, and each dielectric block is integrally integrated with the first dielectric substrate and the second dielectric substrate through dielectric square bar branches at both ends.

[0012] Further, the number of groups of the dielectric blocks is five groups.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] Based on the design strategy of simultaneous multiplexing of multiple structures, with the broadband self-decoupling two-element MIMO planar inverted-F antenna as the main structure, the wide slots required by the microwave self-decoupling scheme are multiplexed into a nested scenario of a 39 GHz low-coupling millimeter-wave antenna array and a 60 GHz low-coupling millimeter-wave antenna array. Additionally, an antenna in the 28 GHz band is multiplexed as the decoupling structure of the microwave antenna, providing decoupling effects at three frequency points of the microwave antenna. The four-frequency antenna is highly integrated but the design and regulation are relatively independent, and the feeding networks are separated. All three millimeter-wave antennas can achieve independent port feeding to obtain beam scanning effects, and the microwave antenna realizes MIMO applications, with significant improvements in bandwidth and mutual coupling compared to the independent working scenario. In addition, the antennas in the 39 GHz and 60 GHz bands can be flexibly replaced with sub-antennas in other frequency bands based on the design criteria of dielectric antennas. The overall design has the advantages of high integration, multi-band coverage, no deterioration in the performance of sub-antennas, and high design flexibility. Description of the Drawings

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention.

[0016] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the technical field to which the present invention pertains.

[0017] Figure 1 It is a schematic diagram of the structure of a four-band highly integrated microwave and millimeter-wave common aperture antenna in a preferred embodiment of the present invention;

[0018] Figure 2 It is a three-dimensional diagram of the structure of a four-band highly integrated microwave and millimeter-wave common aperture antenna in a preferred embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of the reflection coefficient and coupling coefficient excited by a two-element MIMO microwave planar inverted-F antenna unit in a preferred embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of the reflection coefficient and coupling coefficient of a 4.9 GHz two-element MIMO microwave antenna in a preferred embodiment of the present invention;

[0021] Figure 5 It is a schematic diagram of the simulated radiation pattern (only the left unit is excited) of a 4.9 GHz two-element MIMO microwave antenna in a preferred embodiment of the present invention, (a) the radiation pattern at the first reflection null point, (b) the radiation pattern at the second reflection null point;

[0022] Figure 6Schematic diagram of reflection coefficient, coupling coefficient and gain performance of a 28GHz six-element millimeter-wave array in a preferred embodiment of the present invention;

[0023] Figure 7 Schematic diagram of beam scanning performance of a 28GHz six-element millimeter-wave array in a preferred embodiment of the present invention;

[0024] Figure 8 Schematic diagram of reflection coefficient, coupling coefficient and gain performance of a 39GHz five-element millimeter-wave array in a preferred embodiment of the present invention;

[0025] Figure 9 Schematic diagram of beam scanning performance of a 39GHz five-element millimeter-wave array in a preferred embodiment of the present invention;

[0026] Figure 10 Schematic diagram of reflection coefficient, coupling coefficient and gain performance of a 60GHz five-element millimeter-wave array in a preferred embodiment of the present invention;

[0027] Figure 11 Schematic diagram of beam scanning performance of a 60GHz five-element millimeter-wave array in a preferred embodiment of the present invention. Detailed implementation manners

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Embodiment 1: As Figures 1-11 shown, an embodiment of the present invention discloses a compact four-band highly integrated microwave millimeter-wave common aperture antenna,

[0030] The present invention is a four-band highly integrated mutual coupling improved common aperture antenna, and its antenna structure is as Figure 1As shown in the figure. It mainly consists of a first metal structure layer 1, a first dielectric substrate 2, a second dielectric substrate 3, a metal ground layer 4, a feeding dielectric substrate 5, and a feeding metal layer 6. Among them, in the first metal structure layer 1, two rectangular metal patches 11 are symmetrically distributed along the horizontal direction. Each rectangular metal patch has a row of grounding metal vias 12 at its edge and is etched with a rectangular slot 13. All layer structures above the metal ground layer at the position of the rectangular slot 13 are hollowed out. Each rectangular metal patch 11 serves as the radiation part of the microwave planar inverted-F antenna and is excited by feeding through ports #1 and #2 via a feeding probe 14. The central part of the first metal structure layer is a rectangular metal structure group 15 composed of 12 center-loaded grounding vias 41. This group of structures serves as a six-element millimeter-wave antenna array 1 and also as a decoupling structure for the microwave MIMO antenna. At the reserved slots of the two microwave rectangular patches 11, a group of five cuboid dielectric blocks 32 are respectively embedded. Each dielectric block is integrally integrated with the first dielectric substrate 2 and the second dielectric substrate 3 by using dielectric strip branches 33. Each group of dielectric block structures respectively constitutes a five-element millimeter-wave antenna array. In the second millimeter-wave antenna array, small-diameter metal blind vias 21 are loaded in the first dielectric substrate 2 layer to improve the mutual coupling between antenna elements; in the third millimeter-wave antenna array, large-diameter metal blind vias 22 are loaded in the first dielectric substrate 2 to achieve a reduction in dielectric constant and a change in the dielectric block structure, so as to flexibly control the operating frequency of the third millimeter-wave antenna array. The first, second, and third millimeter-wave antenna arrays are respectively excited by coupling signals fed into through corresponding different-sized first feeding metal slots 51, second feeding metal slots 52, and third feeding metal slots 53 in the metal ground layer 5 from corresponding ports #3 - #8, #9 - #13, #14 - #18.

[0031] In this co-aperture antenna, the microwave two-element planar inverted-F antenna realizes two radiation modes based on wide-slot loading, which are TM 1 / 2,2 and TM 3 / 2,0 modes, and an absolute bandwidth greater than 400 MHz can be obtained. At the same time, as Figure 3, during the operation of the microwave antenna, the two units have low mutual coupling within the entire operating frequency band, which benefits from the realization of three mutual coupling null points within the frequency band. Among them, the first mutual coupling null point is due to the fact that the first millimeter-wave antenna located between the two microwave units is a patch-type structure group with a center-loaded shorted ground via. This structure group exhibits an isotropic radiation pattern centered on the center via within the microwave frequency band and achieves a "notch" effect at the resonant frequency point; the second mutual coupling null point is due to the wide slot loading, which generates two exactly orthogonal radiation modes when a single patch radiates. After the two modes are transmitted through the path, they are in-phase superposed at the coupling unit, so that no induced current is generated on the coupling unit; the third mutual coupling null point is due to the fact that the radiation surface of the first millimeter-wave antenna between the two microwave units in the first metal structure layer forms a quarter-wavelength resonator. When the microwave planar inverted-F antenna radiates, a current is also induced on this resonator and radiation is generated, thereby generating an indirect coupling signal to another microwave unit, which cancels out the direct coupling signal generated by the microwave excitation unit to the coupling unit in the opposite direction.

[0032] In this co-aperture antenna, the millimeter-wave antenna unit 1 located between the two microwave planar inverted-F units not only realizes the above-mentioned "notch" structure function 1 and the quarter-wavelength resonator function 2, but also has good performance when radiating as a six-element millimeter-wave antenna array by itself. Among them, each radiation unit consists of two patch structures with center-loaded ground vias, and there are two radiation modes in total, namely the slot mode and the anti-phase TM 20 mode. The polarization direction of the unit is orthogonal to the microwave antenna, and the operating frequency is controlled by the size of the feeding slot at the corresponding position on the metal ground layer and the size of the patch structure group along the polarization direction. The functions of this antenna in the dual frequency bands can be independently adjusted. Specifically, Figure 1 in, the microwave antenna is polarized along the x direction. At this time, the dual functions of the millimeter-wave antenna in the microwave frequency band can be frequency-adjusted by controlling the size of the relevant structure along the x direction; the array radiation frequency in the millimeter-wave frequency band can be adjusted by controlling the size of the relevant structure along the y direction.

[0033] There is a groove space in each of the two microwave planar inverted-F antenna units. An independent five-element millimeter-wave dielectric resonator antenna array is respectively embedded in this space, and the overall connection with the first and second dielectric substrates is realized by means of thin dielectric strip loading. These two dielectric resonator antenna arrays can freely change the operating frequency based on the design criteria of the dielectric resonator and can be used as the second millimeter-wave antenna and the third millimeter-wave antenna respectively. Assuming that the first millimeter-wave antenna operates at 28 GHz, the second millimeter-wave antenna and 3 can be set to operate in other 5G practical frequency bands. Specifically, taking the case where the second millimeter-wave antenna operates at 39 GHz and the millimeter-wave antenna operates at 60 GHz with a large difference between the two frequency bands as an example, the operating frequency band of the second millimeter-wave antenna is determined by the slot mode and the fundamental mode (i.e., TE 101It consists of (a certain module). If the mutual coupling between units is large, small-diameter metal blind vias 21 can be loaded in the second layer of the first dielectric substrate to interfere with the coupling current, thereby improving the mutual coupling between units. At this time, in order to introduce an additional new frequency band and maintain a certain structural symmetry, the third millimeter-wave antenna can change the longitudinal dimension of the antenna dielectric block and the overall dielectric constant by means of large-diameter metal blind vias 22 in the second layer of the first dielectric substrate, so as to operate in a higher-order resonance mode to maintain radiation, such as TE 122 mode, combined with the slot mode to form a new operating frequency band.

[0034] Under the structure of this co-aperture antenna, the design of the radiators of the four-band antenna is relatively independent, and the feeding of the antennas in all frequency bands is separated. Each unit in the millimeter-wave frequency band can achieve independent port phase control, so they all have the ability of beam scanning. On the other hand, this four-frequency co-aperture antenna can be highly integrated in one body based on the multi-layer printed circuit board (multi-layer PCB) process. Due to the large frequency ratio or far distance interval between frequency bands, they all have good port isolation.

[0035] In this embodiment, the materials of the first and second dielectric substrates are F4B, and the material of the third dielectric substrate is RO4003C. The four-band antennas are respectively a two-element planar inverted-F microwave MIMO antenna at 4.9 GHz, a six-element 28-GHz millimeter-wave antenna array, a five-element 39-GHz millimeter-wave antenna array, and a five-element 60-GHz millimeter-wave antenna array.

[0036] In this embodiment, the simulation results of the matching level and mutual coupling level of the two-element antenna in the microwave 4.9-GHz frequency band are as Figure 4 shown. The center frequency of the antenna in this frequency band is 4.925 GHz, and the 10-dB impedance matching bandwidth is 9.1% (4.7 GHz - 5.15 GHz). The overall mutual coupling level within the matching frequency band is lower than -28.9 dB. Compared with the same-frequency antennas operating independently, both the bandwidth and the mutual coupling between units are significantly improved. Figure 5 The simulation radiation patterns at two reflection null points are shown when one unit of this microwave antenna is excited and the other unit is connected to a matching load. This two-element planar inverted-F antenna has a good spatial radiation pattern.

[0037] In this embodiment, the simulation results of the matching and the coupling and mutual coupling levels between units of the six-element 28-GHz millimeter-wave antenna array are as Figure 6 shown. The center frequency of the antenna in this frequency band is 27.9 GHz, and the 10-dB impedance matching bandwidth is 13.6% (26 GHz - 29.8 GHz). The mutual coupling level between units within the matching frequency band is lower than -17.5 dB, and the array gain within the entire frequency band is greater than 14.2 dBi, with a peak gain of 14.85 dBi. Figure 7 The scanning performance of this array is shown. Taking 3 dBi loss as the evaluation criterion, this array can achieve a scanning range of ±45°.

[0038] In this embodiment, the simulation results of the matching and inter-element coupling and mutual coupling levels of the millimeter-wave 39-GHz five-element antenna array are as follows Figure 8 As shown, the center frequency of the antenna in this frequency band is 38.5 GHz, the 10-dB impedance matching bandwidth is 8% (36.9 GHz - 40 GHz), the inter-element mutual coupling level within the matching frequency band is lower than -17.6 dB, the array gain within the entire frequency band is greater than 10.23 dBi, and the peak gain is 11.83 dBi. Figure 9 The scanning performance of the array is shown. Taking 3 dBi loss as the evaluation criterion, the array can achieve a scanning range of ±55°.

[0039] In this embodiment, the simulation results of the matching and inter-element coupling and mutual coupling levels of the millimeter-wave 60-GHz five-element antenna array are as follows Figure 10 As shown, the center frequency of the antenna in this frequency band is 59.8 GHz, the 10-dB impedance matching bandwidth is 6% (58 GHz - 61.6 GHz), the inter-element mutual coupling level within the matching frequency band is lower than -16.8 dB, the array gain within the entire frequency band is greater than 8.24 dBi, and the peak gain is 11.1 dBi. Figure 11 The scanning performance of the array is shown. Taking 3 dBi loss as the evaluation criterion, the array can achieve a scanning range of ±25°.

[0040] Based on the design strategy of simultaneous multiplexing of multiple structures, the present invention multiplexes a millimeter-wave antenna array to simultaneously serve as a decoupling notch structure and a decoupling resonator for a microwave two-element MIMO planar inverted-F antenna, and multiplexes the self-decoupling structure of the two-element microwave MIMO antenna for the nested scenario of two additional millimeter-wave antennas. Under the premise that multiple sub-antennas do not interfere with each other, the feeding networks are separated, and the performance does not deteriorate, a four-band antenna with high integration is realized, and the microwave antenna additionally obtains a significant performance improvement effect. Finally, the realized microwave-millimeter-wave common-aperture antenna has the advantages of high integration, multi-band coverage, and high design flexibility.

[0041] A column of millimeter-wave antenna arrays in the center of the common-aperture antenna is composed of a patch structure group with a center-loaded grounded via. This structure has dual functional characteristics of notch and quarter-wavelength resonator in the microwave frequency band, and can form pairs of elements to achieve radiation functions in the millimeter-wave frequency band. The functions of the two frequency bands can be independently regulated through the relevant dimensions in two orthogonal directions.

[0042] Each unit of the two-element MIMO microwave planar inverted-F antenna on both sides of the common-aperture antenna has a reserved space with a rectangular groove. After loading this groove space structure, the microwave antenna itself can obtain the self-decoupling characteristic at the center frequency point, and a column of independent millimeter-wave dielectric resonator antenna arrays can be embedded in each of the two microwave planar inverted-F antenna units.

[0043] The two millimeter-wave antenna arrays embedded in the microwave planar inverted-F antenna unit can flexibly set the operating frequency and mode according to the actual application requirements, in accordance with the design criteria of dielectric resonator antennas and by combining metallized blind via loading to change the dielectric constant and size structure.

[0044] If strong element mutual coupling occurs in the millimeter-wave antenna embedded in the microwave planar inverted-F antenna due to the small element spacing, measures such as loading with small-diameter metallized blind vias to interfere with the field distribution are used to improve the mutual coupling, and the mutual coupling suppression effect and frequency are regulated by adjusting the loading position and diameter of the small-diameter metallized blind vias.

[0045] The microwave and millimeter-wave common-aperture antenna is integrated in one piece based on the multi-layer printed circuit board (multi-layer PCB) process. Among them, the two millimeter-wave antennas embedded in the microwave planar inverted-F antenna units are integrally connected by means of thin dielectric strip loading.

[0046] The examples described in the present invention are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design idea of the present invention, various deformations and improvements made by those skilled in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention.

Claims

1. A four-band highly integrated microwave and millimeter-wave common-aperture antenna, characterized in that It includes a first metal structure layer, a first dielectric substrate, a second metal structure layer, a second dielectric substrate, a metal ground layer, a feeding dielectric substrate and a feeding metal structure layer; The first metal structure layer includes: two symmetrically arranged rectangular metal patches, and a metal structure group is provided between the two rectangular metal patches; rectangular grooves are respectively etched on the two symmetrically arranged rectangular metal patches, and metal blind vias are respectively provided in the rectangular grooves and the diameters of the metal blind vias in different rectangular grooves are different.

2. The antenna according to claim 1, characterized in that, Ground metal vias are provided on one side of the two symmetrically arranged rectangular metal patches close to the metal structure group; feeding probes are provided on one side of the two symmetrically arranged rectangular metal patches far from the metal structure group.

3. The antenna according to claim 2, characterized in that, The central part of the first metal structure layer is composed of a group of rectangular metal structures with 12 center-loaded ground vias. The rectangular metal structures form a millimeter-wave antenna array and at the same time serve as a decoupling structure for the microwave MIMO antenna.

4. The antenna according to claim 3, wherein Multiple groups of dielectric blocks are respectively provided in the rectangular grooves, and each dielectric block is integrally integrated with the first dielectric substrate and the second dielectric substrate through dielectric square bar branches at both ends.

5. The antenna according to claim 4, characterized in that The number of groups of the dielectric blocks is five groups.

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