Broadband dual-polarized antenna element and interleaved antenna array

Abstract

A multiband antenna element is provided having a stacked pair of first and second low-band patch antenna elements for operation on both a low-band and a high-band, and a high-band patch antenna element. An L-shaped probe in a multi-band antenna is configured to parasitically excite a high-band patch antenna element. A linear slot in the second low-band patch antenna element is configured to resonate in a high-band.

Description

Cross-references to related applications

[0001] This application claims priority and benefit to U.S. non-provisional patent application No. 18 / 490283, filed October 19, 2023, the entire contents of which are incorporated herein by reference, as fully set forth below and for all applicable purposes. Technical Field

[0002] This disclosure relates generally to antennas, and more specifically to broadband dual-polarized antenna elements and interleaved antenna arrays. Background Technology

[0003] Patch antennas are a convenient and relatively low-cost method for millimeter-wave applications. In a patch antenna, the electric field strength is maximum at the edges of the patch and zero at the center. The electric field lines between the ground plane and the radiating patch antenna will therefore bend or bulge beyond the edges of the patch antenna, producing what is represented as an edge field. Due to the edge field, the effective size of the patch antenna is larger than the actual patch size alone. Although patch antennas are a convenient and relatively low-cost antenna architecture, the edge field radiation from patch antennas can result in a relatively narrow bandwidth.

[0004] The narrow bandwidth of patch antennas can be problematic for use in wireless systems employing these antennas in millimeter-wavelength (mmW) spectrum, such as the 24 GHz to 48 GHz band used in the 5G NR high-frequency band (also known as FR2), although higher frequencies can be used. To cover the entire FR2 band using patch antennas, multiple antenna arrays may be required, each dedicated to a specific subset of the FR bandwidth, but this increases manufacturing costs and could potentially require excessive space in mobile devices. Alternatively, interleaved patch antennas can be used on different substrate stacks, which again increases manufacturing costs. Summary of the Invention

[0005] The following summary discusses some aspects of this disclosure to provide a basic understanding of the techniques under discussion. This summary is not an exhaustive overview of all the intended features of this disclosure, and is neither intended to identify key or essential elements of all aspects of this disclosure, nor to define the scope of any or all aspects of this disclosure. The sole purpose of this summary is to present, in a general form, some concepts of one or more aspects of this disclosure as a prelude to the more detailed description that follows.

[0006] According to one aspect of this disclosure, a multi-band antenna element is provided, comprising: a ground plane; a first patch antenna element adjacent to the ground plane; a first L-shaped probe including a first via and a first feed portion, wherein the first via extends from the ground plane to the first feed portion, the first patch antenna element is positioned between the first feed portion and the ground plane, and a plane defined by the first feed portion is orthogonal to the first via; a second patch antenna element, wherein the first feed portion is positioned between the second patch antenna element and the first patch antenna element, and wherein the first L-shaped probe is configured to parasitically excite the second patch antenna element; and a third patch antenna element including a first linear slot, wherein the second patch antenna element is positioned between the third patch antenna element and the first feed portion, the first patch antenna element is configured to parasitically excite the third patch antenna element, and the second patch antenna element is configured to parasitically excite the first linear slot.

[0007] According to another aspect of this disclosure, a multi-band antenna operation method is provided, the method comprising: exciting a first low-frequency band patch antenna to resonate at a first frequency within a low-frequency band; parasitically exciting a second low-frequency band patch antenna to resonate at a second frequency within a low-frequency band in response to the excitation of the first low-frequency band patch antenna; exciting an L-shaped probe with a high-frequency band signal; parasitically exciting a high-frequency band patch antenna to resonate at a third frequency within a high-frequency band in response to the excitation of the L-shaped probe, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band; and parasitically exciting a slot in the second low-frequency band patch antenna to resonate at a fourth frequency within a high-frequency band in response to the excitation of the L-shaped probe.

[0008] According to another aspect of this disclosure, a linear antenna array is provided, comprising: a plurality of multi-band antenna elements, wherein each multi-band antenna element is configured to transmit and receive in a low-frequency band and in a high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band; and a plurality of high-frequency antenna elements, wherein each high-frequency antenna element is configured to transmit and receive in a high-frequency band, the high-frequency antenna elements and the multi-band antenna elements alternating sequentially across the linear antenna array relative to each other, and the spacing between each high-frequency antenna element and adjacent multi-band antenna elements is set according to a maximum scan angle less than or equal to 90 degrees, wherein the scan angle is defined relative to the normal to the plane of the linear antenna array.

[0009] Other aspects, features, and embodiments of this disclosure will be apparent to those skilled in the art after reading the following description of specific exemplary embodiments of the disclosure in conjunction with the accompanying drawings. Although features of this disclosure may be discussed below with respect to certain embodiments and drawings, all embodiments of this disclosure may include one or more of the advantageous features discussed herein. In other words, while one or more embodiments are discussed as having certain advantageous features, one or more such features may also be used according to the various embodiments of this disclosure discussed herein. Similarly, although exemplary embodiments may be discussed below as embodiments of an apparatus, system, or method, it should be understood that such exemplary embodiments may be implemented in various apparatuses, systems, and methods. Attached Figure Description

[0010] The accompanying drawings are used to further illustrate various specific embodiments and explain the various principles and advantages of this disclosure. In the drawings, the same reference numerals are used throughout individual views to refer to the same or functionally similar elements, and the drawings, together with the following detailed description, are incorporated in and form part of the specification.

[0011] Figure 1 This is a cross-sectional view of an example multiband antenna element according to one aspect of this disclosure.

[0012] Figure 2 This is a plan view of a first low-frequency band patch antenna element for a multi-band antenna element according to one aspect of the present disclosure.

[0013] Figure 3 This is a plan view of a high-frequency patch antenna element for a multi-band antenna element according to one aspect of this disclosure.

[0014] Figure 4 This is a plan view of a pair of L-shaped probes for a multi-band antenna element according to one aspect of this disclosure.

[0015] Figure 5 This is a plan view of a second low-frequency patch antenna element including a slot with a rectangular stub, for use as a multi-band antenna element, according to one aspect of this disclosure.

[0016] Figure 6 This is a plan view of a second low-frequency patch antenna element including a slot with a circular stub, for use as a multi-band antenna element, according to one aspect of this disclosure.

[0017] Figure 7 This is a cross-sectional view of a high-frequency band antenna element according to one aspect of this disclosure.

[0018] Figure 8It is a plan view of a linear antenna array including interleaved multi-band antenna elements and high-frequency band antenna elements according to one aspect of this disclosure.

[0019] Figure 9 This is a flowchart of a method for operating a multi-band antenna element according to one aspect of this disclosure.

[0020] The specific embodiments of this disclosure and its advantages can be best understood by referring to the following detailed description. It should be understood that the same reference numerals are used to identify the same elements illustrated in one or more of the figures. Detailed Implementation

[0021] To form a patch antenna, one or more metal layers can be patterned. The metal layers are stacked relative to an intermediate dielectric layer. Patterning each metal layer to form a patch antenna is analogous to patterning metal layers to form leads or other types of conductors in integrated circuit applications. Therefore, patch antennas are a relatively low-cost and convenient antenna architecture for mobile devices. However, as previously noted, edge field radiation from patch antennas typically results in relatively narrow-band performance. This narrow-band performance can be problematic for designing multi-band antenna elements that can provide sufficient performance over a relatively wide frequency band, such as the FR2 band (approximately 24 GHz to 48 GHz).

[0022] Despite the potential narrowband characteristics of patch antennas, this paper discloses a patch-based multi-band antenna element that advantageously provides broadband coverage in both low and high frequency bands. The resulting multi-band antenna element can be advantageously incorporated into a wide variety of communication devices, such as user equipment (UE), base stations, vehicles, customer premises equipment (CPE), etc. As the names of these bands suggest, the center frequency of the low-frequency band is lower than the center frequency of the high-frequency band. More specifically, the lowest frequency of the high-frequency band is higher than the highest frequency of the low-frequency band. The following discussion will refer to a multi-band antenna element designed to provide broadband coverage in the low-frequency band (e.g., 24.25 GHz to 29.5 GHz) of the frequency range 2 (FR2) band and in the high-frequency band (e.g., 37 GHz to 48 GHz) of the FR2 band; however, it should be understood that the multi-band antenna element disclosed herein can be readily adapted to additional frequency bands that are higher or lower than the FR2 band. Regarding the low-frequency band of 24.25 GHz to 29.5 GHz and the high-frequency band of 37 GHz to 48 GHz, it should be noted that the lowest frequency of the high-frequency band is approximately 1.25 times the highest frequency of the low-frequency band. This relatively small spacing between the low-frequency and high-frequency bands presents a challenge in constructing broadband multi-band antenna elements for antenna arrays that can adequately cover both the low-frequency and high-frequency bands. Despite this relatively small spacing, the broadband multi-band antenna elements disclosed herein are advantageously adaptable to both the high-frequency and low-frequency bands.

[0023] This multi-band antenna element not only provides broadband coverage but also enhanced cross-polarization isolation. Therefore, the multi-band antenna element can receive or transmit according to the first linear polarization without significant coupling to a second linear polarization orthogonal to the first linear polarization. Conversely, the multi-band antenna element can receive or transmit according to the second linear polarization without significant coupling to the first linear polarization. In addition to the multi-band antenna element itself, this paper discloses an interleaved antenna array comprising multiple multi-band antenna elements interleaved or alternating with high-frequency band antenna elements. The multi-band antenna elements will now be discussed in more detail, followed by a discussion of the interleaved antenna array.

[0024] The multi-band patch antenna disclosed herein may include a stack of a first patch antenna element, a second patch antenna element, and a third patch antenna element. Each patch antenna element may be formed by patterning a corresponding metal layer. The sizes of the first and third patch antenna elements are configured to resonate at corresponding first and second frequencies within a low-frequency band. The size of the second patch antenna element is configured to resonate at a first frequency within a high-frequency band. The high-frequency band extends from the lowest high-frequency band to the highest high-frequency band. Similarly, the low-frequency band extends from the lowest low-frequency band to the highest high-frequency band, which is frequency-lower than the lowest high-frequency band.

[0025] Since the metal layers are stacked similarly to the layers of a cake, the patch antenna elements have the same stacking. For example, the range of metal layers can be from a first metal layer to a fourth metal layer (excluding the metal layer used for the underlying ground plane). The first metal layer is adjacent to the bottommost dielectric layer that separates the first metal layer from the ground plane layer, although low and high are, of course, a matter of viewing angle. Regarding this stacking, a first patch antenna element can be formed in the first (closest to the bottom) metal layer, while a third patch antenna element can be formed in the fourth (closest to the top) metal layer. Since both the first and third patch antenna elements are sized to resonate at corresponding first and second frequencies within the low-frequency band, the first patch antenna element can also be referred to herein as a first low-frequency band patch antenna element, and the third patch antenna element can also be referred to as a second low-frequency band patch antenna element.

[0026] The resulting stacking of the first and second low-frequency patch antennas, and their respective sizes, provides broadband coverage in the low-frequency band, extending from the lowest frequency to the highest frequency in the low-frequency band. In one embodiment, the first low-frequency patch antenna element can be excited via a first pair of vias directly coupled to it. Each via in the first pair can be considered to form a corresponding port to the first and second low-frequency patch antenna elements. The first pair of vias is positioned such that one via excites the first low-frequency patch antenna element according to a first linear polarization, while the second via excites it according to a second linear polarization orthogonal to the first linear polarization. The second low-frequency patch antenna element is parasiticly excited by the first low-frequency patch antenna element, such that no vias are needed to drive it. Recall that the second low-frequency patch antenna element is formed in a fourth metal layer relatively far from the ground metal layer (the bottom metal layer). Therefore, the parasitic excitation of the second low-frequency patch antenna element is advantageous in terms of avoiding the use of relatively long vias that could couple to the second low-frequency patch antenna element. Such relatively long vias may undesirably act as secondary dipole antennas and also reduce bandwidth due to the parasitic inductance of such relatively long vias.

[0027] Although this document describes a broadband multiband antenna element with four metal layers (excluding a separate ground plane), it should be understood that additional metal layers may be used. However, using only four metal layers is advantageous to reduce construction costs and complexity. Given the expected constraints of four metal layers, similar pairs of stacked patch antennas used to cover high-frequency bands are not used in many examples. For example, suppose a second metal layer in the metal layer stack is used to form a first high-frequency band patch antenna element. Such a high-frequency band patch antenna element may be over-shielded by other structures in the metal layer stack and therefore have too low an antenna gain. Therefore, a second metal layer is used to form a planar feed portion of an L-shaped probe. The L-shape of the L-shaped probe is completed by a corresponding via extending from the ground plane to the planar feed portion. Since the planar feed portion is formed by the second metal layer, it defines a plane that orthogonally protrudes from the corresponding via to form an L-shape. In an alternative embodiment, a similar pair of L-shaped probes may be used to excite a first low-frequency band patch antenna element instead of using a first pair of vias.

[0028] The second metal layer can be patterned to form two feed portions for two corresponding L-shaped probes. Each L-shaped probe is appropriately positioned to excite a corresponding linear polarization in a high-frequency patch antenna element formed in a third metal layer within the metal layer stack. Since the metal layers are stacked sequentially, the second metal layer is above the first metal layer. Similarly, the third metal layer is above the second metal layer. Finally, the fourth metal layer is above the third metal layer. The high-frequency patch antenna element is an example of the second patch antenna element discussed above. The first L-shaped probe in the L-shaped probe parasitically excites the high-frequency patch antenna element to resonate according to a first linear polarization at a first frequency within the high-frequency band. Similarly, the second L-shaped probe in the L-shaped probe parasitically excites the high-frequency patch antenna element to resonate according to a second polarization at a first frequency within the high-frequency band. Therefore, the high-frequency patch antenna element is a dual-polarized high-frequency patch antenna element.

[0029] However, it should be noted that using only dual-polarized high-bandwidth patch antenna elements without further application can result in rather narrow bandwidth performance within the high-frequency band. For example, if the size of the high-bandwidth patch antenna elements is set such that the first frequency in the high-frequency band is relatively close to the lowest frequency in the high-frequency band, operation using only the high-bandwidth patch antenna elements may be unsatisfactory at higher frequencies in the high-frequency band. A second high-bandwidth patch antenna element can be stacked relative to the high-bandwidth patch antenna element, but this may require more than four metal layers. Alternatively, a fourth metal layer can be patterned, with parasitic elements positioned around the second low-bandwidth patch antenna element, and these parasitic elements are sized to resonate at a relatively high second frequency in the high-frequency band. However, such additional elements thus increase the size of the multi-bandwidth antenna element.

[0030] To address this challenge, a second low-band patch antenna element is patterned to have at least one slot antenna configured to resonate at a second frequency within the high-frequency band. For example, the second low-band patch antenna element may include a pair of intersecting linear slots parasitically excited by the high-frequency band antenna and thus sharing the dual-polarized port of that high-frequency band antenna. In this way, an advantageously compact yet high-performance dual-polarized multi-band antenna element is provided.

[0031] exist Figure 1 A cross-sectional view of an example broadband multiband antenna element 100 is shown. The broadband multiband antenna element 100 is formed in a plurality of stacked metal layers, starting with the bottom metal layer. As used herein, the term "metal layer" will be understood to refer to any suitable planar conductive layer and may be formed of deposited metal or conductive film. In the multiband antenna element 100, a ground metal layer 115 (the bottom metal layer) serves as a ground plane for the multiband antenna element 100. Below the ground metal layer 115 may be free space (air) or other components of the component that can be coupled to a communication device. The multiband antenna element 100 spans a first metal layer 120, a second metal layer 125, a third metal layer 130, and a fourth metal layer 135. These metal layers are insulated from each other and supported by corresponding dielectric layers (which may also be represented as substrates), such as a dielectric layer 140 between the ground metal layer 115 and the first metal layer 120.

[0032] The first metal layer 120 is patterned to form a shape such as Figure 2 The first low-frequency patch antenna element 200 is shown in the plan view. The portion of the first metal layer 120 removed by patterning is in... Figure 1 The middle part is shown as a dashed line. Similarly, Figure 1 The similarly removed portions of other metal layers are also shown as dashed lines. In the broadband multiband antenna element 100, the patch antenna element (such as the first low-frequency patch antenna element 200) is a circular patch antenna; however, it should be understood that other patch shapes, such as rectangular patches, square patches, or plus-shaped patches, may be used in alternative embodiments. It should be noted, however, that, as will be further explained herein, circular patches (such as the first low-frequency patch antenna element 200) are advantageously compact in terms of incorporating the broadband multiband antenna element 100 into the antenna array.

[0033] Multiband antenna element 100 is configured for coverage in a low-frequency band different from the high-frequency band. In the following discussion, the low-frequency band extends from 24.25 GHz to 29.5 GHz, while the high-frequency band extends from 37 GHz to 48 GHz. However, it should be understood that such low-frequency and high-frequency band frequencies are merely illustrative, and multiband antenna element 100 can be readily adapted to provide coverage for alternative low-frequency and high-frequency bands. Regarding the low-frequency band, first low-frequency patch antenna element 200 has a diameter sized to resonate at approximately 27.5 GHz. As previously noted, a single patch antenna element (such as the first low-frequency patch antenna element 200) can be relatively narrow-band. Therefore, as will be further explained herein, multiband antenna element 100 includes additional low-frequency patch antenna elements to cover the entire low-frequency band.

[0034] To enable transmission and reception according to the first linear polarization, the first via 145 is coupled to the first low-frequency patch antenna element 200, as can also be achieved in... Figure 1 As seen in the diagram. A suitable transmit line (e.g., a microstrip line, not illustrated) is coupled between via 145 and a transceiver (not illustrated) for transmitting and receiving according to a first linear polarization. Similarly, a second via 205 is coupled to the first low-band patch antenna element 200 for transmitting and receiving according to a second linear polarization orthogonal to the first linear polarization. Another transmit line (not illustrated) is coupled between the second via 205 and the transceiver for transmitting and receiving according to the second linear polarization. Note that circular polarization (both left-hand and right-hand) or elliptical polarization can also be generated by appropriately driving vias 145 and 205. Both vias 145 and 205 are symmetrically displaced relative to the center and edge of the low-band patch antenna element 200. If a line 210 is drawn from the center of the patch to the edge, passing through via 145, and a similar line 215 is drawn from the center to the edge, passing through via 205, then lines 210 and 215 are orthogonal to each other, allowing the corresponding linear polarization to be excited. In one embodiment, the first linear polarization can be vertical, and the second linear polarization can be horizontal; however, it should be understood that other orthogonal polarizations, such as +45 degrees and -45 degrees, can be used in alternative embodiments.

[0035] Similar to patterning the first metal layer 120 to form the first low-frequency patch antenna element 200, the third metal layer 130 can be patterned to form... Figure 3 The high-frequency band patch antenna element 300 is shown in the plan view. Like the first low-frequency band patch antenna element 200, the high-frequency band patch antenna element 300 is a circular patch antenna element; however, it should be understood that other patch topologies, such as square patches, rectangular patches, or plus-shaped patches, may be used in alternative embodiments. See again... Figure 1It should be noted that the third metal layer 130 used to form the high-frequency band patch antenna element 300 is relatively displaced from the first metal layer 120 forming the first low-frequency band patch antenna element 200. If vias are used to drive the high-frequency band patch antenna element 300 in a manner similar to driving the first low-frequency band patch antenna element 200, the resulting via length may cause the via to act as a secondary dipole antenna. Furthermore, such relatively long vias may introduce significant parasitic inductance, thereby limiting the bandwidth. Therefore, the high-frequency band patch antenna element 300 is parasiticly driven. However, in other specific implementations (e.g., with a smaller spacing between the first low-frequency band patch antenna element 200 and the high-frequency band patch antenna element 300), the high-frequency band patch antenna element 300 can be directly driven. The high-frequency band patch antenna element 300 may have a diameter sized to resonate at approximately 45 GHz.

[0036] To provide parasitic drive to the high-frequency patch antenna element 300, the second metal layer 125 is patterned to form a shape such as Figure 4 The rectangular power supply sections 400 and 170 are shown. Figure 4 The high-frequency band patch antenna element 300 is shown in cross-sectional view to illustrate the relationship between rectangular feed sections 400 and 170 and the high-frequency band patch antenna element 300. Rectangular feed sections 400 and 170 may be rounded rectangular feed sections for improved performance. Similar to the alignment of vias 145 and 205 for the first low-frequency band patch antenna element 200, rectangular feed sections 400 and 170 may have a similar orthogonal relationship relative to the high-frequency band patch antenna element 300, such that feed section 400 excites the high-frequency band patch antenna element 300 according to a first linear polarization, while feed section 170 excites the high-frequency band patch antenna element 300 according to a second linear polarization. Each rectangular feed section is driven by a corresponding via. Specifically, via 150 drives feed section 170, as... Figure 1 As shown. The combination of via 150 and feed portion 170 forms an inverted L-shape because via 150 extends vertically, while feed portion 170 extends orthogonally from via 150, due to feed portion 170 being formed within the plane defined by the second metal layer 125. Therefore, the combination of feed portion 170 and via 150 can be represented as an L-shaped probe 180. Similarly, another L-shaped probe 415 is formed by a rectangular feed portion 400 and a corresponding via 410. Referring again... Figure 2 For clarity, openings or holes in the first low-frequency patch antenna element 200 for allowing vias 150 and 410 to pass through the first low-frequency patch antenna element 200 are not shown.

[0037] It is important to note the advantages of the L-shaped probes. As previously noted, the alternative of directly driving the high-frequency patch antenna element 300 with vias could cause the vias to act as secondary dipole antennas due to their relatively long length, as such vias would extend from the ground plane formed by the first metal layer 115 to the third metal layer 130. Furthermore, such relatively long vias can have significant parasitic inductance, which subsequently limits the bandwidth of the high-frequency band. Not only do the use of L-shaped probes 180 and 415 avoid such long vias, but the parasitic capacitance of the rectangular feed sections 400 and 170 can resonate and cancel the parasitic inductance of the corresponding vias 150 and 410. Therefore, the rectangular feed sections 400 and 170 advantageously increase the high-frequency bandwidth.

[0038] The fourth metal layer 135 can be patterned to form, for example, Figure 5 The second low-frequency patch antenna element 500 shown increases the low-frequency bandwidth compared to the bandwidth observed when only the first low-frequency patch antenna element 200 is used. As discussed with respect to other patch antennas, the second low-frequency patch antenna element 500 is a circular patch antenna element; however, it should be understood that other patch topologies, such as rectangular patch antennas, square patch antennas, or plus-shaped patch antennas, may be used in alternative embodiments. To provide coverage in the low-frequency band, the first and second low-frequency patch antenna elements have corresponding diameters, such that one of the patch antenna elements has a lower resonant frequency compared to the other. In the following discussion, it will be assumed that the second low-frequency patch antenna element 500 has a larger diameter, such that the resonant frequency of the second low-frequency patch antenna element 500 is lower than the resonant frequency of the first low-frequency patch antenna element 200. However, it should be understood that in alternative embodiments, the first low-frequency patch antenna element 200 may have a lower resonant frequency. The size of the first low-frequency patch antenna element 200 can be set to resonate at approximately 27.5 GHz, while the size of the second low-frequency patch antenna element 500 can be set to resonate at approximately 25 GHz. The first low-frequency patch antenna element 200 parasitically drives the second low-frequency patch antenna element 500 for combined operation in the low-frequency band. Therefore, the combination of the first low-frequency patch antenna element 200 and the second low-frequency patch antenna element 500 provides coverage from 24.25 GHz to 29.5 GHz, covering the entire low-frequency band.

[0039] To increase the bandwidth of the potential narrowband high-frequency patch antenna 300, a fourth metal layer 135 may be patterned to form smaller parasitic patches surrounding the second low-frequency patch antenna element 500. In this specific implementation, the second low-frequency patch antenna element 500 may be a rectangular patch antenna element. However, the smaller surrounding parasitic patches would increase the overall size of the multi-band antenna element 100, which may be undesirable for integrating the multi-band antenna element 100 into an antenna array. To maintain the compact size of the multi-band antenna element 100, the second low-frequency patch antenna element 500 is therefore configured with horizontally aligned linear slots 505 and vertically aligned linear slots 510, which together extend the bandwidth of the high-frequency band. More generally, slots 505 have a longitudinal axis orthogonal to the longitudinal axis of slots 510. Each slot 505 and 510 may be centrally symmetrical with respect to the second low-frequency patch antenna 500.

[0040] It should be noted that the resonant frequency of the slot antenna varies with the longitudinal length of the slot. Since the size of the high-frequency band patch antenna element 300 can be set to resonate at 45 GHz, the sizes of slots 505 and 510 can be set to extend the coverage at the lower end of the high-frequency band. For example, each slot 505 and 510 can have a certain length to resonate at 39 GHz. Therefore, the second low-frequency band patch antenna element 500 also serves as a pair of high-frequency band slot antenna elements. Compared to the edge field of the patch antenna element, the slot antenna element has an “anti-edge” electric field that is strongest at the center of the slot and weakest at the ends of the slot. The interaction between the edge field of the high-frequency band patch antenna element 300 and the anti-edge field of the slot antenna element advantageously increases the bandwidth of the high-frequency band performance. The longitudinal axis of each slot 505 and 510 is orthogonal to the resulting polarization. For example, if the first polarization is vertical polarization, it can be seen that slot 505 will radiate vertically polarized electromagnetic waves. In this specific implementation, the slit 510 is aligned for the radiation of horizontally polarized electromagnetic waves.

[0041] Another factor limiting performance at the upper edge of the high-frequency band is the parasitic capacitance of the second low-frequency patch antenna element 500. To tune and eliminate this parasitic capacitance, each slot 505 and 510 terminates in an inductive stub (which may also be referred to as a sub-slot) orthogonally aligned to the longitudinal axis of the slot. For example, the upper end of slot 510 is coupled to a rectangular stub 515 having a longitudinal axis orthogonal to the longitudinal axis of slot 510. Similarly, the lower end of slot 510 is coupled to a rectangular stub 520 having a longitudinal axis orthogonal to the longitudinal axis of slot 510. Stubs 515 and 520 are anti-symmetrical, such that stub 515 extends to the right side of slot 510, while stub 520 extends to the left side of slot 510. Similarly, the left end of slot 505 is coupled to a rectangular stub 525 having a longitudinal axis orthogonal to the longitudinal axis of slot 505. Finally, the right end of slot 505 is coupled to a rectangular stub 530 having a longitudinal axis orthogonal to the longitudinal axis of slot 505. Stubs 525 and 530 are aligned in an anti-symmetrical manner, such that stub 525 extends upwards while stub 530 extends downwards. The inductive load from stubs 515 to 530 reduces the bandwidth-limiting effect of parasitic capacitance from the second low-band patch antenna element 500. Furthermore, the stubs extend the dimensions of their respective slots to accommodate the lower-band edges of the high-frequency band (extending performance to 37 GHz). In other examples, there are two stubs extending in opposite directions from the ends of each of slots 505 and 510 (e.g., in a “T” configuration at each end, or an “I” configuration when viewed as a whole).

[0042] It should be understood that the stub does not need to be rectangular, because the shape of the alternative stub implementation can be set to extend orthogonally from the end of the gap in an anti-symmetrical manner. For example, in Figure 6 The image shows an alternative second low-frequency patch antenna element 600. See again... Figure 1The second low-frequency patch antenna element 600 may be patterned by a fourth metal layer 135. The second low-frequency patch antenna element 600 includes a pair of orthogonally aligned slots 605 and 610 arranged in a manner similar to that of the linear slots 505 and 510 in the second low-frequency patch antenna element 500. The upper end of slot 610 is coupled to a circular stub 615 extending orthogonally relative to the longitudinal axis of slot 610. Similarly, the lower end of slot 610 is coupled to a circular stub 620 extending orthogonally relative to the longitudinal axis of slot 510. Stubs 615 and 620 are anti-symmetrical, such that stub 615 extends to the right side of slot 610, while stub 620 extends to the left side of slot 610. Similarly, the left end of slot 605 is coupled to a circular stub 625 extending orthogonally to the longitudinal axis of slot 605. Finally, the right end of slot 605 is coupled to a circular stub 630 extending orthogonally to the longitudinal axis of slot 605. Stubs 625 and 630 are aligned in an anti-symmetrical manner, such that stub 625 extends upward from the longitudinal axis of slot 605, while stub 630 extends downward. The inductive load from stubs 615 to 630 reduces the bandwidth-limiting effect of parasitic capacitance from the second low-frequency patch element 600. Furthermore, the stubs extend the dimensions of their respective slots to accommodate the lower-frequency edge of the high-frequency band (extending performance to 37 GHz). Figure 5 In the example, two short stubs may extend in opposite directions from the ends of each of the slits 605 and 610.

[0043] To achieve the desired resonant frequency, the sizes of various patches, slots, and stubs are set accordingly. In one specific embodiment, the first low-frequency band patch antenna element 200 may therefore have a diameter of 3.2 mm. Similarly, the first low-frequency band patch antenna element 300 may have a diameter of 1.9 mm. Furthermore, the second low-frequency band patch antenna element 500 may have a diameter of 3.3 mm. Slots 505 and 510 may have a length of 2.7 mm and a width of 0.4 mm. Each rectangular stub may have a length of 0.45 mm and a width of 0.35 mm. However, it should be noted that the resonant frequency generated by these characteristics depends on many factors, such as the dielectric constant of the insulating layer in the multi-band antenna element 100. Therefore, it should be understood that these dimensions are merely illustrative.

[0044] Refer again Figure 1 and Figure 2 The fourth metal layer 135 may be adjacent to free space 160 (air). Finally, a non-conductive protective film (or radome) 165 seals the multi-band antenna element 100.

[0045] Linear antenna arrays will now be discussed, in which multiple multi-band antenna elements, as disclosed herein, are interleaved with multiple high-frequency band antenna elements. Each multi-band antenna element in the array may be implemented as discussed for multi-band antenna 100. Figure 7 An example high-frequency band antenna element 700 is shown. For simplicity of construction, the high-frequency band antenna element 700 is implemented using the same layers discussed for the multi-band antenna element 100, and thus includes metal layers 115 to 135, an air layer 160, and a protective film 165. However, since a low-frequency band structure is not required, the first metal layer 120 is patterned away. As similarly discussed for the high-frequency band patch antenna element 300, the first circular high-frequency band patch antenna element 705 ( Figure 3 The third metal layer 130 is formed. Rectangular feed sections 400 and 170 ( Figure 4 The first high-frequency band patch antenna element 705 is formed by a second metal layer 125 and fed by vias 150 and 410 as previously discussed. The second circular high-frequency band patch antenna element 710 is formed by a fourth metal layer 135 in a manner similar to that of the first high-frequency band patch antenna element 705. The stacking of the first high-frequency band patch antenna 705 and the second high-frequency band patch antenna 710, combined with a feed section that cancels coupling from the parasitic inductance of the L-shaped probes, allows the high-frequency band antenna element 700 to serve the entire high-frequency band (e.g., 37 GHz to 48 GHz). Due to the arrangement of the pair of L-shaped probes, the high-frequency band antenna element 700 provides dual-polarized coverage across the high-frequency band.

[0046] The use of circular patch antennas in both multi-band and high-band antenna elements has led to the following: Figure 8 The advantageously compact linear array 800 is shown. The example linear array 800 is formed by an interleaving or alternation of multi-band antenna elements and high-frequency band antenna elements. In this example embodiment, an odd number of multi-band antenna elements are present; however, it should be understood that an even number of multi-band antenna elements may be used in alternative embodiments. In array 800, there are five multi-band antenna elements ranging from a first multi-band antenna element 805 to a fifth multi-band antenna element 825. The use of an odd number of multi-band antenna elements is advantageous with respect to mutual coupling with a third (or central) multi-band antenna element 815. To the left of the central multi-band antenna element 815 are two multi-band antenna elements (first multi-band antenna element 805 and second multi-band element 810) interleaved with two high-frequency band antenna elements 830 and 835. The high-frequency band antenna element 830 is located between the first multi-band antenna element 805 and the second multi-band antenna element 810, while the high-frequency band antenna element 835 is located between the second multi-band antenna element 810 and the third multi-band antenna element 815.

[0047] Therefore, to the left of the third multi-band antenna element 815, there exists an alternating series of two multi-band antenna elements and two high-frequency band antenna elements. A similar alternating series is located to the right of the third multi-band antenna element 815, as formed by the high-frequency band antenna element 840, the fourth multi-band antenna element 820, the high-frequency band antenna element 845, and the fifth multi-band antenna element 825. Thus, it can be seen that the mutual coupling between the central multi-band antenna element 815 and the antenna elements to its left is advantageously symmetrical with the mutual coupling between the central multi-band antenna element 815 and the antenna elements to its right. Each high-frequency band antenna element in array 800 can be implemented as discussed for the high-frequency band antenna 700. Similarly, each multi-band antenna element in array 800 can be implemented as discussed for the multi-band antenna element 100.

[0048] The spacing between adjacent antennas in array 800 will now be discussed. It should be noted that the spacing (which can be represented by the variable d) affects the desired directivity of array 800 in the wide-side direction 850. The wide-side direction 850 is normal to the plane defined by array 800. In this respect, it can be shown that the maximum scan angle θ relative to the wide-side direction 850 is a function of the ratio (d / λ) of the spacing d and the band wavelength λ, as defined by the following equation (1): d / λ ≤ (1 / (1 + │cos(θ│)) Equation (1)

[0049] For example, suppose the maximum scan angle θ is 45 degrees. From equation (1), the ratio d / λ will be less than or equal to approximately 0.585. For this maximum scan angle, the spacing d between adjacent antenna elements in array 800 can be approximately 3 mm. Then, for a maximum scan angle of 45 degrees, the corresponding spacing between consecutive multi-band antenna elements in array 800 will be approximately 6 mm. Assuming that both the high-frequency band antenna elements and the multi-band antenna elements have the same number of input ports (two input ports each for multi-band antenna element 100 and high-frequency band antenna element 700), in some embodiments, the ports to high-frequency band antenna elements 830 and 845 can be terminated. Although array 800 is a linear array, it should be understood that in alternative embodiments, the array can be scaled to form a planar (two-dimensional) array instead. It should be noted that array 800 advantageously provides a relatively optimal array factor in both the low-frequency and high-frequency bands. Furthermore, the directivity obtained for the high-frequency band helps to mitigate the higher propagation loss for the high-frequency band. Furthermore, the use of array 800 enables the aggregation of carriers with any desired bandwidth in both the low-frequency and high-frequency bands. Regarding the FR2 low-frequency and high-frequency bands as defined herein (where the lowest frequency of the high-frequency band is approximately 1.25 times the highest frequency of the low-frequency band), array 800 advantageously provides broadband coverage and an optimized radiation pattern in both the low-frequency and high-frequency bands.

[0050] Now refer to Figure 9 The flowchart discusses an example of a multi-band antenna operation method. The method includes action 900: energizing a first low-band patch antenna to resonate at a first frequency within the low-band. Energizing the first low-band patch antenna element 200 through either via 145 or 205 (each via coupled to a corresponding port) is an example of action 900. The method also includes action 905: parasitically energizing a second low-band patch antenna to resonate at a second frequency within the low-band in response to the energization of the first low-band patch antenna. Parasitically energizing the second low-band patch antenna element 500 in response to the energization of the first low-band patch antenna element 200 is an example of action 905. Furthermore, the method includes action 910: energizing an L-shaped probe with a high-band signal. Energizing either L-shaped probe 180 or L-shaped probe 415 is an example of action 910. Furthermore, the method includes action 915: parasitically exciting a high-frequency patch antenna in response to excitation of an L-shaped probe to resonate at a third frequency within the high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band. Excitation of the high-frequency patch antenna element 300 is an example of action 915. Finally, the method includes action 920: parasitically exciting a slot in a second low-frequency patch antenna in response to excitation of an L-shaped probe to resonate at a fourth frequency within the high-frequency band. Excitation of slot 505 in response to excitation of L-shaped probe 415 is an example of action 920. Similarly, excitation of slot 510 in response to excitation of L-shaped probe 180 is an example of action 920.

[0051] This disclosure will now be outlined in the following example terms. Clause 1. A multi-band antenna element, said multi-band antenna element comprising: Ground level; A first patch antenna element, wherein the first patch antenna element is adjacent to the ground plane; A first L-shaped probe, the first L-shaped probe including a first via and a first feed section, wherein the first via extends from the ground plane to the first feed section, the first patch antenna element is positioned between the first feed section and the ground plane, and the plane defined by the first feed section is orthogonal to the first via. A second patch antenna element, wherein the first feed portion is positioned between the second patch antenna element and the first patch antenna element, and wherein the first L-shaped probe is configured to parasitically excite the second patch antenna element; and A third patch antenna element, the third patch antenna element including a first linear slot, wherein a second patch antenna element is positioned between the third patch antenna element and the first feed section, the first patch antenna element is configured to parasitically excite the third patch antenna element, and the second patch antenna element is configured to parasitically excite the first linear slot. Clause 2. The multiband antenna element according to Clause 1, wherein the first patch antenna element is a first circular patch antenna element having a first diameter, the second patch antenna element is a second circular patch antenna element having a second diameter smaller than the first diameter, and the third patch antenna element is a third circular patch antenna element having a third diameter larger than the second diameter. Clause 3. The multi-band antenna element according to Clause 2, wherein the size of the first diameter is set such that the first patch antenna element resonates at a first frequency in the low-frequency band, and the size of the third diameter is set such that the third patch antenna element resonates at a second frequency in the low-frequency band. Clause 4. The multi-band antenna element according to Clause 3, wherein the second frequency in the low-frequency band is lower than the first frequency in the low-frequency band. Clause 5. The multi-band antenna element according to Clause 3, wherein the second diameter of the second patch antenna element is set such that the second patch antenna element resonates within a first frequency of a high-frequency band, the lowest frequency of the high-frequency band being higher than the highest frequency of the low-frequency band. Clause 6. The multiband antenna element according to Clause 5, wherein the length of the first linear slot is set such that the first linear slot resonates at a second frequency within the high-frequency band. Clause 7. The multi-band antenna element as described in Clause 6, wherein the low-frequency band is the low-frequency band of FR2 and the high-frequency band is the high-frequency band of FR2. Clause 8. The multi-band antenna element according to Clause 6, wherein the first frequency of the low-frequency band is approximately 27.5 GHz and the second frequency of the low-frequency band is approximately 25 GHz. Clause 9. The multiband antenna element according to Clause 6, wherein the first frequency of the high-frequency band is approximately 45 GHz and the second frequency of the high-frequency band is approximately 39 GHz. Clause 10. The multi-band antenna element according to any one of Clauses 1 to 8, wherein the multi-band antenna element further comprises: The second L-shaped probe includes a second via and a second power supply section, wherein the second via extends from the ground plane to the second power supply section, and the second power supply section is located within the plane defined by the first power supply section. Clause 11. The multiband antenna element according to Clause 10, wherein the first L-shaped probe is positioned to parasitically excite the second patch antenna element according to a first linear polarization, and the second L-shaped probe is positioned to parasitically excite the second patch antenna element according to a second linear polarization. Clause 12. The multiband antenna element according to Clause 6, wherein the third patch antenna element further comprises a second linear slot, the second linear slot being positioned to intersect the first linear slot at the center of the third patch antenna element, and wherein the size of the second linear slot is also set to resonate at the second frequency within the high-frequency band. Clause 13. The multi-band antenna element according to Clause 12, wherein the second linear slot is aligned to intersect the first linear slot at a right angle, and the third patch antenna element further comprises: A first stub extends orthogonally from a first end of the first linear gap; A second stub extends orthogonally from the second end of the first linear gap; A third stub extends orthogonally from the first end of the second linear gap; and A fourth stub extends orthogonally from the second end of the second linear gap. Clause 14. The multiband antenna element according to Clause 13, wherein the first stub is antisymmetric relative to the second stub, and the third stub is antisymmetric relative to the fourth stub. Clause 15. The multi-band antenna element according to any one of Clauses 1 to 14, wherein the multi-band antenna element further comprises: A second via, the second via extending from the ground plane to the first patch antenna element; and A third via extends from the ground plane to the first patch antenna element. Clause 16. The multiband antenna element according to Clause 15, wherein the second via is positioned to excite the first patch antenna element according to a first linear polarization, and the third via is positioned to excite the first patch antenna element according to a second linear polarization. Clause 17. The multiband antenna element according to Clause 16, wherein the first linear polarization is orthogonal to the second linear polarization. Clause 18. A multi-band antenna element according to any one of Clauses 1 to 16, wherein the ground plane is adjacent to free space. Clause 19. The multi-band antenna element according to any one of Clauses 1 to 18, wherein the multi-band antenna element further comprises: An air layer covering the third patch antenna element; and A non-conductive protective film covers the air layer. Clause 20. A method for operating a multi-band antenna, the method comprising: Excite the first low-frequency patch antenna to resonate at a first frequency within the low-frequency band; In response to the excitation of the first low-frequency patch antenna, the second low-frequency patch antenna is parasitically excited to resonate at a second frequency within the low-frequency band; The L-shaped probe is excited using a high-frequency band signal; In response to the excitation of the L-shaped probe, a parasitic high-frequency patch antenna is parasitically excited to resonate at a third frequency within the high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band; and In response to the excitation of the L-shaped probe, the slot in the second low-frequency patch antenna is parasitically excited to resonate at a fourth frequency within the high-frequency band. Clause 21. The multi-band antenna operation method according to Clause 20, wherein the first frequency in the low-frequency band is greater than the second frequency in the low-frequency band. Clause 22. The multi-band antenna operation method according to Clause 20, wherein the third frequency in the high-frequency band is greater than the fourth frequency in the high-frequency band. Clause 23. A linear antenna array, said linear antenna array comprising: Multiple multi-band antenna elements, wherein each multi-band antenna element is configured to transmit and receive in a low-frequency band and in a high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band; The system includes multiple high-frequency band antenna elements, each configured to transmit and receive on the high-frequency band. The high-frequency band antenna elements and the multi-band antenna elements alternate sequentially across the linear antenna array relative to each other. The spacing between each high-frequency band antenna element and its adjacent multi-band antenna elements is set according to a maximum scan angle less than or equal to 90 degrees, where the scan angle is defined relative to the normal to the plane of the linear antenna array. Clause 24. The linear antenna array as described in Clause 23, wherein the maximum scan angle is approximately 45 degrees and the minimum scan angle is approximately -45 degrees. Clause 25. The linear antenna array as described in Clause 23, wherein each multi-band antenna element comprises: A first patch antenna element, the first patch antenna element being configured to resonate at a first frequency in the low frequency band; A second patch antenna element, the second patch antenna element being configured to resonate at a first frequency in the high-frequency band; and A third patch antenna element is configured to resonate at a second frequency in the low-frequency band, wherein the first frequency of the low-frequency band is greater than the second frequency of the low-frequency band. Clause 26. The linear antenna array according to Clause 25, wherein each multi-band antenna element further comprises: An L-shaped probe is configured to parasitically excite the second patch antenna. Clause 27. The linear antenna array according to Clause 25, wherein the third patch antenna includes a linear slot configured to resonate at a second frequency of the high-frequency band, wherein the first frequency of the high-frequency band is greater than the second frequency of the high-frequency band.

[0052] In some cases, to avoid obscuring the concepts of the described examples, well-known structures and devices are shown in block diagram form. The descriptions herein are provided to enable those skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-band antenna element, the multi-band antenna element comprising: Ground level; A first patch antenna element, wherein the first patch antenna element is adjacent to the ground plane; A first L-shaped probe, the first L-shaped probe including a first via and a first feed section, wherein the first via extends from the ground plane to the first feed section, the first patch antenna element is positioned between the first feed section and the ground plane, and the plane defined by the first feed section is orthogonal to the first via. The second patch antenna element, wherein the first feed portion is positioned between the second patch antenna element and the first patch antenna element, and wherein the first L-shaped probe is configured to parasitically excite the second patch antenna element; and A third patch antenna element, the third patch antenna element including a first linear slot, wherein a second patch antenna element is positioned between the third patch antenna element and the first feed section, the first patch antenna element is configured to parasitically excite the third patch antenna element, and the second patch antenna element is configured to parasitically excite the first linear slot.

2. The multi-band antenna element according to claim 1, wherein the first patch antenna element is a first circular patch antenna element having a first diameter, the second patch antenna element is a second circular patch antenna element having a second diameter smaller than the first diameter, and the third patch antenna element is a third circular patch antenna element having a third diameter larger than the second diameter.

3. The multi-band antenna element according to claim 2, wherein the size of the first diameter is set such that the first patch antenna element resonates at a first frequency in the low-frequency band, and the size of the third diameter is set such that the third patch antenna element resonates at a second frequency in the low-frequency band.

4. The multi-band antenna element according to claim 3, wherein the second frequency in the low-frequency band is lower than the first frequency in the low-frequency band.

5. The multi-band antenna element according to claim 3, wherein the size of the second diameter of the second patch antenna element is set such that the second patch antenna element resonates within a first frequency of the high-frequency band, wherein the lowest frequency of the high-frequency band is higher than the highest frequency of the low-frequency band.

6. The multiband antenna element according to claim 5, wherein the length of the first linear slot is set such that the first linear slot resonates at a second frequency within the high-frequency band.

7. The multi-band antenna element according to claim 6, wherein the low-frequency band is the low-frequency band of FR2, and the high-frequency band is the high-frequency band of FR2.

8. The multi-band antenna element of claim 6, wherein the first frequency of the low-frequency band is approximately 27.5 GHz, and the second frequency of the low-frequency band is approximately 25 GHz.

9. The multiband antenna element of claim 6, wherein the first frequency of the high-frequency band is approximately 45 GHz, and the second frequency of the high-frequency band is approximately 39 GHz.

10. The multi-band antenna element according to claim 1, wherein the multi-band antenna element further comprises: The second L-shaped probe includes a second via and a second power supply section, wherein the second via extends from the ground plane to the second power supply section, and the second power supply section is located within the plane defined by the first power supply section.

11. The multiband antenna element of claim 10, wherein the first L-shaped probe is positioned to parasitically excite the second patch antenna element according to a first linear polarization, and the second L-shaped probe is positioned to parasitically excite the second patch antenna element according to a second linear polarization.

12. The multiband antenna element of claim 6, wherein the third patch antenna element further comprises a second linear slot, the second linear slot being positioned to intersect the first linear slot at the center of the third patch antenna element, and wherein the size of the second linear slot is also set to resonate at the second frequency within the high-frequency band.

13. The multiband antenna element of claim 12, wherein the second linear slot is aligned to intersect the first linear slot at a right angle, and the third patch antenna element further comprises: A first stub extends orthogonally from a first end of the first linear gap; A second stub extends orthogonally from the second end of the first linear gap; A third stub extends orthogonally from the first end of the second linear gap; and A fourth stub extends orthogonally from the second end of the second linear gap.

14. The multiband antenna element of claim 13, wherein the first stub is antisymmetric relative to the second stub, and the third stub is antisymmetric relative to the fourth stub.

15. The multi-band antenna element according to claim 1, wherein the multi-band antenna element further comprises: A second via extends from the ground plane to the first patch antenna element; and A third via extends from the ground plane to the first patch antenna element.

16. The multiband antenna element of claim 15, wherein the second via is positioned to excite the first patch antenna element according to a first linear polarization, and the third via is positioned to excite the first patch antenna element according to a second linear polarization.

17. The multiband antenna element of claim 16, wherein the first linear polarization is orthogonal to the second linear polarization.

18. The multiband antenna element according to claim 1, wherein the ground plane is adjacent to free space.

19. The multi-band antenna element according to claim 1, wherein the multi-band antenna element further comprises: An air layer that covers the third patch antenna element; and A non-conductive protective film covers the air layer.

20. A method for operating a multi-band antenna, the method comprising: Excite the first low-frequency patch antenna to resonate at a first frequency within the low-frequency band; In response to the excitation of the first low-frequency patch antenna, the second low-frequency patch antenna is parasitically excited to resonate at a second frequency within the low-frequency band; The L-shaped probe is excited using a high-frequency band signal; In response to the excitation of the L-shaped probe, a parasitic high-frequency patch antenna is generated to resonate at a third frequency within the high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band. as well as In response to the excitation of the L-shaped probe, the slot in the second low-frequency patch antenna is parasitically excited to resonate at a fourth frequency within the high-frequency band.

21. The multi-band antenna operation method according to claim 20, wherein the first frequency in the low-frequency band is greater than the second frequency in the low-frequency band.

22. The multi-band antenna operation method according to claim 20, wherein the third frequency in the high-frequency band is greater than the fourth frequency in the high-frequency band.

23. A linear antenna array, the linear antenna array comprising: Multiple multi-band antenna elements, wherein each multi-band antenna element is configured to transmit and receive in a low-frequency band and in a high-frequency band, wherein the lowest frequency of the high-frequency band is greater than the highest frequency of the low-frequency band; The system includes multiple high-frequency band antenna elements, each configured to transmit and receive on the high-frequency band. The high-frequency band antenna elements and the multi-band antenna elements alternate sequentially relative to each other across the linear antenna array. The spacing between each high-frequency band antenna element and its adjacent multi-band antenna elements is set according to a maximum scan angle of less than 90 degrees, where the scan angle is defined relative to the normal to the plane of the linear antenna array.

24. The linear antenna array of claim 23, wherein the maximum scan angle is approximately 45 degrees and the minimum scan angle is approximately -45 degrees.

25. The linear antenna array of claim 23, wherein each multi-band antenna element comprises: A first patch antenna element, the first patch antenna element being configured to resonate at a first frequency in the low frequency band; A second patch antenna element, the second patch antenna element being configured to resonate at a first frequency in the high-frequency band; and A third patch antenna element is configured to resonate at a second frequency in the low-frequency band, wherein the first frequency of the low-frequency band is greater than the second frequency of the low-frequency band.

26. The linear antenna array of claim 25, wherein each multi-band antenna element further comprises: An L-shaped probe is configured to parasitically excite the second patch antenna element.

27. The linear antenna array of claim 25, wherein the third patch antenna element includes a linear slot configured to resonate at a second frequency of the high-frequency band, wherein the first frequency of the high-frequency band is greater than the second frequency of the high-frequency band.

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