Millimeter wave end-fire antenna unit based on LTCC and phased array antenna

Abstract

The application discloses an LTCC-based millimeter wave end-fire antenna unit and phased array antenna, which comprises a ceramic dielectric group, a ring-shaped radiator and a cavity radiator, wherein a microstrip balun structure is arranged in the ring-shaped radiator, and a tapered microstrip feed line is arranged in the cavity radiator. Two excitation signals are processed by the ring-shaped radiator and the cavity radiator respectively, after mutual superposition of the two excitation signals, the scanning angle of the antenna can be changed by changing the phase difference of the excitation signals, so that the antenna beam can be reconfigured without introducing active switching devices, and the scanning range of the array antenna is further widened. The application relates to the technical field of millimeter wave communication.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of millimeter wave communication, and in particular to a millimeter wave end-fire antenna unit based on LTCC and a phased array antenna. BACKGROUND

[0002] With the rapid development of Internet of Things (IoT) technology, millimeter wave frequency bands have attracted widespread attention due to their abundant spectrum resources and high transmission rates. The application prospect of millimeter wave frequency bands is broad, especially in high-bandwidth communication, autonomous driving, intelligent transportation, and high-definition imaging. However, the high-frequency characteristics of millimeter wave frequency bands result in severe free-space path loss, which poses a challenge to system performance. To address this issue, phased array antennas have become a research hotspot due to their adjustable high-gain beams and effective loss compensation capabilities. Phased array antennas can achieve flexible pointing of beams through electrical control, adapting to rapidly changing signal environments, thereby exhibiting superior performance in millimeter wave communication.

[0003] Achieving wide-angle scanning is one of the main challenges faced by millimeter wave phased arrays. This challenge is particularly evident in end-fire antennas, which have higher profile requirements, making the vertical dimension space-limited, and traditional techniques for expanding array scanning range are difficult to implement effectively. Therefore, the scanning range of most end-fire phased array antennas is usually difficult to exceed ±60°.

[0004] To this end, there are also active switching devices in traditional techniques to change beam patterns and thereby widen the scanning range. However, this approach undoubtedly increases the structural complexity of the antenna and also increases the electrical control difficulty. Therefore, how to widen the scanning range of end-fire phased array antennas and reduce the dependence on active switching devices is a technical problem that needs to be solved in the field of millimeter wave communication. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a millimeter wave end-fire antenna unit based on LTCC, which can passively widen the scanning range of the antenna.

[0006] The present application also proposes a phased array antenna having the above-mentioned millimeter wave end-fire antenna unit based on LTCC.

[0007] The millimeter wave end-fire antenna unit based on LTCC according to the first aspect embodiment of the present application comprises:

[0008] a ceramic dielectric group comprising a plurality of ceramic dielectric layers stacked on each other;

[0009] The annular radiator comprises metal layers and metalized vias, the metal layers and the metalized vias are at least two in number, the metalized vias are connected to the metal layers at the top layer and the bottom layer respectively, and the metal layers and the metalized vias jointly form an annular structure.

[0010] The microstrip balun structure is connected to the metal layer at the bottom layer.

[0011] The cavity radiator comprises a feeding probe and a resonant cavity connected to each other, the feeding probe is used to deliver an electrical signal to the resonant cavity, the resonant cavity comprises a first metal ground and a second metal ground, and the second metal ground is connected to the microstrip balun structure.

[0012] The tapered microstrip feed line is connected to the first metal ground.

[0013] The excitation signals of the annular radiator and the cavity radiator are superimposed on each other, the tilt angle of the superimposed beam can be changed by changing the phase difference of the two excitation signals, and when the phase difference is 0° or 180°, the superimposed beam is tilted to the left or right respectively, and the beam reconfiguration is realized by the phase difference.

[0014] The LTCC-based millimeter wave end-fire antenna unit according to the embodiments of the present application has at least the following beneficial effects: two excitation signals are processed by the annular radiator and the cavity radiator respectively, the tilt angle of the antenna can be changed by changing the phase difference of the excitation signals after the two excitation signals are superimposed on each other, thereby realizing the beam reconfiguration without introducing active switching devices, and further widening the scanning range of the antenna in the phased array.

[0015] According to some embodiments of the present application, the metal layers comprise a first metal layer, a second metal layer, a third metal layer and a fourth metal layer, the metalized vias comprise a first metalized via and a second metalized via, and the two ends of the first metalized via are connected to the first metal layer and the third metal layer respectively, and the two ends of the second metalized via are connected to the second metal layer and the fourth metal layer respectively.

[0016] According to some embodiments of the present application, the metal layers further comprise a fifth metal layer and a sixth metal layer, the metalized vias comprise a third metalized via and a fourth metalized via, and the fifth metal layer and the sixth metal layer are located in the space surrounded by the first metal layer, the second metal layer, the third metal layer and the fourth metal layer; the fifth metal layer is connected to the first metal layer and the second metal layer through two third metalized vias respectively, and the sixth metal layer is connected to the third metal layer and the fourth metal layer through two fourth metalized vias respectively.

[0017] According to some embodiments of the present application, the microstrip balun structure is provided with one input port and two output ports, the distance between the input port and the two output ports is not equal, and a set of differential signals is obtained at the two output ports.

[0018] According to some embodiments of the present application, the resonant cavity further comprises a metalized via sidewall, two ends of the metalized via sidewall are connected to the first metal ground and the second metal ground to achieve electrical connection.

[0019] According to some embodiments of the present application, the first metal ground is provided with a first H-shaped gap, and the second metal ground is provided with a second H-shaped gap opposite to the first H-shaped gap.

[0020] According to some embodiments of the present application, the second metal ground is further provided with an I-shaped gap adjacent to the second H-shaped gap.

[0021] According to some embodiments of the present application, the top and bottom of the ceramic dielectric group are provided with pads.

[0022] The phased array antenna according to the second aspect of the embodiments of the present application comprises the above-mentioned LTCC-based millimeter wave end-fire antenna unit, and a plurality of the LTCC-based millimeter wave end-fire antenna units are arranged side by side.

[0023] The working method for the above-mentioned LTCC-based millimeter wave end-fire antenna unit according to the third aspect of the embodiments of the present application comprises the following steps:

[0024] The differential signals are input to the ring-shaped radiator through the microstrip balun structure, and the signals are input to the cavity radiator through the tapered microstrip feed line;

[0025] The ring-shaped radiator and the cavity radiator have respective excitation ports, and when excited separately, the ring-shaped radiator generates an “∞”-shaped end-fire beam, and the cavity radiator generates an “O”-shaped end-fire beam.

[0026] When the ring-shaped radiator and the cavity radiator are excited simultaneously, by changing the phase difference of the two excitation signals, the direction of the superimposed beam of the ring-shaped radiator and the cavity radiator can be changed, passive control beam reconfiguration is realized, and the scanning range of the phased array is expanded.

[0027] According to the working method of the embodiments of the present application, at least the following beneficial effects are achieved: by changing the phase difference of the excitation signals output to the ring-shaped radiator and the cavity radiator, the direction of the finally superimposed beam can be changed, beam reconfiguration is realized without active switching, and the technical effect of expanding the scanning range of the antenna is achieved.

[0028] Additional aspects and advantages of the application will be made apparent by the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. It should be understood that the drawings are provided for purposes of illustration only and that the present application is not limited to the illustrated embodiments.

[0030] Figure 1 Schematic diagram of relative position of ring-shaped radiators and cavity radiators in the embodiment of the present application;

[0031] Figure 2 Exploded view of the LTCC-based millimeter wave end-fire antenna unit in the embodiment of the present application;

[0032] Figure 3 Schematic diagram of ring-shaped radiators and their feed network structure in the embodiment of the present application;

[0033] Figure 4 Schematic diagram of ring-shaped radiators in the embodiment of the present application;

[0034] Figure 5 Schematic diagram of microstrip balun structure in the embodiment of the present application;

[0035] Figure 6 Schematic diagram of cavity radiators and their probe feed structure in the embodiment of the present application;

[0036] Figure 7 Simulation diagram of two-directional beam patterns realized in the embodiment of the present application;

[0037] Figure 8 Schematic diagram of the phased array antenna in the embodiment of the present application;

[0038] Figure 9 Simulation result diagram of the return loss of the phased array antenna in the embodiment of the present application;

[0039] Figure 10 Simulation result diagram of the beam scanning of the phased array antenna in the embodiment of the present application at 26.5 GHz, 27.5 GHz and 29.5 GHz.

[0040] Reference numerals: 1 - ring radiator, 11 - metal layer, 110 - first metal layer, 111 - second metal layer, 112 - third metal layer, 113 - fourth metal layer, 12 - metallized via, 120 - first metallized via, 121 - second metallized via, 130 - fifth metal layer, 131 - sixth metal layer, 140 - third metallized via, 141 - fourth metallized via, 15 - microstrip balun structure, 151 - input port, 152 - first output port, 153 - second output port, 16 - dielectric section, 2 - cavity radiator, 20 - tapered microstrip feed line, 21 - first metal ground, 22 - second metal ground, 23 - first H-shaped slot, 24 - second H-shaped slot, 25 - I-shaped slot, 26 - feed probe, 27 - metallized via sidewall, 5 - upper pad, 8 - lower pad, 90 - SMPM male joint. DETAILED DESCRIPTION

[0041] Embodiments of the present application are described below in detail with reference to examples thereof as illustrated in the accompanying drawings, in which like or similar elements and / or aspects with the same or similar functions and / or properties are designated by the same reference numerals throughout the drawings. The embodiments described below are examples only, and are merely intended to explain the present application, and should not be understood as limiting the present application.

[0042] In the description of the present application, if the orientation description, such as up, down, front, back, left, right, etc. indicates the orientation or positional relationship shown in the drawings, it is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. is understood as not including the number, above, below, etc. is understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of indicated technical features.

[0044] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0045] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0046] With the rapid development of Internet of Things (IoT) technology, the millimeter wave frequency band has attracted widespread attention due to its rich spectrum resources and high transmission rate. The millimeter wave frequency band has broad application prospects, especially in high-bandwidth communication, autonomous driving, intelligent transportation, and high-definition imaging. However, the high-frequency characteristics of the millimeter wave frequency band result in severe free-space path loss, which poses a challenge to the performance of the system. In order to solve this problem, phased array antennas have become a research hotspot due to their adjustable high-gain beams and effective loss compensation capabilities. Phased array antennas can achieve flexible pointing of beams through electrical control, adapting to rapidly changing signal environments, thereby exhibiting superior performance in millimeter wave communication.

[0047] Achieving wide-angle scanning is one of the main challenges faced by millimeter wave phased arrays. This challenge is particularly evident in end-fire antennas, which have higher profile requirements, making the vertical dimension space limited, and traditional techniques for expanding array scanning range are difficult to effectively implement. Therefore, the scanning range of most end-fire phased array antennas is usually difficult to exceed ±60°.

[0048] To this end, there are also active switching devices in traditional techniques to change the beam pattern and thereby widen the scanning range. However, this approach undoubtedly increases the complexity of the antenna structure and also increases the electrical control difficulty. Therefore, how to widen the scanning range of the end-fire phased array antenna and reduce the dependence on active switching devices is a technical problem that needs to be solved in the field of millimeter wave communication.

[0049] To this end, the present application proposes a millimeter wave end-fire antenna unit and phased array antenna based on LTCC, which processes two excitation signals through ring radiators 1 and cavity radiators 2 respectively. After the two excitation signals are superimposed, the beam tilt angle of the superimposed antenna can be changed by changing the phase difference of the excitation signals, thereby realizing antenna beam reconfiguration without introducing active switching devices and further widening the scanning range of the array antenna.

[0050] In addition, the application also provides a working method of the LTCC-based millimeter wave end-fire antenna unit, which can change the direction of the final superimposed beam by changing the phase difference of the excitation signals output to the annular radiator 1 and the cavity radiator 2, thereby achieving the technical effect of expanding the scanning range of the antenna.

[0051] Embodiment 1

[0052] With reference to Figure 1 , the LTCC-based millimeter wave end-fire antenna unit in the first aspect of the application comprises a ceramic dielectric group, an annular radiator 1 and a cavity radiator 2, wherein the ceramic dielectric group comprises a plurality of layers of ceramic dielectric layers stacked on each other, which constitutes the main structure of the LTCC-based millimeter wave end-fire antenna unit. Figure 3 The annular radiator 1 is provided with a microstrip balun structure 15; with reference to Figure 6 The cavity radiator 2 is provided with a tapered microstrip feed line 20. The ceramic dielectric group comprises a plurality of layers of ceramic dielectric layers stacked on each other, which constitutes the main structure of the LTCC-based millimeter wave end-fire antenna unit. The annular radiator 1 is introduced into a differential signal by the microstrip balun structure 15, and the cavity radiator 2 is introduced into a signal by the tapered microstrip feed line 20. The signals of the two are superimposed to obtain the final antenna beam. By changing the phase difference of the two groups of excitation signals, the direction of the final antenna beam can be changed, thereby expanding the scanning range, and compared with the traditional antenna unit, the structure is simplified while having a wider scanning range.

[0053] Specifically, the ceramic dielectric layer is a Ferro A6M ceramic dielectric layer with a thickness of 0.096 mm and a relative dielectric constant of 5.8. With reference to Figure 2 The number of layers of ceramic dielectric layers in the ceramic dielectric group can be increased or decreased according to actual conditions. In this embodiment, the number of layers of ceramic dielectric layers is 24. The top and bottom of the ceramic dielectric group are provided with pads, wherein the pad located at the top is an upper pad 5, and the pad located at the bottom is a lower pad 8.

[0054] With reference to Figure 3 The annular radiator 1 comprises a metal layer 11 and a metalized via 12. The metalized via 12 penetrates through the plurality of layers of ceramic dielectric layers, and the number of the metal layer 11 and the metalized via 12 is at least two. The two ends of the metalized via 12 are connected to the metal layer 11 located at the top layer and the metal layer 11 located at the bottom layer, respectively. The metal layer 11 and the metalized via 12 jointly constitute an annular structure. The microstrip balun structure 15 is connected to the metal layer 11 located at the bottom layer and is used for conveying signals.

[0055] The whole ring-shaped radiator 1 is located at the edge of the antenna whole dielectric block end-fire, but the end needs to reserve a certain length of dielectric part 16 as a guide dielectric for adjusting the impedance matching of the antenna radiation aperture and the free space contact surface. The ring-shaped radiator 1 constructs a ring-shaped antenna structure in the YOZ plane, and the resonant frequency depends on the circumference of the whole ring-shaped structure, that is, the sum of the lengths of all metal layers 11 and metalized vias 12.

[0056] Specifically, referring to Figure 4 , the metal layer 11 includes a first metal layer 110, a second metal layer 111, a third metal layer 112, and a fourth metal layer 113. The metalized via 12 includes a first metalized via 120 and a second metalized via 121. The two ends of the first metalized via 120 are connected to the first metal layer 110 and the third metal layer 112, respectively, and the two ends of the second metalized via 121 are connected to the second metal layer 112 and the fourth metal layer 113, respectively. Thus, each metal layer 11 and metalized via 12 collectively constitute a ring-shaped structure.

[0057] In order to reduce the antenna volume, the ring-shaped radiator 1 needs to be folded to improve the structural compactness. The metal layer 11 further includes a fifth metal layer 130 and a sixth metal layer 131, and the metalized via 12 includes a third metalized via 140 and a fourth metalized via 141. It is worth noting that the fifth metal layer 130 and the sixth metal layer 131 are located in the space surrounded by the first metal layer 110, the second metal layer 111, the third metal layer 112, and the fourth metal layer 113, and the overall structure is concave. The fifth metal layer 130 is connected to the first metal layer 110 and the second metal layer 111 through two third metalized vias 140, respectively, and the sixth metal layer 131 is connected to the third metal layer 112 and the fourth metal layer 113 through two fourth metalized vias 141, respectively. Through this inwardly recessed folded structure, the width occupied in the horizontal direction can be shortened while maintaining the circumference and height of the whole ring-shaped structure, thereby achieving the effect of miniaturization.

[0058] Referring to Figure 5 , the microstrip balun structure 15 is provided with an input port 151 and two output ports, which are a first output port 152 and a second output port 153. The distance between the input port 151 and the two output ports is not equal, so that the transmission time of the two signals is different, which is used to obtain a set of differential signals at the two output ports.

[0059] Referring to Figure 6 , the cavity radiator 2 includes a feeding probe 26 and a resonant cavity electrically connected to each other. The feeding probe 26 is used to deliver an electrical signal to the resonant cavity, and the resonant cavity includes a first metal ground 21 and a second metal ground 22. The second metal ground 22 is connected to the microstrip balun structure 15, thereby constituting the electrical connection of the cavity radiator 2 and the ring-shaped radiator 1.

[0060] The gradual change microstrip feed line 20 is connected with the first metal ground 21 for feeding signals into the resonant cavity. Inside the resonant cavity, the feed probe 26 constructed by the metalized via generates a transmission signal, which excites the TE10 mode inside the cavity and finally realizes the "O" shaped end-fire beam on the antenna aperture.

[0061] Further, the resonant cavity further comprises a metalized via sidewall 27, the two ends of which are connected to the first metal ground 21 and the second metal ground 22 to realize electrical connection.

[0062] Further, the first metal ground 21 is provided with a first H-shaped slot 23, and the second metal ground 22 is provided with a second H-shaped slot 24 opposite to the first H-shaped slot 23. Moreover, the second metal ground 22 is further provided with an I-shaped slot 25 adjacent to the second H-shaped slot 24. By loading these slots, additional resonant points can be generated for the antenna, thereby expanding the bandwidth of the antenna.

[0063] The excitation signals of the ring-shaped radiator 1 and the cavity radiator 2 are superimposed on each other, and the scanning angle of the superimposed beam can be changed by changing the phase difference of the two excitation signals. The ring-shaped radiator 1 and the cavity radiator 2 have respective excitation ports, and when excited separately, they respectively generate "∞" shaped end-fire beams and "O" shaped end-fire beams. Figure 7 When the two input ports are simultaneously excited and the phase difference between them is 0°, the two beams are superimposed to form a left-tilted beam 1; when the two ports are simultaneously excited and the phase difference between them is 180°, the superimposed beam 2 is right-tilted.

[0064] Embodiment 2

[0065] Referring to Figure 8 The phase array antenna in the second aspect embodiment of the present application comprises the above-mentioned LTCC-based millimeter wave end-fire antenna unit, and the number of the LTCC-based millimeter wave end-fire antenna units is multiple and they are arranged side by side. Moreover, the phase array antenna is further provided with SMPM connectors 90, and each LTCC-based millimeter wave end-fire antenna unit is equipped with two SMPM connectors 90, one of which is arranged on the top layer of the antenna and the other of which is arranged on the bottom layer of the antenna.

[0066] Embodiment 3

[0067] The working method for the above-mentioned LTCC-based millimeter wave end-fire antenna unit in the third aspect embodiment of the present application comprises the following steps:

[0068] S100. The differential signal is input to the ring radiator 1 through the microstrip balun structure 15, and the signal is input to the cavity radiator 2 through the tapered microstrip feed line 20;

[0069] S200. The ring radiator 1 and the cavity radiator 2 have their own excitation ports respectively, and when excited separately, the ring radiator 1 generates an "∞" end-fire beam, and the cavity radiator 2 generates an "O" end-fire beam;

[0070] S300. When the ring radiator 1 and the cavity radiator 2 are excited simultaneously, by changing the phase difference of the two excitation signals, the direction of the superimposed beam of the ring radiator 1 and the cavity radiator 2 can be changed, thereby expanding the scanning range.

[0071] Referring to Figures 9 to 10 , the wide-angle scanning end-fire phased array has a return loss less than -10 dB within the bandwidth of 26.5-29.5 GHz. For the scanning performance, three representative frequency points 26.5 GHz, 27.5 GHz and 29.5 GHz are selected, and the 3dB gain roll-off scanning range can exceed ±70°. It can be seen that the millimeter wave end-fire antenna unit based on LTCC has a wider scanning range compared with the traditional antenna unit.

[0072] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range of ordinary skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An LTCC-based millimeter wave end-fire antenna unit, characterized by, Comprise: a ceramic dielectric group, which comprises a plurality of ceramic dielectric layers stacked on each other; a ring-shaped radiator, which comprises a metal layer and a plurality of metallized vias, the plurality of metallized vias penetrating through the plurality of ceramic dielectric layers, the number of the metal layer and the plurality of metallized vias is at least two, two ends of the plurality of metallized vias are connected to the metal layer located at the top layer and the metal layer located at the bottom layer respectively, the metal layer and the plurality of metallized vias jointly form a ring-shaped structure; a microstrip balun structure, which is connected to the metal layer located at the bottom layer; a cavity radiator, which comprises a feed probe and a resonant cavity electrically connected to each other, the feed probe is used to deliver an electrical signal to the resonant cavity, the resonant cavity comprises a first metal ground and a second metal ground, the second metal ground is connected to the microstrip balun structure; a tapered microstrip feed line, which is connected to the first metal ground; wherein the excitation signals of the ring-shaped radiator and the cavity radiator are superimposed on each other, the tilt angle of the superimposed beam can be changed by changing the phase difference of the two excitation signals, when the phase difference is 0° or 180°, the superimposed beam is tilted to the left or right respectively, and the beam reconfiguration is realized by the phase difference.

2. The LTCC-based millimeter-wave end-fire antenna unit of claim 1, wherein: The metal layer comprises a first metal layer, a second metal layer, a third metal layer and a fourth metal layer, the plurality of metallized vias comprises a first metallized via and a second metallized via, two ends of the first metallized via are connected to the first metal layer and the third metal layer respectively, two ends of the second metallized via are connected to the second metal layer and the fourth metal layer respectively.

3. The LTCC-based millimeter-wave end-fire antenna unit of claim 2, wherein: The metal layer further comprises a fifth metal layer and a sixth metal layer, the plurality of metallized vias comprises a third metallized via and a fourth metallized via, the fifth metal layer and the sixth metal layer are located in the space surrounded by the first metal layer, the second metal layer, the third metal layer and the fourth metal layer; the fifth metal layer is connected to the first metal layer and the second metal layer through two third metallized vias respectively, and the sixth metal layer is connected to the third metal layer and the fourth metal layer through two fourth metallized vias respectively.

4. The LTCC-based millimeter-wave end-fire antenna element of claim 1, wherein: The microstrip balun structure is provided with one input port and two output ports, the distance between the input port and the two output ports is not equal, and a set of differential signals is obtained at the two output ports.

5. The LTCC-based millimeter-wave end-fire antenna element of claim 1, wherein: The resonant cavity further comprises a metallized via sidewall, two ends of the metallized via sidewall are connected to the first metal ground and the second metal ground to realize electrical connection.

6. The LTCC-based millimeter-wave end-fire antenna element of claim 1, wherein: The first metal ground is provided with a first H-shaped slot, and the second metal ground is provided with a second H-shaped slot opposite to the first H-shaped slot.

7. The LTCC-based millimeter-wave end-fire antenna unit of claim 6, wherein: The second metal ground is further provided with an I-shaped slot adjacent to the second H-shaped slot.

8. The LTCC-based millimeter-wave end-fire antenna element of claim 1, wherein: The top and bottom of the ceramic dielectric group are provided with pads.

9. A phased array antenna, characterized by The LTCC-based millimeter wave end-fire antenna unit of any one of claims 1 to 8 is provided in a plurality of parallel arrangements.

10. A method of operating the LTCC-based millimeter-wave end-fire antenna unit of any one of claims 1 to 8, characterized by, Comprise: The differential signal is input to the ring radiator through the microstrip balun structure, and the signal is input to the cavity radiator through the tapered microstrip feed line; The ring radiator and the cavity radiator have respective excitation ports, and when excited separately, the ring radiator generates an "∞" end-fire beam, and the cavity radiator generates an "O" end-fire beam; When the ring radiator and the cavity radiator are excited simultaneously, the direction of the superimposed beam of the ring radiator and the cavity radiator can be changed by changing the phase difference between the two excitation signals, thereby expanding the scanning range.

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