Millimeter wave end-on-fire antenna unit based on LTCC (Low Temperature Co-Fired Ceramic) and phased-array antenna

Abstract

The invention discloses an LTCC-based millimeter wave end-on-fire antenna unit and a phased-array antenna, the LTCC-based millimeter wave end-on-fire antenna unit comprises a ceramic dielectric group, an annular radiator and a cavity radiator, a microstrip balun structure is arranged in the annular radiator, and a gradient microstrip feeder line is arranged in the cavity radiator. Two paths of excitation signals are respectively processed through the annular radiator and the cavity radiator, and after the two excitation signals are mutually superposed, the scanning angle of the antenna can be changed by changing the phase difference of the excitation signals, so that antenna beam reconfiguration is realized on the premise of not introducing an active switching device, and the scanning range of the array antenna is further widened. The invention relates to the technical field of millimeter wave communication.

Description

Technical Field

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

[0002] With the rapid development of Internet of Things (IoT) technology, the millimeter wave band has attracted widespread attention due to its rich spectrum resources and high transmission rate. The millimeter wave band has broad application prospects, especially in the fields of high-bandwidth communication, autonomous driving, intelligent transportation, and high-definition imaging. However, the high frequency characteristics of the millimeter wave band lead to severe free space path loss, which poses a challenge to the performance of the system. 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 beam pointing through electrical control and adapt to rapidly changing signal environments, thereby showing superior performance in millimeter wave communications.

[0003] Achieving wide-angle scanning is one of the main challenges facing millimeter-wave phased arrays. This challenge is particularly evident in end-fire antennas, which have high requirements for profiles, resulting in limited space in the vertical dimension, and traditional technologies for extending the 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] In this regard, current traditional technologies also use active switching devices to change the beam mode to widen the scanning range. However, this method undoubtedly increases the structural complexity of the antenna and also increases the difficulty of electrical control. 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 urgently needs to be solved in the field of millimeter wave communications. Summary of the invention

[0005] The present application aims to solve at least 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 broaden the scanning range of the antenna.

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

[0007] According to the first aspect of the present application, the LTCC-based millimeter wave end-fire antenna unit includes:

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

[0009] A ring radiator, comprising a metal layer and a metallized via, wherein the metallized via penetrates multiple layers of the ceramic dielectric layer, the number of the metal layer and the number of the metallized via are at least two, the two ends of the metallized via are respectively connected to the metal layer located at the top layer and the metal layer located at the bottom layer, and the metal layer and the metallized via together form a ring structure;

[0010] A microstrip balun structure connected to the metal layer at the bottom layer;

[0011] A cavity radiator, comprising a feeding probe and a resonant cavity electrically connected to each other, wherein the feeding probe is used to transmit an electrical signal to the resonant cavity, and the resonant cavity comprises a first metal ground and a second metal ground, wherein the second metal ground is connected to the microstrip balun structure;

[0012] A gradient microstrip feed line connected to the first metal ground;

[0013] Among them, the excitation signals of the ring radiator and the cavity radiator are superimposed on each other. By changing the phase difference between the two excitation signals, the tilt angle of the superimposed beam can be changed. When the phase difference is 0° or 180°, the superimposed beam tilts to the left or right respectively, and the beam can be reconfigured through the phase difference.

[0014] The LTCC-based millimeter-wave end-fire antenna unit according to the embodiment of the present application has at least the following beneficial effects: two excitation signals are processed respectively by the ring radiator and the cavity radiator. After the two excitation signals are superimposed on each other, the tilt angle of the antenna can be changed by changing the phase difference of the excitation signals, thereby realizing 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 layer includes a first metal layer, a second metal layer, a third metal layer and a fourth metal layer, and the metallized via includes a first metallized via and a second metallized via, wherein the two ends of the first metallized via are respectively connected to the first metal layer and the third metal layer, and the two ends of the second metallized via are respectively connected to the second metal layer and the fourth metal layer.

[0016] According to some embodiments of the present application, the metal layer also includes a fifth metal layer and a sixth metal layer, the metallized vias include a third metallized via and a fourth metallized via, the fifth metal layer and the sixth metal layer are located in a 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 respectively connected to the first metal layer and the second metal layer through two third metallized vias, and the sixth metal layer is respectively connected to the third metal layer and the fourth metal layer through two fourth metallized vias.

[0017] According to some embodiments of the present application, the microstrip balun structure is provided with an input port and two output ports, and the distances between the input port and the two output ports are unequal, so as to obtain a set of differential signals at the two output ports.

[0018] According to some embodiments of the present application, the resonant cavity further includes a metallized via sidewall, and two ends of the metallized 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, and the I-shaped gap is adjacent to the second H-shaped gap.

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

[0022] The phased array antenna according to the second aspect of the present application includes 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 in parallel with each other.

[0023] According to the third aspect of the present application, the working method for the above-mentioned LTCC-based millimeter wave end-fire antenna unit includes the following steps:

[0024] Inputting a differential signal to the ring radiator through the microstrip balun structure, and inputting a signal to the cavity radiator through the gradient microstrip feed line;

[0025] The annular radiator and the cavity radiator each have their own excitation ports. When excited individually, the annular radiator generates an "∞"-shaped end-fire beam, and the cavity radiator generates an "O"-shaped end-fire beam;

[0026] By simultaneously exciting the annular radiator and the cavity radiator and changing the phase difference between the two excitation signals, the direction of the beam after the annular radiator and the cavity radiator are superimposed can be changed, and passive control beam reconfiguration can be achieved, thereby expanding the phased array scanning range.

[0027] According to the working method of the embodiment 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 radiator and the cavity radiator, the direction of the final superimposed beam can be changed, and the beam can be reconfigured without active switches, thereby achieving the technical effect of expanding the antenna scanning range.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.

[0030] Figure 1 This is a schematic diagram of the relative positions of the ring radiator and the cavity radiator in the embodiment of the present application;

[0031] Figure 2 An exploded diagram of a millimeter-wave end-fire antenna unit based on LTCC according to an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the structure of a ring radiator and its feeding network in an embodiment of the present application;

[0033] Figure 4 This is a schematic diagram of the structure of the annular radiator in the embodiment of the present application;

[0034] Figure 5 This is a schematic diagram of a microstrip balun structure in an embodiment of the present application;

[0035] Figure 6 This is a schematic diagram of the cavity radiator and its probe feeding structure in an embodiment of the present application;

[0036] Figure 7 It is a simulation diagram of beam patterns in two directions implemented in the embodiments of the present application;

[0037] Figure 8 This is a schematic diagram of the structure of the phased array antenna according to an embodiment of the present application;

[0038] Fig. 9 This is a simulation result diagram of the return loss of the phased array antenna according to an embodiment of the present application;

[0039] Fig.10 This is a diagram of the simulation results of beam scanning of the phased array antenna of an embodiment of the present application at 26.5 GHz, 27.5 GHz and 29.5 GHz.

[0040] Figure 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, 152-second output port, 16-dielectric part, 2-cavity radiator, 20-gradient microstrip feed line, 21-first metal ground, 22-second metal ground, 23-first H-shaped gap, 24-second H-shaped gap, 25-I-shaped gap, 26-feeding probe, 27-metallized via side wall, 5-upper pad, 8-lower pad, 90-SMPM sitting joint. DETAILED DESCRIPTION

[0041] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0042] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0043] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0044] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0045] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may 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 band has attracted widespread attention due to its rich spectrum resources and high transmission rate. The millimeter wave band has broad application prospects, especially in the fields of high-bandwidth communication, autonomous driving, intelligent transportation, and high-definition imaging. However, the high frequency characteristics of the millimeter wave band lead to severe free space path loss, which poses a challenge to the performance of the system. 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 beam pointing through electrical control and adapt to rapidly changing signal environments, thereby showing superior performance in millimeter wave communications.

[0047] Achieving wide-angle scanning is one of the main challenges facing millimeter-wave phased arrays. This challenge is particularly evident in end-fire antennas, which have high requirements for profiles, resulting in limited space in the vertical dimension, and traditional technologies for extending the 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°.

[0048] In this regard, current traditional technologies also use active switching devices to change the beam mode to widen the scanning range. However, this method undoubtedly increases the structural complexity of the antenna and also increases the difficulty of electrical control. 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 urgently needs to be solved in the field of millimeter wave communications.

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

[0050] In addition, the present application also proposes a working method for the above-mentioned LTCC-based millimeter-wave end-fire antenna unit. By changing the phase difference of the excitation signal output to the ring radiator 1 and the cavity radiator 2, the direction of the final superimposed beam can be changed, thereby achieving the technical effect of expanding the antenna scanning range.

[0051] Example 1

[0052] Reference Figure 1 The millimeter wave end-fire antenna unit based on LTCC in the first aspect of the present application includes a ceramic dielectric group, a ring radiator 1 and a cavity radiator 2, wherein reference is made to Figure 3 , a microstrip balun structure 15 is provided in the ring radiator 1; Figure 6 , a gradient microstrip feed line 20 is provided in the cavity radiator 2. The ceramic dielectric group includes multiple layers of ceramic dielectric layers stacked on each other, which constitute the main structure of the millimeter-wave end-fire antenna unit based on LTCC. The ring radiator 1 introduces a differential signal through the microstrip balun structure 15, and the cavity radiator 2 introduces a signal through the gradient microstrip feed line 20. The signals of the two are superimposed to obtain the final antenna beam. By changing the phase difference between the two sets of excitation signals, the direction of the final antenna beam can be changed, thereby widening the scanning range. Compared with traditional antenna units, it has a wider scanning range while simplifying the structure.

[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. Figure 2 The number of ceramic dielectric layers in the ceramic dielectric group can be increased or decreased according to actual conditions. In this embodiment, the number of ceramic dielectric layers is 24. Pads are provided on the top and bottom of the ceramic dielectric group, wherein the pad at the top is the upper pad 5, and the pad at the bottom is the lower pad 8.

[0054] Reference Figure 3 The ring radiator 1 includes a metal layer 11 and a metallized via 12. The metallized via 12 penetrates multiple ceramic dielectric layers. The number of the metal layer 11 and the metallized via 12 is at least two. The two ends of the metallized via 12 are respectively connected to the metal layer 11 at the top layer and the metal layer 11 at the bottom layer. The metal layer 11 and the metallized via 12 together form a ring structure. The microstrip balun structure 15 is connected to the metal layer 11 at the bottom layer for transmitting signals.

[0055] The entire ring radiator 1 is located at the end-fire edge of the antenna's overall dielectric block, but a certain length of dielectric portion 16 must be retained at the end as a guide medium to adjust the impedance matching between the antenna radiation aperture and the free space contact surface. The ring radiator 1 constructs a ring antenna structure on the YOZ plane, and the resonant frequency depends on the circumference of the entire ring structure, that is, the sum of the lengths of all metal layers 11 and metallized vias 12.

[0056] Specifically, refer 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 metallized via 12 includes a first metallized via 120 and a second metallized via 121. The two ends of the first metallized via 120 are respectively connected to the first metal layer 110 and the third metal layer 112, and the two ends of the second metallized via 121 are respectively connected to the second metal layer 112 and the fourth metal layer 113. Thus, each metal layer 11 and the metallized via 12 together form a ring structure.

[0057] In order to reduce the volume of the antenna, the annular radiator 1 needs to be folded to improve the compactness of the structure. The metal layer 11 also includes a fifth metal layer 130 and a sixth metal layer 131, and the metallized via 12 includes a third metallized via 140 and a fourth metallized 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 a concave structure. The fifth metal layer 130 is connected to the first metal layer 110 and the second metal layer 111 through two third metallized 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 metallized vias 141. Through this inwardly concave folding structure, the width occupied in the horizontal direction can be shortened while keeping the circumference and height of the entire annular structure unchanged, thereby achieving a miniaturization effect.

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

[0059] Reference Figure 6 The cavity radiator 2 includes a feeding probe 26 and a resonant cavity which are electrically connected to each other. The feeding probe 26 is used to transmit an electrical signal to the resonant cavity. 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 forming an electrical connection between the cavity radiator 2 and the ring radiator 1.

[0060] The gradient microstrip feed line 20 is connected to the first metal ground 21 to feed the signal into the resonant cavity. Inside the resonant cavity, the feed probe 26 constructed by the metallized via generates a transmission signal, excites the TE10 mode inside the cavity, and finally realizes an "O"-shaped end-fire beam on the antenna aperture surface.

[0061] Furthermore, the resonant cavity further includes a metallized via sidewall 27 , and two ends of the metallized via sidewall 27 are connected to the first metal ground 21 and the second metal ground 22 to achieve electrical connection.

[0062] Furthermore, 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 also provided with an I-shaped slot 25, and the I-shaped slot 25 is adjacent to the second H-shaped slot 24. By loading these slots, additional resonance points can be generated for the antenna, thereby expanding the antenna bandwidth.

[0063] The excitation signals of the ring 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 radiator 1 and the cavity radiator 2 each have their own excitation ports. When excited separately, they generate an "∞"-shaped end-fire beam and an "O"-shaped end-fire beam respectively. Figure 7 When the two input ports are excited at the same time and the phase difference between them is 0°, the two beams are superimposed to form beam 1 tilted to the left; when the two ports are excited at the same time and the phase difference between them is 180°, the superimposed beam 2 is tilted to the right.

[0064] Example 2

[0065] Reference Figure 8 The phased array antenna in the second embodiment of the present application includes the above-mentioned LTCC-based millimeter wave end-fire antenna unit. The number of the LTCC-based millimeter wave end-fire antenna units is multiple and they are arranged in parallel with each other. In addition, the phased array antenna is also provided with an SMPM seated connector 90. Each LTCC-based millimeter wave end-fire antenna unit is equipped with two SMPM seated connectors 90, one of which is arranged on the top layer of the antenna, and the other is arranged on the bottom layer of the antenna.

[0066] Example 3

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

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

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

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

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

[0072] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field 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. A millimeter wave end-fire antenna unit based on LTCC, characterized in that: include: A ceramic dielectric group, comprising a plurality of ceramic dielectric layers stacked on top of each other; A ring radiator, comprising a metal layer and a metallized via, wherein the metallized via penetrates multiple layers of the ceramic dielectric layer, the number of the metal layer and the number of the metallized via are at least two, the two ends of the metallized via are respectively connected to the metal layer located at the top layer and the metal layer located at the bottom layer, and the metal layer and the metallized via together form a ring structure; A microstrip balun structure connected to the metal layer at the bottom layer; A cavity radiator, comprising a feeding probe and a resonant cavity electrically connected to each other, wherein the feeding probe is used to transmit an electrical signal to the resonant cavity, and the resonant cavity comprises a first metal ground and a second metal ground, wherein the second metal ground is connected to the microstrip balun structure; A gradient microstrip feed line connected to the first metal ground; Among them, the excitation signals of the ring radiator and the cavity radiator are superimposed on each other. By changing the phase difference between the two excitation signals, the tilt angle of the superimposed beam can be changed. When the phase difference is 0° or 180°, the superimposed beam tilts to the left or right respectively, and the beam can be reconfigured through the phase difference.

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

3. The LTCC-based millimeter-wave end-fire antenna unit according to claim 2, characterized in that: The metal layer also includes a fifth metal layer and a sixth metal layer, the metallized vias include a third metallized via and a fourth metallized via, the fifth metal layer and the sixth metal layer are located in a 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 respectively connected to the first metal layer and the second metal layer through two third metallized vias, and the sixth metal layer is respectively connected to the third metal layer and the fourth metal layer through two fourth metallized vias.

4. The LTCC-based millimeter-wave end-fire antenna unit according to claim 1, characterized in that: The microstrip balun structure is provided with an input port and two output ports, and the distances between the input port and the two output ports are unequal, so as to obtain a set of differential signals at the two output ports.

5. The LTCC-based millimeter-wave end-fire antenna unit according to claim 1, characterized in that: The resonant cavity further includes a metallized via sidewall, and two ends of the metallized via sidewall are connected to the first metal ground and the second metal ground to achieve electrical connection.

6. The LTCC-based millimeter-wave end-fire antenna unit according to claim 1, characterized in that: 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.

7. The LTCC-based millimeter-wave end-fire antenna unit according to claim 6, characterized in that: The second metal ground is further provided with an I-shaped gap, and the I-shaped gap is adjacent to the second H-shaped gap.

8. The LTCC-based millimeter-wave end-fire antenna unit according to claim 1, characterized in that: The top and bottom of the ceramic dielectric group are both provided with pads.

9. A phased array antenna, characterized in that: It comprises the LTCC-based millimeter wave end-fire antenna unit as described in any one of claims 1 to 8, wherein there are a plurality of LTCC-based millimeter wave end-fire antenna units which are arranged in parallel with each other.

10. A working method for the LTCC-based millimeter wave end-fire antenna unit according to any one of claims 1 to 8, characterized in that: include: Inputting a differential signal to the ring radiator through the microstrip balun structure, and inputting a signal to the cavity radiator through the gradient microstrip feed line; The annular radiator and the cavity radiator each have their own excitation ports. When excited individually, the annular radiator generates an "∞"-shaped end-fire beam, and the cavity radiator generates an "O"-shaped end-fire beam; By exciting the annular radiator and the cavity radiator simultaneously and changing the phase difference between the two excitation signals, the direction of the beam after the annular radiator and the cavity radiator are superimposed can be changed, thereby expanding the scanning range.

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