A millimeter-wave broadband circularly polarized differential helical antenna

Abstract

The present invention discloses a millimeter wave broadband circularly polarized differential helical antenna, comprising a helical radiation unit, a dipole feeding unit, a differential metal through hole, a cavity unit and a multilayer dielectric plate; the cavity unit comprises a metal cavity and a dielectric waveguide cavity, the dielectric waveguide cavity is arranged inside the multilayer dielectric plate, the metal cavity is arranged outside the multilayer dielectric plate, the helical radiation unit is arranged on the upper side of the top dielectric plate, the dipole feeding unit is arranged on the lower side of the bottom dielectric plate, the differential metal through hole runs through the multilayer dielectric plate, and the dipole feeding unit transmits a radio frequency differential signal to the helical radiation unit through the differential metal through hole. The present invention is directly fed by a differential transmission line, does not require a conversion structure such as a balun, reduces energy loss during transmission, improves energy transmission efficiency, and utilizes the characteristics of the traveling wave and circular polarization of the helical structure to achieve the radiation of a circularly polarized electromagnetic wave beam within a broadband.

Description

Technical Field

[0001] The present invention relates to the technical field of millimeter wave antennas, and in particular to a millimeter wave broadband circularly polarized differential helical antenna. Background Art

[0002] Due to its large absolute bandwidth, short wavelength, and special atmospheric propagation characteristics, millimeter waves play an important role in many fields such as communication technology, medical imaging, and millimeter-wave radar detection. Millimeter-wave technology has also attracted further in-depth and extensive research by scholars at home and abroad.

[0003] Compared with linearly polarized electromagnetic waves, circularly polarized electromagnetic waves have advantages such as strong anti-interference and reduced channel polarization adaptation. Therefore, the design of circularly polarized antennas has always attracted much attention and been widely studied. Millimeter wave band antennas are physically small in size and difficult to process. In addition, millimeter wave systems are developing towards high integration. At the same time, broadband axial ratio, as an important performance of circularly polarized antennas, has always been a design difficulty. These have severely limited the realization of broadband circularly polarized antennas that can be used in highly integrated millimeter wave systems.

[0004] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention

[0005] In order to solve the above technical defects, the technical solution adopted by the present invention is to provide a millimeter-wave broadband circularly polarized differential helical antenna.

[0006] A millimeter-wave broadband circularly polarized differential helical antenna comprises a helical radiating unit, a dipole feeding unit, a differential metal through-hole, a cavity unit and a multilayer dielectric plate; the cavity unit comprises a metal cavity and a dielectric waveguide cavity, the metal cavity is arranged outside the multilayer dielectric plate and located above the helical radiating unit, the dielectric waveguide cavity is arranged inside the multilayer dielectric plate and located between the helical radiating unit and the dipole feeding unit, the helical radiating unit is arranged on the upper side of the top dielectric plate, the dipole feeding unit is arranged on the lower side of the bottom dielectric plate, the differential metal through-hole runs through the multilayer dielectric plate, the dipole feeding unit transmits a radio frequency differential signal to the helical radiating unit through the differential metal through-hole, the electromagnetic wave beam radiated by the helical radiating unit is optimized and adjusted by the dielectric waveguide cavity and the metal cavity, and then radiated to free space.

[0007] Furthermore, the vibrator feeding unit includes a differential transmission line, which is symmetrically arranged along the vertical axis direction of the multilayer dielectric plate, the middle part of the outer side of the differential transmission line is concave, one end of the outer side of the differential transmission line is stepped, and the other end is inclined, the inner side of the differential transmission line is straight, one end of the differential transmission line is connected to the differential metal through hole, and the other end of the differential transmission line is a feeding port.

[0008] Furthermore, gaps are provided between the differential transmission lines, the gaps extend along the length direction of the differential transmission lines, and the width of the gaps remains unchanged.

[0009] Furthermore, the helical radiation unit includes two helical antenna elements, the ends of the two helical antenna elements are sharp knife-shaped, the head ends of the two helical antenna elements are connected to differential metal through-holes, the differential transmission line transmits the radio frequency differential signal to the helical antenna elements through the differential metal through-holes, and the helical antenna elements radiate circularly polarized electromagnetic wave beams.

[0010] Furthermore, the expressions for the inner and outer helical line radii of the helical antenna element changing with the helical line rotation angle are:

[0011] R1=r0+a0θ,θ∈[θ0,N0*2π],

[0012] R2=r1+a1θ,θ∈[θ1,N1*2π];

[0013] Among them, R1 is the radius of the inner helix of the spiral arm, r0 is the initial radius of the inner helix, and a0 is the growth rate of the inner helix; R2 is the radius of the outer helix of the spiral arm, r1 is the initial radius of the outer helix, and a1 is the growth rate of the outer helix; θ is the helix rotation angle variable, θ0 is the starting angle of rotation of the inner helix, θ1 is the starting angle of rotation of the outer helix, N0 is the number of rotations of the inner helix, and N1 is the number of rotations of the outer helix.

[0014] Furthermore, the dielectric waveguide cavity includes a square SIW cavity and a cylindrical SIW cavity, the square SIW cavity is arranged above the cylindrical SIW cavity, and the cylindrical SIW cavity and the square SIW cavity serve as a dielectric waveguide combined cavity, which work together to adjust the electromagnetic wave beam radiated by the spiral radiation unit.

[0015] Furthermore, prepregs are provided between the multiple layers of the dielectric plates for bonding adjacent dielectric plates.

[0016] Furthermore, the height of the dielectric waveguide cavity is greater than the height of the metal cavity.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] The feeding input port of the antenna in the present invention is a pair of differential transmission lines clad in copper on a dielectric plate, which transmit differential signals through differential metal through holes to feed the helical antenna oscillator, and the antenna gain and far-field pattern of the antenna are improved through a combination design of multiple cavities; structurally, it is more convenient for the integration of microwave subsystem structures; in terms of performance, it is directly fed by differential transmission lines without the need for conversion structures such as baluns, which reduces energy loss during transmission and improves energy transmission efficiency, and utilizes the traveling wave and circular polarization characteristics of the helical structure to achieve radiation of circularly polarized electromagnetic wave beams within a broadband, and at the same time, the design of the cavity unit improves the far-field pattern performance of the radiation beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the millimeter-wave broadband circularly polarized differential helical antenna;

[0020] Figure 2 is a side view of the millimeter-wave broadband circularly polarized differential helical antenna;

[0021] Figure 3 It is a schematic structural diagram of the first copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0022] Figure 4 It is a schematic structural diagram of the second copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0023] Figure 5 It is a schematic structural diagram of the third copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0024] Figure 6 It is a schematic structural diagram of the fourth copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0025] Figure 7 It is a schematic structural diagram of the fifth copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0026] Figure 8 It is a schematic structural diagram of the sixth copper-clad layer of the millimeter-wave broadband circularly polarized differential helical antenna;

[0027] Fig. 9 is a reflection coefficient diagram of the millimeter-wave broadband circularly polarized differential helical antenna;

[0028] Fig.10 is an axial ratio diagram of the millimeter-wave broadband circularly polarized differential helical antenna;

[0029] Fig.11 is an actual gain diagram of the millimeter-wave broadband circularly polarized differential helical antenna;

[0030] Fig.12is a two-dimensional far-field pattern perpendicular to the differential transmission line of the millimeter-wave broadband circularly polarized differential helical antenna;

[0031] Fig.13 It is the two-dimensional far-field radiation pattern of the millimeter-wave broadband circularly polarized differential helical antenna parallel to the differential transmission line.

[0032] The numbers in the figure represent:

[0033] 101-metal shell; 102-metal cavity; 103-metal shell PCB slot; 104-square SIW cavity; 105-cylindrical SIW cavity; 106-leakage-proof metal through hole; 201-helical antenna vibrator; 202-differential metal through hole; 203-differential transmission line; 301-first layer of dielectric board; 302-second layer of dielectric board; 303-third layer of dielectric board; 311-first layer of prepreg; 312-second layer of prepreg; 321-first layer of copper clad layer; 322-second layer of copper clad layer; 323-third layer of copper clad layer; 324-fourth layer of copper clad layer; 325-fifth layer of copper clad layer; 326-sixth layer of copper clad layer. DETAILED DESCRIPTION

[0034] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0035] The present invention discloses a millimeter-wave broadband circularly polarized differential helical antenna, comprising a helical radiating unit, a dipole feeding unit, a differential metal through-hole 202, a cavity unit and a multilayer dielectric plate; the cavity unit comprises a metal cavity 102 and a dielectric waveguide cavity, the dielectric waveguide cavity is arranged inside the multilayer dielectric plate and between the helical radiating unit and the dipole feeding unit, the metal cavity 102 is arranged outside the multilayer dielectric plate and above the helical radiating unit, the helical radiating unit is arranged on the upper side of the top dielectric plate, the dipole feeding unit is arranged on the lower side of the bottom dielectric plate, the differential metal through-hole 202 runs through the multilayer dielectric plate, the dipole feeding unit transmits a radio frequency differential signal to the helical radiating unit through the differential metal through-hole 202, the electromagnetic wave beam radiated by the helical radiating unit is optimized and adjusted by the dielectric waveguide cavity and the metal cavity 102, and then radiated to free space.

[0036] The oscillator feeding unit includes a differential transmission line 203, which is symmetrically arranged along the vertical axis direction of the multilayer dielectric plate. The middle part of the outer side of the differential transmission line 203 is concave, one end of the outer side of the differential transmission line 203 is stepped, and the other end is inclined. The inner side of the differential transmission line 203 is straight, one end of the differential transmission line 203 is connected to the differential metal through hole 202, and the other end of the differential transmission line 203 is a feeding port.

[0037] Gaps are arranged at equal distances between the differential transmission lines 203 . The gaps extend along the length direction of the differential transmission lines 203 , and the widths of the gaps remain unchanged.

[0038] The helical radiation unit includes two helical antenna elements 201, the ends of the two helical antenna elements 201 are sharp knife-shaped, the head ends of the two helical antenna elements 201 are connected to the differential metal through-holes 202, the differential transmission line 203 transmits the radio frequency differential signal to the helical antenna elements 201 through the differential metal through-holes 202, and the helical antenna elements 201 radiate circularly polarized electromagnetic wave beams.

[0039] The dielectric waveguide cavity comprises a square SIW cavity 104 and a cylindrical SIW cavity 105. The square SIW cavity 104 is arranged above the cylindrical SIW cavity 105. The cylindrical SIW cavity 105 and the square SIW cavity 104 serve as a dielectric waveguide combined cavity and work together to adjust the electromagnetic wave beam radiated by the spiral radiation unit.

[0040] A prepreg sheet for bonding adjacent dielectric plates is arranged between the multiple dielectric plates.

[0041] The height of the dielectric waveguide cavity is greater than the height of the metal cavity 102, which can effectively increase the gain of the antenna and improve the far-field radiation pattern.

[0042] Embodiment 1

[0043] like Figure 1 , Figure 2 As shown, Figure 1 and Figure 2 They are respectively a structural schematic diagram and a side view of the millimeter-wave broadband circularly polarized differential helical antenna. The present embodiment includes a metal shell 101 and a multi-layer dielectric board, wherein the multi-layer dielectric board is assembled in a metal shell PCB slot 103, and the multi-layer dielectric board includes a first dielectric board 301, a second dielectric board 302, and a third dielectric board 303. The dielectric board is made of Rogers 3003, the first dielectric board 301 is 0.254 mm thick, the second dielectric board 302 is 0.508 mm thick, and the third dielectric board 303 is 0.254 mm thick. A first prepreg 311 and a second prepreg 312 are used to bond adjacent dielectric boards, and the prepreg is made of CFB278F. In the present embodiment, copper clad layers are provided on the top and bottom layers of each dielectric board, and from the top to the bottom, they are the first copper clad layer 321, the second copper clad layer 322, the third copper clad layer 323, the fourth copper clad layer 324, the fifth copper clad layer 325, and the sixth copper clad layer 326.

[0044] like Figure 3-Figure 8As shown, the first copper-clad layer 321 to the sixth copper-clad layer 326 are schematic structural diagrams, and the sixth copper-clad layer 326 is provided with a vibrator feeding unit, and the vibrator feeding unit includes a differential transmission line 203, such as Figure 8 As shown, the differential transmission line 203 is a multi-section transition structure, which is wide at both ends and narrow in the middle. The differential transmission line 203 is symmetrically arranged along the vertical axis direction of the multilayer dielectric plate. The middle part of the outer side of the differential transmission line 203 is concave, one end of the outer side of the differential transmission line 203 is stepped, and the other end is inclined. The inner side of the differential transmission line 203 is straight, one end of the differential transmission line 203 is an output port, and the output port is connected to the differential metal through hole 202, and the other end of the differential transmission line 203 is a feeding port.

[0045] The line width of the middle part of the differential transmission line 203 is set to w2, the purpose is to maximize the integrity of the cylindrical SIW cavity 105 formed by the metal through hole, and to prevent electromagnetic wave energy from leaking from the opening of the cylindrical SIW cavity 105. The feed input end of the differential transmission line 203 has a line width of w1, and a gap is set in the middle of the differential transmission line 203 along the length direction. The gap width is w0, and the gap width remains unchanged. The line width corresponding to the feed port to the output port of the differential transmission line 203 gradually changes from w1 to w2, and then to w3, completing the impedance matching from the input end of the differential transmission line 203 to the differential metal through hole 202; the gradient design of the differential transmission line 203 is mainly used for the impedance matching between the feed input end of the differential transmission line 203 and the differential metal through hole 202.

[0046] like Figure 3 As shown, a spiral radiation unit is arranged on the first copper cladding layer 321, and the spiral radiation unit includes two spiral antenna elements 201. The ends of the two spiral antenna elements 201 are in a sharp knife shape, which can effectively reduce the terminal capacitance effect and thus improve the working bandwidth of the antenna; the head ends of the two spiral antenna elements 201 are connected to the differential metal through-holes 202, and the differential transmission line 203 transmits the radio frequency differential signal to the spiral antenna element 201 through the differential metal through-holes 202. The input impedance of the differential transmission line 203 is matched to the input impedance of the spiral antenna element 201, and the spiral antenna element 201 radiates a circularly polarized electromagnetic wave beam.

[0047] The helical antenna element 201 has a helical structure, and the traveling wave and circular polarization characteristics of the helical structure realize the radiation of a circularly polarized electromagnetic wave beam within a broadband.

[0048] The broadband circularly polarized differential helical antenna is directly fed by the differential transmission line 203 without the need for a conversion structure such as a balun, thereby reducing energy loss during transmission and improving energy transmission efficiency.

[0049] like Figure 8As shown, the differential metal through hole 202 is a differential multi-layer dielectric metal through hole structure, the diameter of the differential metal through hole 202 is d0, the distance between the two differential metal through holes 202 is l1, and the differential metal through hole 202 passes through the three-layer dielectric board and the two-layer semi-cured sheet from the sixth copper-clad layer to be connected to the inner end of the helical antenna oscillator 201 of the first copper-clad layer.

[0050] The structural dimensions of the helical antenna element 201 have a direct and significant impact on the antenna reflection coefficient, working bandwidth, circular polarization, and far-field radiation performance. The inner and outer helical lines of each helical antenna element 201 are:

[0051]

[0052] In the formula, r0 is the initial radius of the inner helix, r0=0.35mm; a0 is the growth rate of the inner helix, a0=0.19mm / deg; N0 is the number of rotations of the inner helix, N0=0.7; θ0 is the starting angle of rotation of the inner helix, θ0=35deg; r1 is the initial radius of the outer helix, r1=0.55mm; a1 is the growth rate of the outer helix, a1=0.23mm / deg; N1 is the number of rotations of the outer helix, N1=0.7; θ1 is the starting angle of rotation of the outer helix, θ1=-30deg; θ is the variable of the helix rotation angle, R1 is the radius of the inner helix of the spiral arm, which changes with the change of θ, and R2 is the radius of the outer helix of the spiral arm, which changes with the change of θ.

[0053] like Figure 1 As shown, the broadband circularly polarized differential helical antenna is provided with a cavity unit, and the cavity unit is divided into a metal cavity 102 and a dielectric waveguide cavity, and the dielectric waveguide cavity includes a square SIW cavity 104, a cylindrical SIW cavity 105 and an anti-leakage metal through hole 106, and the anti-leakage metal through hole 106 prevents electromagnetic waves from leaking from the opening of the cylindrical SIW cavity 105. The differential metal through hole 202 is provided in the middle of the square SIW cavity 104 and the cylindrical SIW cavity 105, and passes through the three-layer dielectric plate. The cylindrical SIW cavity 105 and the square SIW cavity 104 act as a dielectric waveguide combined cavity and work together to adjust the electromagnetic wave beam radiated by the helical antenna element. The square SIW cavity 104 transitions the cylindrical SIW cavity 105 to the metal cavity 102. The square SIW cavity 104, the cylindrical SIW cavity 105 and the metal cavity 102 jointly optimize and adjust the electromagnetic wave beam radiated by the helical antenna unit.

[0054] like Figure 2As shown, the metal cavity 102 is a square structure, the height of the metal cavity 102 is h1, the total height of the circular SIW cavity and the square SIW cavity is h2, and the height of the dielectric waveguide cavity is greater than the height of the metal cavity 102, which can effectively improve the gain of the antenna and improve the far-field radiation pattern.

[0055] The millimeter-wave broadband circularly polarized differential helical antenna in this embodiment has high-gain, wide-beam far-field radiation performance, mainly because the cavity unit composed of the square SIW cavity 104, the cylindrical SIW cavity 105 and the metal cavity 102 improves the far-field pattern performance of the radiation beam.

[0056] In this embodiment, the circularly polarized differential helical antenna is in the millimeter wave frequency band.

[0057] Antenna working process: The RF differential signal is transmitted through the differential transmission line 203, and the RF differential signal is transmitted from the differential transmission line 203 of the sixth copper clad layer 326 to the spiral inner end of the spiral antenna element 201 of the first copper clad layer 321 via the differential metal through-hole 202, and finally radiates electromagnetic waves through the spiral antenna element 201.

[0058] Embodiment 2

[0059] In electromagnetic simulation software, the structure designed in Example 1 is modeled and analyzed. Fig. 9 This is the port reflection coefficient of the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment. In the frequency band of 28 to 40 GHz, the reflection coefficient is lower than -10 dB, and in the frequency band of 30 to 40 GHz, the reflection coefficient is lower than -12.5 dB. Therefore, the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment has good impedance matching within the operating frequency band.

[0060] Fig.10 is the axial ratio AxialRatio (AR) of the millimeter-wave broadband circularly polarized differential helical antenna of this embodiment. In the range of 28.5 to 40 GHz, the axial ratio is lower than 3.6 dB, and in the range of 29 to 40 GHz, the axial ratio is lower than 2.8 dB. Therefore, this embodiment has excellent axial ratio performance within the working frequency band. Fig.10 It can be seen that f0 = 29GHz, AR = 2.79dB; f1 = 40GHz, AR = 2.6dB; then we can get Substituting the data into the above formula, it can be obtained that the axial ratio relative bandwidth when the axial ratio is lower than 3dB can reach more than 31.5%.

[0061] Fig.11is the actual gain of the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment, including total gain (Total), main circular polarization gain (RHCP) and polarization isolation (RHCP-LHCP). At 28.5-40 GHz, the main polarization gain is higher than 5.6 dBi; at 29-40 GHz, the main polarization gain is higher than 6 dBi, and can reach up to 7.9 dBi. In addition, at 29-40 GHz, the polarization isolation is higher than 15.5 dB. Therefore, the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment has high main circular polarization gain and large polarization isolation.

[0062] Fig.12 and Fig.13 They are respectively the two-dimensional far-field pattern perpendicular to the differential transmission line and the two-dimensional far-field pattern parallel to the differential transmission line of the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment. In the two-dimensional far-field direction perpendicular to the differential transmission line, at frequencies of 29 GHz, 30 GHz, 35 GHz, and 40 GHz, the half-power beam widths are 79°, 76.9°, 69.5°, and 64.7°, respectively; in the two-dimensional far-field direction parallel to the differential transmission line, at frequencies of 29 GHz, 30 GHz, 35 GHz, and 40 GHz, the half-power beam widths are 74.9°, 73.6°, 63.9°, and 55.6°, respectively. Therefore, the millimeter-wave broadband circularly polarized differential spiral antenna of this embodiment has good wide-beam radiation performance.

[0063] In summary, compared with the traditional circularly polarized antenna, the millimeter-wave broadband circularly polarized differential helical antenna of the present invention has the advantages of wide working bandwidth, good circular polarization performance, high gain, wide beam and easy integration. The present invention not only provides a high-performance antenna structure, but also provides a design scheme for an easily integrated broadband circularly polarized antenna, which is of great significance in engineering application and scheme design and is worthy of being promoted and used.

[0064] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A millimeter-wave broadband circularly polarized differential helical antenna, characterized in that: It comprises a spiral radiation unit, a dipole feeding unit, a differential metal through hole, a cavity unit and a multi-layer dielectric plate; the cavity unit comprises a metal cavity and a dielectric waveguide cavity, the metal cavity is arranged outside the multi-layer dielectric plate and located above the spiral radiation unit, the dielectric waveguide cavity is arranged inside the multi-layer dielectric plate and located between the spiral radiation unit and the dipole feeding unit, the spiral radiation unit is arranged on the upper side of the top dielectric plate, the dipole feeding unit is arranged on the lower side of the bottom dielectric plate, the differential metal through hole runs through the multi-layer dielectric plate, the dipole feeding unit transmits a radio frequency differential signal to the spiral radiation unit through the differential metal through hole, the electromagnetic wave beam radiated by the spiral radiation unit is optimized and adjusted by the dielectric waveguide cavity and the metal cavity, and then radiated to the free space; The vibrator feeding unit comprises a differential transmission line, which is symmetrically arranged along the vertical axis direction of the multilayer dielectric plate, the middle part of the outer side of the differential transmission line is concave, the side of the differential transmission line close to the differential metal through hole is stepped, the side close to the feeding port is inclined, the inner side of the differential transmission line is straight, one end of the differential transmission line is connected to the differential metal through hole, and the other end of the differential transmission line is the feeding port; A gap is provided between the differential transmission lines, the gap extends along the length direction of the differential transmission line, and the width of the gap remains unchanged; The helical radiation unit includes two helical antenna elements, the ends of the two helical antenna elements are in a sharp knife shape, the head ends of the two helical antenna elements are connected to differential metal through holes, the differential transmission line transmits radio frequency differential signals to the helical antenna elements through the differential metal through holes, and the helical antenna elements radiate circularly polarized electromagnetic wave beams; The expressions for the changes of the inner and outer spiral line radii of the helical antenna element with the rotation angle of the spiral line are: R1=r0+a0θ,θ∈[θ0,N0*2π], R2=r1+a1θ,θ∈[θ1,N1*2π]; Wherein, R1 is the radius of the inner spiral of the spiral arm, r0 is the initial radius of the inner spiral, and a0 is the growth rate of the inner spiral; R2 is the radius of the outer spiral of the spiral arm, r1 is the initial radius of the outer spiral, and a1 is the growth rate of the outer spiral; θ is the spiral rotation angle variable, θ0 is the starting angle of the inner spiral rotation, θ1 is the starting angle of the outer spiral rotation, N0 is the number of rotations of the inner spiral, and N1 is the number of rotations of the outer spiral; The dielectric waveguide cavity comprises a square SIW cavity and a cylindrical SIW cavity, wherein the square SIW cavity is arranged above the cylindrical SIW cavity, and the cylindrical SIW cavity and the square SIW cavity serve as a dielectric waveguide combined cavity and act together to adjust the electromagnetic wave beam radiated by the spiral radiation unit.

2. The millimeter wave broadband circularly polarized differential helical antenna according to claim 1, characterized in that: A prepreg sheet for bonding adjacent dielectric plates is arranged between the multi-layer dielectric plates.

3. The millimeter wave broadband circularly polarized differential helical antenna according to claim 1, characterized in that: The height of the dielectric waveguide cavity is greater than the height of the metal cavity.

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