A Ka-band conical beam antenna

Abstract

The application discloses a Ka-band conical beam antenna, which is composed of a single-layer metal floor, a coaxial probe, a single-layer dielectric substrate and an antenna patch array. The single-layer metal floor is rectangular, a metal through hole is arranged at the center of the floor, an SMA joint is arranged at the bottom of the floor, the SMA joint is in contact with the floor and is connected with the coaxial probe. The upper layer of the dielectric substrate is the antenna patch array. The whole antenna is composed of eight impedance-matched antenna patch units on the dielectric substrate to form a Chinese character-shaped pattern. Each patch unit is composed of a rectangular microstrip antenna, a parasitic capacitance ring, a transmission microstrip line and an impedance-matching microstrip line. The antenna is connected with a signal from the SMA joint through the coaxial probe penetrating through the single-layer dielectric substrate and the single-layer metal floor. The application can realize the design requirements of a wide beam, high gain and low side lobe.

Description

Technical Field

[0001] This invention relates to the field of microstrip antennas, and more specifically to a Ka-band conical beam antenna. Background Technology

[0002] A microstrip antenna is an antenna constructed by adding a thin conductive sheet to a dielectric substrate with a conductive metal ground plane. It belongs to the category of electrically small antennas. Its principle is to excite a periodic electromagnetic field in the dielectric substrate between the antenna patch and the metal ground plane by feeding through microstrip lines, coaxial lines or slot coupling, and radiating it out through the equivalent slot formed by the edge of the antenna patch and the metal ground plane.

[0003] Microstrip antennas come in various forms, mainly including microstrip patch antennas, microstrip linear antennas, microstrip slot antennas, and microstrip traveling wave antennas. Their advantages include small size, low profile, and light weight. They have simple feeding methods and can usually be integrated with the antenna, making them easy to process as a whole. They are also easy to implement circular polarization, dual polarization, dual frequency band, and other functions.

[0004] Rectangular microstrip antennas are the most commonly used type of microstrip antenna. By adjusting the length and width of the antenna patch, the operating frequency band can be flexibly adjusted. The planar structure of a rectangular microstrip antenna allows it to conform to the surface of the carrier, making it commonly used in missile fuses, satellite communications, and other fields. In satellite communications, two satellite carriers typically operate at an angle and rotate at a certain angular velocity, making ordinary rectangular microstrip antennas insufficient. Conical beam antennas exhibit circumferential symmetry in both their radiation pattern and polarization on the normal plane of the propagation direction, and their maximum radiation direction lies on a conical surface at an angle to the propagation direction. Therefore, conical beam antennas are one of the commonly used antenna types in satellite communication systems.

[0005] The fundamental mechanism for achieving a conical beam is to construct a radially reverse current or electric field. Currently, the mainstream forms include circularly polarized conical beam antennas, linearly polarized conical beam antennas, and reconfigurable conical beam antennas. The main beam of these antennas is concentrated near 0°, which cannot meet specific scanning requirements. The development direction of conical beam antennas is to achieve high gain and large beam coverage. Summary of the Invention

[0006] The purpose of this invention is to provide a Ka-band conical beam antenna that utilizes a common rectangular microstrip antenna to achieve design requirements such as wide beam, high gain, and low sidelobes in the Ka-band.

[0007] The technical solution to achieve the purpose of this invention is: a Ka-band conical beam antenna, comprising a single-layer metal ground plane, a coaxial probe, a single-layer dielectric substrate, and an antenna patch array;

[0008] The single-layer metal floor is rectangular, with a metal through hole in the center and an SMA connector at the bottom that contacts the floor and connects to a coaxial probe.

[0009] The coaxial probe passes through a single-layer dielectric substrate and a single-layer metal ground plane, and connects to the SMA connector;

[0010] The upper and lower surfaces of the single-layer dielectric substrate are both metal, with an antenna patch array on the upper surface and a single-layer metal ground plane on the lower surface.

[0011] The antenna patch array operates in the Ka band; the antenna as a whole consists of multiple impedance-matched antenna patch units, each of which consists of a rectangular microstrip antenna, a parasitic capacitance loop, a transmission microstrip line, and an impedance-matching microstrip line; the antenna patch array is integrated with a single-layer dielectric substrate, and signals are received from the SMA connector through a coaxial probe that passes through the single-layer dielectric substrate and the single-layer metal ground plane.

[0012] Compared with the prior art, the significant advantages of this invention are:

[0013] (1) The present invention uses a single-layer dielectric substrate and a single SMA coaxial feeding structure, thereby achieving a significant reduction in the complexity of the antenna structure.

[0014] (2) The antenna involved in this invention constructs a novel “rice” shaped array through eight antenna array elements, thereby constructing a radially reverse electric field and realizing a cone-shaped beam.

[0015] (3) The antenna involved in this invention is derived from a rectangular microstrip antenna, which is small in size and light in weight; and has a planar structure that can conform to the surface of the satellite carrier.

[0016] (4) The antenna involved in this invention uses a parasitic capacitance loop, which significantly increases the main lobe beamwidth of the antenna without changing other characteristics of the antenna, while suppressing the amplitude of the sidelobe level.

[0017] (5) The antenna involved in this invention has a longitudinal profile height that is only one-twentieth of the wavelength of the medium corresponding to its center frequency point, compared to the traditional conical beam antenna; thus effectively reducing the longitudinal profile height of the antenna. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the Ka-band conical beam antenna principle structure of the present invention.

[0019] Figure 2 The simulation curve of the Ka-band conical beam antenna S11 of this invention is shown.

[0020] Figure 3 This is a simulated normalized radiation pattern of the XOZ plane of the Ka-band conical beam antenna of this invention.

[0021] Figure 4 This is a simulated normalized radiation pattern of the YOZ plane of the Ka-band conical beam antenna of this invention.

[0022] Figure 5 The normalized radiation pattern of the XOY plane of the Ka-band conical beam antenna of this invention is a simulation result. Detailed Implementation

[0023] This invention can be applied to systems such as ground satellite communication terminals, indoor WLAN, micro base stations, and radio fuses, and specifically relates to a Ka-band conical beam antenna for a satellite communication system.

[0024] like Figure 1 As shown, a novel linearly polarized conical beam antenna includes a single-layer metal ground plane 1, a coaxial probe 2, a single-layer dielectric substrate 3, and an antenna patch array 4.

[0025] The single-layer metal floor 1 is rectangular, with a metal through hole in the center and an SMA connector 5 at the bottom that contacts the floor and is connected to the coaxial probe 2.

[0026] The coaxial probe 2 passes through the single-layer dielectric substrate 3 and the single-layer metal ground plane 1, and is connected to the SMA connector 5;

[0027] The upper and lower surfaces of the single-layer dielectric substrate 3 are both metal, the upper surface is provided with an antenna patch array 4, and the lower surface is a single-layer metal ground plane 1;

[0028] The antenna patch array 4 operates in the Ka band; the antenna as a whole consists of eight impedance-matched antenna patch units, each patch unit consisting of a rectangular microstrip antenna, a parasitic capacitance loop, a transmission microstrip line and an impedance-matching microstrip line; the antenna patch array 4 is integrated with the single-layer dielectric substrate 3, and the signal is received from the SMA connector 5 through the coaxial probe 2 passing through the single-layer dielectric substrate 3 and the single-layer metal ground plane 1.

[0029] The single-layer dielectric substrate 3 is made of Rogers-4350b material with a dielectric constant of 3.66 and a thickness of 0.254 mm, which is about one-twentieth of the dielectric wavelength, effectively reducing the longitudinal profile height of the antenna.

[0030] The antenna patch array 4 consists of eight impedance-matched antenna patch units. Each patch unit is arranged in a "rice" shape on the upper surface of the single-layer dielectric substrate 3 with the coaxial probe as the center. The spacing angle between each patch unit is 45°. This is used to construct a radially reverse electric field to form a cone-shaped beam.

[0031] The rectangular microstrip antenna has grooves recessed into the antenna on its side. The purpose of these grooves is to change the transmission path of the guided wave inside the antenna, thereby adjusting the output impedance to meet engineering requirements.

[0032] The parasitic capacitance loop is located on the periphery of the rectangular microstrip antenna. Its function is to change the antenna's beam characteristics in the far field by influencing the antenna's near-field electric field. Through precise calculations, the beamwidth of the rectangular microstrip antenna in the far field can be effectively extended.

[0033] The transmission microstrip lines are available in 50Ω and 100Ω versions. After precise calculation, the linewidth of the 50Ω microstrip line was determined to be 0.576 mm, and the linewidth of the 100Ω microstrip line was determined to be 0.13 mm.

[0034] The impedance matching microstrip line is a quarter-wavelength impedance matching microstrip line; its line length is one-quarter of the dielectric wavelength, and its line width is 0.29 mm; this impedance matching method is simple, easy to implement, and has a good matching effect.

[0035] The single-layer metal floor 1, the metal through-holes, and the antenna patch array 4 are all made of copper.

[0036] The following is a preferred design example of a Ka-band conical beam planar antenna:

[0037] Using a dielectric constant of ε r =3.66, height h = 0.254mm, using Rogers-4350b dielectric substrate. A single-layer metal ground plane of the same size is set on the lower surface of the dielectric substrate, with a metal through-hole in the center of the ground plane and an SMA connector at the bottom, contacting the ground plane and connecting to a coaxial probe. The upper surface of the dielectric substrate is the antenna array unit, which consists of eight impedance-matched antenna patch units. Each patch unit consists of a rectangular microstrip antenna, a parasitic capacitance loop, a transmission microstrip line, and an impedance-matching microstrip line. The dimensions of the rectangular microstrip antenna satisfy the following formula:

[0038]

[0039]

[0040] Where W represents the wide side of the rectangular microstrip antenna, L represents the long side of the rectangular microstrip antenna, with the side perpendicular to the feed line being the wide side and the side parallel to the feed line being the long side, c represents the speed of light in vacuum, and ε... r\(\epsilon_r\) represents the dielectric constant of the material filled in the dielectric substrate, and \(f\) is the operating frequency. Through the calculations in (1) and (2), and with simulation debugging, the width \(W = 2.55\) mm and the length \(L = 1.87\) mm of the rectangular microstrip antenna are finally determined; at the center position of the wide side of the rectangular microstrip antenna, a groove that recesses inward is opened to change the output impedance of the antenna. The width of the groove is about one-third of the wide side of the antenna, and the length is about one-sixth of the long side of the rectangular microstrip antenna; a transmission microstrip line is led out at the groove in the center of the wide side of the rectangular microstrip antenna, and its resistance value is the same as the absolute value of the output impedance of the rectangular microstrip antenna; in the present invention, the absolute value of the output impedance of the rectangular microstrip antenna and the resistance value of the transmission microstrip line are both 100 Ω; a quarter-wave matching microstrip line is used to connect the 100 Ω transmission line and the 50 Ω transmission line; a parasitic capacitance ring is arranged outside the rectangular microstrip antenna, and by changing the near-field parameters of the antenna, the beam characteristics of the antenna in the far field are affected, so as to achieve the purpose of broadening the antenna beam range.

[0041] Each antenna patch unit is distributed in a "rice" shape on the upper surface of the single-layer dielectric substrate with the coaxial probe as the center; the interval angle between each patch unit is 45°; in this way, a radial reverse electric field is constructed to form a conical beam; the single-layer metal floor, metal vias and the antenna patch array are all made of metal copper.

[0042] Figure 2 This is the S11 simulation curve graph of the Ka-band conical beam antenna of the present invention. The radial coordinate represents the normalized gain value of the antenna, and the horizontal coordinate represents the frequency. It can be seen from the figure that the antenna has two resonance points, which are respectively near 37.5 GHz and 42 GHz; in the present invention, 37.5 GHz is selected as the main resonance frequency, and the S11 at this point is about -25 dB, achieving good impedance matching; the impedance bandwidth is about 1 GHz.

[0043] Figure 3 This is the simulated normalized radiation pattern of the Ka-band conical beam antenna of the present invention in the XOZ plane. The radial coordinate represents the normalized gain value of the antenna, and the circumferential coordinate represents the angle; it can be seen from the figure that the beam pointing angle of this antenna is 25°, and the 3 dB beam width is about 30°; the gain of this antenna is about 9.2 dB.

[0044] Figure 4 This is the simulated normalized radiation pattern of the Ka-band conical beam antenna of the present invention in the YOZ plane. The radial coordinate represents the normalized gain value of the antenna, and the circumferential coordinate represents the angle; it can be seen from the figure that the beam characteristics of the XOZ plane and the YOZ plane of the antenna are consistent.

[0045] Figure 5This is a simulated normalized radiation pattern of the Ka-band conical beam antenna of this invention on the XOY plane. The radial coordinates represent the antenna's normalized gain, and the circumferential coordinates represent angles. As can be seen from the figure, the antenna exhibits circumferential symmetry in the normal plane of the propagation direction.

[0046] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A Ka-band conical beam antenna, characterized by, It includes a single-layer metal floor, a coaxial probe, a single-layer dielectric substrate and an antenna patch array; The single-layer metal floor is rectangular, with a metal through-hole provided at the center of the floor, and an SMA connector is provided at the bottom of the floor, which contacts the floor and is connected to the coaxial probe; The coaxial probe passes through the single-layer dielectric substrate and the single-layer metal floor and is connected to the SMA connector; Both the upper and lower surfaces of the single-layer dielectric substrate are metal. An antenna patch array is provided on the upper surface, and the lower surface is the single-layer metal floor; The antenna patch array operates in the Ka band; the whole antenna consists of multiple impedance-matched antenna patch units, and each antenna patch unit consists of a rectangular microstrip antenna, a parasitic capacitance loop, a transmission microstrip line and an impedance-matching microstrip line; the antenna patch array is integrated with the single-layer dielectric substrate, and signals are accessed from the SMA connector through the coaxial probe passing through the single-layer dielectric substrate and the single-layer metal floor; a groove recessed inward into the antenna is provided on the side of the rectangular microstrip antenna for adjusting the output impedance; the parasitic capacitance loop is located on the periphery of the rectangular microstrip antenna; The antenna patch array consists of eight impedance-matched antenna patch units, and each patch unit is distributed in a "rice" shape on the upper surface of the single-layer dielectric substrate with the coaxial probe as the center; the interval angle between each patch unit is 45°.

2. The Ka-band tapered-beam antenna of claim 1, wherein, The transmission microstrip line comprises The transmission microstrip line is connected to The transmission microstrip line.

3. The Ka-band tapered-beam antenna of claim 2, wherein, The microstrip line has a line width of 0.576 mm, The microstrip line has a line width of 0.13 mm.

4. The Ka-band tapered-beam antenna of claim 1, wherein, The impedance-matching microstrip line is a quarter-wave impedance-matching microstrip line.

5. The Ka-band tapered-beam antenna of claim 4, wherein, The length of the impedance-matching microstrip line is a quarter of the dielectric wavelength, and the width of the microstrip line is 0.29 mm.

6. The Ka-band tapered-beam antenna of claim 1, wherein, The single-layer metal floor, the metal through-hole and the antenna patch array are all made of copper.

7. The Ka-band tapered-beam antenna of claim 1, wherein, The single-layer dielectric substrate is made of Rogers 4350b board material, with a dielectric constant of 3.66 and a thickness of 0.254 mm.

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