A VHF and UHF band antenna

Abstract

This invention provides a VHF and UHF band antenna, comprising: a conductive ground plane, a top loading plate, and a radiator. The top loading plate and the conductive ground plane are arranged face-to-face, and the radiator is connected between the top loading plate and the conductive ground plane. At least two short-circuit conductive plates are also connected between the top loading plate and the conductive ground plane. Each side of the radiator has at least one slot. This VHF and UHF band antenna achieves miniaturization and broadband operation, while also possessing high gain and a good radiation pattern, making it suitable for use in airborne VHF / UHF communication systems.

Description

[Technical Field]

[0001] This invention relates to the field of antenna technology, and more particularly to a VHF and UHF band antenna. [Background Technology]

[0002] As an omnidirectional antenna, the monopole antenna possesses excellent radiation performance and is widely used in many communication devices. Ground radios, vehicle-mounted radios, soldier backpacks, ships, and aircraft are all equipped with various types of monopole antennas. In the VHF / UHF bands, omnidirectional monopole antennas are generally quite large, which is not conducive to antenna concealment during installation. For airborne blade antennas, their aerodynamic shape also limits their performance. Therefore, broadband miniaturization of monopole antennas is necessary. Existing monopole antennas struggle to simultaneously achieve broadband, miniaturization, and high gain. [Summary of the Invention]

[0003] In view of the above problems, the purpose of this invention is to provide a VHF and UHF band antenna, thereby improving the impedance matching effect of VHF and UHF band antennas and realizing the miniaturization, broadband and high-gain design of VHF and UHF band antennas.

[0004] This invention provides a VHF and UHF band antenna, comprising:

[0005] Conductive grounding;

[0006] The top loading plate is positioned facing the conductive ground plane.

[0007] A radiator is connected between the top loading plate and the conductive ground plate;

[0008] At least two short-circuit conductive plates are also connected between the top loading plate and the conductive ground plate;

[0009] Each side of the radiator has at least one slit.

[0010] Preferably, the at least two short-circuit conductive plates are respectively disposed on the front and rear sides of the radiator, and the at least two short-circuit conductive plates are parallel to the radiator.

[0011] Preferably, the VHF and UHF band antenna further includes: at least two coupling plates located between the top loading plate and the conductive ground plate and connected to the conductive ground plate; the at least two coupling plates are respectively disposed on the left and right sides of the radiator, and the at least two coupling plates are perpendicular to the radiator.

[0012] Preferably, on the sides of the VHF and UHF band antennas, the at least two coupling plates completely cover the at least one gap on both sides of the radiator.

[0013] Preferably, each of the at least two coupling plates is rectangular in shape, and each of the at least two short-circuit conductive plates is rectangular in shape.

[0014] Preferably, on the top view of the VHF and UHF band antennas, the top loading plate completely covers the at least two short-circuit conductive sheets and the at least two coupling sheets.

[0015] Preferably, the at least two short-circuit conductive plates are arranged axially symmetrically along the axis of symmetry of the radiator, and the at least two coupling plates are arranged axially symmetrically along the axis of symmetry of the radiator.

[0016] Preferably, the top end of the radiator has a protrusion, which is connected to the top loading plate;

[0017] The width of each of the at least two short-circuit conductive sheets is less than the length of the protrusion.

[0018] Preferably, the bottom end of the radiator has a gradient portion, which is connected to a conductive ground plane; the length of the end of the gradient portion closer to the conductive ground plane is less than the length of the end of the gradient portion farther from the conductive ground plane.

[0019] Preferably, the VHF and UHF band antenna further includes: a first capacitor, a first inductor, a second inductor, a second capacitor, a third inductor, a third capacitor, and a fourth inductor;

[0020] The first capacitor, the first inductor, the second inductor, and the second capacitor are connected in series between the coaxial port and the feed point of the VHF and UHF band antennas; the third inductor is connected between the connection point of the first capacitor and the first inductor and ground; the third capacitor is connected between the connection point of the first inductor and the second inductor and ground; and the fourth inductor is connected between the connection point of the second capacitor and the feed point and ground.

[0021] The VHF and UHF band antennas provided by this invention include a conductive ground plane, a top loading plate, and a radiator connected between the conductive ground plane and the top loading plate, as well as at least two short-circuit conductive plates connected between the top loading plate and the conductive ground plane. Each side of the radiator has at least one slot. The design of the short-circuit conductive plates and slots in the VHF and UHF band antennas of this invention can extend the antenna bandwidth under certain height limitations, optimize the impedance matching effect of the antenna, reduce the antenna height, and achieve miniaturized design of VHF and UHF band antennas.

[0022] By placing a coupling patch on the conductive ground plane, antenna performance can be further optimized and antenna height can be reduced.

[0023] The height of the rectangular slots on both sides of the radiator is within the height coverage range of the coupling plate, which can optimize the spatial radiation of the antenna and improve the radiation efficiency of the antenna.

[0024] The bottom of the antenna is designed as a gradient section, which can further extend the antenna bandwidth.

[0025] Setting up a broadband matching network between the coaxial port and the feed point can optimize impedance matching, reduce voltage standing wave ratio, and improve antenna performance. [Attached Image Description]

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A three-dimensional structural schematic diagram of VHF and UHF band antennas according to an embodiment of the present invention is shown;

[0028] Figure 2 A front view of a VHF and UHF band antenna according to an embodiment of the present invention is shown;

[0029] Figure 3 A schematic diagram of the matching network structure for VHF and UHF band antennas according to an embodiment of the present invention is shown;

[0030] Figure 4A The VHF and UHF band antennas according to embodiments of the present invention are shown to be unloaded. Figure 3 The voltage standing wave ratio of the matching network shown;

[0031] Figure 4B The VHF and UHF band antennas according to embodiments of the present invention are shown to be loaded. Figure 3 The voltage standing wave ratio of the matching network shown;

[0032] Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5E , Figure 5F , Figure 5G , Figure 5H The H-plane (θ = 90°) radiation patterns of eight frequency points of VHF and UHF band antennas according to an embodiment of the present invention are shown.

Detailed Implementation Methods

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Figure 1 A three-dimensional structural schematic diagram of VHF and UHF band antennas according to an embodiment of the present invention is shown. Figure 2 A front view schematic diagram of a VHF and UHF band antenna according to an embodiment of the present invention is shown. The Z-axis direction is the length direction, the X-axis direction is the width direction, and the Y-axis direction is the height direction.

[0035] The VHF and UHF band antennas of this invention include a conductive ground plane 1, a radiator 2, a top loading plate 3, a coupling plate 4, at least two short-circuit conductive plates 5, and a feed point 21. The conductive ground plane 1, radiator 2, top loading plate 3, coupling plate 4, and short-circuit conductive plates 5 are all conductive plate-like structures. Preferably, the radiator 2, top loading plate 3, coupling plate 4, and short-circuit conductive plates 5 are all all-metal structures.

[0036] The conductive ground plane 1 and the top loading plate 3 are arranged facing each other. Specifically, the conductive ground plane 1 and the top loading plate 3 are arranged parallel to each other. The radiator 2 is connected between the top loading plate 3 and the conductive ground plane 1. Specifically, the radiator 2 is vertically connected between the top loading plate 3 and the conductive ground plane 1. The feed point 21 is located at the bottom of the radiator 2, passes through the conductive ground plane 1 and is connected to the coaxial port, and the top of the radiator 2 is connected to the top loading plate 3. The radiator 2 is preferably a left-right symmetrical structure. The design elements of the symmetrical structure are easy to realize, and the regular physical structure facilitates theoretical calculation and analysis. The feed point 21 is preferably set on the left-right axis of symmetry of the left-right symmetrical radiator 2, which is beneficial for impedance matching in all directions, so that the VHF and UHF band antennas have good omnidirectional gain.

[0037] Each side of the radiator 2 has at least one slot 22. At least two short-circuit conductive plates 5 are also connected between the top loading plate 3 and the conductive ground plate 1. Specifically, the at least two short-circuit conductive plates 5 are respectively disposed on the front and rear sides of the radiator 2, and both short-circuit conductive plates 5 are parallel to the radiator 2.

[0038] Furthermore, the VHF and UHF band antennas also include at least two coupling plates 4. The at least two coupling plates 4 are located between the top loading plate 3 and the conductive ground plane 1 and are connected to the conductive ground plane 1; the at least two coupling plates 4 are respectively disposed on the left and right sides of the radiator 2, and both at least two coupling plates 4 are perpendicular to the radiator 2. Specifically, neither of the at least two coupling plates 4 is connected to the top loading plate 3.

[0039] In this embodiment, at least two short-circuit conductive plates 5 are arranged symmetrically along the axis of symmetry of the radiator 2, and at least two coupling plates 4 are arranged symmetrically along the axis of symmetry of the radiator 2.

[0040] The radiator 2 has a protrusion 23 at its top end, which is connected to the top loading plate 3. The width of each of the at least two short-circuit conductive pieces 5 is less than the length of the protrusion 23.

[0041] The length of the protrusion 23 is greater than the length of the gap 22, and the width of the gap 22 is greater than the width of the protrusion 23 (or the height of the protrusion 23).

[0042] The radiator 2 has a gradient section at its bottom end, which is connected to the conductive ground plane 1; the length of the end of the gradient section near the conductive ground plane 1 is less than the length of the end of the gradient section away from the conductive ground plane 1. In an optional embodiment, the shape of the gradient section may be trapezoidal.

[0043] The gradient section can also be designed as a triangle, with a feeding point set at one end near the conductive ground 1 to receive the feeding information. It is preferably an isosceles trapezoid or an equilateral triangle, which can improve the radiation effect of the radiator 2.

[0044] Specifically, there are two slits 22, that is, two symmetrical slits 22 are opened on both sides of the radiator 2, and the shape of the two slits 22 is rectangular.

[0045] A rectangular design for the gap 22 and the protrusion 23 is preferred, as it provides good impedance matching and facilitates manufacturing. The gap 22 is not limited to a pair, nor is its shape limited to rectangles; it can be designed as a fan shape or triangle. In this embodiment, the gap 22 is located in the middle in the vertical direction for good impedance matching; it can also be designed to be off-center, closer to the upper or lower end. The protrusion 23 connects to the top loading plate 3. The width (or height) of the protrusion 23, which connects the radiator 2 to the top loading plate 3, is smaller than the overall height of the radiator 2, resulting in better impedance matching.

[0046] Specifically, there are at least two coupling plates 4, located on the left and right sides of the radiator 2 respectively, and both connected to the conductive ground plane 1. Preferably, the structure is symmetrical, perpendicular to both the radiator 2 and the conductive ground plane 1, and on the Z-axis direction (i.e., the side of the antenna), the coupling plate 4 completely covers the slot 22, meaning the top height of the coupling plate 4 is greater than the top height of the slot 22. Simultaneously, the protrusion 23 of the radiator 2 is fully exposed on the side of the VHF and UHF band antennas; this optimizes spatial radiation and improves antenna performance.

[0047] Specifically, the number of at least two short-circuit conductive pieces 5 is preferably matched and disposed at the middle position of the radiator 2, parallel to the radiator 2, and connected between the top loading plate 3 and the conductive ground plate 1. In the VHF and UHF band antennas of this embodiment, the shape of the short-circuit conductive piece 5 is rectangular.

[0048] In this embodiment of the invention, the top loading plate 3 of the VHF and UHF band antenna has a length of 0.18λ and a width of 0.073λ. The overall height of the VHF and UHF band antenna is 0.09λ, where λ is the wavelength of the lowest frequency electromagnetic wave of the VHF and UHF band antenna.

[0049] A through-hole is provided in the center of the conductive ground plate 1. The feed point 21 is connected to the coaxial port through the through-hole to receive the feed. Coupler plates 4 are arranged on the left and right sides of the radiator 2. There are two short-circuit conductive plates 5, symmetrically arranged on the front and rear sides of the radiator 2, without contact with the radiator 2, forming a sleeve-like structure. The top loading plate 3 is elliptical, but can also be designed as circular or square. Both the coupler plates 4 and the short-circuit conductive plates 5 are rectangular and stand on the conductive ground plate 1. The short-circuit conductive plates 5 connect the conductive ground plate 1 and the top loading plate 3, which can expand the antenna bandwidth and reduce the width of the top loading plate 3 in the X-axis direction. The coupler plates 4 are only connected to the conductive ground plate 1, which is beneficial for expanding the antenna bandwidth and reducing the antenna height. The width of the coupling piece 4 and any one of the short-circuit conductive pieces 5 is less than or equal to the size of the corresponding area of ​​the top loading plate 3. That is, from the top view (i.e., the top view perspective), the top loading plate 3 completely covers or obscures the two coupling pieces 4 and the two short-circuit conductive pieces 5. Only the top loading plate 3 can be seen on the top view, and no coupling piece 4 or short-circuit conductive piece 5 is exposed within the size range of the top loading plate 3.

[0050] With the central through-hole of the conductive ground plane 1 as a reference, each structure of the antenna is preferably a centrally symmetrical structure in the top view.

[0051] The short-circuit conductive plates 5 are designed as a pair, or multiple pairs, symmetrically arranged with respect to the left and right axes of symmetry of the radiator 2. The conductive ground plate 1 can be rectangular, polygonal, elliptical, or circular, and its size is conventionally chosen to be larger than the size of the top loading plate 3. The top loading plate 3 can be elliptical, rectangular, or polygonal, and is preferably elliptical to match the radiator 2.

[0052] Figure 3A schematic diagram of a broadband matching network for VHF and UHF band antennas according to an embodiment of the present invention is shown. The broadband matching network includes a first capacitor C1, a first inductor L1, a second inductor L2, a second capacitor C2, a third inductor L3, a third capacitor C3, and a fourth inductor L4. The first capacitor C1, the first inductor L1, the second inductor L2, and the second capacitor C2 are connected in series between the coaxial port IN and the feed point 21 of the VHF and UHF band antennas; the third inductor L3 is connected between the connection point of the first capacitor C1 and the first inductor L1 and ground; the third capacitor C3 is connected between the connection point of the first inductor L1 and the second inductor L2 and ground; and the fourth inductor L4 is connected between the connection point of the second capacitor C2 and the feed point 21 and ground.

[0053] In this embodiment, the coaxial port IN is a 50-ohm coaxial port, capacitor C1 = 25.8844pF (picofarad), inductor L1 = 12.9478nH (nahen), inductor L2 = 53.8626nH, capacitor C2 = 6.16959pF, inductor L3 = 6.8315nH, capacitor C3 = 7.07228pF, and inductor L4 = 9.4896nH.

[0054] Figure 4A The VHF and UHF band antennas according to embodiments of the present invention are shown to be unloaded. Figure 3 The voltage standing wave ratio (VSWR) of the broadband matching network is shown. The horizontal axis represents frequency, and the vertical axis represents VSWR. Here, flow represents the lowest frequency point of the VHF and UHF band antennas in this embodiment of the invention, fhigh represents the highest frequency point of the VHF and UHF band antennas in this embodiment of the invention, and f1 to f6 are the six intermediate frequency points. Point 1 (flow, 11.033), point 2 (f... high (2.0207). The VHF and UHF band antennas in this embodiment of the invention are not loaded. Figure 3 The voltage standing wave ratio (VSWR) of the broadband matching network shown is as high as 11.033 in the low-frequency band, indicating extremely poor impedance matching performance at low frequencies. The VSWR in the frequency bands from f1 to f6 is less than 2, while the VSWR at the high-frequency point fhigh is 2.0207, indicating better impedance matching performance at high frequencies.

[0055] Figure 4B The VHF and UHF band antennas according to embodiments of the present invention are shown to be loaded. Figure 3 The voltage standing wave ratio (VSWR) of the broadband matching network shown. Frequency 1 (f low , 2.6223), frequency point 2 (f high (1.8684), each frequency point and Figure 4A The marked frequency points are the same, and the VHF and UHF band antennas in this embodiment of the invention are loaded with... Figure 3 The low-frequency point f after the broadband matching network shown lowThe voltage standing wave ratio (VSWR) is reduced to 2.6223 < 3, and the antenna's full-band bandwidth is maintained. low to f high The overall voltage standing wave ratio is less than 3, which meets the engineering requirements.

[0056] Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5E , Figure 5F , Figure 5G , Figure 5H The H-plane (θ = 90°) radiation patterns of eight frequency points of VHF and UHF band antennas according to an embodiment of the present invention are shown. Figure 5A , Figure 5B , Figure 5C , Figure 5D , Figure 5E , Figure 5F , Figure 5G , Figure 5H Corresponding to f respectively low , f1, f2, f3, f4, f5, f6, f high Frequency point.

[0057] Reference Figure 5A f low The main lobe gain at the frequency point is -0.415dB, and the main lobe direction is 90.0 degrees.

[0058] Reference Figure 5B The main lobe gain at frequency f1 is -1.07dB, and the main lobe direction is 90.0 degrees.

[0059] Reference Figure 5C The main lobe gain at frequency f2 is -1.52dB, and the main lobe direction is -29.0 degrees.

[0060] Reference Figure 5D The main lobe gain at frequency f3 is -2.27dB, and the main lobe direction is 178.0 degrees.

[0061] Reference Figure 5E The main lobe gain at frequency f4 is -1.59dB, and the main lobe direction is 0.0 degrees.

[0062] Reference Figure 5F The main lobe gain at frequency f5 is -0.388dB, and the main lobe direction is -9.0 degrees.

[0063] Reference Figure 5G The main lobe gain at frequency f6 is 0.437dB, the main lobe direction is -178 degrees, and the 3dB beamwidth is 124.3 degrees.

[0064] Reference Figure 5H fhigh The main lobe gain at the specified frequency is 0.907dB, the main lobe direction is 180 degrees, the 3dB beamwidth is 78.6dB, and the sidelobe gain is -3.6dB.

[0065] The results show that the VHF and UHF band antennas of the embodiments of the present invention are under load Figure 3 The broadband matching network shown has good full-band gain and good omnidirectionality.

[0066] The VHF and UHF band antennas of this invention utilize a short-circuit conductive sheet to reduce the width of the top loading plate, while simultaneously incorporating slots (e.g., rectangular slots) on the sides of the radiator to expand the antenna bandwidth, optimize impedance matching, and reduce antenna size. The top loading plate design further expands the antenna bandwidth and reduces antenna height. A coupling sheet is designed as a grounding post to expand the antenna bandwidth and reduce antenna height. A broadband matching network is loaded between the feed point and the 50-ohm coaxial port to optimize impedance, effectively reducing the voltage standing wave ratio (VSWR) at low frequencies and expanding the antenna bandwidth. The overall structure is simple, with dimensions of (0.18λ, 0.073λ, 0.09λ), where λ is the wavelength of the lowest frequency electromagnetic wave. The small overall size conforms to miniaturized antenna design, achieving a VSWR of less than 3 across the entire frequency band, good impedance matching, and excellent omnidirectional gain, resulting in superior performance for both VHF and UHF bands.

[0067] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A VHF and UHF band antenna, characterized by include: Conductive grounding; The top loading plate is positioned facing the conductive ground plane. A radiator is connected between the top loading plate and the conductive ground plate; At least two short-circuit conductive plates are also connected between the top loading plate and the conductive ground plate; At least two coupling plates are located between the top loading plate and the conductive ground plate and are connected to the conductive ground plate; Each side of the radiator has at least one slit. The at least two short-circuit conductive plates are respectively disposed on the front and rear sides of the radiator; The at least two coupling plates are respectively disposed on the left and right sides of the radiator; On the sides of the VHF and UHF band antennas, the at least two coupling plates completely cover the at least one gap on both sides of the radiator.

2. The VHF and UHF band antenna according to claim 1, characterized in that: Both of the at least two short-circuit conductive plates are parallel to the radiator.

3. The VHF and UHF band antenna according to claim 1, characterized in that, Also includes: Both of the at least two coupling plates are perpendicular to the radiator.

4. The VHF and UHF band antenna according to claim 3, characterized in that: Each of the at least two coupling plates is rectangular in shape, and each of the at least two short-circuit conductive plates is rectangular in shape.

5. The VHF and UHF band antenna according to claim 3, characterized in that: On the top view of the VHF and UHF band antennas, the top loading plate completely covers the at least two short-circuit conductive plates and the at least two coupling plates.

6. The VHF and UHF band antenna according to claim 3, characterized in that: The at least two short-circuit conductive plates are arranged axially symmetrically along the axis of symmetry of the radiator, and the at least two coupling plates are arranged axially symmetrically along the axis of symmetry of the radiator.

7. The VHF and UHF band antenna according to claim 1, characterized in that: The radiator has a protrusion at its top end, and the protrusion is connected to the top loading plate; The width of each of the at least two short-circuit conductive sheets is less than the length of the protrusion.

8. The VHF and UHF band antenna according to claim 1, characterized in that: The bottom end of the radiator has a gradient section, which is connected to a conductive ground plane; the length of the end of the gradient section near the conductive ground plane is less than the length of the end of the gradient section away from the conductive ground plane.

9. The VHF and UHF band antenna according to claim 1, characterized in that, Also includes: First capacitor, first inductor, second inductor, second capacitor, third inductor, third capacitor and fourth inductor; The first capacitor, the first inductor, the second inductor, and the second capacitor are connected in series between the coaxial port and the feed point of the VHF and UHF band antennas; the third inductor is connected between the connection point of the first capacitor and the first inductor and ground; the third capacitor is connected between the connection point of the first inductor and the second inductor and ground; and the fourth inductor is connected between the connection point of the second capacitor and the feed point and ground.

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