A small multi-frequency octagonal monopole antenna

Abstract

This invention discloses a small multi-frequency octagonal monopole antenna in the field of monopole antenna technology, aiming to solve the problems of large size, poor performance, and unfavorable application of existing small monopole antennas. It includes a dielectric substrate, a feed microstrip line, an octagonal monopole, a rectangular ring, and a rectangular ring antenna ground. The feed microstrip line, octagonal monopole, and rectangular ring are all disposed on the upper surface of the dielectric substrate, with the octagonal monopole located inside the rectangular ring. The feed microstrip line is connected to the octagonal monopole and the rectangular ring, and the rectangular ring antenna ground is located on the lower surface of the dielectric substrate. This invention is applicable to monopole antennas. By cooperating the rectangular ring disposed on the upper surface of the dielectric substrate with the rectangular ring antenna ground on the lower surface, the operating frequency of the antenna is reduced, allowing the antenna to operate in multiple frequency bands and achieve quasi-omnidirectional radiation. This is beneficial for reducing the antenna's electrical size, improving antenna performance, and meeting application requirements.

Description

Technical Field

[0001] This invention relates to a small multi-frequency octagonal monopole antenna, belonging to the field of monopole antenna technology. Background Technology

[0002] Since its inception in the 20th century, the monopole antenna has seen rapid technological advancements, resulting in a wide variety of monopole antennas. Due to their simple structure, monopole antennas are widely used in various communication systems. However, the excessively large size of traditional monopole antennas not only affects the overall size of communication equipment but also increases antenna costs. Monopole antennas include the commonly used three-dimensional whip monopole antenna and PCB-printable planar monopole antennas. Generally, for both three-dimensional and planar monopole antennas, the antenna size is inversely proportional to the antenna's lowest operating frequency. The antenna floor size and feeding method also significantly impact antenna performance. To reduce antenna size and meet application requirements, miniaturized multi-frequency monopole antennas have become a research hotspot.

[0003] Common small monopole antennas are miniaturized by bending the antenna arm to shorten the antenna length. However, the length that can be shortened by this method is still very limited, resulting in a large antenna size, poor antenna performance, and hindering technological applications. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a small multi-frequency octagonal monopole antenna, which solves the problems of common small monopole antennas having large size, poor antenna performance, and being unfavorable for technical applications.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0006] This invention provides a small multi-frequency octagonal monopole antenna, comprising a dielectric substrate, a fed microstrip line, an octagonal monopole, a rectangular ring, and a rectangular ring antenna ground. The fed microstrip line, the octagonal monopole, and the rectangular ring are all disposed on the upper surface of the dielectric substrate. The octagonal monopole is located inside the rectangular ring. The fed microstrip line is connected to the octagonal monopole and the rectangular ring. The rectangular ring antenna ground is located on the lower surface of the dielectric substrate.

[0007] Furthermore, two notches are provided on the left side, right side, and top side of the inner wall of the rectangular ring, and the notches are spaced apart.

[0008] Furthermore, the rectangular ring is composed of two first rectangular strips, a first upper strip, and a first lower strip joined together.

[0009] Furthermore, the width of the two first rectangular bars is the same as the width of the first upper rectangular bar.

[0010] Furthermore, the rectangular ring antenna ground comprises two second rectangular strips, a second upper strip, and a second lower strip spliced ​​together, wherein the width of the second upper strip is smaller than the width of the second lower strip.

[0011] Furthermore, the two first rectangular bars are respectively located directly above the two second rectangular bars, and the first lower rectangular bar is located directly above the second lower rectangular bar.

[0012] Furthermore, the distance between the second upper strip and the lower edge of the dielectric substrate is greater than the distance between the first upper strip and the lower edge of the dielectric substrate.

[0013] Furthermore, the feed microstrip line includes a trapezoidal microstrip line and a rectangular microstrip line connected to the trapezoidal microstrip line.

[0014] Furthermore, there is a gap between the octagonal monopole and the inner wall of the rectangular ring.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0016] 1. This octagonal monopole antenna, by cooperating with the rectangular ring antenna ground on the upper surface of the dielectric substrate and the rectangular ring antenna ground on the lower surface of the dielectric substrate, reduces the antenna's operating frequency and allows the antenna to operate in multiple frequency bands, achieving quasi-omnidirectional radiation. This is beneficial for reducing the antenna's electrical size, improving antenna performance, and meeting application requirements.

[0017] 2. This invention can adjust the antenna frequency and input impedance by adjusting the size and relative position of the feed microstrip line, octagonal monopole, rectangular ring, and rectangular ring antenna ground.

[0018] 3. The present invention has two notches on the left side, the right side and the top side of the inner wall of the rectangular ring, which further extend the current path and reduce the antenna operating frequency. Attached Figure Description

[0019] Figure 1 This is a front structural schematic diagram of a small multi-frequency octagonal monopole antenna according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the back structure of a small multi-frequency octagonal monopole antenna according to an embodiment of the present invention;

[0021] Figure 3 This is an S11 frequency response curve of a small multi-frequency octagonal monopole antenna provided according to an embodiment of the present invention;

[0022] Figure 4This is a 1268MHz normalized radiation pattern of a small multi-frequency octagonal monopole antenna provided according to an embodiment of the present invention;

[0023] Figure 5 This is a normalized radiation pattern of a small multi-frequency octagonal monopole antenna at 1839MHz according to an embodiment of the present invention;

[0024] Figure 6 This is a 2638MHz normalized radiation pattern of a small multi-frequency octagonal monopole antenna provided according to an embodiment of the present invention.

[0025] In the diagram: 1. Feed microstrip line; 2. Octagonal monopole; 3. Rectangular ring; 31. First rectangular bar; 32. First upper rectangular bar; 33. First lower rectangular bar; 4. Rectangular ring antenna ground; 41. Second rectangular bar; 42. Second upper rectangular bar; 43. Second lower rectangular bar; 5. Dielectric substrate; 6. Notch. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] like Figure 1 and Figure 2 As shown, the present invention provides a small multi-frequency octagonal monopole antenna, including a dielectric substrate 5, a feed microstrip line 1, an octagonal monopole 2, a rectangular ring 3, and a rectangular ring antenna ground 4. The feed microstrip line 1, the octagonal monopole 2, and the rectangular ring 3 are all disposed on the upper surface of the dielectric substrate 5. The octagonal monopole 2 is located inside the rectangular ring 3. The feed microstrip line 1 is connected to the octagonal monopole 2 and the rectangular ring 3. The rectangular ring antenna ground 4 is located on the lower surface of the dielectric substrate 5.

[0030] Specifically, the rectangular ring 3 has two notches 6 on its left, right, and upper inner walls, with multiple notches 6 spaced apart; the rectangular ring 3 is composed of two first rectangular bars 31, a first upper bar 32, and a first lower bar 33 joined together; the width of the two first rectangular bars 31 is the same as the width of the first upper bar 32; the rectangular ring antenna ground 4 is composed of two second rectangular bars 41, a second upper bar 42, and a second lower bar 43 joined together, with the width of the second upper bar 42 being smaller than that of the first upper bar 32. The width of the second lower strip 43; the two first rectangular strips 31 are respectively located directly above the two second rectangular strips 41, and the first lower strip 33 is located directly above the second lower strip 43; the distance between the second upper strip 42 and the lower edge of the dielectric substrate 5 is greater than the distance between the first upper strip 32 and the lower edge of the dielectric substrate 5; the feed microstrip line 1 includes a trapezoidal microstrip line and a rectangular microstrip line connected to the trapezoidal microstrip line; there is a gap between the octagonal monopole 2 and the inner wall of the rectangular ring 3.

[0031] In one embodiment, optionally, the dielectric substrate 5 is a Rogers RO4350 substrate with a thickness of 0.6 mm (relative permittivity εr = 3.66, dielectric loss tangent tanδ = 0.004). The monopole antenna is optimized using the simulation software HFSS, and the overall length and width of the monopole antenna are L = 59 mm and W = 55 mm, respectively.

[0032] Optionally, the trapezoidal microstrip line has a short side base width W1 = 6.4 mm, a long side base width W2 = 12.8 mm, a height L1 = 5.4 mm, a total height L2 = 10.7 mm for the feed microstrip line 1, a side length L3 = 16.5 mm for the octagonal monopole 2, a width W3 = 3 mm for the first rectangular strip 31, an outer perimeter length L4 = 50.5 mm, an outer perimeter width W4 = 50 mm for the rectangular ring 3, a distance D1 = 22 mm between the two notches 6 on the upper side of the inner wall of the rectangular ring 3, and a width W4 = 50 mm for the inner wall of the rectangular ring 3. The spacing between the two notches 6 on the left side of the wall and the spacing between the two notches 6 on the right side of the inner wall of the rectangular ring 3 are both D2 = 22.5 mm. The spacing between the lower left notch 6 and the lower right notch 6 on the inner wall of the rectangular ring 3 and the lower edge of the dielectric substrate 5 is both D3 = 24 mm. The width of the second rectangular strip 41 is 7.5 mm. The width of the second upper strip 42 is 1.2 mm. The width of the second lower strip 43 is W5 = 16.2 mm. The spacing between the second upper strip 42 and the second lower strip 43 is L5 = 41.6 mm.

[0033] Depend on Figure 3 It can be seen that, Figure 3 The simulation characteristic curve of the S11 parameter of a dual-ring loaded octagonal monopole antenna as a function of frequency is provided for an embodiment of the present invention. When the antenna reflection coefficient S11 < -10dB corresponds to a standing wave ratio (VSWR) ≤ 2, the antenna operating frequency bands are 1.27 / 1.84 / 2.64GHz. Table 1 lists the antenna's reflection coefficient, antenna efficiency, gain, and other parameters at each resonant point. The gains at each resonant point are 3.36dBi (1268MHz), 3.49dBi (1839MHz), and 3.5dBi (2638MHz), which can meet the requirements of conventional applications.

[0034] Table 1 Antenna Parameters

[0035]

[0036] like Figures 4 to 6 As can be seen, taking the antenna center as the origin, the x-axis is taken along the long side of the antenna, and the y-axis is taken along the narrow side of the antenna. The solid line in the figure shows the radiation pattern of the monopole antenna of the present invention in the xoz plane (Ф=0°) perpendicular to the antenna, and the dashed line shows the radiation pattern of the monopole antenna of the present invention in the yoz plane (Ф=90°) perpendicular to the antenna. Figures 4 to 6 It can be seen that the antenna exhibits near-omnidirectional radiation in the yoz plane (Ф=90°), which can meet the application requirements of reading information from all directions and can be used in fields such as Beidou satellite navigation system B3 and 4G mobile communication.

[0037] As can be seen from the above, the present invention reduces the operating frequency of the antenna by cooperating with the rectangular ring 3 on the upper surface of the dielectric substrate 5 and the rectangular ring antenna ground 4 on the lower surface of the dielectric substrate 5, and allows the antenna to operate in multiple frequency bands, achieving quasi-omnidirectional radiation. This is beneficial for reducing the electrical size of the antenna, improving antenna performance, and meeting application requirements.

[0038] This invention can adjust the antenna frequency and input impedance by adjusting the size and relative position of the feed microstrip line 1, the octagonal monopole 2, the rectangular ring 3, and the rectangular ring antenna ground 4.

[0039] The present invention provides two notches 6 on the left side, right side and upper side of the inner wall of the rectangular ring 3, which serve to further extend the current path and reduce the antenna operating frequency.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A compact multi-band octagonal monopole antenna, characterized by, The application relates to a rectangular loop antenna, which comprises a medium substrate (5), a feeding microstrip line (1), an octagonal monopole (2), a rectangular loop (3) and a rectangular loop antenna ground (4), wherein the feeding microstrip line (1), the octagonal monopole (2) and the rectangular loop (3) are arranged on the upper surface of the medium substrate (5), the octagonal monopole (2) is located on the inner side of the rectangular loop (3), the feeding microstrip line (1) is connected with the octagonal monopole (2) and the rectangular loop (3), and the rectangular loop antenna ground (4) is located on the lower surface of the medium substrate (5). The rectangular loop (3) is composed of two first long strips (31), a first upper long strip (32) and a first lower long strip (33). The rectangular loop antenna ground (4) is composed of two second long strips (41), a second upper long strip (42) and a second lower long strip (43), and the width of the second upper long strip (42) is smaller than that of the second lower long strip (43). The two first long strips (31) are located above the two second long strips (41) respectively, and the first lower long strip (33) is located above the second lower long strip (43).

2. A compact multi-band octagonal monopole antenna according to claim 1, wherein Two notches (6) are arranged on the left side, the right side and the upper side of the inner wall of the rectangular loop (3).

3. A compact multi-band octagonal monopole antenna according to claim 1, wherein The width of the two first long strips (31) is the same as that of the first upper long strip (32).

4. A compact multi-band octagonal monopole antenna according to claim 1, wherein The distance between the second upper long strip (42) and the lower edge of the medium substrate (5) is greater than that between the first upper long strip (32) and the lower edge of the medium substrate (5).

5. A compact multi-band octagonal monopole antenna according to claim 1, wherein The feeding microstrip line (1) comprises a trapezoidal microstrip line and a rectangular microstrip line connected with the trapezoidal microstrip line.

6. A compact multi-band octagonal monopole antenna according to claim 1, wherein A gap exists between the octagonal monopole (2) and the inner wall of the rectangular loop (3).

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