Miniaturized foldable ultra-wideband monopole antenna

Abstract

The invention discloses a miniaturized foldable ultra-wideband monopole antenna which comprises a dielectric substrate, a monopole radiation arm, a meander line radiation arm, a short-circuit metal wire, a feed probe and a cylindrical metal body. The monopole radiation arm, the meander line radiation arm and the short circuit metal wire are all attached to the same dielectric substrate, and a corresponding radiator structure can be formed through folding of the dielectric substrate. The monopole radiation arm is formed by bending a gradual change metal sheet and serves as a main radiation structure of the antenna. The feed probe is connected with the monopole radiation arm and provides feed excitation for the antenna; the meander line radiation arm is formed by bending a metal line, and is used as a parasitic loading structure for expanding the bandwidth of the antenna in a low-frequency band; and the meander line radiation arms are connected with the cylindrical metal body through short-circuit metal wires. According to the monopole antenna, the impedance bandwidth of an ultra wide band is achieved, the radiation structure can be formed by bending a single-layer printed circuit board, the monopole antenna has the advantages of being compact in structure and easy to manufacture, and integration with wireless communication equipment is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to a wireless communication device, in particular to a kind of ultra-wideband monopole antenna. BACKGROUND

[0002] In modern wireless communication systems, the working bandwidth of the antenna is always the core performance to be considered. With the continuous development of wireless communication technology, ultra-wideband antenna has broad application potential in short-wave communication, high-precision positioning, radar detection and other fields due to its extremely wide effective bandwidth and good anti-interference performance. The commonly used ultra-wideband antennas at present mainly include Vivaldi antenna, monopole antenna, spiral antenna, fractal antenna, logarithmic periodic antenna, etc. The traditional ultra-wideband antenna design often faces the contradiction between size and performance. The size of these antennas is usually larger than one quarter of the wavelength corresponding to the lowest working frequency of the antenna, and the size is relatively large, while reducing the size of the antenna will easily lead to the problem of narrow antenna bandwidth and gain decline. With the development of wireless communication equipment towards miniaturization and integration, it is urgently required to greatly reduce the size of the antenna while realizing the ultra-wideband radiation performance.

[0003] The monopole antenna has higher miniaturization potential because its resonant length is only half of that of the dipole antenna at the same frequency. The existing miniaturized monopole antenna design methods mostly achieve it by top capacitive loading, parasitic radiation structure loading or introducing lumped elements, which have relatively complex structure, need to be assembled in three dimensions, have relatively high cost, and the introduction of lumped elements will bring additional loss, leading to the decline of antenna gain. Therefore, it is necessary to design a miniaturized monopole antenna with simple and compact structure, convenient processing and manufacturing, and ultra-wideband radiation capability. SUMMARY

[0004] The present application provides a kind of miniaturized foldable ultra-wideband monopole antenna, which can realize the miniaturization of antenna size while having ultra-wideband radiation performance.

[0005] Technical scheme: a kind of miniaturized foldable ultra-wideband monopole antenna, comprising: dielectric substrate, monopole radiation arm, zigzag line radiation arm, short-circuit metal line, feed probe and cylindrical metal body; The monopole radiation arm, zigzag line radiation arm and short-circuit metal line are attached to the same dielectric substrate, and the zigzag line radiation arm is arranged in parallel with the monopole radiation arm. A three-dimensional radiator structure is formed by folding the dielectric substrate. The feed probe is connected to the monopole radiation arm to provide feed excitation for the antenna, and the zigzag line radiation arm is connected to the cylindrical metal body through the short-circuit metal line, and the cylindrical metal body serves as a common reference ground for the antenna.

[0006] Further, in the radiator structure, the portions of the meander line radiating arm and the monopole radiating arm folded into L shapes are parallel to each other, and the meander line radiating arm serves as a parasitic loading structure for extending the bandwidth of the antenna at a low frequency band.

[0007] Further, the total length of the cylindrical metal body in the axial direction should be greater than the diagonal length of the smallest cube completely surrounding the monopole radiating arm and the meander line radiating arm in the radiator structure.

[0008] Further, the material of the dielectric substrate is a radio frequency microwave dielectric substrate or a polymer material that is easy to bend.

[0009] Further, the monopole radiating arm, as the main radiating structure of the antenna, adopts a metal sheet with uniform width at the upper part and gradually changing width at the lower part, and the portion with gradually changing width is used to realize a gentle impedance transition and extend the operating bandwidth of the antenna.

[0010] Further, the meander line radiating arm is composed of a meander metal line.

[0011] Further, the feed probe adopts a coaxial line probe, a microstrip line probe, or a balun converter.

[0012] Further, the cross-sectional shape of the cylindrical metal body is circular, elliptical, or polygonal.

[0013] Further, the cylindrical metal body is equivalent to an antenna mounting platform in a cylindrical or near-cylindrical shape.

[0014] Further, the size of the monopole antenna is enlarged or reduced to operate in a short wave, very high frequency, microwave, or millimeter wave frequency band.

[0015] Beneficial effects: 1. The monopole antenna has a small antenna size while having super wideband radiation performance.

[0016] 2. The entire radiator part of the antenna is a single component, and the structure is simple and compact, occupying a small space volume, easy to install, and convenient for integration with a wireless communication system.

[0017] 3. The radiator of the monopole antenna can be folded from a single layer of dielectric substrate, and can be directly manufactured using standard printed circuit board technology, which is beneficial to reduce processing cost and improve assembly precision.

[0018] 4. The monopole antenna can be converted between a planar structure and a three-dimensional structure by folding and unfolding, and the planar state can be stacked and placed, which is convenient for batch carrying and transportation. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1A structural schematic diagram of the small-sized foldable ultra-wideband monopole antenna according to the present application; Figure 2 An unfolded state schematic diagram of the small-sized foldable ultra-wideband monopole antenna according to the present application; Figure 3 A folding and unfolding mode schematic diagram of the small-sized foldable ultra-wideband monopole antenna according to the present application; Figure 4 A structural diagram of an embodiment of the small-sized foldable ultra-wideband monopole antenna according to the present application working in the UHF band; Figure 5 A simulation VSWR curve diagram of the small-sized foldable ultra-wideband monopole antenna according to the embodiment of the present application; Figure 6 A simulation radiation pattern diagram of the small-sized foldable ultra-wideband monopole antenna according to the embodiment of the present application; In the figure: 1 - dielectric substrate, 2 - monopole radiation arm, 3 - zigzag line radiation arm, 4 - short-circuit metal line, 5 - feed probe, 6 - cylindrical metal body, 11 - first folding mark, 12 - second folding mark, 13 - third folding mark, 14 - fourth folding mark. DETAILED DESCRIPTION

[0020] The present application will be further explained below in conjunction with the accompanying drawings.

[0021] As shown in Figure 1 and Figure 2 , the small-sized foldable ultra-wideband monopole antenna according to the present embodiment comprises a dielectric substrate 1, a monopole radiation arm 2, a zigzag line radiation arm 3, a short-circuit metal line 4, a feed probe 5 and a cylindrical metal body 6.

[0022] The monopole radiation arm 2, the zigzag line radiation arm 3 and the short-circuit metal line 4 are all attached to the same dielectric substrate 1.

[0023] Among them, the monopole radiation arm 2 serves as the main radiation structure of the antenna. The monopole radiation arm 2 adopts a metal sheet with uniform width in the upper part and gradually changing width in the lower part. The width gradually changing part is used to realize a gentle impedance transition and expand the working bandwidth of the antenna. The outer contour of the gradually changing part can be a straight line, an exponential curve, an elliptical curve, etc.

[0024] The feed probe 5 is connected to the lower bottom end of the monopole radiation arm 2 and is used to provide feed excitation for the antenna. The feed probe 5 can adopt a coaxial line probe, a microstrip line probe, a balun converter, etc.

[0025] The zigzag line radiation arm 3 is composed of zigzag metal lines and is arranged in parallel with the monopole radiation arm 2, so that the current on the monopole radiation arm 2 can excite induced current on the zigzag line radiation arm 3. The zigzag line radiation arm 3 serves as a parasitic loading structure to extend the bandwidth of the antenna at low frequency band. The zigzag line radiation arm 3 adopts zigzag metal lines, which can prolong the current path and reduce the resonant frequency.

[0026] The medium substrate 1 adopts a radio frequency microwave medium plate material or a polymer material which is easy to bend, and the polymer material can be PET, PI, PTFE or the like.

[0027] Through the folding of the medium substrate 1, the antenna is changed from a planar structure of a single layer medium plate to a three-dimensional radiator structure, and the zigzag line radiation arm 3 and the monopole radiation arm 2 are arranged in parallel. One end of the zigzag line radiation arm 3 is connected to the columnar metal body 6 located below the radiator structure through the short-circuit metal line 4. The columnar metal body 6 serves as a common reference ground of the antenna, and the short-circuit metal line 4 provides a current path for the zigzag line radiation arm 3 to return to the columnar metal body 6, so that the antenna produces a new resonance at a low frequency band, reduces the lowest working frequency of the antenna, and realizes the miniaturization of the antenna.

[0028] The cross-sectional shape of the columnar metal body 6 can be circular, oval, polygonal or the like, and the total length of the axial direction should be greater than the diagonal length of the smallest cube completely surrounding the monopole radiation arm 2 and the zigzag line radiation arm 3 in the radiator structure, so as to ensure that the corresponding mirror current can be excited on the columnar metal body 6 as the common reference ground of the monopole antenna, so that the monopole antenna can resonate at the lowest frequency band. The columnar metal body 6 is equivalent to the columnar or nearly columnar antenna mounting platform of an aircraft fuselage, a satellite, a ship or the like.

[0029] As shown in Figure 3 The folding process is as follows: first, the medium substrate 1 is folded along the first folding mark 11 to construct the short-circuit metal line 4 which is led outwards to be connected to the columnar metal body 6; then, the medium substrate 1 is folded along the second folding mark 12 to change the zigzag line radiation arm 3 arranged in a plane to an L-shaped three-dimensional structure, thereby reducing the space occupied by the zigzag line radiation arm 3 and realizing the miniaturization of the antenna; then, the medium substrate 1 is folded along the third folding mark 13 to make the zigzag line radiation arm 3 parallel to one side of the L-shaped monopole radiation arm 2, so that the current on the monopole radiation arm 2 can excite induced current on the zigzag line radiation arm 3 to realize the parasitic loading effect; finally, the medium substrate 1 is folded along the fourth folding mark 14 to change the monopole radiation arm 2 arranged in a plane to an L-shaped three-dimensional structure, so that the two sides of the monopole radiation arm 2 are respectively parallel to the two sides of the L-shaped monopole radiation arm 2, thereby reducing the space occupied by the monopole radiation arm 2 and further realizing the miniaturization of the antenna. Through the above folding process, the monopole antenna is changed from a planar state shown in Figure 2 to a three-dimensional radiator structure shown inFigure 1 The stereoscopic folding state is shown, and further assembled in connection with the feeding probe 5 and the cylindrical metal body 6.

[0030] In order to illustrate the structure and working performance of the ultra-wideband monopole antenna of the present application, a specific embodiment working in the UHF band is designed by optimizing and adjusting the structure sizes of each part of the antenna, as shown in the figure. Figure 4 The size parameter table of each part of the monopole antenna of the embodiment is shown in Table 1.

[0031] Table 1 Size parameter table of the UHF band monopole antenna (unit: millimeter) Figure 5 The VSWR simulation results of the embodiment of the present application are plotted. The antenna of the embodiment of the present application has a VSWR < 3 in the frequency band of 0.5 GHz ~ 2 GHz, and the impedance bandwidth reaches 4 times of the frequency, having an ultra-wideband impedance matching performance.

[0032] Figure 6 The radiation pattern simulation results of the embodiment at the frequency points of 500 MHz, 1000 MHz, 1500 MHz and 2000 MHz are plotted. The radiation pattern of the antenna of the embodiment in the azimuth plane is approximately omnidirectional radiation, and the main beam direction of the antenna in the elevation plane is approximately located in the plane perpendicular to the monopole, and gradually shifts to the direction of the monopole with the increase of the working frequency of the antenna.

[0033] By appropriately enlarging or reducing the size of the miniaturized foldable ultra-wideband monopole antenna, the antenna can work in the microwave, millimeter wave and terahertz bands.

[0034] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A miniaturized foldable ultrawideband monopole antenna, characterized in that, include: Dielectric substrate (1), monopole radiating arm (2), zigzag radiating arm (3), short-circuit metal line (4), feed probe (5) and cylindrical metal body (6); The monopole radiating arm (2), the zigzag radiating arm (3), and the short-circuit metal line (4) are all attached to the same dielectric substrate (1), and the zigzag radiating arm (3) is arranged parallel to the monopole radiating arm (2). A three-dimensional radiator structure is formed by folding a dielectric substrate (1); The feed probe (5) is connected to the monopole radiating arm (2) to provide feed excitation for the antenna; the zigzag radiating arm (3) is connected to the cylindrical metal body (6) through the short-circuit metal line (4), and the cylindrical metal body (6) serves as the common reference ground of the antenna.

2. The miniaturized foldable ultrawideband monopole antenna as described in claim 1, characterized in that, In the radiator structure, the zigzag radiating arm (3), which is folded into an L-shape, is parallel to each other with the monopole radiating arm (2). The zigzag radiating arm (3) serves as a parasitic loading structure to extend the bandwidth of the antenna in the low-frequency band.

3. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The total axial length of the cylindrical metal body (6) should be greater than the diagonal length of the smallest cube that completely surrounds the monopole radiating arm (2) and the tortuous radiating arm (3) in the radiating body structure.

4. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The dielectric substrate (1) is made of easily bendable radio frequency microwave dielectric material or polymer material.

5. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The monopole radiating arm (2) serves as the main radiating structure of the antenna. It is made of a metal sheet with a uniform upper width and a gradually changing lower width. The gradually changing width is used to achieve a smooth impedance transition and expand the antenna's operating bandwidth.

6. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The zigzag radial arm (3) is composed of zigzag metal wires.

7. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The power supply probe (5) is a coaxial line probe, a microstrip line probe, or a balun converter.

8. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The cross-sectional shape of the cylindrical metal body (6) is circular, elliptical or polygonal.

9. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, The cylindrical metal body (6) is an equivalent of a cylindrical or near-cylindrical antenna mounting platform.

10. A miniaturized foldable ultrawideband monopole antenna as described in claim 1 or 2, characterized in that, By enlarging or reducing the size of the monopole antenna, it can be made to operate in the shortwave, VHF, microwave, or millimeter wave frequency bands.

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