阅读说明：本技术 一种渐变型巴伦馈电的宽带全向偶极子天线 (gradual change type balun feed broadband omnidirectional dipole antenna ) 是由 王志龙 周理想 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种渐变型巴伦馈电的宽带全向偶极子天线,包括两个辐射体、渐变型巴伦、金属底板、两个支撑座和若干根支撑杆；采用轴对称天线形式,两个辐射体水平面对称辐射体,由锥台和若干圆柱组成,通过渐变型巴伦馈电,利用辐射体直径渐变式结构调节驻波。本发明天线阻抗带宽为1.25GHz~10GHz。工作频段范围内驻波比基本小于2.2,不圆度低频部分小于3dB,高频部分小于6dB,增益典型值为3dBi,在工作频带内具有良好阻抗带宽和辐射方向图,适用于无人机侦察等民防领域。(The invention discloses an gradient balun fed broadband omnidirectional dipole antenna, which comprises two radiators, a gradient balun, a metal bottom plate, two supporting seats and a plurality of supporting rods, wherein an axially symmetric antenna form is adopted, the two radiators are horizontally symmetric radiators and consist of a frustum and a plurality of cylinders, standing waves are adjusted by using a gradient structure of the diameters of the radiators through the gradient balun feed, the impedance bandwidth of the antenna is 1.25 GHz-10 GHz, the standing-wave ratio in the working frequency band range is basically less than 2.2, the out-of-roundness low-frequency part is less than 3dB, the high-frequency part is less than 6dB, the typical gain value is 3dBi, the antenna has good impedance bandwidth and radiation pattern in the working frequency band, and the antenna is suitable for the civil defense field such as unmanned aerial vehicle reconnaissance.)

1, A broadband omnidirectional dipole antenna fed by gradual change type balun, comprising

a supporting seat (4) and a second supporting seat (7), the supporting seat (4) is arranged in parallel right above the second supporting seat (7),

the plurality of supporting rods (3) are connected with the th supporting seat (4) and the second supporting seat (7) to form a supporting structure together;

the method is characterized in that: also comprises

th radiator (1) and second radiator (6), wherein the th radiator (1) is arranged right above the second radiator (6), the top surface of the th radiator (1) is fixed on the bottom surface of the th supporting seat (4), the second radiator (6) is fixed on the top surface of the second supporting seat (7), and a plurality of supporting rods (3) pass through the edges of the th radiator (1) and the second radiator (6) to support and fix the th supporting seat (4), the th radiator (1), the second radiator (6) and the second supporting seat (7);

the graded balun (2) is arranged in the second radiating body (6), an outer conductor of the graded balun (2) is fixedly connected with the second radiating body (6), and an inner conductor extends upwards to be fixedly connected with the th radiating body (1);

and the round metal bottom plate (5) is fixed on the bottom surface of the second supporting seat (7).

2. A broadband omnidirectional dipole antenna fed by a gradually changing balun according to claim 1, characterized in that the -th radiator (1) and the second radiator (6) are both hollow as dipoles, and have no end caps at the top and bottom.

3. The broadband omnidirectional dipole antenna fed by the gradually-varying balun according to claim 1, wherein an oblique notch is formed at an end portion of an outer conductor of the gradually-varying balun (2), an opening angle of the oblique notch is changed according to a specific rule to change characteristic impedance of each point, so that balanced feeding within a wide frequency band is realized, broadband matching is realized, and radiation is performed through the th radiator (1) and the second radiator (6).

4. A wideband omnidirectional dipole antenna fed by a graded balun as claimed in claim 1 or claim 3 in which:

the gradient length L equation of the gradient balun (2) is as follows:

the characteristic impedance equation is:

in the formula of_maxIs the maximum wavelength, Z₁、Z₂Are characteristic impedances, Г_mTo allow maximum reflection coefficient, ∈_rAnd b is the external radius size of the gradually-changed balun, and a is the internal radius size of the gradually-changed balun respectively.

5. A broadband omnidirectional dipole antenna fed by a gradually changing balun according to claim 1 or 2, characterized in that the -th radiator (1) and the second radiator (6) are identical in structure.

6. A broadband omnidirectional dipole antenna fed by a gradually varying balun according to claim 1, 2 or 5, characterized in that the th radiator (1) is composed of two structurally identical sub-radiators symmetrical about a horizontal plane, said sub-radiators comprising a frustum and a plurality of columns, the cross-sectional areas of the columns decrease sequentially from end to end , the column with the smallest cross-sectional area is connected to the plane with the largest diameter in the frustum, and the supporting rod (3) passes through the edge of the column with the largest diameter.

7. A broadband omnidirectional dipole antenna fed by a gradually changing balun according to claim 1, 2 or 5, characterized in that the wall thickness of the th radiator (1) and the second radiator (6) are both 2mm and the height is 0.3 λ_max～0.4λ_max。

8. A broadband omnidirectional dipole antenna fed by a gradually changing balun according to claim 1, 2 or 5, characterized in that the diameter of the cylinder with the largest cross-sectional area among the -th radiator (1) and the second radiator (6) is 0.25 λ_max～0.35λ_max，λ_maxThe corner is chamfered by 1mm for the maximum wavelength of the operating wavelength.

9. A tapered balun fed broadband omnidirectional dipole antenna according to claim 1, characterized in that: diameter L of the circular metal base plate (5)₂Is 0.25 lambda_max～0.35λ_maxAnd the thickness is 3 mm.

10. The broadband omnidirectional dipole antenna with the gradually-changed balun feed function as claimed in claim 1, wherein the supporting rod (3), the -th supporting seat (4) and the second supporting seat (7) are made of insulating materials.

Technical Field

The invention belongs to communication antennas, and particularly relates to an gradually-changed balun fed broadband omnidirectional dipole antenna.

Background

Dipole antenna is the antenna used in radio communications, the earliest used in most applications, and it is composed of pairs of symmetrically placed conductors, the radiation field generated by this antenna at a distance is axisymmetric, theoretical analysis shows that the current distribution in the elongated dipole antenna has the form of a standing wave, the wavelength of which is exactly the wavelength of the electromagnetic wave generated or received by the antenna, has several methods to extend the bandwidth of the antenna (1) the antenna ends are connected to matching loads, and the electricity on them is connected to matching loadsThe flow is distributed as traveling wave, the input impedance is equal to the characteristic impedance of the transmission line and does not change along with the frequency; (2) the protruding angle is not the length, the structure of the antenna is only related to the angle, and therefore the radiation characteristic and the impedance characteristic of the antenna are independent of the frequency; (3) the thick conductor increases the wire diameter of the resonant antenna such as a vibrator antenna, and can increase the impedance bandwidth, so that the frequency bandwidth can be increased; (4) self-complementary structures, structures covering exactly their complementary structures by means of translation or rotation, with an input impedance Z_inη/2, independent of frequency.

For example, high-gain broadband omnidirectional antennas disclosed in patent document 1(CN103000987A) achieve broadband matching by using a thick conductor and a matching station through direct coaxial feeding, and improve gain by using a reflector, where the dipole diameter d1 is 0.1 λ₀The diameter of the reflector is 1-4 lambda₀The gain can reach 6dBi, and when the frequency is 2.5GHz, 2.6GHz and 2.7GHz, the beam pointing is stable, so that the method has the advantages of larger gain, stable beam pointing and the like. The out-of-roundness is typically 6dB in the operating band. However, for the broadband omnidirectional antenna, the working bandwidth is not enough to support the application requirements, the out-of-roundness is poor, the longitudinal dimension is too large, and the broadband omnidirectional antenna is not suitable for the vehicle-mounted or airborne installation environment.

Disclosure of Invention

The invention aims to provide kinds of gradually-changed balun fed broadband omnidirectional dipole antennas, and solves the problems of narrow frequency band, large size, poor non-circularity and the like of a conventional broadband omnidirectional antenna.

The technical scheme includes that broadband omnidirectional dipole antennas fed by gradually-varying balun comprise the gradually-varying balun, a circular metal base plate, a radiator, a second radiator, a 0 th supporting seat, a second supporting seat and a plurality of supporting rods, wherein the 1 th supporting seat is arranged right above the second supporting seat in parallel, the th radiator is arranged right above the second radiator, the top surface of the radiator is fixed to the bottom surface of the th supporting seat, the second radiator is fixed to the top surface of the second supporting seat, the supporting rods penetrate through the edges of the radiator and the second radiator to support and fix the th supporting seat, the th radiator, the second radiator and the second supporting seat, the th radiator and the second radiator are both hollow structures serving as dipoles, end covers are not arranged at the top end and the bottom end, the gradually-varying balun is arranged in the second radiator, an outer conductor of the gradually-varying balun is fixedly connected with the second radiator, an inner conductor extends upwards to be fixedly connected with the , and the circular metal base plate is fixed to the bottom surface of the second radiator.

Compared with the prior art, the invention has the following advantages:

(1) the frequency bandwidth is wide, the impedance bandwidth is 1.25G-10G, and exceeds 3 octaves.

(2) Small longitudinal dimension and maximum outer diameter dimension of about 0.3 lambda_maxWhile the height is about 0.7 lambda_max。

(3) The out-of-roundness is small, the low-frequency part is less than 3dB, and the high-frequency part is less than 6 dB.

Drawings

Fig. 1 is a three-dimensional diagram of a structure of a broadband omni-directional dipole antenna fed by a graded balun of the present invention.

Fig. 2 is a cross-sectional view of a wideband omni-directional dipole antenna structure fed by a graded balun of the present invention.

Fig. 3 is a standing wave diagram of a broadband omni-directional dipole antenna fed by a graded balun of the present invention.

Fig. 4 is an E-plane pattern of a broadband omni-directional dipole antenna fed by a graded balun of the present invention.

Fig. 5 is an H-plane pattern of a broadband omni-directional dipole antenna fed by a graded balun of the present invention.

In the figure, 1- th radiator, 2-graded balun, 3-support rod, 4- th support seat, 5-circular metal bottom plate, 6-second radiator and 7-second support seat.

Detailed Description

The invention is described in further detail with reference to the figures and the specific embodiments:

with reference to fig. 1 and 2, kinds of gradually-changed balun-fed broadband omnidirectional dipole antennas include a gradually-changed balun 2, a circular metal base plate 5, a radiator 1, a second radiator 6, a 0 support seat 4, a second support seat 7, and a plurality of support rods 3, wherein the support seat 4 is disposed in parallel right above the second support seat 7, the radiator 1 is disposed right above the second radiator 6, a top surface of the radiator 1 is fixed to a bottom surface of the support seat 4, the second radiator 6 is fixed to a top surface of the second support seat 7, the plurality of support rods 3 penetrate edges of the radiator 1 and the second radiator 6 to support and fix the support seat 4, the radiator 1, the second radiator 6 and the second radiator 7, the and the second radiator 6 serve as dipoles, both are hollow structures, no end caps are disposed at top and bottom ends, the gradually-changed balun 2 is disposed in the second radiator 6, an outer conductor of the gradually-changed balun 2 is fixedly connected to the second radiator 6, an inner conductor of the second radiator is fixedly connected to the second support seat, and fixedly connected to the circular radiator base plate 585, and the second radiator is fixedly connected to the second.

An oblique notch is arranged at the end part of an outer conductor of the gradually-changed balun 2, the opening angle of the oblique notch is changed according to a specific rule so as to change the characteristic impedance of each point, realize balanced feed in a broadband, realize broadband matching, and radiate through the th radiation body 1 and the second radiation body 6.

The equation of the gradient length L of the gradually-changed balun 2 is as follows:

the characteristic impedance equation is:

in the formula of_maxIs the maximum wavelength, Z₁、Z₂Are characteristic impedances, Г_mTo allow maximum reflection coefficient, ∈_rAnd b is the external radius size of the gradually-changed balun, and a is the internal radius size of the gradually-changed balun respectively.

The th radiator 1 and the second radiator 6 have the same structure, and the th radiator 1 is taken as an example for structural explanation.

The irradiator 1 comprises two sub irradiators that the structure is the same about horizontal plane symmetry, sub irradiator includes frustum and a plurality of cylinder, and a plurality of cylinders reduce in proper order from end to another end cross-sectional area, and the cylinder of minimum cross-sectional area links to each other with the big face of diameter in the frustum, and bracing piece 3 passes the cylinder edge of diameter the biggest.

The wall thickness of the th radiator 1 and the wall thickness of the second radiator 6 are both 2mm, and the height is 0.3 lambda_max～0.4λ_max。

The diameter of the cylinder having the largest cross-sectional area among the th radiator 1 and the second radiator 6 is 0.25 lambda_max～0.35λ_max，λ_maxThe corner is chamfered by 1mm for the maximum wavelength of the operating wavelength.

Diameter L of circular metal base plate 5₂Is 0.25 lambda_max～0.35λ_maxAnd the thickness is 3 mm.

The support rod 3, the th support seat 4 and the second support seat 7 are made of insulating materials.