A UWB balloon conformal heterogeneous array antenna with half-space beam coverage

Abstract

The present invention discloses a half-space beam coverage ultra-wideband balloon conformal heterogeneous array antenna, which relates to the technical field of balloon conformal antennas and is arranged on a conformal carrier. It includes a number of conformal sub-arrays composed of array antenna A with high-gain directional beams and array antenna B with medium-gain wide-beam coverage. The several conformal sub-arrays are arranged along the circumferential axis of the conformal carrier. Array antenna A is a high-gain end-fire balloon array antenna that meets any bandwidth and size conditions. Array antenna B includes two half-wave dipole antenna arrays with gradually changing sizes and is fed in parallel through a T-junction power divider. The half-space beam coverage ultra-wideband balloon conformal heterogeneous array antenna with the above structure of the present invention has the characteristics of half-space beam coverage, ultra-wideband, lightweight, and relatively high gain, and can meet the requirements of high-speed communication and large-range communication in mountainous and dense forest environments.

Description

Technical Field

[0001] The invention relates to the technical field of balloon conformal antennas, and in particular to an ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage. Background Art

[0002] In recent years, natural disasters such as earthquakes, forest fires, and mudslides have occurred frequently, making emergency communications in this scenario a focus of attention. The use of aerial base stations can effectively assist emergency communications. Common aerial base stations include drones and balloons. However, drones are greatly restricted in their application due to their shortcomings such as short flight time, low load capacity, and high cost. As an aerial base station, balloons have the advantages of lower cost, longer hovering time, and smaller size after deflation. These advantages make it possible to replace drones as a new type of aerial base station and be used in emergency rescue in mountainous forests.

[0003] Emergency communications in natural disaster scenarios, while receiving much attention, also face many major challenges. One challenge is that for long-distance transmission, the special terrain of mountainous and dense forests will cause serious multipath effects and huge transmission losses, hindering long-distance high-quality communication services. Another challenge is that in search and rescue operations, large-capacity broadband communications are required for a large number of users, who are distributed in a vast space. For remote users or other aerial users, high-gain and highly directional beams are required; for other users in the lower half of the space, beams with wide coverage and medium gain are required, and they are oriented toward the lower half of the space so that multiple ground users can access the network at the same time. Therefore, in order to improve the quality of long-distance communications in mountainous and dense forest environments and to achieve large-scale communications, it is crucial to design an ultra-wideband balloon antenna with beam coverage in the lower half of the space. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage, which has the characteristics of half-space beam coverage, ultra-wideband, stable communication within the beam coverage range, and light weight, and can meet the requirements of high-speed communication and large-scale communication in mountainous and dense forest environments.

[0005] To achieve the above-mentioned purpose, the present invention provides an ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage, which is arranged on a conformal carrier and includes a plurality of conformal sub-arrays consisting of an array antenna A with a high-gain directional beam and an array antenna B with a medium-gain wide beam coverage. The plurality of conformal sub-arrays are arranged axially along the circumference of the conformal carrier. The array antenna A is a high-gain edge-emitting balloon array antenna that meets arbitrary bandwidth and size conditions. The array antenna B includes two size-gradient half-wave dipole antenna arrays and a conformal T-junction power divider. The two half-wave dipole antenna arrays are fed in parallel through the T-junction power divider.

[0006] Preferably, the half-wave dipole antenna array includes a central collecting line and a plurality of dipole arms arranged on both sides of the central collecting line. A widening unit is provided at the end of each dipole arm. The dipole arms are connected in series through the central collecting line. The upper and lower surfaces of the central collecting line are both conductive surfaces. The dipole arms symmetrically arranged on both sides of the central collecting line are alternately electrically connected to the upper or lower surface of the central collecting line, and adjacent dipole arms are electrically connected to the same surface of the central collecting line.

[0007] Preferably, the T-junction power divider includes a dielectric substrate and T-junction microstrip lines, tapered quarter-wavelength transformers, and output microstrip lines arranged on both sides of the dielectric substrate. The input section of the T-junction microstrip line is fed by a broadband balun with an exponential-shaped edge. The two output ends of the T-junction microstrip line are connected to the output microstrip line through tapered quarter-wavelength transformers. The output microstrip line is composed of two mutually perpendicular uniform microstrip lines. The input end of the broadband balun is fed by an SMA cable.

[0008] Preferably, the input impedance of the T-junction microstrip line is 50 Ω, the impedances of the two output ends of the T-junction microstrip line are 100 Ω respectively, the input impedance of the quarter-wavelength transformer is 100 Ω, the output impedance of the quarter-wavelength transformer is 50 Ω, and the impedance of the output microstrip line is 50 Ω.

[0009] Preferably, the expression of the exponential-shaped edge of the broadband balun is as follows:

[0010]

[0011] where W b represents the width of the end of the broadband balun in the x direction, L b2 represents the length of the exponential-shaped microstrip of the broadband balun, x(t) represents the curve of the distance between the exponential edge of the broadband balun and the central axis of the balun in the x direction changing with t, t represents the distance between the exponential edge of the broadband balun and the end of the balun in the y direction. When t = 0, it corresponds to the position where the width of the exponential edge of the broadband balun is the widest. When t = L b2 it corresponds to the position where the width of the edge of the broadband balun is the narrowest.

[0012] Preferably, the array antenna A includes an artificial magnetic conductor array and a full-wave dipole antenna array. The full-wave dipole antenna array is disposed at the center above the artificial magnetic conductor array, and a foam spacer is provided between the full-wave dipole antenna array and the artificial magnetic conductor array. The artificial magnetic conductor array includes a metal floor, a substrate, and a plurality of reflection patches disposed above the substrate. The reflection patches include circular metal patches and four arrow-shaped arms disposed at the edges of the circular metal patches. Four slots are further provided at the edges of the circular metal patches. The arrow-shaped arms and the slots are distributed at intervals, and the arrow-shaped arms point to the four diagonals of the reflection patches. The full-wave dipole antenna array includes a central collecting line and a plurality of dipole arms distributed on both sides of the central collecting line. A widening unit is provided at the end of the dipole arm, and a broadband balun is provided at the end of the central collecting line. The dipole arms are connected in series and cross-fed through the central collecting line. The upper surface and the lower surface of the central collecting line are both conductive surfaces. The dipole arms symmetrically disposed on both sides of the central collecting line are alternately electrically connected to the upper surface or the lower surface of the central collecting line, and adjacent dipole arms are alternately electrically connected to the upper surface or the lower surface of the central collecting line.

[0013] Preferably, the number of conformal sub-arrays is an odd number. On the horizontal plane, the beam width of the array antenna B is half of the beam width of the array antenna A, and the beam of the array antenna B is symmetric about the axis of the conformal carrier.

[0014] Preferably, the conformal carrier is a cylindrical airbag or a cylindrical balloon, and a plurality of array antennas are all distributed on the side surface of the conformal carrier, and the central collecting line is parallel to the axis of the conformal carrier.

[0015] Therefore, the semi-space beam coverage ultra-wideband balloon conformal heterogeneous array antenna with the above structure of the present invention has the following beneficial effects:

[0016] 1. Ultra-wideband: By increasing the equivalent width of the dipole arm through the widening unit at the end and changing the characteristic of its impedance change distance, the broadband of the antenna unit is realized; using a dipole unit array with gradually changing dimensions increases new resonant frequency points, thereby broadening the bandwidth of the array antenna. In addition, by applying an exponentially tapered broadband balun, it is more convenient for feeding during actual use.

[0017] 2. Semi-space beam coverage: Through the heterogeneous structure combined by a high-gain end-fire array antenna and a wide-beam coverage medium-gain broadside array antenna, the beam coverage of the lower half space is realized.

[0018] 3. Stable communication quality within the beam range: For relatively long-distance or air-to-air communication, a high-gain broadside array antenna is used for communication. For short-distance air-to-ground communication, a medium-gain end-fire array antenna is used for communication, thereby realizing stable communication within the beam coverage range.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of an embodiment of a semi-space beam coverage ultra-wideband balloon conformal heterogeneous array antenna of the present invention;

[0021] Figure 2 It is a schematic structural diagram of the array antenna A of the embodiment of the present invention;

[0022] Figure 3 It is a schematic structural diagram of the reflection patch of the array antenna A of the embodiment of the present invention;

[0023] Figure 4 It is a schematic structural diagram of the array antenna B of the embodiment of the present invention;

[0024] Figure 5 It is a schematic structural diagram of the half-wave dipole antenna array of the embodiment of the present invention;

[0025] Figure 6 It is a schematic structural diagram of the T-junction power divider of the embodiment of the present invention;

[0026] Figure 7 It is the bottom view of the broadband balun of the embodiment of the present invention;

[0027] Figure 8 It is the simulated coefficient reflection diagram of the array antenna B of the embodiment of the present invention.

[0028] Figure 9 It is the gain and radiation efficiency diagram of the array antenna B of the embodiment of the present invention.

[0029] Figure 10 It is the true gain direction diagram of the array antenna B of the embodiment of the present invention;

[0030] Figure 11 It is the beam width comparison diagram of the array antenna A and the array antenna B in the xy plane of the embodiment of the present invention;

[0031] Figure 12 It is the true gain direction diagram of the array antenna A and the array antenna B in the yz plane of the embodiment of the present invention.

[0032] Reference Signs

[0033] 100, conformal sub - array; 200, array antenna A; 210, artificial magnetic conductor array; 211, reflection patch; 212, circular metal patch; 213, slot; 214, arrow - shaped arm; 220, full - wave dipole antenna array; 300, array antenna B; 310, T - junction power divider; 311, dielectric substrate; 312, T - junction microstrip line; 313, quarter - wavelength transformer; 314, output microstrip line; 320, half - wave dipole antenna array; 321, central collecting line; 322, dipole arm; 323, widening unit. Detailed implementation mode

[0034] The technical solution of the present invention will be further described below through the accompanying drawings and embodiments.

[0035] Embodiment

[0036] As Figure 1 shown, a half - space beam - covering ultra - wideband balloon conformal heterogeneous array antenna is arranged on a conformal carrier, and the conformal carrier is a cylindrical airbag or a cylindrical balloon. Figure 1 In it, R represents the radius of the conformal carrier. The balloon conformal heterogeneous array antenna includes several conformal sub - arrays 100 composed of array antenna A 200 with high - gain directive beams and array antenna B 300 with medium - gain wide - beam coverage. Several conformal sub - arrays 100 are arranged along the circumferential axis of the conformal carrier.

[0037] Array antenna A 200 is a high - gain end - fire balloon array antenna that meets any bandwidth and size conditions. A possible structure of array antenna A 200 is the array antenna structure proposed in the invention patent "A Conformal Balloon Array Antenna with Ultra - Wideband High - Gain Based on Artificial Magnetic Conductor" with the application number CN202410421398.X. Array antenna A 200 includes an artificial magnetic conductor array 210 and a full - wave dipole antenna array 220. The full - wave dipole antenna array 220 is arranged at the center above the artificial magnetic conductor array 210, and a foam spacer is arranged between the full - wave dipole antenna array 220 and the artificial magnetic conductor array 210.

[0038] The artificial magnetic conductor array 210 includes a metal floor, a substrate, and several reflection patches 211 arranged above the substrate. The center frequency points of the reflection patches 211 and the full - wave dipole antenna array 220 are the same. As Figure 3 shown, the reflection patch 211 includes a circular metal patch 212 and four arrow - shaped arms 214 arranged at the edge of the circular metal patch 212. Four slots 213 are also arranged at the edge of the circular metal patch 212. The arrow - shaped arms 214 and the slots 213 are distributed at intervals, and the arrow - shaped arms 214 point to the four diagonals of the reflection patch 211. Figure 2 and Figure 3 in:

[0039] Lz1 : The length of the full-wave dipole antenna array 220 in the z direction;

[0040] L y1 : The length of the full-wave dipole antenna array 220 in the y direction;

[0041] r a : The radius of the circular metal patch 212;

[0042] L a : The length of the reflection patch 211 in the y direction;

[0043] L s : The length of the upper slot 213;

[0044] w s : The width of the slot 213;

[0045] d1: The length of one side of the arrow-shaped arm 214;

[0046] d0: The distance between the edge of the arrow-shaped arm 214 and the edge of the adjacent reflection patch 211.

[0047] As Figure 2 shown, the full-wave dipole antenna array 220 includes a central collector line 321 and a number of dipole arms 322 distributed on both sides of the central collector line 321. A widening unit 323 is provided at the end of the dipole arm 322, and a broadband balun is provided at the end of the central collector line 321. The dipole arms 322 are connected in series and cross-fed through the central collector line 321. The upper surface and the lower surface of the central collector line 321 are both conductive surfaces. The dipole arms 322 symmetrically arranged on both sides of the central collector line 321 are alternately electrically connected to the upper surface or the lower surface of the central collector line 321, and adjacent dipole arms 322 are alternately electrically connected to the upper surface or the lower surface of the central collector line 321.

[0048] As Figure 4 shown, the array antenna B300 includes two half-wave dipole antenna arrays 320 with gradually changing sizes and a co-directional T-junction power divider 310. The two half-wave dipole antenna arrays 320 are fed in parallel through the T-junction power divider 310. As Figure 6 shown, the T-junction power divider 310 includes a dielectric substrate 311 and T-junction microstrip lines 312, tapered quarter-wavelength converters 313, and output microstrip lines 314 provided on both sides of the dielectric substrate 311. The input section of the T-junction microstrip line 312 adopts a broadband balun structure, and the two output ends of the T-junction microstrip line 312 are connected to the output microstrip line 314 through the tapered quarter-wavelength converters 313.

[0049] The input impedance of the T-junction microstrip line 312 is 50 Ω. Since the two output segments of the T-junction microstrip line 312 are in parallel, at the connection of the output segments, the impedance is distributed to both ends, and the impedances of the two output ends of the T-junction microstrip line 312 are 100 Ω respectively. The input impedance of the quarter-wavelength transformer 313 is 100 Ω, and the impedance also changes gradually during the process of the width change, so that the output impedance is 50 Ω, thus matching the impedance of the output microstrip line 314, which is 50 Ω. The output microstrip line 314 consists of two mutually perpendicular uniform microstrip lines with lengths of W b8 and W b9 , and the input end of the broadband balun is fed through an SMA cable.

[0050] To achieve the conversion from balanced to unbalanced, the input section of the T-junction microstrip line 312 is fed by a broadband balun with an exponential edge, as Figure 7 shown. The expression of the exponential edge of the broadband balun is as follows:

[0051]

[0052] where W b represents the width of the broadband balun end in the x direction, L b2 represents the length of the exponential microstrip of the broadband balun, x(t) represents the curve of the distance between the exponential edge of the broadband balun and the central axis of the balun in the x direction changing with t, t represents the distance between the exponential edge of the broadband balun and the end of the balun in the y direction. When t = 0, it corresponds to the position where the width of the exponential edge of the balun is the widest, and when t = L b2 , it corresponds to the position where the width of the exponential edge of the balun is the narrowest.

[0053] The two half-wave dipole antenna arrays 320 have a shared radiation aperture. Compared with a single array, the radiation aperture size in the circumferential direction is enlarged, which can not only increase the gain but also generate the required fan-shaped end-fire beam.

[0054] As Figure 5 shown, the half-wave dipole antenna array 320 includes a central collector line 321 and a number of dipole arms 322 arranged on both sides of the central collector line 321. The central collector line 321 of the full-wave dipole antenna array 220 and the central collector line 321 of the half-wave dipole antenna array 320 are both parallel to the axis of the conformal carrier. The upper and lower surfaces of the central collector line 321 are both metal conductors, and the middle part is Rogers 5880 material with a thickness of 1 mm, a relative dielectric constant of 2.2, and a loss tangent of 0.0009. The dipole arms 322 are fed in series through the central collector line 321. The dipole arms 322 symmetrically arranged on both sides of the central collector line 321 are alternately electrically connected to the upper or lower surface of the central collector line 321, and adjacent dipole arms 322 are electrically connected to the same surface of the central collector line 321.

[0055] Each pair of dipole arms 322 forms a dipole unit. To reduce the impedance of the half-wave dipole antenna array 320 and match it with a 50 Ω feeder line, a widening unit 323 is provided at the end of the dipole arm 322 to increase its equivalent radius, thereby broadening the impedance bandwidth of a single dipole unit. Three dipole units are arranged along the central aggregation line 321, and the sizes of the three pairs of dipole arms 322 gradually decrease. The dipole units with gradually changing sizes introduce new resonant frequencies, thereby broadening the impedance bandwidth of the half-wave dipole antenna array 320. The three pairs of dipole units are separated by an optimized spacing to achieve the desired radiation characteristics.

[0056] The dimensional parameters in the array antenna B300 are shown in Table 1:

[0057] Parameter Dimension / mm Physical meaning <![CDATA[W a1 > 36 Length of the first dipole arm / Width of the first widening unit <![CDATA[W a2 > 48 Length of the second dipole arm / Width of the second widening unit <![CDATA[W a3 > 60 Length of the third dipole arm / Width of the third widening unit <![CDATA[W a4 > 2 Width of the dipole arm <![CDATA[W a5 > 20 Spacing between the first dipole and the second dipole arm <![CDATA[W a6 > 20 Spacing between the second dipole arm and the third dipole arm <![CDATA[W a7 > 30 Length from the third dipole arm to the end of the central collecting line <![CDATA[W a8 > 1.9 Width of the central collecting line <![CDATA[W a > 1.9 Width of the narrow end of the broadband balun <![CDATA[W b > 28 Width of the wide end of the broadband balun <![CDATA[L b > 35 Total length of the broadband balun <![CDATA[W b1 > 60 Width of the dielectric substrate <![CDATA[W b2 > 100 Length of the dielectric substrate <![CDATA[W b3 > 1.8 Width of the input end of the T-junction microstrip line / Width of the 50Ω microstrip line <![CDATA[W b4 > 30 Length of the input section of the T-junction microstrip line / Length of the broadband balun <![CDATA[W b5 > 1 Width of the output end of the T-junction microstrip line / Width of the 100Ω microstrip line <![CDATA[W b6 > 5 Length of the output end of the T-junction microstrip line <![CDATA[W b7 > 30 Length of the quarter-wavelength transformer <![CDATA[W b8 > 5 Length of the first uniform microstrip line in the output microstrip line <![CDATA[W b9 > 21.4 Length of the second uniform microstrip line in the output microstrip line <![CDATA[L b1 > 7 Length of the narrow end of the broadband balun <![CDATA[L b2 > 28 Length of the exponential microstrip of the broadband balun

[0058] Table 1

[0059] The simulated reflection coefficients of the half-wave dipole antenna array 320 and the microstrip balun are as Figure 8 shown. Considering that the frequency band with the reflection coefficient modulus less than -10 dB is the bandwidth of the antenna and the balun, it can be seen that the bandwidths of the planar array and the conformal array are almost the same, both in the range of 2.08 - 3.03 GHz, and the relative bandwidth is about 39.6%. The balun exhibits an ultra-wideband of 1.94 - 3.26 GHz, which well covers the operating bandwidth of the array antenna.

[0060] Figure 9 shows the gain and radiation efficiency achieved by the conformal array and its planar structure. It can be seen that bending causes a slight decrease in the performance of the antenna gain (from 7.20 dB to 6.79 dB at 2.4 GHz) and radiation efficiency (from 96.7% to 95.4% at 2.4 GHz). For the conformal array, a peak gain of 7.86 dB is obtained at a frequency of 2.9 GHz. In addition, the radiation efficiency is relatively smooth and exceeds 90% throughout the target frequency band.

[0061] Table 2 compares the radiation performance of the conformal array at different cylindrical radii. It can be seen that in terms of gain and sidelobe level, the array with a larger conformal radius exhibits better performance. In the xy plane, the beam width of the conformal array is relatively narrow, but in the yz plane, its beam is close to 180°. This is crucial for promoting beam combination for half-space beam coverage while achieving medium gain.

[0062]

[0063] Table 2

[0064] Figure 10Among (a)-(f), the true gain simulation patterns of the conformal array antenna B300 in the xz and yz planes at different frequencies are shown respectively. It can be found that at different frequencies, the radiation performance of the antenna array is relatively stable, maintaining medium gain and a fan-shaped beam in the yz plane. At the center frequency, the measured half-power beam widths are approximately 36° and 171° in the xy and yz planes respectively.

[0065] The array antenna A200 and the array antenna B300 have similar widths, which is very beneficial for forming a shared radiation aperture. As Figure 11 shown, in the xy plane (horizontal plane, equivalent to the cross-section of the conformal carrier), although the beam width of the array antenna B is half of that of the array antenna A, the beam of the array antenna B is symmetric about the axis of the conformal carrier. Therefore, by using an odd number of conformal sub-arrays 100, full-angle beam coverage based on the balloon can be achieved. The measured bandwidth of the array antenna A200 is 2.1 - 2.82 GHz, which is completely within the bandwidth of the array antenna B300 (i.e., 2.08 - 3.12 GHz), enabling the conformal heterogeneous array to have an ultra-wide operating bandwidth. Although the gain of the array antenna B300 is lower than that of the array antenna A200, since its service object is users in the lower half space and the transmission distance is short, it will not have a negative impact on actual use.

[0066] As Figure 12 shown, in the yz plane (equivalent to the longitudinal section of the conformal carrier), the true gain of the array antenna B300 shows a beam width greater than 170°, and its shape is a fan-shaped towards the ground, suitable for short-distance air-to-ground communication. The radiation of the array antenna A200 is towards the radial direction of the conformal carrier, suitable for long-distance air-to-ground or air-to-air communication. A single array antenna A200 can only solve the radiation coverage problem on one side. To achieve full-angle coverage in the horizontal direction, the distribution of the array antenna A200 should be as Figure 11 shown in (a). Figure 12 The sub-array A` in it represents an antenna array symmetric to the array antenna A. Part of the array antenna B300 overlaps with part of the array antenna A200. Therefore, the conformal heterogeneous array can achieve a wide beam coverage of 360°×108°, which is very beneficial for emergency communication scenarios in mountainous areas and dense forest environments.

[0067] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage, characterized in that: It is arranged on a conformal carrier, and includes a plurality of conformal sub-arrays consisting of an array antenna A with a high-gain directional beam and an array antenna B with a medium-gain wide beam coverage. The plurality of conformal sub-arrays are arranged axially along the circumference of the conformal carrier. The array antenna A is a high-gain side-firing balloon array antenna that meets arbitrary bandwidth and size conditions. The array antenna B includes two size-gradient half-wave dipole antenna arrays and a conformal T-junction power divider. The two half-wave dipole antenna arrays are fed in parallel through the T-junction power divider. The half-wave dipole antenna array includes a central collective line and a plurality of dipole arms arranged on both sides of the central collective line. A widening unit is arranged at the end of the dipole arm. The dipole arm is fed in series through the central collective line. The upper surface and the lower surface of the central collective line are both conductive surfaces. The dipole arms symmetrically arranged on both sides of the central collective line are alternately electrically connected to the upper surface or the lower surface of the central collective line, and adjacent dipole arms are electrically connected to the same surface of the central collective line.

2. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 1, characterized in that: The T-junction power divider includes a dielectric substrate and a T-junction microstrip line, a gradient quarter-wavelength converter, and an output microstrip line arranged on both sides of the dielectric substrate. The input end of the T-junction microstrip line is fed by a broadband balun with an exponential edge. The two output ends of the T-junction microstrip line are connected to the output microstrip line through a gradient quarter-wavelength converter. The output microstrip line consists of two sections of uniform microstrip lines perpendicular to each other. The input end of the broadband balun is fed through an SMA cable.

3. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 2, characterized in that: The input impedance of the T-junction microstrip line is 50Ω, the impedances of the two output ends of the T-junction microstrip line are 100Ω respectively, the input impedance of the quarter-wave converter is 100Ω, the output impedance of the quarter-wave converter is 50Ω, and the impedance of the output microstrip line is 50Ω.

4. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 3, characterized in that: The expression for the exponential edge of a broadband balun is as follows: Among them, W b It represents the width of the broadband balun end in the x direction, L b2 represents the length of the broadband balun exponential microstrip, x(t) represents the curve of the distance between the broadband balun exponential edge and the balun center axis in the x direction as t changes, t represents the distance between the broadband balun exponential edge and the balun end in the y direction, t = 0, corresponding to the position where the broadband balun exponential edge has the widest width, t = L b2 , which corresponds to the position where the edge width of the broadband balun is the narrowest.

5. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 1, characterized in that: Array antenna A includes an artificial magnetic conductor array and a full-wave dipole antenna array. The full-wave dipole antenna array is arranged at the center above the artificial magnetic conductor array, and a foam partition is arranged between the full-wave dipole antenna array and the artificial magnetic conductor array; the artificial magnetic conductor array includes a metal floor, a substrate and a plurality of reflective patches arranged above the substrate, the reflective patches include a circular metal patch and four arrow-shaped arms arranged at the edge of the circular metal patch, and four slots are also arranged at the edge of the circular metal patch. The arrow-shaped arms are spaced apart from the slots, and the arrow-shaped arms point to the four diagonals of the reflective patch; the full-wave dipole antenna array includes a central collective line and a plurality of dipole arms distributed on both sides of the central collective line, a widening unit is arranged at the end of the dipole arm, a broadband balun is arranged at the end of the central collective line, the dipole arms are cross-fed in series through the central collective line, the upper surface and the lower surface of the central collective line are both conductive surfaces, the dipole arms symmetrically arranged on both sides of the central collective line are alternately electrically connected to the upper surface or the lower surface of the central collective line, and adjacent dipole arms are alternately electrically connected to the upper surface or the lower surface of the central collective line.

6. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 5, characterized in that: The number of conformal subarrays is an odd number. In the horizontal plane, the beam width of array antenna B is half of the beam width of array antenna A, and the beam of array antenna B is symmetrical about the axis of the conformal carrier.

7. The ultra-wideband balloon conformal heterogeneous array antenna with half-space beam coverage according to claim 6, characterized in that: The conformal carrier is a cylindrical airbag or a cylindrical balloon, and a plurality of array antennas are distributed on the side of the conformal carrier, and a central collection line is parallel to the axis of the conformal carrier.

Images