A spaceborne VHF antenna

Abstract

The application discloses a satellite-borne VHF antenna, which comprises a metal base plate, a feed line joint arranged below the metal base plate, an insulating support seat arranged above the metal base plate, a conical vibrator in the shape of a truncated cone arranged in the insulating support seat, a helical vibrator mounted above the conical vibrator, the helical vibrator comprising copper wires extending upwards in the shape of a helix, the copper wires being wound on an insulating support column, and the lower ends of the copper wires being connected with the helical vibrator. The satellite-borne VHF antenna is small and simple, has a stable and reliable structure, guarantees the continuity of the feed current, realizes high gain of the antenna in a unit size azimuth, and realizes high efficient conversion between space electromagnetic waves and radio frequency current.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of satellite antennas, in particular to a satellite-borne VHF antenna. BACKGROUND

[0002] The antenna is a kind of transformer for establishing a two-way information transmission channel between satellites, so as to complete inter-satellite communication. The signal frequency of VHF frequency band is low, and the wavelength is relatively long, so that the corresponding antenna size in the prior art is large, the reliability is low, good matching cannot be realized, and the large size is easy to cause the antenna to be broken in the movement process, thereby affecting the performance of the antenna, and the current continuity at the antenna joint position is low, which is not conducive to the widening of the antenna frequency band bandwidth.

[0003] Therefore, how to make the VHF antenna structure stable and miniaturized without reducing its matching performance, and ensure the continuity of the antenna feed current is a technical problem to be solved by the technical personnel in the technical field. SUMMARY

[0004] The technical problem solved by the present application is to provide a satellite-borne VHF antenna to solve the problems of large volume, unstable structure and low current continuity of the VHF frequency band antenna in the prior art, and low antenna performance.

[0005] To solve the above technical problems, the technical solution adopted by the present application is to provide a satellite-borne VHF antenna, which comprises a metal base, a feed line joint is arranged below the metal base, an insulating support seat is arranged above the metal base, a conical vibrator in the shape of a conical frustum is arranged inside the insulating support seat, a spiral vibrator is installed above the conical vibrator, the spiral vibrator comprises a copper wire extending upward in the shape of a spiral, the copper wire is wound on an insulating support column, and the lower end of the copper wire is connected with the spiral vibrator.

[0006] In another embodiment of the satellite-borne VHF antenna of the present application, a metal support rod extending in the vertical direction is arranged between the conical vibrator and the spiral vibrator.

[0007] In another embodiment of the satellite-borne VHF antenna of the present application, an external thread is formed in the lower end of the metal support rod, a vertical hole is arranged vertically upward in the inside of the conical vibrator, an internal thread is arranged in the inside of the vertical hole, and the metal support rod is connected with the vertical hole in a threaded manner.

[0008] In another embodiment of the satellite-borne VHF antenna of the present application, a vertical hole is arranged in the upper part of the metal support rod, the length of the vertical hole is half of the length of the metal support rod, and the lower part of the metal support rod is a solid structure.

[0009] In another embodiment of the satellite-borne VHF antenna, the feed line joint comprises a metal inner core and a metal outer shell insulated from each other, the metal inner core is connected with the conical bottom surface of the conical vibrator through the metal base plate, and the metal outer shell is electrically connected with the metal base plate.

[0010] In another embodiment of the satellite-borne VHF antenna, the top end of the metal support rod extends radially outward with a flange, and the lower end of the copper wire is connected with the metal support rod through the flange.

[0011] In another embodiment of the satellite-borne VHF antenna, the flange is provided with a threaded hole vertically penetrating through the flange, a copper screw or a copper stud penetrates through the threaded hole, and the upper end of the copper screw or the copper stud is connected with the copper wire, and the lower end of the copper screw or the copper stud is connected with the metal support rod, or the copper screw or the copper stud is provided with an axial through hole, and the copper wire penetrates through the through hole to connect the metal support rod.

[0012] In another embodiment of the satellite-borne VHF antenna, the flange is provided with a threaded hole vertically penetrating through the flange, a copper screw or a copper stud penetrates through the threaded hole, and the copper screw or the copper stud is provided with an axial through hole, and the copper wire penetrates through the through hole to connect the metal support rod.

[0013] In another embodiment of the satellite-borne VHF antenna, the diameter of the conical vibrator is 30 mm, the height is 42 mm, the length of the metal support rod is 154 mm, the length of the spiral vibrator is 90 mm, and the spiral interval between the copper wires is 10 mm.

[0014] The satellite-borne VHF antenna is small and simple, has a stable and reliable structure, ensures the continuity of the feeding current, realizes high gain of the antenna in a unit size direction, and realizes high-efficiency conversion between spatial electromagnetic waves and radio frequency current. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is an embodiment schematic diagram of the satellite-borne VHF antenna of the present application;

[0016] Figure 2 is Figure 1 the exploded schematic diagram of the embodiment;

[0017] Figure 3 is Figure 1 the sectional view of the embodiment;

[0018] Figure 4 is a schematic view of the connection between the tapered monopole and the insulating support seat and the metal base plate in another embodiment of the satellite-borne VHF antenna of the present application;

[0019] Figure 5 is a partial sectional view of the insulating support column in another embodiment of the satellite-borne VHF antenna of the present application;

[0020] Figure 6 is a partial sectional view of the insulating support column in another embodiment of the satellite-borne VHF antenna of the present application;

[0021] Figure 7 is a schematic view of the standing wave ratio in another embodiment of the satellite-borne VHF antenna of the present application;

[0022] Figure 8 is a 3D pattern at 159 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0023] Figure 9 is a 2D pattern at 156 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0024] Figure 10 is a 2D pattern at 159 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0025] Figure 11 is a 2D pattern at 163 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0026] Figure 12 is a 3D gain pattern at 159 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0027] Figure 13 is a XOZ and YOZ plane gain pattern at 159 MHz in another embodiment of the satellite-borne VHF antenna of the present application;

[0028] Figure 14 is a XOY plane gain pattern at 159 MHz in another embodiment of the satellite-borne VHF antenna of the present application. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0030] It should be noted that unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0031] Figure 1 is a schematic diagram of an embodiment of the satellite VHF antenna, Figure 2 is Figure 1 is an exploded schematic diagram of the embodiment shown, Figure 3 is Figure 1 is a cross-sectional view of the embodiment shown, Figure 4 is a schematic diagram of the connection of the conical vibrator and the insulating support seat and the metal base, Figure 5 and Figure 6 is a partial cross-sectional view of the insulating support column, in combination Figures 1-6 The satellite VHF antenna includes a metal base 1, a feed line connector 2 disposed below the metal base 1, an insulating support seat 3 disposed above the metal base 1, a conical vibrator 4 in the shape of a truncated cone disposed inside the insulating support seat 3, a helical vibrator 5 mounted above the conical vibrator 4, the helical vibrator 5 including a copper wire 51 extending upward in the shape of a helix, the copper wire 51 being wound around an insulating support column 6, and the lower end of the copper wire 51 being connected to the helical vibrator 5.

[0032] The antenna has a small volume, a light weight, and a simple structure. The antenna has a lower application frequency band, about 160 MHz, and the height of the antenna should not be too high because the antenna moves on a satellite. However, the copper wire extending upward in the shape of a helix is used to form the helical vibrator, which increases the electrical length of the antenna in a virtual manner, thereby ensuring that the antenna current has a long enough current path in a limited height, and thereby improving the antenna gain.

[0033] Preferably, the surface of the antenna structure has a rough structure (i.e., the roughness of the surface of the antenna is increased, such as the surface of the copper wire of the helix is roughened), and the increase in the roughness makes the antenna feed current transmission more tortuous, further increases the antenna current flow path, reduces the surface wave conduction rate of the antenna, thereby expanding the volume of the antenna's induction field area, improving the actual receiving aperture of the antenna, facilitating the increase of the electrical length of the antenna, and thereby improving the receiving gain of the antenna, and further improving the electrical performance of the antenna.

[0034] Preferably, the feed line connector 2 includes a metal inner core 21 and a metal outer shell 22 that are insulated from each other, the metal inner core 21 passes through the metal base 1 and is connected to the conical bottom surface of the conical vibrator 4, and the metal outer shell 22 is electrically connected to the metal base 1.

[0035] Further preferably, the metal shell 22 wraps and protects the metal inner core 21, the bottom surface of the metal base plate 1 is further embedded with a metal bottom plate 11, the metal bottom plate 11 is provided with screw holes for being fixed on the metal base plate 1 by screws, the size of the metal bottom plate 11 is much smaller than that of the metal base plate 1, the metal inner core 21 passes through the metal bottom plate 11 to connect the conical vibrator 4, and the metal shell 22 is electrically connected to the metal bottom plate 11.

[0036] Further preferably, the metal base plate 1 is provided with a groove 13 at the center of the bottom surface, the shape of the groove 13 is matched with that of the metal bottom plate 11, the groove 13 is arranged to accommodate and fix the metal bottom plate 11, thereby stabilizing the connection between the metal bottom plate 11 and the feed line joint 2, and the overall length of the antenna can be shortened.

[0037] Preferably, the feed line joint 2 is an SMA joint, the feed line joint 2 is fixed on the metal base plate 1 by screws, and further preferably, four screws are uniformly fixed on the metal base plate 1, and in order to tighten the screws, thread sealant is applied on the screws.

[0038] Further preferably, the metal base plate 1 is provided with a via hole 12 for the metal inner core 21 to pass through.

[0039] Preferably, a metal support rod 7 extending in the vertical direction is arranged between the conical vibrator 4 and the helical vibrator 5, the metal support rod 7 supports and fixes the conical vibrator 4 and the helical vibrator 5, and directly increases the electrical length of the antenna, thereby improving the electrical performance of the antenna.

[0040] Further preferably, the inductance or capacitance of the metal support rod and the helical vibrator changes with the length of the metal support rod and the helical vibrator, the inductance and capacitance refer to the phase relationship between voltage and current, when the load is (or contains) inductive, the voltage phase leads the current, and the load is inductive; when the load is (or contains) capacitive, the voltage phase lags behind the current, and the load is capacitive, the main parameters of the metal support rod are its height and radius, the main parameters of the helical vibrator are its radius, height, pitch of the copper wire and diameter of the copper wire, the quality factor Q of the metal support rod or the helical vibrator can be adjusted by adjusting the main parameters, the bandwidth of the antenna is affected by the quality factor Q, the antenna bandwidth BW = W0 / Q, wherein W0 represents the resonant frequency of the antenna, and the higher the quality factor Q, the narrower the bandwidth BW of the antenna, the adjustment of the bandwidth of the antenna further affects the matching of the antenna, therefore, by adjusting the main parameters of the metal support rod and the helical vibrator, the antenna can be well matched, and the signal acquisition rate of the antenna is improved.

[0041] Further preferably, the lower end 71 of the metal supporting rod 7 is provided with external threads 711, the vertical hole 41 is vertically upwardly arranged in the interior of the cone vibrator 4, the interior of the vertical hole 41 is provided with internal threads 411, the metal supporting rod 7 is threadedly connected with the vertical hole 71, in particular, the external threads 711 of the lower end 71 of the metal supporting rod 7 are threadedly connected with the internal threads 411 of the vertical hole 41. The threadedly connected connection is fast and accurate, the metal supporting rod 7 is directly connected with the cone vibrator 4, the intermediate connecting member is omitted, and the continuous transmission of the feeding current is facilitated.

[0042] Further preferably, the external threads 711 of the lower end 71 of the metal supporting rod 7 and the internal threads 411 of the cone vibrator 4 are threadedly connected, and thread glue is applied to the threadedly connected position, so as to further stabilize the connection of the metal supporting rod and the cone vibrator. In order to avoid that the application of too much thread glue affects the electrical performance of the antenna, the application area of the thread glue is controlled to be 40%-70% of the total area of the external threads.

[0043] Preferably, the upper portion of the metal supporting rod 7 is provided with a vertical hole 72, the length of the vertical hole 72 is half of the length of the metal supporting rod 7, and the lower portion of the metal supporting rod 7 is a solid structure. The lower portion of the metal supporting rod is provided as a solid structure, which lowers the center of gravity of the antenna, controls the center of gravity in the lower half of the metal supporting rod, and prevents the center of gravity from being too high. Too high center of gravity will cause the antenna to be easily broken at the middle connecting position during movement. Therefore, the center of gravity of the antenna should not be too high, and the structure of the intermediate connecting member should also be firm and stable. Here, the metal supporting rod also assumes the function of the intermediate connecting member, the lower half is a solid structure, which not only lowers the center of gravity but also realizes firm and stable structure, and avoids the situation that the antenna is broken during movement.

[0044] Preferably, the cone vibrator 4 comprises a cylindrical portion 42 and a tapered head portion 43. The cylindrical portion 42 is in a cylindrical shape, the vertical hole 41 is arranged on the upper end face of the cylindrical portion 42, the tapered head portion 43 gradually extends downward, the diameter of the tapered head portion 43 gradually decreases with the extension, and finally stops extending at the bottom end of the tapered head portion 43 to form a horizontal bottom end 431. A conductive hole 4311 is arranged in the middle of the horizontal bottom end 431, the diameter of the conductive hole 4311 is much smaller than the diameter of the vertical hole 41, and the conductive hole 4311 is provided with internal threads.

[0045] Further preferably, the metal inner core 21 of the feeder joint penetrates the through hole 12 of the metal base 1 and is welded to the conductive hole 4311. The tapered vibrator cone head reduces the current variation amplitude of the feeder current flowing therethrough, improves the continuity and smoothness of the feeder current, avoids the generation of feeder current distortion, and better enables the feeder current to be transmitted from the metal inner core of the feeder joint to the tapered vibrator, and then to flow through the metal support rod, thereby improving the antenna matching effect and facilitating the widening of the frequency band of the antenna and the improvement of the antenna gain.

[0046] Preferably, a helical thread groove 61 is formed in the insulating support column 6, and the helical vibrator 5 is arranged in the thread groove 61. The thread groove 61 limits the excessive exposure of the helical vibrator, reduces the probability of damage to the helical vibrator, and better fixes the helical vibrator 5 during the movement of the antenna, and the helical vibrator is not easy to be separated from the insulating support column 6.

[0047] Preferably, the insulating support column 6 is hollow and has a hollow hole 65, which reduces the weight of the antenna.

[0048] Preferably, the thread groove 61 is formed around the outer surface of the insulating support column 6, and a first vibrator wire passage 63 is formed on the outer side of the top of the insulating support column 6. The first vibrator wire passage 63 penetrates the side wall of the insulating support column 6, and the upper end 511 of the copper wire 51 penetrates the first vibrator wire passage 63 and vertically extends to the top of the insulating support column 6.

[0049] Further preferably, thread glue can be applied in the thread groove 61 to further fix the helical vibrator and prevent the helical vibrator 5 from loosening and falling off due to external vibration.

[0050] Further preferably, two reinforcing ribs 64 are added to the two sides of the insulating support column 6 to further fix the helical vibrator.

[0051] Preferably, the metal support rod 7 has a flange 73 radially extending outward at the top end thereof, and the lower end of the copper wire 51 penetrates the flange 73 and is connected to the metal support rod 7. Further preferably, the lower end 512 of the copper wire 51 penetrates the flange 73 and is connected to the metal support rod 7. The penetration of the copper wire 51 through the flange 73 saves copper wire material and avoids the exposure of the copper wire, thereby protecting the copper wire from external damage.

[0052] Further preferably, the flange 73 has a second vibrator wire passage 731 for the lower end 512 of the copper wire 51 to penetrate, and the second vibrator wire passage 731 includes a vertical portion 7311 and a horizontal portion 7312. After penetrating the vertical portion 7311 and the horizontal portion 7312, the lower end 512 of the copper wire 51 is connected to the metal support rod.

[0053] Further preferably, the bottom of the insulating support column 6 has an outwardly extending flange 62, the flange 73 at the top end of the metal support rod 7 is shaped to match the flange 62 at the bottom of the insulating support column 6, and the two are spliced together and fastened by a screw L1.

[0054] Preferably, the flange 73 is provided with a screw hole 732 vertically through the flange, a copper screw or stud Z1 penetrates through the screw hole 732, the upper end of the copper screw or stud Z1 is connected to the copper wire 51, and the lower end of the copper screw or stud Z1 is connected to the metal support rod 7. Specifically, the upper end of the copper screw or stud Z1 is connected to the lower end of the copper wire 51, and the lower end of the copper screw or stud Z1 is connected to the metal support rod 7.

[0055] Further preferably, the flange 73 is provided with a screw hole 732 vertically through the flange, a copper screw or stud Z1 penetrates through the screw hole 732, the copper screw or stud Z1 is provided with an axial through hole Z11, and the copper wire 51 passes through the axial through hole Z11 to connect the metal support rod 7. Further preferably, the lower end of the copper wire 51 and the axial through hole Z11 of the copper screw or stud Z1 are welded together.

[0056] Preferably, the horizontal cross-section of the insulating support seat 3 is gear-shaped, and a recess 32 is formed between the tooth roots 311 of each gear tooth 31. The recess 32 is vertically provided and is a half-through groove. The insulating support seat 3 is fixed to the metal base plate 1 by a screw L2 vertically downward along the recess 32. The gear teeth 31 of the insulating support seat 3 can better provide lateral support for the root of the antenna, avoiding the breakage caused by unstable support of the root of the antenna during movement.

[0057] Further preferably, the insulating support seat 3 is provided with an upper opening 34 and a lower opening 35 vertically through the insulating support seat 3. The upper opening 34 is slightly larger than the lower end of the metal support rod, and the lower opening 35 is shaped to match the shape of the conical vibrator 4 and is larger than the upper opening 34. A plurality of fixing holes 36 are provided around the upper opening 34, and a plurality of fixing holes 44 are provided around the vertical hole 41 on the upper end surface of the conical vibrator 4. The fixing holes 36 and the fixing holes 44 are connected by a screw L3, so as to fixedly connect the insulating support seat 3 and the conical vibrator 4.

[0058] Preferably, the copper wire material is red copper, which has a melting point of 1083℃, is tough and soft, and has good ductility, electrical conductivity and corrosion resistance.

[0059] Preferably, the material of the metal base and the metal support rod is 2A12 aluminum, the material of the conical vibrator is 2A12 aluminum plated with silver, and the soldering points are welded by using lead-tin soldering to prevent tin pest from occurring at the soldering points at low temperatures.

[0060] Preferably, the material of the insulating support seat and the insulating support column is polyimide, which has good high-temperature resistance, can be used stably for more than 400 DEG C, and can be used stably in the temperature range of -200 DEG C to 300 DEG C, and has good insulation performance, with a dielectric loss of only 0.004 to 0.007.

[0061] Further preferably, the screw connection part can be coated with thread glue for further bonding and sealing.

[0062] Preferably, when the antenna is installed, the installation steps need to be followed, and the installation steps are as follows:

[0063] 1) The feed line connector is fixed on the metal base by screws (the metal inner core passes through the via hole of the metal base, and the metal shell contacts the metal base to contact the metal base), and thread glue is applied at the screw connection part;

[0064] 2) The conical vibrator is placed into the insulating support seat from the lower opening below the insulating support seat, the conical head of the conical vibrator faces downward, and the conical vibrator and the insulating support seat are fixed by screws, and thread glue is applied at the screw connection part;

[0065] 3) The metal inner core of the feed line connector is inserted into the conductive hole below the conical vibrator and contacts the internal thread in the conductive hole, until the insulating support seat contacts and cooperates with the metal base, and then the insulating support seat and the metal base are fixed by screws, and thread glue is applied at the screw connection part;

[0066] 4) The metal inner core of the feed line connector and the internal thread in the conductive hole are logically measured by using a multimeter, and the metal inner core and the internal thread in the conductive hole should present a short-circuit state and be disconnected from the metal base;

[0067] 5) The copper wire is embedded in the threaded groove of the insulating support column, the upper end of the copper wire passes through the first vibrator wire passage and faces the top end of the insulating support column, and the lower end of the copper wire passes through the second vibrator wire passage of the insulating support column, and then the lower end of the copper wire passes through the vertical through-hole screw hole of the top flange of the metal support rod;

[0068] 6) The insulating support column and the metal support rod are fixed and connected by screwing, and thread glue is applied at the screw connection part;

[0069] 7) the lower end of the copper wire is passed through the axial through hole of the copper stud, the copper stud is screwed into the screw hole of the flange at the top end of the metal support rod, the connection between the copper stud and the screw hole of the flange at the top end of the metal support rod is coated with thread glue, and the lower end of the copper wire is welded to the axial through hole of the copper stud;

[0070] 8) the metal support rod and the upper end of the copper wire are logically measured by using a multimeter, and should present a short circuit state;

[0071] 9) thread glue is applied to the gap between the copper wire and the threaded groove, and thread glue should also be applied to the position where the copper wire passes through the through hole of the reinforcing rib;

[0072] 10) the lower end of the metal support rod is passed through the upper opening of the insulating support seat and is screwed tightly with the conical vibrator, and thread glue is applied to the middle part of the outer thread of the metal support rod before tightening (thread glue cannot be applied to the entire outer thread);

[0073] 11) the metal inner core of the metal support rod and the feeder joint is logically measured by using a multimeter, and should present a short circuit state and a short circuit state with the metal base;

[0074] 12) the antenna is placed vertically and waits for 24 hours for curing.

[0075] Preferably, the conical vibrator 4 has a diameter of 30 mm and a height of 42 mm, the metal support rod 7 has a maximum diameter of 40 mm and a length of 154 mm, the helical vibrator 5 has a length of 90 mm, and the helical interval between the copper wires 51 is 10 mm. The helical interval determines the inductance value of the helical vibrator, the larger the helical interval, the smaller the inductance value, and the helical interval can be adjusted according to the working frequency of the antenna.

[0076] The distance from the bottom surface of the metal base to the top end of the helical antenna is 289 mm, and the distance range in which the feeder joint is exposed from the bottom surface of the metal base is 5.5 mm-9.5 mm.

[0077] The metal base is a square metal base with a side length of 52 mm, and the metal base is.

[0078] The flanges of the metal support rod and the insulating support column both have a diameter of 40 mm, and the insulating support column has a length of 100 mm.

[0079] The insulating support seat has a diameter of 49 mm and a height of 51 mm.

[0080] The overall height of the antenna is not higher than 300 mm (including the height of the feeder joint), realizing the miniaturization of the antenna, and the antenna also meets the low weight requirement due to the selected materials.

[0081] Preferably, the antenna metal base, the insulating support seat, the metal support rod and the insulating support column have similar lateral (horizontal) dimensions, which is conducive to the reasonable structural arrangement of the antenna.

[0082] Preferably, as shown in Figure 7 , the matching impedance of the feed line joint is 50 ohms, and the standing wave ratio in the frequency range of 156 MHz to 163 MHz is less than 1.8. The standing wave ratio formula is: SWR = R / r = (1+K) / (1-K), where the reflection coefficient K = (R-r) / (R+r), K is negative when the phase is opposite, R and r are the output impedance and the input impedance respectively, when the output impedance and the input impedance are the same, the impedance of the feed line and the antenna is completely matched, the standing wave ratio is 1, and the high-frequency energy is radiated by the antenna without energy reflection loss. However, this is an ideal state, and the actual standing wave ratio is greater than 1. Here, the standing wave ratio is less than 1.8, which achieves good antenna impedance matching and improves the transmission efficiency of the feed line.

[0083] Preferably, the radiation pattern represents the ability of the antenna to transmit and receive electromagnetic waves in various directions in space, as shown in Figure 8 , the antenna presents an apple-shaped 3D radiation pattern at a frequency of 159 MHz, and the antenna radiation direction is symmetrically distributed around the antenna axis, with the positive and negative ends of the X and Y axes as the main radiation directions, and the positive and negative ends of the Z axis as the radiation suppression directions. The maximum radiation direction of the antenna is at Theta = 90°, and the gain of the antenna is lowest in the axial direction, while the antenna presents 360° omnidirectional radiation in the horizontal direction Theta = 90°.

[0084] Preferably, in the Cartesian coordinate system, Theta represents the azimuth angle from +Z to XOY plane, and phi represents the horizontal angle from +X to +Z axis.

[0085] Preferably, Figure 9 , Figure 10 and Figure 11 represent the 2D radiation patterns of the antenna at frequencies of 156 MHz, 159 MHz and 163 MHz respectively. It can be seen that the simulated gain of the antenna in the frequency band is about 2.3dBi, the antenna has good omnidirectionality, and the gain distribution in each direction is uniform. At this time, the lobe width is about 92 degrees. In practice, the antenna is placed on the uneven satellite top surface, and the directivity is more prominent, and the maximum gain will be further improved.

[0086] Further preferably, at a frequency of 156 MHz, curve S1 represents Phi = 0°, and curve S2 represents Phi = 90°, S1 and S2 are approximately coincident.

[0087] At a frequency of 159MHz, curve S3 represents Phi = 0°, and curve S4 represents Phi = 90°. S3 and S4 approximately coincide.

[0088] At a frequency of 163MHz, curve S5 represents Phi = 0°, and curve S6 represents Phi = 90°. S5 and S6 approximately coincide.

[0089] Preferred, such as Figure 12 As shown, due to the directional effect of celestial bodies on electromagnetic waves, the antenna pattern will be significantly biased towards the celestial body, with a total gain of up to 2.88 dBi and a deterioration in the non-circularity of the pattern.

[0090] Preferred, Figure 13 The image shows the XOZ and YOZ plane gain plots of the antenna at a frequency of 159MHz. Figure 14 The image shows the gain plot of the antenna in the XOY plane at 159MHz. Due to the influence of the celestial body, its total gain coverage of 0dBi does not change significantly, with most of the energy being vertically polarized (i.e., the polarization direction is parallel to the OZ direction). Figure 13 S7 and S8 represent the antenna gain at Phi = 0° and Phi = 90° in this cross-section, respectively. The antenna structure is not perfectly symmetrical, so there will be slight differences in different directions. Comparisons can be made between different cross-sections. Figure 14 The figure shows the gain variation of the antenna in different horizontal directions on the horizontal plane.

[0091] Based on the above embodiments, this invention discloses a spaceborne VHF antenna, including a metal chassis, a feed line connector disposed below the metal chassis, and an insulating support base disposed above the metal chassis. A frustum-shaped conical vibrator is disposed inside the insulating support base, and a helical vibrator is mounted above the conical vibrator. The helical vibrator includes a copper wire extending upward in a helical shape, the copper wire being wound around the insulating support column, and the lower end of the copper wire being connected to the helical vibrator. This spaceborne VHF antenna is compact and simple, with a robust and reliable structure, ensuring the continuity of the feed current and achieving high antenna gain per unit size azimuth and efficient conversion between space electromagnetic waves and radio frequency current.

[0092] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A spaceborne VHF antenna, characterized in that, The device includes a metal chassis, a feeder connector located below the metal chassis, and an insulating support base located above the metal chassis. Inside the insulating support base is a frustum-shaped conical vibrator, and above the conical vibrator is a helical vibrator. A vertically extending metal support rod is positioned between the conical vibrator and the helical vibrator. The helical vibrator includes a copper wire extending upwards in a spiral shape, which is wound around the insulating support rod, with its lower end connected to the metal support rod. A helical threaded groove is formed on the insulating support rod, and the copper wire is adapted to be arranged within the threaded groove.

2. The spaceborne VHF antenna according to claim 1, characterized in that, The lower end of the metal support rod is provided with an external thread, and the conical vibrator has a vertical hole that is set vertically upward inside. The vertical hole is provided with an internal thread, and the metal support rod is threadedly connected to the vertical hole.

3. The spaceborne VHF antenna according to claim 2, characterized in that, The upper part of the metal support rod is provided with a vertical hole, the length of which is half the length of the metal support rod, and the lower part of the metal support rod is a solid structure.

4. The spaceborne VHF antenna according to claim 3, characterized in that, The feeder connector includes a mutually insulated metal inner core and a metal outer shell. The metal inner core passes through the metal chassis and is connected to the conical bottom surface of the conical vibrator. The metal outer shell is electrically connected to the metal chassis.

5. The spaceborne VHF antenna according to claim 4, characterized in that, The metal support rod has a flange extending radially outward from its top end, and the lower end of the copper wire passes through the flange and connects to the metal support rod.

6. The spaceborne VHF antenna according to claim 5, characterized in that, The flange has a vertical threaded hole through it, and a copper screw or copper stud passes through the threaded hole. The upper end of the copper screw or copper stud is connected to the copper wire, and the lower end is connected to the metal support rod.

7. The spaceborne VHF antenna according to claim 5, characterized in that, The flange has a vertical threaded hole that passes through the flange. A copper screw or copper stud passes through the threaded hole. The copper screw or copper stud has an axial through hole. The copper wire passes through the through hole and connects to the metal support rod.

8. The spaceborne VHF antenna according to claim 6 or 7, characterized in that, The conical vibrator has a diameter of 30mm and a height of 42mm. The metal support rod has a length of 154mm. The helical vibrator has a length of 90mm. The helical spacing between the copper wires is 10mm.

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