Retractable log-periodic antenna

Abstract

The invention discloses a foldable log-periodic antenna, and relates to the technical field of antennas, the foldable log-periodic antenna comprises an antenna main body, and the lower end of an unmanned aerial vehicle is provided with the antenna main body; the antenna body comprises an upper connecting plate, a lower connecting plate, a fixing rod, a vertical stroke electronic lock, a vertical pull-up spring set, a pulley, a connecting wire, a joint, a connecting rod and a first oscillator winder, the lower connecting plate is arranged at the lower end of the upper connecting plate, and the fixing rod is arranged at the lower end of the lower connecting plate. And vertical stroke electronic locks are arranged between the upper connecting plate and the lower connecting plate and between the lower connecting plate and the fixing rod. After the technical scheme is adopted, the antenna has the beneficial effects that the antenna has the advantages of self-folding and unfolding, large size and low surface density by adopting the high-rigidity and high-folding and unfolding log-periodic antenna.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and specifically to a retractable log-periodic antenna. Background Art

[0002] The log-periodic antenna is a type of directional plate antenna. It is a wide-band antenna, or a frequency-independent antenna, commonly used for indoor distribution and elevator signal coverage. The log-periodic antenna is mainly used in the ultra-short wave band, and can also be used as a short-wave communication antenna and a medium-wave and short-wave broadcast transmission antenna. In addition, the log-periodic antenna can also be used as a feed source for microwave reflector antennas. At present, the log-periodic antenna is often used in a new reconnaissance and early warning method of a vehicle + multi-rotor drone. The ground mobile vehicle arrives at the designated location, the antenna is fixed on the multi-rotor drone, the multi-rotor drone carries the antenna into the air, and the antenna is connected to the communication terminal of the ground vehicle through a cable for direct signal transmission. When the multi-rotor drone reaches a suitable height, the antenna starts working.

[0003] However, the traditional log-periodic antenna in the same frequency band has certain defects: when the operating frequency of the antenna is 27-110Hz, the length of the antenna is about 5 meters, the weight is large, and the energy consumption is high. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-large retractable log-periodic antenna suitable for mounting on unmanned aerial vehicles and a storage method in view of the defects and shortcomings of the prior art. The antenna adopts a new shape memory alloy material for retractable key design and a high-rigidity and high-strength carbon fiber material for antenna structure skeleton design, so as to realize the design and manufacture of an ultra-light new retractable log-periodic antenna structure.

[0005] The present invention is achieved through the following technical solutions:

[0006] A retractable logarithmic periodic antenna, comprising a plurality of antenna elements; further comprising an upper support rod 21, a middle support rod 22 and a lower support rod 23; the upper support rod 21, the middle support rod 22 and the lower support rod 23 are arranged in parallel, wherein the middle support rod 22 is located between the upper support rod 21 and the lower support rod 23; a travel electronic lock 24 is arranged between the upper support rod 21 and the middle support rod 22 and between the middle support rod 22 and the lower support rod 23;

[0007] The left and right ends of the upper support rod 21 are provided with a pulley 26 on the outside of the two pulley spring groups 25, and a connecting wire 261 is wound around the pulley 26. One end of the connecting wire is connected to the action end of the pulley spring group, and the other end of the connecting wire 261 passes through the two travel electronic locks 24 in sequence and is fixed on the lower support rod 23.

[0008] The antenna element is installed on the middle supporting rod.

[0009] Furthermore, the pulley is installed on the upper support rod 21.

[0010] Furthermore, both ends of the upper support rod 21 , the middle support rod 22 , and the lower support rod 23 are connected with joints 27 , and the other end of the joint 27 is installed with an extension rod 28 .

[0011] Furthermore, the upper support rod, the lower support rod and the extension rod connected to the upper support rod and the lower support rod are all provided with a plurality of dipole winding devices; a plurality of antenna dipoles are arranged on the middle support rod and the extension rod connected to the middle support rod;

[0012] The middle part of the antenna vibrator is connected to the corresponding middle support rod and the extension rod, and the two ends of the antenna vibrator are respectively connected to the corresponding vibrator winding machine, and the vibrator winding machine realizes the winding and releasing of the line.

[0013] Furthermore, two travel electronic locks are respectively installed on the bottom of the upper support rod and the middle support rod.

[0014] Further, the lifting spring group 25 includes an SMA lifting spring and a spring restraining component; the SMA lifting spring is extended or shortened along the spring restraining component;

[0015] One end of the SMA lifting spring is fixed, and the other end is connected to the connecting wire; the circuit controls the extension and contraction of the SMA lifting spring.

[0016] Furthermore, the spring restraining component is a rod; the rod is fixedly mounted on the upper support rod, and one end of the SMA tension spring is fixedly connected to the rod.

[0017] Furthermore, the spring restraint component is a sliding groove arranged at the bottom of the upper support rod; sliding blocks are provided at both ends of the SMA tension spring; the sliding blocks are hoisted in the sliding groove, one sliding block is fixed in the sliding groove, and the other sliding block is connected to one end of the connecting line.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This device uses a new shape memory alloy material for the retractable key design and a high-rigidity and high-strength carbon fiber material for the antenna structure skeleton design, so as to realize the design and manufacture of an ultra-light new retractable log-periodic antenna structure; the total weight of the antenna is 8kg, which is 1 to 2 orders of magnitude less than the current retractable log-periodic antenna in the same frequency band; the retractable log-periodic antenna has the advantages of self-retractability, large size and low surface density. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the structure of the drone of the present invention carrying this embodiment,

[0021] Figure 2 is a schematic structural diagram of the antenna body in the present invention,

[0022] Figure 3 is an expanded view of the antenna body in the present invention,

[0023] Figure 4 This is a vertical storage diagram of the antenna body in the present invention.

[0024] Figure 5 It is a schematic diagram of the right structure in the present invention,

[0025] Figure 6 It is a schematic diagram of the structure on the left side of the present invention,

[0026] Figure 7 yes Figure 4 A magnified image of

[0027] Figure 8 yes Figure 5 The enlarged view of B in the middle.

[0028] Fig. 9 It is a top view of the structure of the support rod and the extension rod in the storage state of the present invention.

[0029] Fig.10 is a schematic structural diagram of a joint according to an embodiment of the present invention;

[0030] Fig.11 is a schematic diagram of the joint structure in the unfolded state according to an embodiment of the present invention;

[0031] Fig.12 is a schematic diagram of the joint structure in the stowed state of an embodiment of the present invention;

[0032] Fig.13 is a structural exploded diagram of a joint according to an embodiment of the present invention;

[0033] Fig.14 It is a schematic diagram of a connecting seat and a bearing of a connecting plate of a joint according to an embodiment of the present invention.

[0034] Fig.15 A schematic diagram of a structure of a tension spring assembly in an embodiment of the present invention;

[0035] Fig.16 Schematic diagram of the second mechanism of the tension spring assembly in the embodiment of the present invention.

[0036] Explanation of the reference numerals: drone 1, antenna body 2, antenna vibrator 3, upper support rod 21, middle support rod 22, lower support rod 23, travel electronic lock 24, lifting spring group 25, pulley 26, joint 27, connecting rod 28, first vibrator reel 29, connecting piece 211, second vibrator reel 212, connecting wire 261, connecting block 231.

[0037] 27-1, support cover plate, 27-2, connecting seat, 27-3, spring connector, 27-4, SMA spring a, 27-5, SMA spring b, 27-6, micro electromagnetic lock, 27-7, bearing, 27-8, support body, 27-9, extended connecting end, 27-10, locking hole.

[0038] 25-11, rod, 25-22, 25-2, SMA tension spring, 25-1, sliding block. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0040] See also Figure 1-8 As shown, the technical solution adopted in this embodiment is: an ultra-large retractable logarithmic periodic antenna suitable for mounting on a drone, which includes a drone 1 and an antenna body 2, and a plurality of antenna bodies 2 are installed at the lower end of the drone 1;

[0041] The antenna body 2 includes an upper support rod 21, a middle support rod 22, a lower support rod 23, a travel electronic lock 24, a pull-up spring group 25, a pulley 26, a connecting line 261, a joint 27, a connecting rod 28, and a first vibrator reel 29. Connecting parts 211 are fixedly provided on both sides of the upper support rod 21, and the other end of the connecting part 211 is rotatably connected to the joint 27, and the other end of the joint 27 is rotatably connected to the connecting rod 28. The first vibrator reel 29 is provided at the inner lower end of the two connecting rods 28, and the first vibrator reel 29 is provided next to the joint 27.

[0042] Connecting pieces 211 are provided at both ends of the middle supporting rod 22 , and the other end of the connecting piece 211 is rotatably connected to a connecting rod 28 .

[0043] Both ends of the lower support rod 23 are provided with a connection block 231, and the connection block 231 is L-shaped. The connection block 231 is rotatably connected to one end of the joint 27, and the other end of the joint 27 is connected to the connection rod 28. The inner upper ends of the two connection rods 28 are provided with a first vibrator reel 29, and the first vibrator reel 29 is arranged on the side of the joint 27. The upper end of the connection block 231 is connected to the bottom end of a travel electronic lock 24, and the upper end of the travel electronic lock 24 is connected to the side bottom end of the middle support rod 22. The top end of the connection piece 211 on the side of the middle support rod 22 is connected to the bottom end of another travel electronic lock 24, and the upper end of the travel electronic lock 24 is connected to the side bottom end of the upper support rod 21.

[0044] A lifting spring group 25 is provided at both left and right ends of the upper support rod 21. A pulley 26 is connected to the outer side of each of the two lifting spring groups 25. A connecting line 261 is installed on the pulley 26. The lower end of the connecting line 261 passes through two travel electronic locks 24 and is connected to the bottom end of the lower support rod 28. Several antenna vibrators 3 are provided on the middle support rod 22 and the connecting rods 28 at both ends. The two ends of the antenna vibrator 3 are arranged in the relative first vibrator reel 29. The connecting block 231 is L-shaped. The circumferential antenna in the unfolded state is lifted in the vertical direction of the antenna under the drive of the thermal recovery force of the memory alloy (SMA) spring of the lifting spring group 25. After it is in place, the travel electromagnetic lock realizes structural locking to prevent it from falling back, and then it is driven by the six antagonistic SMA joints 27 to achieve S-shaped folding in the horizontal direction.

[0045] In this embodiment, the short antenna element is wound on the element winder via an auxiliary wire connected to the end.

[0046] The joint 27 is an antagonistic memory alloy joint.

[0047] The connecting rod 28 is a carbon fiber tube.

[0048] A second vibrator wire reel 212 is disposed at the lower right end of the upper support rod 21 , and a connecting wire 261 is collected in the second vibrator wire reel 212 .

[0049] In this embodiment, two types of extension spring groups are provided. Fig.15 In one structural form, the spring restraining component is a rod; the rod is fixedly mounted on the upper support rod, and one end of the SMA lifting spring is fixedly connected to the rod.

[0050] Reference Fig.16 In its second structural form, the spring restraining component is a sliding groove arranged at the bottom of the upper support rod; sliding blocks are provided at both ends of the SMA lifting spring; the sliding blocks are hoisted in the sliding groove, one of the sliding blocks is fixed in the sliding groove, and the other sliding block is connected to one end of the connecting line.

[0051] A storage method for an ultra-large retractable log-periodic antenna suitable for mounting on an unmanned aerial vehicle comprises the following steps:

[0052] Step 1: First, stow the antenna in the vertical direction. The lifting spring group 25 in the unfolded state generates a restoring force by heating. The restoring force is greater than the antenna's own weight and acts on the pulley 26, thereby driving the connecting line 261, so that the middle support rod 22 and the lower support rod 23 are upward, and the antenna is lifted in the vertical direction; at room temperature, the vertical lifting spring group 25 in the folded state is stretched under the action of the antenna's own gravity, and the martensitic phase transformation induced by stress is generated, thereby following the flexible rope to realize the vertical pulling of the antenna; the 27MHz-110MHz vertically polarized logarithmic periodic antenna selects the vertical lifting spring group 25 with two layers of long-stroke changes in cooperation with the pulley group to realize the lifting and lowering of the antenna in the vertical direction.

[0053] The current excites the long-stroke SMA lifting spring and cooperates with the pulley group to achieve a 4:1 stroke scaling, completing the vertical reverse displacement of the SMA spring with a stroke change of 55cm to 220cm. The two-layer SMA lifting spring + pulley group solution can achieve a five-meter vertical lifting and lowering of the antenna.

[0054] Step 2: The antenna is then retracted in the horizontal direction. The joint 27 can drive the connection rod 28 to be retracted through current excitation control, thereby achieving S-shaped folding in the horizontal direction.

[0055] The joints in this embodiment are specifically referred to Figures 10 to 14 The joint of this embodiment includes an intermediate support and two connecting seats, both ends of the intermediate support are connected to the corresponding connecting seats through bearings; each connecting seat is provided with an upper and a lower set of spring connecting heads, the two upper sets of spring connecting heads facing each other are connected through SMA springs a, and the two lower sets of spring connecting heads facing each other are connected through SMA springs b, and the SMA springs a and SMA springs b are respectively located above and below the intermediate support.

[0056] The extending directions of the SMA spring a and the SMA spring b are parallel to each other, and two of each are provided.

[0057] One end of the spring connector is connected to the SMA spring, and the other end is hinged to the connecting seat where it is located.

[0058] Two micro electromagnetic locks are arranged in the middle support; a locking hole is arranged on the support platform of the connecting seat; the micro electromagnetic lock faces the support platform on its outside; in the locked state, the lock core of the micro electromagnetic lock passes through the outer wall of the middle support and is located in the corresponding locking hole.

[0059] The inner side of the connecting seat is provided with a supporting platform; the extended connecting end of the intermediate support and the supporting platform are respectively located on both sides of the bearing and realize connection with the bearing.

[0060] The intermediate support comprises a support body and a support cover; the support cover is buckled on the support body to form a closed space; the micro electromagnetic locks are all located in the closed space; the outer side of the support body is provided with an extended connection end designed integrally with it;

[0061] The bearings are provided on both sides of each support platform, and there are four bearings in total;

[0062] The outer sides of the bearings on both sides of the support platform are the ends of the support cover plate and the extended connection ends respectively.

[0063] The steps of joint extension and contraction can be summarized as follows:

[0064] The initial state is Fig.11 As shown, the micro electromagnetic lock is in a power-off state and the joint is in a locked state; at the same time, the SMA spring a and the SMA spring b are in a force balance state.

[0065] In the first step, through circuit control, the micro electromagnetic lock cylinder is retracted to meet the unlocking conditions.

[0066] The second step is to heat the SMA spring b, and the spring b returns to its initial state. The overall structure shrinks, and the SMA spring a is stretched, so that the spring a is in a low-temperature martensite state. At the same time, the micro electromagnetic lock circuit is disconnected, and the lock core rebounds. Fig.12 .

[0067] In the third step, the micro electromagnetic lock is energized, the lock core is retracted, and the unlocking condition is achieved; the SMA spring a is heated, the spring a returns to its initial state, the overall structure is unfolded again, and the SMA spring b is stretched and is in a low-temperature martensite state.

[0068] In the fourth step, the micro electromagnetic lock is powered off, the lock core pops out, the locking structure is reset, and the entire structure is locked again.

[0069] At this point, a cycle of development is completed.

[0070] The logarithmic periodic antenna of this specific embodiment has the function of automatic deployment and folding. The antenna is vertically suspended on the bottom bracket of the UAV platform. The antenna is deployed after the UAV takes off and folded before landing. The maximum size of the logarithmic periodic antenna in the deployed state is 5000mm×4500mm×50mm; the maximum size of the antenna in the retracted state is: 2200mm×600mm×300mm. When the total power is less than 200W, the antenna deployment time is less than 210s, and the folding time is less than 150s. This new retractable logarithmic periodic antenna has the advantages and characteristics of self-folding, large size, and low surface density. The weight of a single antenna is no more than 7 kilograms, and the antenna of this device has a certain wind resistance.

[0071] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A retractable log-periodic antenna, comprising a plurality of antenna elements; characterized in that: It also includes an upper support rod (21), a middle support rod (22) and a lower support rod (23); the upper support rod (21), the middle support rod (22) and the lower support rod (23) are arranged in parallel, wherein the middle support rod (22) is located between the upper support rod (21) and the lower support rod (23); a travel electronic lock (24) is arranged between the upper support rod (21) and the middle support rod (22) and between the middle support rod (22) and the lower support rod (23); The left and right ends of the upper support rod (21) are provided with a lifting spring group (25), and the outer sides of the two lifting spring groups (25) are provided with pulleys (26), and a connecting wire (261) is wound around the pulley (26), one end of the connecting wire is connected to the action end of the lifting spring group, and the other end of the connecting wire (261) passes through the two travel electronic locks (24) in sequence and is fixed on the lower support rod (23). The antenna element is installed on the middle supporting rod.

2. The retractable log-periodic antenna according to claim 1, characterized in that: The pulley is mounted on the upper support rod (21).

3. The expandable log-periodic antenna according to claim 1, characterized in that: Both ends of the upper support rod (21), the middle support rod (22) and the lower support rod (23) are connected with joints (27), and the other end of the joint (27) is installed with an extension rod (28).

4. The retractable log-periodic antenna according to claim 3, characterized in that: The upper support rod, the lower support rod and the extension rod connected to the upper support rod and the lower support rod are all provided with a plurality of dipole winding devices; a plurality of antenna dipoles are arranged on the middle support rod and the extension rod connected to the middle support rod; The middle part of the antenna vibrator is connected to the corresponding middle support rod and the extension rod, and the two ends of the antenna vibrator are respectively connected to the corresponding vibrator winding machine, and the vibrator winding machine realizes the winding and releasing of the line.

5. The retractable log-periodic antenna according to claim 3, characterized in that: Two travel electronic locks are respectively mounted on the bottom of the upper support rod and the middle support rod.

6. The retractable log-periodic antenna according to claim 1, characterized in that: The lifting spring group (25) comprises an SMA lifting spring and a spring restraining component; the SMA lifting spring is extended or shortened along the spring restraining component; One end of the SMA lifting spring is fixed, and the other end is connected to the connecting wire; the circuit controls the extension and contraction of the SMA lifting spring.

7. The retractable log-periodic antenna according to claim 6, characterized in that: The spring restraining component is a rod; the rod is fixedly mounted on the upper support rod, and one end of the SMA lifting spring is fixedly connected to the rod.

8. The retractable log-periodic antenna according to claim 6, characterized in that: The spring restraining component is a sliding groove arranged at the bottom of the upper support rod; sliding blocks are arranged at both ends of the SMA lifting spring; the sliding blocks are hoisted in the sliding groove, one of the sliding blocks is fixed in the sliding groove, and the other sliding block is connected to one end of the connecting line.

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