Segmented combined shipborne ground wave radar broadband transmitting antenna, antenna array and method

Abstract

A segmented modular shipborne ground wave radar broadband transmitting antenna, antenna array, and method include a segmented modular transmitting antenna mast fixed to a horizontal support platform on the deck, multiple guyed ground anchors, and a matching network. The horizontal support platform is provided with a hydraulic swing cylinder, the hydraulic swing cylinder is provided with an antenna base, and a segmented modular transmitting antenna mast is mounted on the antenna base. The antenna array includes two transmitting antennas, which are separated on both sides of the ship's side and arranged in a staggered manner. The method is to input the phase of the excitation signal of the first antenna, continuously adjust the phase of the excitation signal of the second antenna, and design a multi-channel switching broadband LC matching network to obtain maximum radiation energy intensity. The present invention adopts a whip antenna form with a relatively small volume and simple appearance. Through the segmented modular design and high-strength components and fixing method design, it can be deployed in the limited space of the shipborne platform and adapt to the harsh environment of the ocean and the hull. The overall structure of the antenna is compact, and broadband transmission characteristics are achieved in a small size; the connection is reliable, and installation and replacement are simple and convenient.

Description

Technical Field

[0001] The present invention relates to a segmented combined shipborne ground wave radar broadband transmitting antenna, an antenna array and a method, and belongs to the technical field of radar antennas. Background Art

[0002] As a new type of oceanographic radar, ground wave radar systems have the ability to detect surface targets beyond the horizon. Consequently, they have attracted increasing attention in various countries, with applications for shore-based ground wave radar for ocean state remote sensing and ship target surveillance and monitoring. Integrating these systems onto shipborne platforms can further expand their detection range and improve their maneuverability. However, with the widespread use of modern radar and communications and other electronic information systems on ships, the number and variety of shipborne antennas are increasing. The superstructure is filled with a variety of devices, including antennas for detection, communications, and electronic countermeasures systems, as well as masts, bridges, funnels, and halyards. Consequently, the space available for installing shipborne ground wave radar antennas is limited, making conventional shortwave antennas such as trifilar / quadrifilar truss antennas, multi-element antennas, conical antennas, and column cage antennas difficult to use as broadband transmitting antennas for shipborne ground wave radars.

[0003] This puts higher demands on the design of shipborne ground wave radar antennas, and the following problems still need to be solved:

[0004] 1. The harsh ocean and ship environments place even greater demands on the antenna's strength and installation, and even the antenna structure itself needs to be redesigned.

[0005] 2. The antenna needs to meet the broadband transmission requirements of different radar transmission frequencies. However, its height and volume are limited, which makes the electrical length of the antenna very small at the short-wave and low-frequency end. It is difficult to meet the broadband performance in the entire frequency band by simply relying on the antenna impedance loading.

[0006] Require;

[0007] 3. The standing wave of the antenna that is usually well matched in the open coastal area becomes worse after being put on board, which greatly reduces the matching performance of the matching network. Summary of the Invention

[0008] In view of the above problems, the present invention proposes a segmented combined shipborne ground wave radar broadband transmitting antenna, antenna array and method that can be lowered by hydraulic pressure to overcome the shortcomings of the existing technology.

[0009] The segmented combined shipborne ground wave radar broadband transmitting antenna is characterized by comprising a horizontal support platform 22 fixed to the deck, a plurality of guy wire anchors 23 and a matching network 21. The horizontal support platform 22 is provided with a hydraulic swing cylinder, the hydraulic swing cylinder is provided with an antenna base 20, and a segmented combined transmitting antenna mast 18 is mounted on the antenna base 20;

[0010] The hydraulic swing cylinder 26 is used to achieve the tilting of the segmented modular transmitting antenna mast 18 between 0 and 90 degrees. The hydraulic swing cylinder is equipped with a manual reversing valve for switching the rotation direction of the hydraulic swing cylinder. When the antenna mast 18 is erected, the hydraulic swing cylinder self-locks to maintain the upright position, while the side is fixed with a pin 27. The erected segmented modular transmitting antenna mast 18 is supported by a detachable steel pipe 19 located on the base 20 and connected to each guy wire anchor 23 by a pull rope.

[0011] The segmented combined transmitting antenna mast 18 is assembled by plugging in the upper and lower parts, and each section is made of carbon fiber. The segmented assembly takes into account both the structural strength and strong tensile strength of the shipborne transmitting antenna, and also greatly reduces the overall weight of the antenna. The feed line is connected to the feeding point at the bottom of the segmented combined transmitting antenna mast 18. The segmented combined transmitting antenna mast 18 acts as the entire radiator and radiates the shortwave signal after receiving the radio frequency input.

[0012] The RF input has multiple frequency bands, and the matching network 21 includes multiple ceramic high-voltage vacuum relays 24 corresponding to the RF input strength, an adjustment knob 25 for switching the relays, and a broadband LC circuit capable of multi-channel switching; different high-voltage vacuum relays 24 are selected by energizing and closing them through the adjustment knob 25, thereby selecting the required frequency band channel.

[0013] The segmented combined transmitting antenna pole 18 has three segments, namely, a carbon fiber composite tube 1 4, a carbon fiber composite tube 2 8, and a carbon fiber composite tube 3 12 from bottom to top, and further includes a base 1 with a slot for connecting to the antenna base 20, the slot being inserted with a connector 1 2, a pressure ring 2 17 being sleeved at the joint between the two, the carbon fiber composite tube 1 4 being inserted at the upper end of the connector 1 2, and a pressure ring 1 3 being sleeved at the joint between the two;

[0014] A connector 3 16 is inserted into the upper end of the carbon fiber composite tube 14, and the carbon fiber composite tube 2 8 is inserted into the upper end of the connector 3 16. A shaft end retaining ring 1 5 with an external thread is provided on the upper outer side surface of the carbon fiber composite tube 14, and a shaft end retaining ring 2 6 is provided on the lower outer side surface of the carbon fiber composite tube 2 8. After the carbon fiber composite tube 14, the connector 3 16 and the carbon fiber composite tube 2 8 are assembled with each other, the upper end surface of the shaft end retaining ring 1 5 and the lower end surface of the shaft end retaining ring 2 6 are in contact with each other, and a locking ring 1 7 with an internal thread is used to lock the shaft end retaining ring 1 5 and the shaft end retaining ring 2 6 with each other;

[0015] The upper end of the carbon fiber composite tube 2 8 is inserted with a connector 2 14, and the carbon fiber composite tube 3 12 is inserted into the upper end of the connector 2 14. The upper outer side surface of the carbon fiber composite tube 2 8 is provided with an axial end retaining ring 3 9 with an external thread, and the lower outer side surface of the carbon fiber composite tube 3 12 is provided with an axial end retaining ring 4 10. After the carbon fiber composite tube 2 8, the connector 2 14 and the carbon fiber composite tube 3 12 are assembled with each other, the upper end surface of the axial end retaining ring 3 9 and the lower end surface of the axial end retaining ring 4 10 are in contact with each other, and the locking pressure ring 2 10 with an internal thread is used to lock the axial end retaining ring 3 9 and the axial end retaining ring 4 10 with each other;

[0016] The locking ring is made of titanium alloy, which has high unit strength, excellent rigidity, light weight and good corrosion resistance, so the connectors connecting the carbon fiber tube are all made of titanium alloy;

[0017] A plurality of drawstring fixing members 15 are provided on the outside of the second carbon fiber composite tube 8 , and an end cap 13 is provided on the top end of the third carbon fiber composite tube 12 .

[0018] The radio frequency interface of the matching network 21 is a standard 50 ohm NK, and the input voltage is 24V; the hydraulic swing cylinder 26 is hydraulically driven, and the power interface of the hydraulic device is an input of 380V and a power of 1.5KW.

[0019] The matching network 21 uses a mobile charging power supply 28 to provide 24V voltage to the relay; the adjustment knob 25 has three gears, gear 1 corresponds to an input frequency band of 4.40-4.61MHz, gear 2 corresponds to a frequency band of 4.61-4.76MHz, and gear 3 corresponds to a frequency band of 4.76-4.92MHz. By adjusting the switch to the desired frequency band, the electrical indicators that meet the requirements can be obtained. The matching network 21 and the horizontal support platform 22 are connected by bolts, and the horizontal support platform 22 is then welded to the deck.

[0020] When the segmented combined shipborne ground wave radar broadband transmitting antenna is used, the fewer the segments, the higher the frequency, and the more segments, the lower the frequency. By switching between different gears of the matching box, a wider span of resonant transmitting frequency can be adjusted.

[0021] , a segmented combined shipborne ground wave radar broadband transmitting antenna array, characterized in that it includes two said segmented combined shipborne ground wave radar broadband transmitting antennas, and the two segmented combined shipborne ground wave radar broadband transmitting antennas are separated on both sides of the ship's side and arranged in a staggered manner.

[0022] The application of the transmitting antenna array is characterized in that the transmitting antenna array is used to transmit and enhance radiation energy in a directionally directed manner.

[0023] , a method for achieving end-fire using the segmented combined shipborne ground wave radar broadband transmitting antenna array, characterized in that the phase of the excitation signal input to the first antenna is first set; the phase of the excitation signal to the second antenna is continuously adjusted, and the intensity of the radiation energy is measured in the far field; by continuously adjusting the phase of the excitation signal to the second antenna, the maximum radiation energy intensity is obtained, and the direction of the maximum radiation energy intensity is the end-fire direction.

[0024] The present invention adopts a whip antenna form with a small volume and relatively simple appearance. Through a segmented modular design and high-strength components and fixing method design, it can be deployed in the limited space of the ship-borne platform and adapt to the harsh environment of the ocean and the hull.

[0025] By gradually thickening the antenna main body oscillator, designing an adjustable matching network, and assembling it in sections according to the radar frequency, the change in antenna impedance caused by frequency changes is compensated, thereby widening the impedance bandwidth, achieving good impedance matching and effective radiation at each radar frequency.

[0026] Through the above technical approach, the overall structure of the shipborne ground wave radar broadband transmitting antenna is compact, and broadband transmission characteristics are achieved in a smaller size; the connection is reliable, and the installation and replacement are simple and convenient. As the transmitting antenna of the shipborne ground wave radar, it has good matching and good environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a segmented combined shipborne ground wave radar broadband transmitting antenna.

[0028] Figure 2 Schematic diagram of the segmented combined transmitting antenna mast.

[0029] Figure 3 Schematic diagram of the antenna base, Figure 3 When a is erected, Figure 3 b. When lodging.

[0030] Figure 4 Schematic diagram of multi-channel switching broadband LC matching within the matching network.

[0031] Figure 5 Schematic diagram of the matching network appearance.

[0032] Figure 6 Measured standing wave ratio curve of the matching network in the second position.

[0033] Figure 7 Schematic diagram of the segmented combined shipborne ground wave radar broadband transmitting antenna array in the lying state at the bow.

[0034] Figure 8 Schematic diagram of the segmented combined shipborne ground wave radar broadband transmitting antenna array in the erected state at the bow.

[0035] Figure 9 Endfire 2D pattern of the array element.

[0036] Figure 10 Endfire 3D pattern of the array element.

[0037] Figure 11 Non-endfire 2D pattern of the array element.

[0038] Figure 12 Non-endfire 3D pattern of the array element.

[0039] Among them, the base 1, the connector 2, the pressure ring 3, the carbon fiber composite tube 4, the shaft end retaining ring 5, the shaft end retaining ring 2 6, the locking pressure ring 1 7, the carbon fiber composite tube 2 8, the shaft end retaining ring 3 9, the shaft end retaining ring 4 10, the locking pressure ring 2 11, the carbon fiber composite tube 3 12, the end cover 13, the connector 2 14, the pull rope fixing part 15, the connector 3 16, the pressure ring 2 17, the segmented combined transmitting antenna pole 18, the supporting steel pipe 19, the antenna base 20, the matching network 21, the horizontal support platform 22, the guy wire anchor 23, the ceramic high-voltage vacuum relay 24, the adjusting knob 25, the hydraulic swing cylinder 26, the positioning pin shaft 27, the mobile charging power supply 28, the conversion switch power interface 29, the transmitting cable 30, the protection box 31, and the N-shaped feeder port 32. DETAILED DESCRIPTION

[0040] 1. Structure of a single segmented combined shipborne ground wave radar broadband transmitting antenna

[0041] First, a single segmented combined shipborne ground wave radar broadband transmitting antenna is constructed. Its overall structure is as follows: Figure 1 As shown. The segmented combined transmitting antenna pole 18 serves as the antenna radiation body, and transmits signals to the outside world through the design of thickening the antenna body oscillator section by section and assembling in sections according to the radar frequency, so as to achieve effective radiation of each radar frequency. The supporting steel pipe 19, the antenna base 20, the horizontal support platform 22, and the guy wire anchor 23 fix the antenna pole 18, improve the wind resistance of the antenna pole, and realize deployment in the limited space of the ship-borne platform through the design of high-strength components and fixing methods, and adapt to the harsh environment of the ocean and the hull. The matching network 21 adjusts the antenna input impedance to achieve a broadband matching state. Through the design of the adjustable matching network, it compensates for the changes in the antenna impedance caused by the frequency change, so as to achieve the purpose of widening the impedance bandwidth, so as to achieve good impedance matching and effective radiation of each radar frequency. Since the hull deck is non-horizontal, the antenna pole support frame cannot be placed normally on the slope, so the antenna base is designed to support the horizontal mounting platform 22 to keep the antenna level. The specific construction method and function of each component are as follows:

[0042] Sectional combined transmitting antenna mast 18

[0043] As the main body of the antenna, each section of the antenna pole is made of carbon fiber. Through the combination of sections, the structural strength and strong tensile strength of the shipborne transmitting antenna are taken into account while the overall weight of the antenna is greatly reduced. Its specific gravity is lighter than aluminum, less than 1 / 4 of steel, and its specific strength is 20 times that of iron.

[0044] Taking three sections as an example, the specific structure is as follows Figure 2 As shown, the combined length of the carbon fiber antenna is approximately 11 meters, with each section no longer than 4 meters. It utilizes three sections of carbon fiber rods, with the second section inserted into the inner diameter of the first, and the third section inserted into the inner diameter of the second. Each section is connected by a high-strength threaded ring structure. The threaded ring structure uses titanium alloy as the structural components. Titanium alloy has high specific strength, excellent rigidity, light weight, and good corrosion resistance, so the structural components connecting the carbon fiber tube structure are also made of titanium alloy.

[0045] During assembly, insert the connector three 16 into the carbon fiber composite tube one 4, and use a wrench to lock the internal thread of the locking pressure ring one 7 and the external thread of the shaft end retaining ring one 5; there is a fixing screw on the cylindrical surface of the shaft end retaining ring two 6, which passes through the carbon fiber composite tube two 8 and the connector three 16 as a whole. At the same time, the shaft end retaining ring two 6 also plays a role in locking the pressure ring one 7 to prevent it from falling off.

[0046] Connector 2 (14) is inserted into carbon fiber composite tube 2 (8). The internal threads of locking ring 2 (11) mate with the external threads of shaft end retaining ring 3 (9) and are tightened with a wrench. Carbon fiber composite tube 3 (12) serves as a crucial height guarantee for the antenna radiator, crucially impacting electrical performance. End cap 13 prevents rainwater from entering the inner hole during rain, where it could accumulate. Drawstring fixture 15, acting as a drawstring position fixture, is secured to carbon fiber composite tube 2 (8) via screws on the cylindrical surface. Pressing ring 2 (17) provides protection and reinforcement, preventing connector 1 (2) from breaking off from the upper edge of base 1 during swinging. It is connected to base 1 and connector 1 (2) via screws and epoxy glue on the cylindrical surface. After these steps, the entire antenna mast is assembled. Bolted to the carrier platform through the mounting holes in the first section of base 1, the feeder is connected to the feed point on the outer cylindrical surface of press ring 3. The antenna mast acts as the entire radiator, radiating shortwave signals.

[0047] The main material of the antenna rod is carbon fiber. The carbon fiber rod is used as the antenna radiator to reduce weight while ensuring its strength. It is made of organic fibers such as flaky graphite microcrystals stacked along the fiber axial direction. After carbonization and graphitization treatment, the carbon content exceeds 95%. The strength is relatively high. The mass is only one-fourth of steel, but the strength is 7 to 9 times that of steel. The tensile elastic modulus is also stronger than that of steel. It has the characteristics of high temperature resistance, friction resistance, electrical conductivity, thermal conductivity and corrosion resistance. The auxiliary materials are mainly S31603 and TC4, of which S31603 is stainless steel 316L and TC4 is titanium alloy. The materials involved are shown in Table 1 below.

[0048] Table 1 Materials of segmented combined transmitting antenna pole

[0049] serial number name Material Section 1 base Stainless steel 316L Section 1 2 Connector 1 Carbon fiber-T300 Section 1 3 Pressure ring 1 S31603 (GB / T20878) Section 1 4 Carbon fiber composite tube 1 (∅130-115) Carbon fiber-T300 Section 1 5 Shaft end retaining ring 1 TC4 (GB / T3620.1) Section 1 6 Shaft end retaining ring 2 TC4 (GB / T3620.1) Section 2 7 Locking ring 1 TC4 (GB / T3620.1) Section 2 8 Carbon fiber composite tube 2 (∅115-100) Carbon fiber-T300 Section 2 9 Shaft end retaining ring three TC4 (GB / T3620.1) Section 2 10 Shaft end retaining ring 4 TC4 (GB / T3620.1) Section 3 11 Locking ring 2 TC4 (GB / T3620.1) Section 3 12 Carbon fiber composite tube three (∅100-80) Carbon fiber-T300 Section 3 13 End cap TC4 (GB / T3620.1) Section 3 14 Connector 2 TC4 (GB / T3620.1) Section 3 15 Drawstring fixings S31603 (GB / T20878) Section 2 16 Connector three Carbon fiber-T300 Section 2 17 Pressure ring 2 S31603 (GB / T20878) Section 1

[0050] The antenna's carbon fiber rod experiences the highest stress at the bottom mounting point, ensuring it withstands gale forces of at least force 10. With the shipborne platform's maximum swing amplitude no less than 45 degrees and a minimum swing period no longer than 6 seconds (3 seconds one-way), the resulting bottom swing force on the antenna (calculated based on maximum force analysis) is less than the antenna's allowable tensile / shear stress. Theoretical calculations and actual swing tests have proven that this structure meets the requirements for shipborne ground wave radar transmitting antennas in harsh environments. In sea conditions exceeding force 10, the antenna is lowered using a designed antenna-tumbling device for protection.

[0051] Support steel pipe 19:

[0052] The entire antenna is fixed in a triangular configuration using three Q235B steel pipes and corresponding sheet metal components. One end of the steel pipe is bolted to the sheet metal component and secured to the antenna at a point one-fifth the antenna's height from the ground. The other end of the pipe is bolted to three other metal components and then welded to the horizontal base. To prevent the steel pipe from connecting to the antenna ground, fiberglass insulation is added between the three sheet metal components and the carbon fiber tube. Solid steel columns with the same outer diameter are welded to the steel pipe at both ends. The columns are slotted, and the sheet metal components are inserted into the slots and bolted together. The sheet metal components are then welded to the deck. The three steel pipes securing the antenna are evenly spaced at 120° angles, and the welds to the deck are located on a circle centered on the antenna axis.

[0053] Antenna base 20:

[0054] Specific as Figure 3 As shown, the actuator uses a hydraulic swing cylinder 26 to achieve a 0-90° tilt, and a manual reversing valve is used to switch the rotation direction of the hydraulic swing cylinder 26. When the antenna is to be operated, the antenna mast needs to be erected. Once the mast is erected, the hydraulic swing cylinder 26 self-locks and locks the mast in the upright position. The side is also locked with a fixed pin 27. A clamp-like device is used to secure the mast to the ship's side. Each antenna also has a cable ring around it, which can be used to pull the mast. When the antenna is not in operation or entering port, the mast can be laid down. After being laid down, the hydraulic tilting device has two locking pins. The hydraulic swing cylinder 26 self-locks to prevent the two locking pins from being accidentally tightened, and the mast is placed flat on the mast support.

[0055] Broadband matching network 21:

[0056] This shipborne ground wave radar's broadband transmitting antenna utilizes a hybrid approach of thickening the array and adding a matching network to optimize its electrical performance. For electric dipole antennas, to broaden the frequency band, a larger dipole cross-section is often used. This reduces the dipole's length-to-diameter ratio, also known as the slenderness ratio. This significantly improves the antenna's impedance characteristics within the frequency band. This antenna features a segmented, modular design with a larger diameter at the base and a gradually decreasing diameter toward the top, with the base diameter being more than three times that of the top. However, since the dipole cannot be infinitely thickened in practical applications, a broadband matching network has been added to the back end.

[0057] For end-fire whip antennas on land, where the ground environment approaches the theoretically infinite Earth, a fixed matching network using a dual-whip binary array antenna can relatively easily achieve the desired standing wave and gain requirements within the desired frequency band. However, for shipborne end-fire whip antennas, due to the limited installation space onboard, the presence of existing antennas, and the vessel's surroundings, traditional fixed matching networks struggle to achieve the desired electrical specifications (standing wave ratio: less than 2.5, gain: greater than or equal to 2dBi) within the narrow 4.4-4.9MHz frequency band. Therefore, we propose manually switching multiple matching networks to achieve the desired electrical specifications within the desired frequency band.

[0058] The internal circuit of the matching network is as follows Figure 4 As shown in the figure, a multi-channel switching broadband LC matching network is designed using ceramic high-voltage vacuum relays to achieve broadband matching. The relays are energized to close, selecting the desired frequency channel. The dispersed distribution of components within the matching network reduces mutual coupling and internal noise between high frequencies. While conventional broadband matching cannot achieve a standing wave ratio (SWR) below 3 across the entire frequency band, the improved multi-channel matching network achieves a SWR below 2.5 within each sub-band, achieving optimized performance, low loss, and improved gain. Compared to conventional, inefficient multi-stage, composite π-type broadband matching LC networks, this reduces system complexity while achieving lower SWR across the broadband, higher efficiency, and greater suitability for engineering applications.

[0059] The external matching network Figure 5As shown, the RF interface is a standard 50-ohm NK, the mobile power supply input voltage is 220V, the mobile power supply output voltage is 24V, and the matching network solenoid valve input voltage is 24V. The hydraulic station power interface has a 380V input and a power output of 1.5kW. A protective box 31 and an N-shaped feeder port 32 are located outside the matching network 21, and a transmission cable 30 is connected. The protective box 31 houses the transfer switch power interface 29 and the transfer switch 25. Considering that the protective box 31 is installed outdoors and exposed to wind and rain, it is made of aging-resistant engineering plastic, and the hinges are equipped with a metal buckle structure to facilitate opening and closing when needed. During use, the waterproof box is opened and a mobile charging power supply 28 is used to provide 24V power to the transfer switch circuit. The transfer switch 25 has three gears: 1st gear is 4.40-4.61MHz, 2nd gear is 4.61-4.76MHz, and 3rd gear is 4.76-4.92MHz. By adjusting the transfer switch to the desired frequency range, the required electrical specifications can be achieved. The matching box is connected to the deck using a steel plate bolted to the matching box, which is then welded to the deck.

[0060] Then the measured results of the matching network are given as follows Figure 6 , which shows the measured standing wave ratio curve for the shipborne ground wave radar broadband antenna in the matching network's second position. This shows that this design effectively adapts to the marine shipborne environment within the 4.61 to 4.76 MHz broadband, with standing wave ratios below 2. Furthermore, combining this patented matching network in positions 1 and 3 further expands the transmit antenna's bandwidth while maintaining antenna gain above 2 dBi.

[0061] Horizontal support platform 22:

[0062] To ensure the antenna is level, place an antenna mast support platform beneath the antenna body. The top of the support platform is connected to the antenna base, and the bottom is welded to nine evenly spaced, height-adjustable iron columns. The height of the columns varies with the inclination of the hull, keeping the antenna level.

[0063] Guy wire anchor 23:

[0064] Anchor rings for auxiliary fixing of the pull ropes are welded on the edge of one side of the hull and in the direction of the ship's width. Three pull ropes are connected at 2 / 3 of the height of the transmitting antenna body, two of which are fixed on the mast at the edge of the ship, and one is fixed on the deck in the direction of the ship's width. The fixed angles are spaced at intervals of 120°.

[0065] 2. Formation of the segmented combined shipborne ground wave radar broadband transmitting antenna array

[0066] Next, after completing the two segmented combined shipborne ground wave radar broadband transmitting antennas according to the above process, the segmented combined shipborne ground wave radar broadband transmitting antenna array is formed according to the following steps. After the construction is completed, the structure of the bow is as follows: Figure 7 、 8 The specific construction steps are as follows:

[0067] Two segmented, modular shipborne surface wave radar broadband transmitting antennas were installed on either side of the vessel. The two antennas were staggered horizontally, with a vertical spacing of ≥12m and a center-to-center spacing of 300mm. This ensured that the antennas did not collide during collapse and that no objects were located beneath the masts during and after collapse. Two antenna base support platforms were designed and fabricated. These platforms were connected to the antenna bases and supported the antennas. The base support platforms had 25 70mm-high M24 anchor bolts with a strength of 12.9 and a hot-dip galvanized finish. Each bolt was supplied with a spring washer, a flat washer, and two 12.9-strength nuts. The 20-M6 screw holes were 10mm deep.

[0068] The antenna is approximately 11 meters tall and features a multi-section structure. The base is approximately 0.5 meters high, and the combined height of the mast and base is approximately 11.6 meters. The matching network measures 430mm x 430mm in length and width and weighs approximately 30kg. The transmitting antennas are a set of two, each with a feeder cable approximately 16mm in diameter. The feeder cable is unfolded for easy use and does not need to be coiled. The peak power of a single transmitting antenna is 1kW. The hydraulic station included with the hydraulic lodging mechanism weighs approximately 120kg, operates at 380V, and produces approximately 1.5kW of power.

[0069] 3. Operation of the segmented combined shipborne ground wave radar broadband transmitting antenna and antenna array

[0070] Furthermore, the operation process of the segmented combined shipborne ground wave radar broadband transmitting antenna array is as follows:

[0071] The first step is to turn on the power supply to preheat the hydraulic retraction device for 15 to 30 minutes, then control the hydraulic cylinder to raise the antenna, insert the safety pin, and turn off the power supply; the second step is to determine the operating frequency of the antenna, select the corresponding gear on the two matching boxes, and connect the feeder; the third step is to turn on the transmitter to preheat and make preparations before launching; the fourth step is that the transmitter works to transmit the corresponding power and the antenna starts working; the fifth step is that the transmitter stops working when the frequency is changed, the operator selects the corresponding frequency gear on the matching box, and repeats the fourth step; the sixth step is that the launch mission is completed, the transmitter stops working and shuts down, the power supply is turned on, the safety pin is pulled out, and the hydraulic cylinder is controlled to lower the antenna.

[0072] 4. Directional emission and enhancement of antenna array radiation energy

[0073] Ultimately, end-fire radar transmission signals are achieved through a segmented, modular shipborne ground wave radar broadband transmitting antenna array, achieving directional radiation and energy enhancement. First, the phase of the radar transmitter excitation signal input to the first antenna is set; the phase of the radar transmitter excitation signal input to the second antenna is continuously adjusted, and the intensity of the radiated energy is measured in the far field. By continuously adjusting the phase of the radar transmitter excitation signal for the second antenna, the maximum radiated energy intensity is achieved. The direction of maximum radiated energy intensity is the end-fire direction, thus achieving variable-direction end-fire. In applications, if the end-fire direction is fixed, the phase difference between the radar transmitter input antennas can be equivalently achieved by using the difference in the length of the feed cables of the two segmented modular shipborne ground wave radar broadband transmitting antennas.

[0074] Taking the end-fire direction along the middle axis of the antenna array as an example, the operating frequency bands of the two segmented combined shipborne ground wave radar broadband transmitting antennas must all meet a 90° phase difference, pointing from the phase-advanced antenna to the phase-lag antenna. If the phase of antenna one is 90° ahead of antenna two, the end-fire direction is along the middle axis, from antenna one to antenna two. Calculated based on the radar center frequency of 4.7MHz, the wavelength is 63.83 meters. Taking into account the actual shipboard installation environment, if the equivalent input of the two segmented combined shipborne ground wave radar broadband transmitting antennas is 90° phase difference, it depends on the difference in the length of the feeder cable. The lengths of the two feeder cables need to differ by a quarter wavelength (15.96 meters). The transmitting antenna connected to the short feeder cable is 90° ahead of the transmitting antenna connected to the long feeder cable, and the antenna array radiates toward the transmitting antenna end connected to the long feeder cable. The end-fire 2D pattern, end-fire 3D pattern, non-end-fire 2D pattern, and non-end-fire 3D pattern of the antenna array are as follows: Figure 9-12 As shown in the figure, it can be seen that compared with non-endfire, the energy of endfire is concentrated in the endfire radiation direction rather than being distributed omnidirectionally. The radiated energy has better directionality and is more conducive to concentrating the energy in the radar detection direction.

Claims

1. Segmented combined shipborne ground wave radar broadband transmitting antenna, characterized by The invention comprises a segmented combined transmitting antenna pole (18), a horizontal supporting platform (22) fixed on the deck, a plurality of guy wire anchors (23) and a matching network (21); a hydraulic swing cylinder (26) is provided on the horizontal supporting platform (22); an antenna base (20) is provided on the hydraulic swing cylinder (26); and a segmented combined transmitting antenna pole (18) is mounted on the antenna base (20); The hydraulic swing cylinder (26) is used to achieve the flipping of the segmented combined transmitting antenna pole (18) in the range of 0-90 degrees. The hydraulic swing cylinder (26) is equipped with a manual reversing valve for switching the rotation direction of the hydraulic swing cylinder (26); after the antenna pole (18) is erected, the hydraulic swing cylinder (26) is self-locked and locked to maintain an upright state, and the side is fixed with a positioning pin (27); the erected segmented combined transmitting antenna pole (18) is supported by a detachable steel pipe (19) located on the base (20) and connected to each pull-wire anchor (23) by a pull rope; The segmented combined transmitting antenna pole (18) is assembled by plugging in the upper and lower parts, and each segment is made of carbon fiber. The segmented combined method takes into account the structural strength and strong tensile strength of the shipborne transmitting antenna while significantly reducing the overall weight of the antenna. The feed line is connected to the feeding point at the bottom of the segmented combined transmitting antenna pole (18), and the segmented combined transmitting antenna pole (18) acts as a whole radiator to radiate the shortwave signal. The radio frequency input has multiple frequency bands, and the matching network (21) includes a plurality of ceramic high-voltage vacuum relays (24) corresponding to the radio frequency input strength, an adjustment knob (25) for switching the relays, and a broadband LC circuit capable of multi-channel switching; different ceramic high-voltage vacuum relays (24) are selected by energizing and closing them through the adjustment knob (25), thereby selecting a desired frequency band channel; The segmented combined transmitting antenna rod (18) has three segments, which are carbon fiber composite tube 1 (4), carbon fiber composite tube 2 (8) and carbon fiber composite tube 3 (12) from bottom to top, and also includes a base (1) with a slot for connecting with the antenna base (20), the slot is inserted with connector 1 (2), and a pressure ring 2 (17) is sleeved at the joint between the two, the carbon fiber composite tube 1 (4) is inserted at the upper end of connector 1 (2), and a pressure ring 1 (3) is sleeved at the joint between the two; The upper end of the carbon fiber composite tube 1 (4) is inserted with a connector 3 (16), and the carbon fiber composite tube 2 (8) is inserted into the upper end of the connector 3 (16). The upper outer side surface of the carbon fiber composite tube 1 (4) is provided with an axial end retaining ring 1 (5) with an external thread, and the lower outer side surface of the carbon fiber composite tube 2 (8) is provided with an axial end retaining ring 2 (6). After the carbon fiber composite tube 1 (4), the connector 3 (16) and the carbon fiber composite tube 2 (8) are assembled with each other, the upper end surface of the axial end retaining ring 1 (5) and the lower end surface of the axial end retaining ring 2 (6) contact each other, and the locking ring 1 (7) with an internal thread is used to lock the axial end retaining ring 1 (5) and the axial end retaining ring 2 (6) with each other; The upper end of the carbon fiber composite tube 2 (8) is inserted with a connector 2 (14), and the carbon fiber composite tube 3 (12) is inserted into the upper end of the connector 2 (14). The upper outer side surface of the carbon fiber composite tube 2 (8) is provided with an axial end retaining ring 3 (9) with an external thread, and the lower outer side surface of the carbon fiber composite tube 3 (12) is provided with an axial end retaining ring 4 (10). After the carbon fiber composite tube 2 (8), the connector 2 (14) and the carbon fiber composite tube 3 (12) are assembled with each other, the upper end surface of the axial end retaining ring 3 (9) and the lower end surface of the axial end retaining ring 4 (10) contact each other, and the locking ring 2 (11) with an internal thread is used to lock the axial end retaining ring 3 (9) and the axial end retaining ring 4 (10) with each other; The outer side of the second carbon fiber composite tube (8) is provided with a plurality of drawstring fixing members (15), and the top end of the third carbon fiber composite tube (12) is provided with an end cap (13); The radio frequency interface of the matching network (21) is a standard 50 ohm NK, and the input voltage is 24V; the hydraulic swing cylinder (26) is hydraulically driven, and the power interface of the hydraulic device is an input of 380V and a power of 1.5KW; The matching network (21) uses a mobile charging power supply (28) to provide a 24V voltage to the relay. The adjustment knob (25) has three gears. The input frequency band corresponding to gear 1 is 4.40-4.61MHz, the frequency band of gear 2 is 4.61-4.76MHz, and the frequency band of gear 3 is 4.76-4.92MHz. By adjusting the frequency band to the desired frequency band by the conversion switch, the electrical indicators that meet the requirements can be obtained. The outside of the matching network is connected to the horizontal support platform (22) by bolts, and the horizontal support platform (22) is then welded to the deck.

2. Segmented combined shipborne ground wave radar broadband transmitting antenna array, characterized by The invention comprises two segmented combined shipborne ground wave radar broadband transmitting antennas as described in claim 1, and the two segmented combined shipborne ground wave radar broadband transmitting antennas are separated on both sides of the ship and arranged in a staggered manner.

3. The use of the transmitting antenna array according to claim 2, characterized in that The transmitting antenna array is used for directional emission and enhancement of radiation energy of shipborne ground wave radar.

4. A method for realizing end-fire using the segmented combined shipborne ground wave radar broadband transmitting antenna array according to claim 2, characterized in that First, set the phase of the excitation signal input to the first antenna; The phase of the excitation signal of the second antenna is continuously adjusted, and the intensity of the radiated energy is measured in the far field. By continuously adjusting the phase of the excitation signal of the second antenna, the maximum radiated energy intensity is obtained. The direction of the maximum radiated energy intensity is the end-fire direction, thereby realizing end-fire with a variable direction. In application, if the end-fire direction is fixed, the phase difference between the radar transmitter input antennas can also be equivalently realized by using the difference in the length of the feeding cables of the two segmented combined shipborne ground wave radar broadband transmitting antennas.

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