CN205621857U - A of drop shape antenna of ultra wide band for wearing wall radar - Google Patents

Abstract

The utility model discloses an ultra-wideband drop-shaped antenna for through-wall radar. Metal radiation arms are symmetrically printed on the front of an insulating medium plate. There is a preset interval between the metal radiation arms, and two metal radiation arms adjacent to the interval The input ports are respectively provided as their respective feed ends, the output ends of the impedance converter are electrically connected to the feed ends of the two metal radiation arms, and the input ends of the impedance converter are connected to one end of the coaxial connector. The other end of the connector is connected to the transmitter or receiver of the ultra-wideband through-the-wall radar, and the metal shielding cavity is located directly above the insulating dielectric plate, and the inside of the metal shielding cavity is filled with wave-absorbing materials. The utility model has the characteristics of large working bandwidth, good time-domain radiation characteristics, small antenna volume, compact structure, and smooth outline.

Description

An ultra-wideband drop-shaped antenna for through-wall radar

technical field

The utility model belongs to the technical field of ultra-wideband through-wall radar antennas, in particular to an ultra-wideband drop-shaped antenna for through-wall radar.

Background technique

Ultra-wideband penetrating wall radar is a new type of real-time imaging radar system that can detect and locate targets through partition walls. It can perform non-invasive imaging and tracking detection of people and internal structures in the object, and has the advantages of not damaging the detected wall, high detection resolution and high work efficiency. In recent years, with the continuous advancement of urbanization, my country's urban infrastructure construction, urban housing construction, industrial and energy base construction, and transportation facility construction have also developed rapidly. The use of ultra-wideband radar detection technology to investigate engineering hidden dangers has begun to gain widespread application.

The antenna is a crucial part of the ultra-wideband through-the-wall radar system. It plays the dual role of transmitting radar signals and receiving the echo signals of the detected targets. Its performance directly affects the detection accuracy and detection accuracy of the entire radar system. Detection distance. Limited by the attenuation of the radar signal in the wall scattering interference and the wall medium, as well as the uncertainty of the radar scattering cross section of the detected target, considering the portable and miniaturized requirements in practical engineering applications, the antenna is required to have good radiation characteristics, Ultra-bandwidth characteristics, light weight and low profile characteristics.

At present, the antennas used for ultra-wideband through-wall radar mainly include resistor-capacitor loaded butterfly antennas, horn antennas, and Vivaldi antennas, among which impedance-loaded butterfly antennas are the main ones. Although the impedance-loaded butterfly antenna has good dielectric coupling characteristics and time-domain radiation waveform, its radiation efficiency is poor, which affects the actual detection range of the radar; the horn antenna and the Vivaldi antenna have poor near-ground coupling and have a large lateral It is not conducive to the miniaturization and integration of the system, and affects the application of the through-wall radar system in actual engineering. Therefore, the development of an ultra-wideband antenna with both small size and relatively good gain is of great significance for the miniaturized portable ultra-wideband through-wall radar system.

Contents of the invention

The technical problem solved by the utility model is to provide an ultra-wideband drop-shaped antenna that can be used for detecting targets under cover such as ground and walls.

The utility model adopts the following technical scheme to solve the above-mentioned technical problems, an ultra-wideband drop-shaped antenna for through-wall radar, which is characterized in that it includes a metal radiation arm, an insulating medium plate, a metal shielding cavity, a wave-absorbing material, and an impedance converter And coaxial connector, in which the metal radiation arm is symmetrically printed on the front of the insulating dielectric board. The metal radiation arm is drop-shaped, and its transverse cross-sectional shape can be represented by the following curve: , 0≤t≤0.5, x is the direction of the long axis of the metal radiation arm, y is the direction of the short axis of the metal radiation arm, there is a preset interval between the metal radiation arms, and the two metal radiation arms adjacent to the interval are respectively equipped with input The ports are used as their respective feed terminals, and the impedance converter is a commercial transmission line transformer with 1:2 impedance conversion function and unbalanced 50Ω to 100Ω balance conversion, preferably ADTL2-18+, and a FR4 dielectric board is designed to carry and fix it. The output ends of the impedance converter are electrically connected to the feed ends of the two metal radiation arms respectively for impedance matching, the input end of the impedance converter is connected to one end of the coaxial connector, and the other end of the coaxial connector is connected to the super The transmitter or receiver of the broadband through-the-wall radar is connected, and the metal shielding cavity is located directly above the insulating medium plate, and the interior of the metal shielding cavity is filled with wave-absorbing materials.

Further preferably, the preset distance between the metal radiating arms is 1.5-2.5 mm.

Further preferably, the insulating dielectric board is a single-sided copper-clad epoxy resin glass fiber cloth dielectric board with a thickness of 1mm and a dielectric constant of 4.4, and the insulating dielectric board is fixed at the bottom opening of the metal shielding cavity.

Further preferably, the metal shielding cavity is a rectangular cavity with an open bottom, and its height is 1/8 of the free space wavelength corresponding to the center frequency of the antenna.

Further preferably, the absorbing material is in close contact with the metal shielding cavity and the insulating medium plate, and the absorbing material is made of multi-layer polyurethane foam with a relative permittivity of 2.2 and an electrical conductivity of 0.125 S/m.

Further preferably, the size of the FR4 dielectric board is 16mm×18mm×1.6mm.

Further preferably, the coaxial connector is installed on the back of the insulating medium board.

The utility model has the characteristics of large working bandwidth, good time-domain radiation characteristics, small antenna volume, compact structure and smooth outline. Engineering Requirements for Ultra-Wideband Portable Miniaturized Radar Systems.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the structural representation of the FR4 dielectric plate printed with 1:2 impedance converter in the utility model;

Fig. 3 is the voltage standing wave ratio curve of the utility model;

Fig. 4 is the gain curve of the present utility model;

Fig. 5 is the front and rear radiation waveform curves received at the position of 0.5m in the axial direction of the system of the utility model.

In the figure: 1. Metal radiation arm, 2. Insulation dielectric board, 3. Metal shielding cavity, 4. Absorbing material, 5. FR4 dielectric board, 6. Input end of impedance transformer, 7. Transmission line transformer, 8. Impedance transformation output terminal.

detailed description

The specific content of the utility model is described in detail in conjunction with the accompanying drawings. Figure 1 is a schematic structural diagram of an ultra-wideband drop-shaped antenna for through-wall radar. As shown in Figure 1, the ultra-wideband drop-shaped antenna for through-wall radar includes a metal radiation arm 1, an insulating dielectric plate 2, and a metal shielding cavity 3. Wave-absorbing material 4, impedance transformer and coaxial connector, wherein the metal radiation arm 1 is printed symmetrically on the front of the insulating medium plate 2, the metal radiation arm 1 is drop-shaped, and its transverse cross-sectional shape can be represented by the following curve: , 0≤t≤0.5, x is the direction of the long axis of the metal radiating arm 1, y is the direction of the short axis of the metal radiating arm 1, there is a preset interval between the metal radiating arms 1, and two metal radiating arms 1 adjacent to the interval The input ports are respectively provided as their respective feed terminals, and the impedance converter is a microstrip feed structure with a 1:2 impedance conversion function and unbalanced to balanced output characteristics. The output terminals 8 of the impedance converter are respectively connected to two metal radiation The feed end of the arm 1 is electrically connected for impedance matching, and the input end 6 of the impedance transformer is connected to one end of the coaxial connector, and the other end of the coaxial connector is connected to the transmitter or receiver of the ultra-wideband through-the-wall radar Connected, the metal shielding cavity 3 is located directly above the insulating dielectric plate 2 , and the interior of the metal shielding cavity 3 is filled with a wave-absorbing material 4 .

The preset distance between the metal radiating arms 1 is 1.5-2.5mm, and the two metal radiating arms 1 adjacent to each other are provided with input ports as their respective feed terminals, which can be selected according to the antenna technical indicators such as input impedance It is required to adjust the interval between the two metal radiating arms 1 .

The insulating dielectric board 2 is an epoxy resin fiberglass cloth dielectric board clad with copper on one side, with a thickness of 1 mm and a dielectric constant of 4.4. The insulating dielectric board 2 is fixed at the bottom opening of the metal shielding cavity 3 .

The metal shielding cavity 3 is a rectangular cavity with an opening on the bottom surface, and its height is 1/8 of the free space wavelength corresponding to the antenna center frequency. According to the simulation optimization design results, the size of the metal shielding cavity 3 is: length 100mm, Width 60mm, height 20mm.

The absorbing material 4 is in close contact with the metal shielding cavity 3 and the insulating medium plate 2, and the absorbing material 4 is made of multi-layer polyurethane foam with a relative permittivity of 2.2 and an electrical conductivity of 0.125 S/m.

The impedance converter has a 1:2 impedance conversion function and a conversion function from unbalanced 50Ω to 100Ω balanced output, and its balanced output terminals are respectively connected to the feed terminals of two drop-shaped metal radiation arms for antenna impedance matching , the input end is connected to the coaxial connector.

The coaxial connector is installed on the back of the insulating medium board 2, one end of which is electrically connected to the unbalanced input end 6 of the impedance converter, and the other end is connected to the transmitter or receiver of the ultra-wideband radar.

As shown in FIG. 2 , it is a schematic structural diagram of an FR4 dielectric board printed with a 1:2 impedance transformer. In the figure, the impedance converter includes a commercially available transmission line transformer 7 with 1:2 impedance transformation function and unbalanced 50Ω to 100Ω balanced conversion and a self-designed FR4 dielectric board 5 for carrying a fixed transmission line transformer 7. The transmission line transformer 7 is preferably ADTL2-18+; the size of the FR4 dielectric board 5 is 16mm×18mm×1.6mm, on which a transmission line transformer 7 is printed by circuit board printing technology; the input terminal 6 of the impedance converter is printed with a useful The microstrip line connected to the coaxial connector has a value of 50Ω; the output terminal 8 of the impedance converter is printed with parallel double lines for welding two drop-shaped metal radiation arms, according to the microstrip line and parallel double lines The impedance formula of the line, if the input end adopts 50Ω microstrip input, then the output end is a 100Ω parallel double line.

As shown in Figure 3, it is the voltage standing wave ratio curve of the ultra-wideband drop-shaped antenna used for through-wall radar. In the figure, the abscissa represents the frequency variable, and the unit is GHz, and the ordinate represents the amplitude variable. It can be seen from the figure that in the frequency range of 0.7-4GHz, the voltage standing wave coefficient is less than 2, which can well meet the resolution requirements of the ultra-wideband through-the-wall radar system.

As shown in Figure 4, it is the gain curve of the ultra-wideband drop-shaped antenna used for through-wall radar. In the figure, the abscissa represents the frequency variable, the unit is GHz, and the ordinate represents the gain, the unit is dB. It can be seen from the figure that the gain change of the antenna in the passband is relatively flat, basically maintained at about 0dB, which can meet the detection distance requirements of the ultra-wideband through-wall radar.

As shown in Figure 5, it is the front and rear radiation waveforms received at the position 0.5m in the axial direction of the ultra-wideband drop-shaped antenna system used for through-wall radar. In the figure, the abscissa indicates the time variable, and the unit is ns, and the ordinate indicates the amplitude variable, and the unit is V. It can be seen from the figure that the radiation waveform of the antenna is relatively clean, the oscillation following the main radiation wave is relatively small, and the ratio of the radiation waveform before and after the instant is 12.5dB. Detection accuracy and resolution requirements of broadband through-wall radar antenna.

In summary, the ultra-wideband drop-shaped antenna for through-wall radar provided by the utility model has the characteristics of large working bandwidth, good time-domain radiation characteristics, small antenna volume, compact structure, and smooth outline. The feeding method is simple and easy Processing and maintenance can meet the engineering needs of ultra-wideband miniaturized portable radar systems.

The basic principles, main features and advantages of the present utility model have been shown and described above. On the premise of not departing from the spirit and scope of the present utility model, the present utility model also has various changes and improvements, and these changes and improvements all fall into the claims. The scope of the utility model.

Claims (7)

1. the ultra broadband water-drop-shaped antenna for through-wall radar, it is characterised in that include metal radiation arm, insulation medium board, Metallic enclosure, absorbing material, impedance transformer and coaxial connector, wherein metal radiation arm symmetry is printed on insulation medium board Front, this metal radiation arm is water-drop-shaped, and its transverse cross-sectional shape can be represented by following curve: , 0≤t≤0.5, x is the long axis direction of metal radiation arm, and y is the short-axis direction of metal radiation arm, presets between metal radiation arm There is interval, two metal radiation arms of adjacent partition are respectively equipped with input port as respective feed end, impedance transformer For having 1:2 impedance transformation function and the commercial transmission line transformer of uneven 50 Ω to 100 Ω balance conversion, it is preferably ADTL2-18+, and it is fixing in order to carry to design one block of FR4 dielectric-slab, this impedance transformer outfan respectively with two metal spokes The feed end penetrating arm is electrically connected with, and for impedance matching, impedance transformer input is connected with one end of coaxial connector, and this is same The other end of mandrel connector is connected with transmitter or the receiver of ultra-broadband wall-through radar, and metallic enclosure is positioned at insulation medium board Surface, the inside of this metallic enclosure is filled with absorbing material.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described metal The spacing distance preset between radiation arm is 1.5-2.5mm.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described insulation Dielectric-slab is the epoxy resin fiberglass cloth dielectric-slab that one side covers copper, and its thickness is 1mm, and dielectric constant is 4.4, and this insulation is situated between Scutum is fixed at the bottom end opening of metallic enclosure.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described metal Shielding cavity is the rectangular cavities of bottom surface opening, and its height is the 1/8 of free space wavelength corresponding to center of antenna frequency.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described suction ripple Material is in close contact with metallic enclosure and insulation medium board, and the material of this absorbing material is multilayer polyurethane foam, is relatively situated between Electric constant is 2.2, and electrical conductivity is 0.125S/m.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described FR4 The size of dielectric-slab is 16mm × 18mm × 1.6mm.

Ultra broadband water-drop-shaped antenna for through-wall radar the most according to claim 1, it is characterised in that: described is coaxial Adapter is installed on the back side of insulation medium board.