An ultra-wideband pulse antenna

Abstract

The application discloses an ultra-wideband pulse antenna, which adopts a double-ridge feeding structure, a semicylindrical cavity is arranged on the back side of the double-ridge feeding structure, and a radiation plate pair with a splayed distribution is adopted from a feeding point to free space, so that impedance conversion from a coaxial feeder to free space is completed, and the two radiation plates and a shielding shell are in a whole horn shape, so that the structure is stable and reliable, the application adopts a shielding cavity outside a radiation surface to shield external interference signals and enhance the one-way radiation performance of the antenna, the application sets a lumped resistor to improve low-frequency impedance matching of the antenna and reduce ringing effect, and the application sets a first semicircular plate to improve low-frequency impedance matching of the antenna.

Description

Technical Field

[0001] This invention relates to an ultra-wideband pulse antenna, belonging to the field of microwave antenna technology. Background Technology

[0002] Ground penetrating radar (GPR) is a highly effective target detection device, serving as a powerful tool for non-destructive testing and through-wall imaging of subsurface structures and buried objects. Since the 1960s, GPR has evolved from its initial concept to its current state of development, significantly enhancing humanity's ability to understand and modify objective reality. During equidistant measurements on the ground, the GPR antenna acquires reflected signals that change with spatial position. These variations in amplitude and time delay imply changes in medium parameters. By analyzing and processing the acquired reflected signals, it is possible to detect targets and determine their spatial shape, medium properties, and burial depth.

[0003] Ground penetrating radar (GPR) detects underground structures by using time-domain narrow pulse signals. These signals have suitable material penetration capabilities and contain rich spectral content. They exhibit different signal characteristics when in contact with different materials, thus enabling detection. To transmit these time-domain narrow pulse signals, an ultra-wideband pulse antenna is required.

[0004] Patent CN116169468A discloses an ultra-wideband directional radiation antenna that uses a metal reflector to reflect the energy radiated upwards from the ground downwards to achieve directional radiation. It also uses a metasurface to improve impedance matching and increase gain. However, the entire antenna adopts a multi-layer structure, which requires the addition of fixing components. In some application environments, the structural stability of the entire antenna is poor. Summary of the Invention

[0005] This invention provides an ultra-wideband pulse antenna that solves the problems disclosed in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] An ultra-wideband pulse antenna includes a shielding shell, and a dual-ridge feed structure and a radiating plate pair disposed within the shielding shell;

[0008] The back side of the dual-ridge feeding structure is provided with a semi-cylindrical cavity, and the convex side of the semi-cylindrical cavity faces the rear end of the shielding shell.

[0009] The rear end of one radiating plate of the radiating plate pair is connected to the feed point of the upper ridge of the double ridge feeding structure, and the rear end of the other radiating plate of the radiating plate pair is connected to the feed point of the lower ridge of the double ridge feeding structure. The two radiating plates are arranged in a figure-eight pattern with the narrow side close to the feed point. The two radiating plates and the shielding shell are in a trumpet shape as a whole. A lumped resistor is provided between the front end of the radiating plate and the front end of the corresponding side of the shielding shell.

[0010] A first semicircular plate is provided on the inner wall of the shielding shell opposite to the radiation plate, with the protruding side of the first semicircular plate facing the radiation plate.

[0011] The upper and lower ridges of the dual-ridge power supply structure are both cuboid structures, coaxially arranged, and a distance is left between them.

[0012] The width of the radiating plate increases sequentially from the rear end to the front end.

[0013] The radiating plate is composed of several flat plates connected in series, and the flat plates of the two radiating plates are symmetrical to each other.

[0014] The front end of the radiating plate is connected to a second semicircular plate that folds backward. There is a gap between the free side of the second semicircular plate and the front end of the corresponding shielding shell side. The lumped resistor is set in the gap.

[0015] The lumped resistors are set between opposite apex angles, one of which is the apex angle of the free side of the second semicircular plate, and the other apex angle is the apex angle of the front end of the shielding shell side.

[0016] The beneficial effects achieved by this invention are as follows: 1. This invention adopts a double-ridge feeding structure and sets a semi-cylindrical cavity on the back side of the double-ridge feeding structure. The feed point to free space adopts a pair of radiating plates distributed in a figure-eight pattern, which completes the impedance transformation from the coaxial feed line to free space. Moreover, the two radiating plates and the shielding shell are horn-shaped as a whole, and the structure is stable and reliable; 2. This invention uses a shielding cavity outside the radiating surface to shield external interference signals and enhance the unidirectional radiation performance of the antenna; 3. This invention improves the low-frequency impedance matching of the antenna and reduces the ringing effect by setting a lumped resistor; 4. This invention improves the low-frequency impedance matching of the antenna by setting a first semi-circular plate. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an ultra-wideband pulse antenna;

[0018] Figure 2 Diagram of the port reflection coefficient of an ultra-wideband pulse antenna;

[0019] Figure 3 The radiation pattern of the ultra-wideband pulse antenna at a frequency of 200MHz;

[0020] Figure 4 The radiation pattern of the ultra-wideband pulse antenna at a frequency of 500MHz;

[0021] Figure 5 The radiation pattern of the ultra-wideband pulse antenna at 700MHz;

[0022] Figure 6 The radiation pattern of the ultra-wideband pulse antenna at a frequency of 1000MHz;

[0023] Figure 7 The results are the time-domain performance test results of the ultra-wideband pulse antenna. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0025] like Figure 1 As shown, an ultra-wideband pulse antenna includes a shielding shell 1, and a double-ridged feed structure and a radiating plate pair fixed inside the shielding shell 1.

[0026] A semi-cylindrical cavity 2 is fixed on the back side of the double-ridge feeding structure, with the convex side of the semi-cylindrical cavity 2 facing the rear end of the shielding shell 1. The rear end of one radiating plate 5 of the radiating plate pair is connected to the feed point of the upper ridge 3 of the double-ridge feeding structure, and the rear end of the other radiating plate 5 of the radiating plate pair is connected to the feed point of the lower ridge 4 of the double-ridge feeding structure. The two radiating plates 5 are arranged in a V-shape with their narrow sides close to the feed points. The two radiating plates 5 and the shielding shell 1 are generally funnel-shaped. A lumped resistor is fixed between the front end of the radiating plate 5 and the front end of the corresponding side of the shielding shell 1. A first semi-circular plate 6 is fixed on the inner wall of the shielding shell 1 opposite to the radiating plate 5, with the convex side of the first semi-circular plate 6 facing the radiating plate 5.

[0027] Shielding shell 1 is a metal shielding shell. By setting a metal shielding shell outside the radiating surface, external interference signals are shielded, thus preventing the antenna from receiving interference from waves arriving from other directions and enhancing the antenna's unidirectional radiation performance.

[0028] The upper ridge 3 and lower ridge 4 of the dual-ridge feeding structure are both cuboid structures. The upper ridge 3 and lower ridge 4 are coaxially arranged and there is a distance between them. The coaxial feed line feeds the signal through the dual-ridge feeding structure. The coaxial outer conductor is connected to the lower ridge 4 and the coaxial inner conductor is connected to the upper ridge 3. The impedance matching is improved by the semi-cylindrical cavity 2 fixed on the back.

[0029] The radiating plate pair is a gradually changing structure from the coaxial feed point to free space. From the rear end to the front end of the radiating plate 5, the width of the radiating plate 5 increases sequentially. Each radiating plate 5 is composed of several flat plates connected in series, specifically 14 flat plates, each of which is trapezoidal. The flat plates of the two radiating plates 5 are symmetrical to each other. Through the double-ridge feed structure, the semi-cylindrical cavity 2, and the figure-eight distributed radiating plate pair, the impedance transformation from the coaxial feed line to free space is completed. Furthermore, since the two radiating plates 5 and the shielding shell 1 are horn-shaped as a whole, the structure is stable and reliable.

[0030] To ensure the smoothness of the antenna, a second semicircular plate 7, which is folded backward, is connected to the front end of the radiating plate 5. The second semicircular plate 7 is a metal semicircular plate. There is a gap between the free side of the second semicircular plate 7 and the front end of the corresponding shielding shell 1. Lumped resistors are installed in the gap. Specifically, two lumped resistors are installed in the gap, and each lumped resistor is installed between opposite vertices. One vertices is the vertices of the free side of the second semicircular plate 7, and the other vertices are the vertices of the front end of the shielding shell 1. The lumped resistors are generally 50 ohms. By loading the lumped resistors, the reflection of the current at the end of the antenna is weakened, the impedance matching of the antenna in the low-frequency band is improved, and the ringing effect of the antenna is reduced.

[0031] The first semicircular plate 6 is also a metal semicircular plate, placed between the radiating plate 5 and the shielding shell 1, after the feeding section, which can improve the impedance matching of the antenna in the low frequency band.

[0032] To verify the effectiveness of the antenna, its performance was tested, and the test results are shown below. Figures 2-7 .in, Figure 2 The antenna port reflection coefficient diagram shows that the antenna of this invention has a reflection coefficient of less than -10dB in the frequency range of 168MHz-1000MHz, and a bandwidth of about 5.9:1, achieving ultra-wideband performance. Figures 3-6 The radiation patterns of the antenna at 200MHz, 500MHz, 700MHz and 1000MHz are shown respectively. It can be seen that the antenna of the present invention maintains good unidirectional radiation performance in the ultra-wideband operating frequency band. At the same time, the antenna gain increases with the frequency, reaching about 9.77dBi at 1000MHz. Figure 7 The antenna's time-domain performance test results show that the antenna of this invention, as a receiving antenna, receives a Gaussian pulse signal. As can be seen from the figure, the main pulse waveform of the received signal in the time domain is clear and basically maintains the shape of the original Gaussian pulse main waveform. At the same time, the tail decays rapidly, indicating that the antenna of this invention has good time-domain performance.

[0033] In summary, the antenna of this invention has an impedance matching bandwidth of over 5.9:1, unidirectional radiation performance within the operating frequency band, stable phase center, good signal fidelity, and a compact and stable overall structure, making it a promising candidate for application in the field of ground-penetrating radar.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultra-wideband pulse antenna, characterized in that, Includes a shielding shell, and a double-ridged power supply structure and a pair of radiating plates disposed within the shielding shell; The back side of the dual-ridge feeding structure is provided with a semi-cylindrical cavity, and the convex side of the semi-cylindrical cavity faces the rear end of the shielding shell. The rear end of one radiating plate of the radiating plate pair is connected to the feed point of the upper ridge of the double ridge feeding structure, and the rear end of the other radiating plate of the radiating plate pair is connected to the feed point of the lower ridge of the double ridge feeding structure. The two radiating plates are arranged in a figure-eight pattern with the narrow side close to the feed point. The two radiating plates and the shielding shell are in a trumpet shape as a whole. A lumped resistor is provided between the front end of the radiating plate and the front end of the corresponding side of the shielding shell. A first semicircular plate is provided on the inner wall of the shielding shell opposite to the radiation plate, with the protruding side of the first semicircular plate facing the radiation plate.

2. The ultra-wideband pulse antenna according to claim 1, characterized in that, The upper and lower ridges of the dual-ridge power supply structure are both cuboid structures, coaxially arranged, and a distance is left between them.

3. The ultra-wideband pulse antenna according to claim 1, characterized in that, The width of the radiating plate increases sequentially from the rear end to the front end.

4. The ultra-wideband pulse antenna according to claim 1 or 3, characterized in that, The radiating plate is composed of several flat plates connected in series, and the flat plates of the two radiating plates are symmetrical to each other.

5. The ultra-wideband pulse antenna according to claim 1, characterized in that, The front end of the radiating plate is connected to a second semicircular plate that folds backward. There is a gap between the free side of the second semicircular plate and the front end of the corresponding shielding shell side. The lumped resistor is set in the gap.

6. The ultra-wideband pulse antenna according to claim 5, characterized in that, The lumped resistors are set between opposite apex angles, one of which is the apex angle of the free side of the second semicircular plate, and the other apex angle is the apex angle of the front end of the shielding shell side.

Images