Double-plane tapered slot antenna

Abstract

The invention discloses a biplane tapered slot antenna, and belongs to the technical field of antennas. The antenna comprises a dielectric substrate, a metal radiation patch, a metal conduction band and a resistor. The radiation patch is arranged in a double-plane manner, so that the different-plane tapered slot line is constructed, and the impedance matching of the antenna is improved while the power capacity is improved. The metal radiation patch comprises an upper radiation patch and a lower radiation patch, the metal conduction band and the lower radiation patch form a microstrip line, and the resistor, the upper radiation patch and the lower radiation patch are connected in series into a whole, so that the effective suppression of the reflection voltage of the antenna is realized; therefore, resistance loading does not affect the radiation efficiency of the antenna. Technical index parameters such as power capacity, reflection voltage and radiation efficiency are considered at the same time, a technical scheme with excellent comprehensive performance is provided for ultra-wideband microwave pulse radiation, and the ultra-wideband microwave pulse radiation model can be used as an antenna basic model.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a dual-plane tapered slot antenna. Background Art

[0002] The tapered slot antenna, also known as the TSA (Tapered Slot Antenna) or Vivaldi antenna, is a planar end-fire antenna. Due to its relatively stable phase center and advantages such as ultra-wideband, high gain, good directivity, lightweight and easy integration, it is often used as a radiating antenna for nanosecond ultra-wideband microwave pulses. It is widely used in technical fields such as target non-destructive detection or imaging, intentional electromagnetic interference, and ultra-wideband short-range communication.

[0003] Common tapered slot antennas include coplanar tapered slot antennas and symmetrical tapered slot antennas. Coplanar tapered slot antennas, when used for ultra-wideband microwave pulse radiation, suffer from insufficient power capacity and reflections at the feed end. The insufficient power capacity stems from the narrow initial width of the tapered slot between the coplanar radiating structures, making high-voltage breakdown more likely to occur. The reflections at the feed end stem from the microstrip slot-coupled feeding structure. The quarter-open stub prevents the DC and low-frequency components of the excitation pulse from coupling and transmitting to the antenna radiating structure, resulting in emission at the feed end. The large reflected voltage is very likely to damage the pulse generator, impacting its lifespan and reliability.

[0004] In comparison, the symmetrical tapered slot antenna's radiating structure is arranged on both sides of the dielectric substrate, and it uses a microstrip line-to-parallel dual-line structure for feeding. This improves power capacity and allows the DC and low-frequency components of the excitation pulse to be effectively transmitted to the antenna's radiating structure. However, due to antenna size limitations, the DC and low-frequency components propagate and reflect back and forth within the antenna, ultimately reflecting back to the feedback terminal to form a large reflected voltage. In other words, compared to the coplanar tapered slot antenna, the only difference is the location and timing of the reflection. The resulting reflected voltage also poses a risk of damage to the pulse generator.

[0005] Resistor loading can effectively absorb DC and low-frequency components, but most existing studies load resistors on the gradient slot antenna radiation patch. Although this can reduce antenna reflection, it also reduces the antenna's radiation efficiency, thus losing sight of one thing while focusing on another, making it difficult to take into account multiple key requirements.

[0006] In summary, the existing tapered slot antenna has technical difficulties such as low power capacity, large reflection voltage and inability to take into account radiation efficiency at the same time. Therefore, it is necessary to explore and research a tapered slot antenna form that can take into account multiple index requirements at the same time, and provide an antenna technology solution with outstanding comprehensive performance for ultra-wideband microwave pulse radiation. Summary of the Invention

[0007] In order to solve the problems in the prior art, the present invention provides a dual-plane tapered slot antenna.

[0008] The technical solutions of the present invention are as follows:

[0009] The present invention discloses a dual-plane tapered slot antenna, comprising a dielectric substrate, a metal radiating patch, a metal conductive strip, and a resistor; the dielectric substrate is a rectangular thin plate made of dielectric material; the metal radiating patch comprises an upper radiating patch and a lower radiating patch, which are respectively printed on the front and back surfaces of the dielectric substrate and have the same shape and are centrally symmetrical with the axis of the dielectric substrate along the radiation direction as the axis; the contour lines of the two radiating patches each include a tapered curve away from the feed end and a concave arc curve close to the feed end, and the tapered curve in each radiating patch is connected to the concave arc curve; wherein the tapered curves of the two radiating patches constitute skew tapered slot lines, and form a non-coplanar horn-shaped opening radiation. The invention discloses a radiating structure, wherein the starting end of the unequal-surface gradient groove line, i.e., the smallest end of the trumpet-shaped opening, is close to the feeding end; the two concave arc curves together constitute a planar resonant cavity; the metal conductive strip and the upper radiating patch are located on the front surface of the dielectric substrate, and are directly connected to the upper radiating patch at the connection point of the gradient curve and the concave arc curve of the upper radiating patch; the metal conductive strip and the lower radiating patch together constitute a microstrip line, the lower radiating patch serves as the ground plane of the microstrip line, and the metal conductive strip serves as the conductive strip of the microstrip line; the resistor is arranged on the dielectric substrate and is located between the feeding end and the planar resonant cavity, and the resistor is connected in series with the upper radiating patch and the lower radiating patch to absorb the DC and low-frequency components of the excitation pulse signal input from the feeding end.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1) The present invention effectively increases the power capacity of the antenna by arranging the radiation patches in two planes. At the same time, the width adjustment range of the gradient slot lines between the radiation patches is wider, making it easier to achieve impedance matching of the antenna.

[0012] 2) The metal conductive strip of the present invention is directly connected to the upper radiating patch and together with the lower radiating patch forms a microstrip line. The microstrip line improves the feeding efficiency of the antenna to a certain extent and effectively suppresses the antenna reflection voltage through the loading of the resistor. The resistor loading position is far away from the main current path on the antenna surface, so it does not affect the radiation efficiency of the antenna.

[0013] 3) The present invention does not make any changes to the main body of the radiating patch, so it can be used as a basic antenna model. Related antenna designs can be carried out on this basis. It is worth mentioning that this basic model has its own reflection voltage suppression characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the three-dimensional structure of a dual-plane tapered slot antenna provided by the present invention;

[0015] Figure 2 A front view of a dual-plane tapered slot antenna provided by the present invention;

[0016] Figure 3 An S11 curve diagram of the antenna with and without resistance loading in an embodiment of a dual-plane tapered slot antenna provided by the present invention;

[0017] Figure 4 This is an excitation pulse waveform diagram of an embodiment of a dual-plane tapered slot antenna provided by the present invention;

[0018] Figure 5 A waveform diagram of the reflected voltage of the antenna with and without resistance loading in an embodiment of a dual-plane tapered slot antenna provided by the present invention;

[0019] Figure 6 This is a waveform diagram of the antenna's main axis far-zone radiation field with and without resistance loading in an embodiment of a dual-plane tapered slot antenna provided by the present invention.

[0020] Among them: 1-dielectric substrate; 2-upper radiation patch; 21-gradient curve of the upper radiation patch; 22-arc curve of the upper radiation patch; 3-lower radiation patch; 31-gradient curve of the lower radiation patch; 32-arc curve of the lower radiation patch; 4-metal conduction strip; 5-resistor; 6-metal via. DETAILED DESCRIPTION

[0021] The present invention will be further described and illustrated below in conjunction with specific embodiments. The embodiments are merely illustrative of the present disclosure and do not limit its scope. The technical features of the various embodiments of the present invention may be combined accordingly, provided that there is no conflict between them.

[0022] The purpose of the present invention is to provide a dual-plane gradient slot antenna to solve the technical problem that the existing antenna model cannot simultaneously take into account low reflection voltage, high power capacity and high radiation efficiency when used for ultra-wideband microwave pulse radiation, and provide an antenna technology solution with outstanding comprehensive performance for ultra-wideband microwave pulse radiation.

[0023] In order to achieve the above objectives and solve the above technical problems, the technical solutions of the present invention are as follows:

[0024] like Figure 1 and Figure 2As shown, the present invention proposes a dual-planar tapered slot antenna comprising a dielectric substrate 1, a metal radiating patch, a metal conductive strip 4, and a resistor 5. The dielectric substrate is a rectangular thin plate made of dielectric material. The metal radiating patches include an upper radiating patch 2 and a lower radiating patch 3, printed on the front and back surfaces of the dielectric substrate, respectively. They are identical in shape and centrally symmetric about the substrate's axis along the radiation direction. The contour of each radiating patch includes a tapered curve away from the feed end and a concave arc curve near the feed end. The tapered curves of the two radiating patches together form a non-coplanar tapered slot, ultimately forming a non-coplanar horn-shaped radiating structure. The smallest end of the horn-shaped opening is close to the feed end, forming a horn-shaped radiating structure in the +x direction. On the other side of the horn-shaped radiating structure, the concave arcs of the two radiating patches together form a planar resonant cavity, forming a planar resonant cavity in the -x direction. Both the non-coplanar horn-shaped radiating structure and the planar resonant cavity improve the antenna's power capacity.

[0025] Metal strip 4, along with upper radiating patch 2, is located on the front surface of dielectric substrate 1. It is directly connected to the upper radiating patch at the intersection of the planar resonant cavity and the out-of-plane tapered slot line. Specifically, it is directly connected to the upper radiating patch at the junction of the tapered curve and the concave arc curve of the upper radiating patch. Metal strip 4 and lower radiating patch 3 together form a microstrip line, with lower radiating patch 3 serving as the ground plane of the microstrip line and metal strip 4 serving as the guide strip of the microstrip line.

[0026] Resistor 5 is disposed on dielectric substrate 1 and located between the feed end and the planar resonant cavity. Resistor 5 is connected in series with upper radiating patch 2 and lower radiating patch 3 to absorb the DC and low-frequency components of the excitation pulse signal input from the feed end. Resistor 5 is located along the axis of dielectric substrate 1 along the radiation direction and can be disposed on either the front or back side of the dielectric substrate. When resistor 5 is disposed on the front side of dielectric substrate 1, one end of resistor 5 is electrically connected to upper radiating patch 2, and the other end is electrically connected to lower radiating patch 3 via a metal via 6 extending through dielectric substrate 1. When resistor 5 is disposed on the back side of dielectric substrate 1, one end of resistor 5 is electrically connected to lower radiating patch 3, and the other end is electrically connected to upper radiating patch 2 via a metal via 6 extending through dielectric substrate 1.

[0027] In the present invention, the dielectric material of the dielectric substrate 1 can be reasonably selected based on the actual operating frequency band, size, cost, etc. Specifically, for large-scale array and ultra-wideband applications, inexpensive boards with low dielectric constants, such as FR4, can be used. For high-frequency applications such as microwave and millimeter-wave applications with higher efficiency requirements, boards such as Rogers RO3003 and RO4003C should be used.

[0028] In a preferred embodiment of the present invention, the upper radiating patch 2 and the lower radiating patch 3 are made of a metal such as copper. The gradient curve 21 of the upper radiating patch and the gradient curve 31 of the lower radiating patch have a gradient form such as exponential, linear, or elliptical. Furthermore, the gradient forms of the gradient curves 21 and 31 of the upper radiating patch and the lower radiating patch are identical.

[0029] The concave arc curve 22 of the upper radiation patch and the concave arc curve 32 of the lower radiation patch are generally semicircular or half elliptical, and the shapes of the concave arc curve 22 of the upper radiation patch 2 and the concave arc curve 32 of the lower radiation patch 3 are the same.

[0030] Looking from the front of the dielectric substrate 1, that is, from Figure 2 From the perspective of , the upper radiation patch 2 and the lower radiation patch 3 can overlap at the starting position of the non-planar gradient groove line, that is, they can overlap at the starting position of the gradient curve, and whether the upper radiation patch 2 and the lower radiation patch 3 overlap and the overlapping width can be determined according to the degree of impedance matching. With the goal of optimizing the impedance matching of the antenna, whether the upper radiation patch 2 and the lower radiation patch 3 overlap at the starting position of the gradient curve and the overlapping width are adjusted, thereby maximizing the transmission efficiency of the antenna.

[0031] In a preferred embodiment of the present invention, slots may be formed at the same position of the upper radiation patch 2 and the lower radiation patch 3 to further improve the current distribution of the antenna and enhance the radiation capability of the antenna.

[0032] Preferably, the metal conductive strip 4 of the present invention can be either linear or L-shaped (i.e., right-angled), and its material is consistent with that of the upper and lower radiating patches. Whether it is linear or L-shaped depends on the convenience of the actual installation and erection of the antenna. The specific type of metal conductive strip 4 selected is primarily for the purpose of facilitating connection with an external signal source for outputting the excitation pulse signal. The characteristic impedance of the microstrip line can be adjusted by adjusting the width of the metal conductive strip 4. The metal conductive strip 4 is coplanar with the upper radiating patch 2 and is directly connected to it. This allows the vast majority of the frequency components of the excitation pulse signal to be efficiently transmitted to the antenna radiation structure, avoiding reflections at the feed end and providing a structural foundation for absorbing DC and low-frequency components.

[0033] The characteristic impedance of the microstrip line is generally 50 ohms, and can also be selected and designed according to actual needs. That is, the characteristic impedance of the microstrip line should match the output impedance of the signal source. If it is a 75 ohm signal source, a 75 ohm microstrip line should be used to avoid the additional design of an impedance matching network; if a multi-point feeding structure or power splitter network is used to feed the antenna, it must be consistent with the characteristic impedance of its output end.

[0034] Resistor 5 can be mounted on either the front or back side of dielectric substrate 1. The position of metal via 6 is adjusted accordingly to ensure that the upper radiating patch 2, lower radiating patch 3, and resistor 5 are connected in series and electrically connected. The resistor loading value is typically 50 ohms, but can be adjusted based on actual needs. If minimizing reflections is the primary goal, the resistor loading value should be consistent with the characteristic impedance of the microstrip line. To improve impedance matching within the operating frequency band, a larger resistor of 1000 ohms or greater can be used. To increase the power capacity of the resistor loading, multiple resistors can be connected in parallel to achieve the desired loading value.

[0035] The working principle and working process of the dual-plane tapered slot antenna provided by the present invention are as follows:

[0036] like Figure 1 、 2 As shown, the positive and negative electrodes of the external signal source for outputting the excitation pulse signal are connected to the metal conductive strip 4 and the lower radiating patch 3, respectively. The excitation pulse signal is fed into the microstrip line formed by the metal conductive strip 4 and the lower radiating patch 3. The microstrip line transmits the signal to the out-of-plane gradient slot line formed by the gradient curve 21 of the upper radiating patch and the gradient curve 31 of the lower radiating patch, and then radiates in the +x direction through the horn-shaped opening radiating structure. The DC and low-frequency components of the excitation pulse signal cannot be radiated and are reflected back to the power terminal, where they are absorbed and consumed by the loaded resistor, significantly reducing the voltage reflection at the feeding terminal. The planar resonant cavity is used to construct a resistive absorption loop, guiding the DC and low-frequency components of the reflected excitation pulse signal to the location of the resistor, allowing the loaded resistor to absorb and consume the DC and low-frequency components of the feedback excitation pulse signal, while also improving the power capacity of the antenna. As for the non-coplanar horn-shaped opening radiating structure, it is used to achieve impedance gradient and enable the antenna to radiate electromagnetic waves of different frequencies.

[0037] Because the metal radiating patches are arranged on both the front and back surfaces of the dielectric substrate 1, the power capacity of the antenna of the present invention is significantly improved compared to the coplanar tapered slot antenna. The dual-plane structural layout allows the metal conductive strip to be directly connected to the upper radiating patch, facilitating efficient signal transmission and avoiding emission at this location. The connection location is between the planar resonant cavity and the minimum end of the horn-shaped opening radiation structure, so that the planar resonant cavity and the antenna horn-shaped opening radiation structure are in parallel, providing structural conditions for resistive loading. The resistive loading is not in the main path of the antenna surface current, so it has little effect on the radiation efficiency. That is, while maintaining the radiation efficiency, it also achieves effective suppression of the reflected voltage. In addition, the antenna does not have any additional special treatment for the metal radiating patch, so it can be used as a basic antenna model. On this basis, it can be optimized and designed to further improve its radiation performance and meet the actual application requirements in different scenarios.

[0038] Example

[0039] The embodiment of the present invention will now be further described with reference to specific parameters.

[0040] like Figure 1 As shown, a dual-plane tapered slot antenna includes a dielectric substrate 1, an upper radiation patch 2, a lower radiation patch 3 and a resistor 5.

[0041] like Figure 2 As shown, the dielectric substrate 1 has a length of l=360 mm, a width of w=260 mm, and a thickness of 2 mm. The material thereof is FR4, and the relative dielectric constant is 4.3 and the loss tangent is 0.025.

[0042] like Figure 2 As shown, the upper radiation patch 2 and the lower radiation patch 3 have the same shape and are printed on the front and back surfaces of the dielectric substrate 1 respectively. The two overlap with an overlapping width g = 0.75mm and are centrally symmetrical about the axis of the dielectric substrate 1 along the x-direction. The two radiation patches together form an exponentially gradient horn-shaped radiation structure along the +x direction. The width of the horn-shaped structure in the y direction (i.e., the E-plane direction) is w-2w1 = 246.4mm; while on the other side, i.e., in the -x direction, the two radiation patches together form a circular resonant cavity structure. The radius of the circular planar resonant cavity structure is r = 15.4mm. The gradient curve 21 of the upper radiation patch and the gradient curve 31 of the lower radiation patch are exponential gradient lines, and their equations are as follows:

[0043] y=±(1.28exp(0.0144x)-2.03)

[0044] Among them, x and y represent the position coordinates of a point in the gradient curve in the xy coordinate system, such as Figure 2 shown.

[0045] like Figure 2 As shown, the metal conductive strip 4 is L-shaped and is located below the planar resonant cavity along the -y direction. The characteristic impedance of the microstrip line is 50 ohms. The width w of the metal conductive strip 4 can be calculated based on the thickness of the dielectric substrate and the dielectric parameters. f =3.75mm.

[0046] like Figure 2 As shown, resistor 5 is loaded on the side of the planar resonant cavity near the edge of dielectric substrate 1, located on the front surface of dielectric substrate 1. Metal via 6 is located in the -y direction, below resistor 5, and has a radius of 1.5 mm. The two ends of resistor 5 are soldered to the upper radiating patch 2 and metal via 6, respectively, to form an electrical connection. Metal via 6 passes through dielectric substrate 1 and connects to the lower radiating patch 3. The resistance of resistor 5 is 50 ohms.

[0047] The full-wave simulation calculation of the antenna is performed using the time domain finite integration technology, and its S11 (reflection coefficient) curve is obtained as follows: Figure 3 As shown in the figure, when there is no resistance loading, the operating frequency band of the antenna S11 < -10dB is 0.55 ~ 3.62GHz, while after resistance loading, the operating frequency band is 0.53 ~ 3.63GHz, which is basically the same. In addition, due to the existence of resistance loading, the frequency components below 150MHz are effectively absorbed.

[0048] When Figure 4 When the unipolar Gaussian pulse with a half-width of 1.6 ns is used as the excitation signal, the reflected voltage waveform of the antenna with and without resistance loading can be obtained, as shown in FIG. Figure 5 As shown in the figure, the antenna provided by the present invention reduces the ratio of the peak value of the reflected voltage to the incident voltage from 0.58 when there is no loading to 0.27 by means of resistance loading, indicating that the antenna achieves effective suppression of the reflected voltage by means of resistance loading. Figure 6 As shown in FIG, the radiation field intensities of the two at a position 5 m from the main axis are basically the same, that is, while significantly suppressing reflection, sufficient radiation efficiency is also guaranteed.

[0049] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. Persons skilled in the art will readily appreciate that variations and modifications may be made without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A dual-plane tapered slot antenna, characterized in that: It includes a dielectric substrate, a metal radiation patch, a metal conductive strip and a resistor; The dielectric substrate is a rectangular thin plate made of dielectric material; The metal radiating patch includes an upper radiating patch and a lower radiating patch, which are respectively printed on the front and back surfaces of a dielectric substrate and have the same shape and are centrally symmetrical about an axis along the radiation direction of the dielectric substrate. The contour lines of the two radiating patches each include a gradient curve away from the feed end and a concave arc curve near the feed end, and the gradient curve in each radiating patch is connected to the concave arc curve. The gradient curves of the two radiating patches constitute skew gradient slot lines and form a radiation structure with a non-coplanar horn-shaped opening. The starting end of the skew gradient slot line, i.e., the smallest end of the horn-shaped opening, is close to the feed end. The two concave arc curves together constitute a planar resonant cavity. The metal conductive strip and the upper radiating patch are both located on the front surface of the dielectric substrate and are directly connected to the upper radiating patch at the connection point of the gradient curve and the concave arc curve of the upper radiating patch; the metal conductive strip and the lower radiating patch together form a microstrip line, the lower radiating patch serves as a ground plane of the microstrip line, and the metal conductive strip serves as a conductive strip of the microstrip line; The resistor is arranged on the dielectric substrate and located between the feed end and the planar resonant cavity. The resistor is connected in series with the upper radiation patch and the lower radiation patch to absorb the DC and low-frequency components of the excitation pulse signal input from the feed end.

2. The dual-plane tapered slot antenna according to claim 1, wherein: The gradient of the gradient curve is exponential gradient, linear gradient or elliptical gradient.

3. The dual-plane tapered slot antenna according to claim 1, wherein: The concave arc curve is a semicircle or a half ellipse.

4. The dual-plane tapered slot antenna according to claim 1, wherein: The upper radiation patch and the lower radiation patch can overlap at the starting position of the gradient curve. Whether the upper radiation patch and the lower radiation patch overlap at the starting position of the gradient curve and the overlapping width are adjusted with the goal of optimizing the impedance matching of the antenna.

5. The dual-plane tapered slot antenna according to claim 1, wherein: The current distribution of the antenna can be improved and the radiation capability of the antenna can be enhanced by making grooves at the same position on the upper radiation patch and the lower radiation patch.

6. The dual-plane tapered slot antenna according to claim 1, characterized in that: The metal conductive strip is straight or L-shaped, and the characteristic impedance of the microstrip line is 50 ohms.

7. The dual-plane tapered slot antenna according to claim 1, characterized in that: The resistor is arranged on the front or back side of the dielectric substrate; when the resistor is arranged on the front side of the dielectric substrate, one end of the resistor is electrically connected to the upper radiation patch, and the other end is electrically connected to the lower radiation patch through a metal via hole penetrating the dielectric substrate; when the resistor is arranged on the back side of the dielectric substrate, one end of the resistor is electrically connected to the lower radiation patch, and the other end is electrically connected to the upper radiation patch through a metal via hole penetrating the dielectric substrate.

8. The dual-plane tapered slot antenna according to claim 1, characterized in that: The resistor is arranged on the axis of the dielectric substrate along the radiation direction. The loading value of the resistor is equal to the characteristic impedance of the microstrip line to absorb the DC and low-frequency components of the excitation pulse signal input from the feeding end and reduce voltage reflection; and the required loading value can be achieved by connecting multiple resistors in parallel.

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