A double-sided Vivaldi antenna with an I-shaped matching slot and multiple slot radiating elements

Abstract

A double-sided Vivaldi antenna with an I-shaped matching slot and multiple slot radiating elements belongs to the technical field of Vivaldi antennas. It consists of a lower copper conductor layer, a lower dielectric layer, a copper feeder layer, an upper dielectric layer, and an upper copper conductor layer. The lower copper conductor layer has the same structure as the upper copper conductor layer, with a symmetrical trumpet-shaped structure with a circular hole in the middle. An I-shaped matching slot is provided on the right side of the structure, and three vertical rectangular slots perpendicular to the lower edge of the copper conductor layer and a horizontal rectangular slot parallel to the lower edge of the copper conductor layer are provided on the left side of the structure. The horizontal rectangular slot cuts across the three vertical rectangular slots. The copper feeder layer is formed from right to left by three sections of rectangular microstrip lines with stepwise narrowing widths and hollow circular rings connected in sequence. The present invention broadens the bandwidth of the antenna without changing the original size of the basic Vivaldi antenna, successfully shifting the operating frequency band of the Vivaldi antenna to a lower frequency.

Description

Technical Field

[0001] The present invention belongs to the technical field of Vivaldi antennas, and in particular relates to a double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements. Background Art

[0002] Ultra-wideband technology uses nanosecond pulse signals to transmit information, so it exhibits corresponding ultra-wideband characteristics in the frequency domain. Ultra-wideband technology was first used for high-speed data transmission, with the characteristics of good confidentiality, fast transmission rate, and low power. 【1】 With the continuous expansion of application scenarios, it is currently also widely used in wireless positioning 【2】 , and then various types of ultra-wideband antennas appeared one after another 【3-6】 .

[0003] Modern technology has continuously increased the requirements for antenna miniaturization and integration. Planar printed ultra-wideband antennas have attracted widespread attention due to their low profile and easy integration. For example, printed monopole antennas have been widely used in various devices such as wireless communications and indoor positioning. 【7,8】 As a typical type of planar printed ultra-wideband antenna, Vivaldi antenna has a good position in ultra-wideband antenna due to its high gain, strong directivity, low cross-polarization and other advantages. 【9】 However, according to its radiation principle, the lowest frequency of the Vivaldi antenna is often determined by the maximum width of the gradient slot line.

[10] Therefore, the lower the operating frequency, the larger the volume, which is not conducive to integration with radio frequency circuits. Figure 1 As shown, the basic Vivaldi antenna includes a radiating conductor layer and a feeder layer. A symmetrical horn structure with a circular hole is opened on a 23.5mm×30mm rectangular conductor layer to form the radiating conductor layer. Summary of the Invention

[0004] The purpose of the present invention is to provide a double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements.

[0005] like Figure 2 As shown, the double-sided Vivaldi antenna with an I-shaped matching slot and multiple open slot radiating elements described in the present invention has a five-layer structure, which is composed of a lower copper conductor layer, a lower dielectric layer, a copper feed line layer, an upper dielectric layer and an upper copper conductor layer from bottom to top (along the +Z axis direction). The lower copper conductor layer, the lower dielectric layer, the upper dielectric layer and the upper copper conductor layer are rectangular structures of the same size, and their edges are aligned. The upper copper conductor layer and the lower copper conductor layer are antenna radiators.

[0006] like Figure 3As shown, the lower copper conductor layer and upper copper conductor layer of a double-sided Vivaldi antenna with an I-shaped matching slot and multiple slot radiating elements described in the present invention have the same structure, with a symmetrical trumpet structure with a circular hole in the middle. In addition to the symmetrical trumpet structure with a circular hole, an I-shaped matching slot is provided on the right side of the upper and lower conductor layers. The I-shaped matching slot consists of three rectangular sections: a right slot, a middle slot, and an inner slot. These three sections share a common axis of symmetry parallel to the lower edge (x-axis) of the copper conductor layer. On the left side of the symmetrical trumpet structure with circular holes in the upper and lower conductor layers, three vertical rectangular slots are provided, perpendicular to the lower edge (x-axis) of the copper conductor layer, and one horizontal rectangular slot is provided, parallel to the lower edge (x-axis). The horizontal rectangular slot transversely cuts through the three vertical rectangular slots.

[0007] like Figure 4 As shown, the copper feed line layer is composed of three sections of rectangular microstrip lines with step-wise narrowing widths and hollow circular ring pieces connected in sequence from right to left. The right edge of the microstrip feed line is aligned with the right edges of the upper and lower conductor layers. The three sections of rectangular microstrip lines and the hollow circular ring piece have a common symmetry axis parallel to the lower edge of the copper feed line layer (x-axis).

[0008] The present invention introduces a double-sided symmetrical structure on the basic Vivaldi antenna, introduces an I-shaped matching slot on the feeder side of the radiating conductor layer (on the right side of the trumpet structure) to improve the overall impedance matching characteristics, and introduces multiple open slots as slot radiation elements in the redundant part of the non-feeder side of the radiating conductor layer (on the left side of the trumpet structure) to stimulate a new operating frequency point. Without changing the original size of the basic Vivaldi antenna, the bandwidth of the antenna is widened, and the operating frequency band of the Vivaldi antenna is successfully moved to a low frequency. The final overall size of the antenna is only 23.5mm×30mm×2.505mm, achieving S 11 The relative bandwidth of <-10dB reaches 142% (2.49GHz to 14.78GHz), and the average gain within the operating band is 4.87dBi. The basic Vivaldi antenna of the same planar dimensions is a dual-band antenna, operating at 3.44GHz (bandwidth of 3.10GHz to 3.99GHz) and 6.08GHz (bandwidth of 5.55GHz to 6.63GHz). BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 : Schematic diagram of the basic Vivaldi antenna radiation conductor layer and feeder layer structure;

[0010] Figure 2 : Schematic diagram of the structure of the double-sided Vivaldi antenna with I-shaped matching slots and multiple opening slot radiating elements according to the present invention;

[0011] Figure 3 (a, b, c): Schematic diagram of the conductor layer structure of the double-sided Vivaldi antenna with I-shaped matching slots and multiple open slot radiating elements according to the present invention;

[0012] Figure 4 : Schematic diagram of the copper feeder layer structure of the double-sided Vivaldi antenna with I-shaped matching slots and multiple open slot radiating elements according to the present invention;

[0013] Figure 5 : Reflection coefficient curve of the double-sided Vivaldi antenna with I-shaped matching slots and multiple opening slot radiating elements according to the present invention;

[0014] Figure 6 (a): Xoy cross-sectional radiation pattern of the double-sided Vivaldi antenna with I-shaped matching slots and multiple opening slot radiating elements according to the present invention;

[0015] Figure 6 (b): Zoy cross-sectional radiation pattern of the double-sided Vivaldi antenna containing I-shaped matching slots and multiple opening slot radiating elements according to the present invention. DETAILED DESCRIPTION

[0016] Example 1:

[0017] like Figure 2 As shown, the double-sided Vivaldi antenna with I-shaped matching slots and multiple open slot radiating elements described in the present invention has a five-layer structure. From bottom to top (along the +Z axis direction), it consists of a lower copper conductor layer, a lower dielectric layer, a copper feed line layer, an upper dielectric layer, and an upper copper conductor layer. The lower copper conductor layer, the lower dielectric layer, the upper dielectric layer, and the upper copper conductor layer are a 23.5mm×30mm rectangular structure with their edges aligned on all sides. The upper copper conductor layer and the lower copper conductor layer are antenna radiators, and the copper conductor layer and the copper feed line layer are 0.035mm thick. The dielectric layer adopts an F4B dielectric substrate with a thickness of 1.2mm and a relative dielectric constant of 2.2. The overall thickness of the antenna is 0.035*3+1.2*2mm=2.505mm.

[0018] The double-sided Vivaldi antenna with an I-shaped matching slot and multiple slot radiating elements of the present invention has the same structure as the lower copper conductor layer and the upper copper conductor layer, and a symmetrical trumpet structure with a circular hole is opened in the middle. Figure 1 As shown in the figure, assuming that the coordinate origin is at the lower edge of the conductor layer corresponding to the center of the circular hole, the curve equation of the symmetrical bell-mouth structure is:

[0019] x=±0.13e 0.212(y-3.5) ±0.07(5.5mm≤y≤23.5mm)

[0020] The lower end of the bell-mouth structure is connected to a circular hole with a radius R1 of 1.92 mm. The distance d1 between the center of the circular hole and the lower edge of the conductor layer is 3.60 mm. The distance d2 between the connection between the symmetrical bell-mouth structure and the circular hole and the lower edge of the conductor layer is 5.50 mm.

[0021] like Figure 3 As shown, in addition to the symmetrical trumpet-mouth structure with circular holes on the upper and lower conductor layers, an I-shaped matching slot is opened on the right side of the structure; the I-shaped matching slot consists of three parts, a right slot, a middle slot and an inner slot, all of which are rectangular structures, and the three parts have a common symmetry line parallel to the x-axis; the dimensional parameters of the right slot are Y7=3.4mm, X7=4.0mm, and the distance between its lower edge and the lower edge of the conductor layer is d5=5.95mm; the dimensional parameters of the middle slot are Y6=2.0mm, X6=1.7mm, and the distance between its lower edge and the lower edge of the conductor layer is d4=6.65mm; the dimensional parameters of the inner slot are Y7=3.4mm, X5=2.0mm, and the distance between its lower edge and the lower edge of the conductor layer is d5=5.95mm.

[0022] On the left side of the symmetrical trumpet-shaped structure with circular holes in the upper and lower conductor layers, there are three vertical (perpendicular to the x-axis) rectangular slits and one transverse (parallel to the x-axis) rectangular slit. The transverse rectangular slit transversely cuts through the three vertical rectangular slits. The dimensional parameters of the first vertical rectangular slit at a distance of X11 = 2 mm from the left edge of the conductor layer are Y3 = 20 mm and X3 = 1 mm. The dimensional parameters of the second vertical rectangular slit at a distance of X12 = 3.0 mm from the first vertical rectangular slit are Y4 = 12 mm and X3 = 1 mm. The dimensional parameters of the third vertical rectangular slit at a distance of X13 = 3.0 mm from the second vertical rectangular slit are Y5 = 14 mm and X4 = 1 mm. The distance of the transverse rectangular slit from the lower edge of the conductor layer (x-axis) is d6 = 8.15 mm. The width of the transverse rectangular slit is Y2 = 1.35 mm, and its length is from the left edge of the conductor layer to the third vertical rectangular slit.

[0023] like Figure 1 and Figure 4As shown, the copper feed line layer is composed of three sections of rectangular microstrip lines with step-wise narrowing widths and hollow circular rings connected in sequence from right to left. The right edge of the microstrip feed line is aligned with the right connecting edges of the upper and lower conductor layers. The three sections of rectangular microstrip lines and the hollow circular ring have a common symmetry line parallel to the x-axis; the distance d3 = 6.85 mm between the lower edge of the rightmost rectangular microstrip line of the copper feed line layer and the lower edge of the conductor layer; the length and width of the rightmost rectangular microstrip line are X10 = 9 mm and Y10 = 1.6 mm, respectively; the length and width of the middle rectangular microstrip line are X9 = 5 mm and Y9 = 1 mm, respectively; the length and width of the leftmost rectangular microstrip line are X8 = 3.8 mm and Y8 = 0.8 mm, respectively; the inner diameter of the hollow circular ring is R3 = 1.5 mm, and the outer diameter is R2 = 4.3 mm, as detailed in Table 1.

[0024] Table 1: Dimensional parameters of the antenna of the present invention

[0025] X1 X2 X3 X4 X5 X6 X7 X8 30mm 1mm 1mm 1mm 2mm 1.70mm 4mm 3.82mm X9 X10 X11 X12 X13 5mm 9mm 2mm 3mm 3mm Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 23.5mm 1.35mm 20mm 12mm 14mm 2mm 3.4mm 0.8mm Y9 Y10 1mm 1.6mm R1 R2 R3 1.92mm 4.3mm 1.5mm d1 d2 d3 d4 d5 d6 3.6mm 5.5mm 6.85mm 6.65mm 5.95mm 8.15mm

[0026] Example 2:

[0027] Figure 5 The reflection coefficient of the feeder end of the antenna of the present invention measured by a vector network analyzer is given. The absolute bandwidth with the reflection coefficient S11 less than -10dB reaches 12.29GHz, and the relative bandwidth reaches 147%.

[0028] Figure 6 The antenna radiation pattern within the frequency band of the antenna of the present invention is given. Figure 6 (a) is the xoy section direction diagram, Figure 6 (b) shows the zoy-plane radiation pattern. It can be seen that within the operating frequency band, the antenna's maximum radiation direction is essentially along the +y-axis. However, due to the introduction of multiple slots on one side of the conductor layer, the maximum radiation direction deviates slightly from the y-axis at 10 GHz for the xoy-plane radiation pattern. Overall, the directivity is similar across all frequencies within the band, with an average in-band gain of 4.82 dBi.

[0029] References:

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Claims

1. A double-sided Vivaldi antenna with an I-shaped matching slot and multiple slot radiating elements, characterized by: It is a five-layer structure, consisting of a lower copper conductor layer, a lower dielectric layer, a copper feeder layer, an upper dielectric layer, and an upper copper conductor layer from bottom to top. The lower copper conductor layer, the lower dielectric layer, the upper dielectric layer, and the upper copper conductor layer are rectangular structures of the same size, and their edges are aligned. The upper copper conductor layer and the lower copper conductor layer are antenna radiators; The lower copper conductor layer has the same structure as the upper copper conductor layer, with a symmetrical trumpet-shaped structure with a circular hole in the middle. Symmetrical trumpet-shaped structures with circular holes are provided on the upper and lower conductor layers, with an I-shaped matching slot provided on the right side of the structure. The I-shaped matching slot consists of three rectangular sections: a right slot, a middle slot, and an inner slot. These three sections share a common axis of symmetry parallel to the lower edge of the copper conductor layer. On the left side of the symmetrical trumpet-shaped structures with circular holes in the upper and lower conductor layers, three vertical rectangular slots are provided, perpendicular to the lower edge of the copper conductor layer, and one transverse rectangular slot is provided, parallel to the lower edge of the copper conductor layer. The transverse rectangular slot transversely cuts through the three vertical rectangular slots. The copper feed line layer is composed of three sections of rectangular microstrip lines with gradually narrowing widths and hollow circular ring pieces connected in sequence from right to left. The right edge of the rectangular microstrip line is aligned with the right edges of the upper and lower conductor layers. The three sections of rectangular microstrip lines and the hollow circular ring piece have a common symmetry axis parallel to the lower edge of the copper feed line layer.

2. The double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements according to claim 1, characterized in that: The lower copper conductor layer, lower dielectric layer, copper feeder layer, upper dielectric layer and upper copper conductor layer are 23.5mm The 30mm rectangular structure has a copper conductor layer and a copper feeder layer with a thickness of 0.035mm. The dielectric layer uses an F4B dielectric substrate with a thickness of 1.2mm and a relative dielectric constant of 2.

2.

3. The double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements according to claim 1, characterized in that: The structure of the lower copper conductor layer is the same as that of the upper copper conductor layer. A symmetrical bell-mouth structure with a circular hole is opened in the middle. Assume that the coordinate origin is at the lower edge of the conductor layer corresponding to the center of the circular hole, the lower edge of the conductor layer is the x-axis direction, and the direction perpendicular to the lower connecting edge in the plane of the conductor layer is the y-axis direction. Then the curve equation of the symmetrical bell-mouth structure is: ； The lower end of the bell-mouth structure is connected to a circular hole with a radius R1 of 1.92 mm. The distance d1 between the center of the circular hole and the lower edge of the conductor layer is 3.60 mm. The distance d2 between the connection between the symmetrical bell-mouth structure and the circular hole and the lower edge of the conductor layer is 5.50 mm.

4. The double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements according to claim 1, characterized in that: The dimensional parameters of the right notch in the I-shaped matching groove are Y7=3.4mm, X7=4.0mm, and the distance between its lower edge and the lower edge of the conductor layer is d5=5.95mm; the dimensional parameters of the middle gap are Y6=2.0 mm, X6=1.7mm, and the distance between its lower edge and the lower edge of the conductor layer is d4=6.65mm; the dimensional parameters of the inner gap are Y7=3.4mm, X5=2.0mm, and the distance between its lower edge and the lower edge of the conductor layer is d5=5.95mm.

5. The double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements according to claim 1, characterized in that: The dimensional parameters of the first vertical rectangular gap at a distance of X11=2mm from the left edge of the conductor layer are Y3=20mm and X3=1mm; the dimensional parameters of the second vertical rectangular gap at a distance of X12=3.0mm from the first vertical rectangular gap are Y4=12mm and X3=1mm; the dimensional parameters of the third vertical rectangular gap at a distance of X13=3.0mm from the second vertical rectangular gap are Y5=14mm and X4=1mm; the distance between the transverse rectangular gap and the lower edge of the conductor layer is d6=8.15mm, the width of the transverse rectangular gap is Y2=1.35mm, and its length starts from the left edge of the conductor layer and ends at the third vertical rectangular gap.

6. The double-sided Vivaldi antenna comprising an I-shaped matching slot and multiple opening slot radiating elements according to claim 1, characterized in that: The distance d3 between the lower edge of the rightmost rectangular microstrip line of the copper feed layer and the lower edge of the conductor layer is 6.85 mm. The length and width of the rightmost rectangular microstrip line are X10 = 9 mm and Y10 = 1.6 mm, respectively. The length and width of the middle rectangular microstrip line are X9 = 5 mm and Y9 = 1 mm, respectively. The length and width of the leftmost rectangular microstrip line are X8 = 3.8 mm and Y8 = 0.8 mm, respectively. The inner diameter of the hollow circular ring is R3 = 1.5 mm, and the outer diameter is R2 = 4.3 mm.

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