Conical beam antenna based on Fabry-Perot cavity

Abstract

The present invention discloses a conical beam antenna based on a Fabry-Perot resonant cavity. The antenna comprises a first dielectric substrate, a second dielectric substrate, a first metal layer, a second metal layer, and a single-port feed. A first metal printed circuit is printed on the side of the first dielectric substrate facing the second dielectric substrate, and a second metal printed circuit is printed on the side of the second dielectric substrate facing the first dielectric substrate. An FP cavity is formed between the first and second metal printed circuits, and the first metal layer. The second metal layer is disposed on a side of the second dielectric substrate facing away from the second metal printed circuit. A metal E-shaped cavity is formed by partially removing the metal between the second metal layer and the second dielectric substrate. The single-port feed is disposed at the center of the bottom of the second dielectric substrate and passes through the metal E-shaped cavity and the second metal layer. The present invention utilizes peripheral feeding to achieve high gain, a simple structure, and ease of implementation.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a high-gain conical beam antenna based on Fabry-Perot (FP). Technical Background

[0002] A conical beam antenna is a special antenna with a different directional pattern than a standard antenna. The direction of maximum gain in the pattern does not lie on the antenna normal, but rather at a certain angle to the normal and axially symmetrical around the normal, forming a circular ring-like pattern. This axially symmetrical pattern is characteristic of antennas. Engineering systems such as radio communications, electronic countermeasures, radar, television, remote sensing, navigation, broadcasting, and radio astronomy all require antennas to transmit or receive electromagnetic waves. Different application scenarios require specific antennas to maximize device performance. As an important type of antenna, the conical beam antenna's maximum radiation pattern is angled relative to the zenith, enabling 360° coverage in azimuth. Therefore, it has important applications in systems such as in-vehicle communications, drone remote control, missile-borne fuzes, and large-area detection. Mobile communications require conical beams with different inclination angles corresponding to different frequencies.

[0003] In order to achieve a high-gain conical beam, today's conical beam antennas choose spiral antennas and slot array antennas engraved on three-dimensional objects. However, their disadvantages are that they are relatively bulky, ordinary spiral antennas are not easy to install, the gain of patch antennas is not high, and the array antenna is complex. Summary of the Invention

[0004] The object of the present invention is to provide a conical beam antenna based on a Fabry-Perot resonant cavity.

[0005] A technical solution for achieving the objectives of the present invention is as follows: a conical beam antenna based on a Fabry-Perot resonant cavity, comprising a first dielectric substrate, a second dielectric substrate, a first metal layer, a second metal layer, and a single-port feed. The first dielectric substrate and the second dielectric substrate are arranged parallel to each other. A first metal printed circuit is printed on a surface of the first dielectric substrate facing the second dielectric substrate, and a second metal printed circuit is printed on a surface of the second dielectric substrate facing the first dielectric substrate. The first metal layer is arranged between a portion of the first dielectric substrate not printed with the first metal printed circuit and a portion of the second dielectric substrate not printed with the second metal printed circuit. An FP cavity is formed between the first metal printed circuit, the second metal printed circuit, and the first metal layer. The second metal layer is arranged on a surface of the second dielectric substrate away from the second metal printed circuit, and a metal E-shaped cavity is formed by partially removing the metal between the second metal layer and the second dielectric substrate. The single-port feed is arranged at the bottom center of the second dielectric substrate and passes through the metal E-shaped cavity and the second metal layer.

[0006] Preferably, the single-port feed includes a horn radial waveguide and an SMA connector, the horn radial waveguide is arranged at the center of the metal E-shaped cavity, and the SMA connector is arranged on the second metal layer and connected to the horn radial waveguide.

[0007] Preferably, the first metal printed circuit includes 8 metal ring bull's eye patterns, and the arrangement rule of the pattern is: a circle at the center, n rings are added along the radial direction with a period of P length, the width of each ring is W, and the outer circle radius of the nth ring from the center outward satisfies the formula: R = W + n * P, where n is an integer.

[0008] Preferably, the second dielectric substrate includes a disk and a ring, the ring is arranged around the disk, and the disk and the ring are connected by 30 branches arranged at equal intervals.

[0009] Preferably, the second metal printed circuit is printed on the disc of the second dielectric substrate, covering the entire circle.

[0010] Preferably, a branch having a width three times that of the remaining branches is provided every 120 degrees among the 30 branches.

[0011] Preferably, the cavity edge of the FP cavity is inclined toward the second dielectric substrate.

[0012] Preferably, the cavity edge of the metal E-shaped cavity is inclined toward the second dielectric substrate.

[0013] Compared with the prior art, the present invention has the following significant advantages:

[0014] The present invention utilizes a Fabry-Perot cavity antenna to construct a low-profile, simple-structure, high-gain conical beam antenna. The structure is relatively simple and the production and processing costs are lower.

[0015] The present invention adopts the structural design of the metal E-shaped cavity in the radial line slot antenna. The second dielectric substrate is used to form a double-layer structure of a radial line waveguide. The center of the metal E-shaped cavity is fed through the horn radial waveguide and the SMA connector to generate a radially outward TEM mode. The TEM mode is converted into a radially inward traveling wave mode in the FP cavity through the metal E-shaped cavity. Part of the energy is radiated from the first dielectric substrate, thereby realizing the process of feeding from the four edges to the center.

[0016] The present invention selects a ring-shaped bull's-eye structure frequency selective surface printed on a dielectric plate, which can effectively improve the directivity and gain of the conical beam. By changing the period and width of the ring, the angular pointing of the radiation pattern can be improved. Compared with ordinary leaky wave antennas, the bull's-eye structure can achieve a larger beam angle scanning.

[0017] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a front view of the conical beam antenna based on the Fabry-Perot resonant cavity of the present invention.

[0019] Figure 2 It is a top view of the conical beam antenna based on the Fabry-Perot resonant cavity of the present invention.

[0020] Figure 3 This invention Figure 1 Schematic diagram of the dimensions of the first dielectric substrate.

[0021] Figure 4 This invention Figure 1 Schematic diagram of the size of the second dielectric substrate.

[0022] Figure 5 This invention Figure 1 Schematic diagram of the dimensions of the middle FP cavity and the metal E-shaped cavity.

[0023] Figure 6 This invention Figure 1 Cross-section of the radial waveguide and SMA connector in the middle horn.

[0024] Figure 7 These are the E-plane and H-plane radiation patterns of the embodiment of the present invention at 12.5 GHz.

[0025] Figure 8 1 is a graph showing the relationship between return loss and frequency of a conical beam antenna according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] like Figure 1As shown, a conical beam antenna based on a Fabry-Perot resonant cavity includes a first dielectric substrate 6, a second dielectric substrate 8, a first metal layer, a second metal layer, and a single-port feed 2. The first dielectric substrate 6 and the second dielectric substrate 8 are arranged parallel to each other. A first metal printed circuit 7 is printed on the surface of the first dielectric substrate 6 facing the second dielectric substrate 8, and a second metal printed circuit 9 is printed on the surface of the second dielectric substrate 8 facing the first dielectric substrate 6. The first metal layer is arranged between the portion of the first dielectric substrate 6 not printed with the first metal printed circuit and the portion of the second dielectric substrate 8 not printed with the second metal printed circuit 9. An FP cavity 1 is formed between the first metal printed circuit 7, the second metal printed circuit 9, and the first metal layer. The second metal layer is arranged on the surface of the second dielectric substrate 8 away from the second metal printed circuit 9, and a metal E-shaped cavity 3 is formed between the second metal layer and the second dielectric substrate 8 by removing a portion of the metal. The single-port feed 2 is arranged at the bottom center of the second dielectric substrate 8 and passes through the metal E-shaped cavity 3 and the second metal layer. The single-port feed 2 feeds power from the center to the surrounding areas. The emitted electromagnetic wave is reflected twice by the metal E-shaped cavity 3 and the FP cavity 1, forming a beam forming network and finally forming a cone beam.

[0027] Specifically, the first dielectric substrate 6 is Rogers RO4350, and its dielectric constant is 3.66.

[0028] Specifically, the second dielectric substrate 8 is Rogers RO4003, and its dielectric constant is 3.55.

[0029] In a further embodiment, the single-port feed 2 includes a horn radial waveguide 4 and an SMA connector 5. The horn radial waveguide 4 is disposed at the center of the metal E-shaped cavity 3. The SMA connector 5 is disposed on the second metal layer and connected to the horn radial waveguide 4. The single-port feed 2 radiates horizontal electromagnetic waves outward through the horn radial waveguide 4. The waves are reflected twice by the metal E-shaped cavity 3 and then reach the FP cavity 1.

[0030] In a further embodiment, the first metal printed circuit 7 includes a bull's-eye pattern of eight metal rings. The pattern is arranged as follows: a circle at the center, with n rings added radially with a period of length P. Each ring has a width of W, and the outer radius of the nth ring from the center outward satisfies the formula: R = W + n * P, where n is an integer. By varying the period and width of the rings, the angular directionality of the pattern can be improved.

[0031] In a further embodiment, the second dielectric substrate 8 includes a disk 16 and a ring 12. The ring 12 is disposed around the disk 16, and the disk 16 and the ring 12 are connected by 30 equally spaced branches 13. The thinner the 30 equally spaced branches 13, the more radiation passes through, and the better the directionality and transmission performance.

[0032] In a further embodiment, the second metal printed circuit 9 is printed on the disc 21 of the second dielectric substrate 8, covering the entire circle.

[0033] In a further embodiment, a branch 14 having a width three times that of the remaining branches 15 is provided every 120 degrees among the 30 branches 13. Based on the stability of the present invention, branches of different widths are provided to prevent the possibility of insufficient support force during application.

[0034] In a further embodiment, the cavity edge of the FP cavity 1 is tilted toward the second dielectric substrate to form a beam radiating toward the center of the FP cavity 1 .

[0035] In a further embodiment, the cavity edge of the metal E-shaped cavity 3 is tilted toward the second dielectric substrate to form a beam radiating toward the edge of the FP cavity 1 .

[0036] This invention provides a ring-shaped bull's-eye frequency selective surface printed on a dielectric substrate. By utilizing the FP cavity structure, it effectively improves the directivity and gain of a tapered beam. By varying the period and width of the ring, the angular pointing pattern can be further modified. This invention utilizes the structural design of a metal E-shaped cavity in a radial line slot antenna to implement a novel feeding method that feeds power from the edges to the center. This invention has high application value in mobile communications.

[0037] Example

[0038] See also Figure 3 is a schematic diagram of the dimensions of the first dielectric substrate 6, wherein the radius of the first dielectric substrate 6 is R F =106mm, the radius of the first metal printed circuit 7 is R s = 100mm, add n circles along the radius with a length of P = 13.35mm as a period, and the width of each circle is W = 11.65mm. Figure 1 As shown, t=0.1 mm is the thickness of the first dielectric substrate 6 .

[0039] See also Figure 4 is a schematic diagram of the dimensions of the second dielectric substrate 8, wherein the radius of the second dielectric substrate 8 is R p =120mm The radius of the second metal printed circuit 9 is R s = 100mm; the length of the 30 branches 13 connecting the disk 16 and the ring 12 is W s=5.8mm, wherein a branch 14 with a width three times the width of the remaining branches 15 is set every 120 degrees as L s =1.1mm, the width of the remaining branches 15 is L p =0.36mm, see Figure 5 , the thickness of the second dielectric substrate 8 is H=0.5 mm.

[0040] See also Figure 5 The schematic diagram of the dimensions of the FP cavity 1 and the metal E-shaped cavity 3 is shown in FIG. The diameter of the connection surface between the FP cavity 1 and the first dielectric substrate 6 is the same as D. s =2*R s = 200mm, the height of the FP cavity 1 is h1 = 14.5mm; the height of the second metal layer is h2 = 10mm, the height of the metal E-shaped cavity 3 is hh = 6mm, the length of the FP cavity 1 and the metal E-shaped cavity 3 from the edge is the same as the length of the 30 branches 13 of the second dielectric plate substrate 8, which is W s =5.8mm.

[0041] See also Figure 6 This is a cross-sectional view of the speaker radial waveguide 6 and the SMA connector 5. The speaker cross-sectional view is a trapezoid, and the length of the trapezoidal upper base 17 is D a =5.4mm, the length of the lower base 18 is D r = 0.8mm, height hh = 6mm; the probe diameter inside the SMA connector 5 is D r =0.8mm, the diameter of the Teflon layer (19) is D t =4mm.

[0042] See also Figure 7 Using HFSS simulation software, the E-plane and H-plane radiation patterns at 12.5GHz, it can be seen from the figure that the antenna can achieve a maximum gain of 14.3dB at this frequency, forming a conical beam with a directional angle of 30 degrees. Figure 1 To.

[0043] See also Figure 8 Using HFSS simulation software, based on the relationship between the return loss and frequency of the Fabry-Perot resonant cavity tapered beam antenna, the reflection coefficient is -19.7dB at the center frequency of 12.5GHz, and the bandwidth is between 12.42GHz and 12.69GHz, reaching approximately 2.2%.

Claims

1. A conical beam antenna based on a Fabry-Perot resonant cavity, characterized in that: The invention comprises a first dielectric substrate (6), a second dielectric substrate (8), a first metal layer, a second metal layer and a single-port feed source (2). The first dielectric substrate (6) and the second dielectric substrate (8) are arranged in parallel. A first metal printed circuit (7) is printed on the side of the first dielectric substrate (6) facing the second dielectric substrate (8). A second metal printed circuit (9) is printed on the side of the second dielectric substrate (8) facing the first dielectric substrate (6). The first metal layer is arranged between a portion of the first dielectric substrate (6) not printed with the first metal printed circuit and a portion of the second dielectric substrate (8) not printed with the second metal printed circuit (9). An FP cavity (1) is formed between the first metal printed circuit (7), the second metal printed circuit (9) and the first metal layer. The second metal layer is arranged on a side of the second dielectric substrate (8) away from the second metal printed circuit (9). A metal E-shaped cavity (3) is formed between the second metal layer and the second dielectric substrate (8). The single-port feed source (2) is arranged at the bottom center of the second dielectric substrate (8) and passes through the metal E-shaped cavity (3) and the second metal layer.

2. The conical beam antenna based on the Fabry-Perot resonant cavity according to claim 1, characterized in that: The single-port feed source (2) comprises a horn radial waveguide (4) and an SMA connector (5); the horn radial waveguide (4) is arranged at the center of a metal E-shaped cavity (3); and the SMA connector (5) is arranged on a second metal layer and connected to the horn radial waveguide (4).

3. The conical beam antenna based on the Fabry-Perot resonant cavity according to claim 1, characterized in that: The first metal printed circuit (7) comprises 8 metal ring bull's eye patterns, and the pattern arrangement rule is: a circle at the center, n rings are added along the radial direction with a length P as a period, the width of each ring is W, and the outer circle radius of the nth ring from the center outward satisfies the formula: R=W+n*P, where n is an integer.

4. The conical beam antenna based on the Fabry-Perot cavity according to claim 1, characterized in that: The second dielectric substrate (8) comprises a disk (16) and a ring (12), wherein the ring (12) is arranged around the disk (16), and the disk (16) and the ring (12) are connected by 30 branches (13) arranged at equal intervals.

5. The conical beam antenna based on the Fabry-Perot cavity according to claim 4, characterized in that: The second metal printed circuit (9) is printed on the disc (16) of the second dielectric substrate (8), covering the entire circle.

6. The conical beam antenna based on the Fabry-Perot cavity according to claim 4, characterized in that: Among the 30 branches (13), a branch (14) having a width three times that of the remaining branches (15) is provided every 120 degrees.

7. The conical beam antenna based on the Fabry-Perot cavity according to claim 1, characterized in that: The cavity edge of the FP cavity (1) is inclined toward the second dielectric substrate.

8. The conical beam antenna based on the Fabry-Perot cavity according to claim 1, characterized in that: The cavity edge of the metal E-shaped cavity (3) is inclined toward the second dielectric substrate.

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