End-on-fire leaky-wave antenna with fixed wave beam

Abstract

The invention relates to the technical field of wireless communication, and particularly discloses a fixed-beam end-on-fire leaky-wave antenna which comprises a dielectric substrate and parallel double lines located on the upper surface and the lower surface of the dielectric substrate. Resonant cavities are arranged on the left and right sides of the parallel double lines; the upper and lower ends of the parallel double lines are provided with feeder lines of a cross-shaped structure. The center line of the parallel double lines is provided with a short-circuit pin, and the upper and lower parts of the short-circuit pin are respectively connected with the parallel double lines. According to the leaky-wave antenna, the short circuit nails are loaded at the center lines of the parallel double lines, the resonant cavities are loaded on the two sides, the resonant frequency of the resonant cavities is kept consistent with the frequency corresponding to the end-fire condition of the leaky-wave antenna, and the characteristics of broadband, end-fire and unchanged beam shape can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to an end-fire leaky-wave antenna with a fixed beam. Background Art With the rapid development of wireless communication technology, the demand for high-performance antennas is growing. Among the many types of antennas, leaky-wave antennas have been widely used in microwave communications, radar systems and other fields due to their unique radiation characteristics. Although traditional leaky-wave antennas can achieve good radiation effects, they have some limitations in practical applications. For example, the beam direction of most leaky-wave antennas will shift with changes in frequency, making it difficult to maintain a stable radiation direction in broadband communications, affecting the communication quality and system stability. Studies have found that when the normalized phase constant is 1, the leaky-wave antenna will point in the end-fire direction, but as the normalized phase constant increases, the antenna's radiation will have problems such as narrow beam width and shape distortion. In order to meet the higher requirements of modern wireless communication systems for antenna performance, it is particularly important to develop a leaky-wave antenna that can achieve broadband fixed end-fire within a broadband range and whose shape does not change. Summary of the Invention

[0002] The object of the present invention is to provide an end-fire leaky-wave antenna with a fixed beam to solve the problems raised in the above background technology.

[0003] To achieve the above object, the present invention adopts the following technical solutions, including: A dielectric substrate and parallel double wires located on the upper and lower surfaces of the dielectric substrate; resonant cavities are provided on the left and right sides of the parallel double wires; cross-shaped feed lines are provided at the upper and lower ends of the parallel double wires for connecting to antennas to achieve impedance matching; shorting spikes are provided at the center line of the parallel double wires, and the shorting spikes are connected to the parallel double wires at the top and bottom. The parallel double wires typically exhibit slow-wave characteristics with a normalized phase constant greater than 1. Loading the shorting spikes with an appropriate period length can generate a fast-wave region and achieve beam scanning. Furthermore, the parallel double wires, the shorting spikes and the resonant cavities on both sides of the shorting spikes together constitute a periodic unit of the leaky wave antenna, with the shorting spikes as the center of the periodic unit. The length of a periodic unit is no more than half the wavelength of the guided wave.

[0004] Furthermore, the resonant cavity includes a metal patch on the surface of a dielectric substrate, a cavity communicating with the metal patch up and down, and an inner wall of the cavity is covered with a metal layer.

[0005] Furthermore, the center lines of the parallel double wires are loaded with n periodically arranged shorting spikes, where n>1; wherein, the normalized phase constant of the parallel double wires loaded with shorting spikes can only achieve end-fire at a single frequency point. By introducing a resonant cavity, the normalized phase constant can have a negative slope and maintain the end-fire condition within the bandwidth, thereby generating a stable end-fire beam.

[0006] Furthermore, the length of the parallel double lines is determined by the period number m of the periodic unit, m>3, and the width can be arbitrarily selected so as not to generate high-order modes.

[0007] Furthermore, the length of the resonant cavity is a quarter of the wavelength, and the width can be arbitrarily selected so as not to generate higher-order modes. By adjusting the length and width of the resonant cavity, the resonant frequency of the resonant cavity is kept consistent with the frequency corresponding to the end-fire condition of the leaky wave antenna, and a broadband end-fire characteristic can be achieved. Furthermore, the relative distance between the short-circuiting nail and the center of the resonant cavity in the z-axis direction is within a period range. By adjusting the distance between the short-circuiting nail and the center of the resonant cavity in the direction of the leaky wave antenna, the coupling strength between the resonant cavity and the parallel double wires can be controlled, thereby controlling the equivalent resistance of the cavity and achieving a stable phase constant under end-fire conditions.

[0008] Furthermore, the dielectric substrate and the resonant cavity are both rectangular.

[0009] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The present invention loads short-circuiting nails on the center line of the parallel double wires and resonant cavities on both sides, and keeps the resonant frequency of the resonant cavity consistent with the frequency corresponding to the end-fire condition of the leaky wave antenna, thereby achieving broadband, end-fire and unchanged beam shape characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is the S parameter diagram of the present invention; Figure 3 The left and right figures are the radiation patterns of the antenna's xoz and yoz planes at 5.4 GHz respectively; Figure 4 The left and right figures are the radiation patterns of the antenna's xoz and yoz planes at 5.5 GHz respectively; Figure 5 The left and right figures are the radiation patterns of the antenna xoz and yoz planes at 5.6 GHz respectively.

[0011] As shown in the figure: 1- dielectric substrate, 2- feed line, 3- parallel double wires, 4- metal patch, 5- cavity, 6- short-circuit nail. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0013] Reference Figure 1 As shown, the present invention provides a fixed beam end-fire leaky wave antenna: The device comprises a dielectric substrate 1 and parallel double wires 3 located on the upper and lower surfaces of the dielectric, wherein the dielectric substrate 1 has a relative dielectric constant of 2.25 and a thickness of 3 mm; resonant cavities are provided on the left and right sides of the parallel double wires 3; a cross-shaped feeder 2 is provided at the upper and lower ends of the parallel double wires 3; a shorting spike 6 is provided at the center line of the parallel double wires 3, and the shorting spike 6 is connected to the parallel double wires 3 at the upper and lower ends, wherein n shorting spikes 6 are periodically arranged at the center line of the parallel double wires 3.

[0014] In one specific embodiment, the parallel double wires 3, the shorting spike 6, and the resonant cavities on either side of the shorting spike 6 collectively constitute a periodic unit of the leaky-wave antenna, with the shorting spike 6 as the center of the periodic unit. The length of a periodic unit is no greater than half the wavelength of the guided wave, specifically 16.78 mm. The leaky-wave antenna structure is composed of six periodic units, each 16.78 mm long and 15.5 mm wide.

[0015] In a specific embodiment, the length of the parallel double line 3 is determined by the period number m of the period unit. When m=6, the length is 136.66 mm and the width is 5 mm.

[0016] In a specific embodiment, the resonant cavity includes a metal patch 4 on the surface of the dielectric substrate 1, and a cavity 5 connected to the metal patch 4 from top to bottom, and the inner wall of the cavity 5 is covered with a metal layer.

[0017] In a specific embodiment, the resonant cavity has a length of 9.14 mm and a width of 4.5 mm.

[0018] In a specific embodiment, the distance between the resonant cavity and the parallel double wires 3 is 3 mm.

[0019] In a specific embodiment, the relative distance between the short-circuit nail 6 and the center of the resonant cavity in the z-axis direction is 5 mm.

[0020] In a specific embodiment, the diameter of the shorting nail 6 is 1 mm.

[0021] In a specific embodiment, the antenna operates at a frequency of 5.5 GHz, and the radiation direction within the range of 5.30-5.60 GHz is an end-fire direction with a consistent beam shape.

[0022] like Figure 2 The S parameter diagram of the antenna shows that when the feed line is excited, the antenna can achieve broadband matching. In the 5.35-5.6GHz frequency band, the antenna's radiation direction is end-fire and the shape is consistent. The maximum radiation beam is in the xoz plane, and the radiation direction is as follows: Figure 3 As shown, the left and right figures are the radiation patterns of the antenna xoz plane (E plane) and yoz plane (H plane) at 5.4GHz, respectively. The red line is co-polarization, the blue dotted line is cross-polarization, and the radiation direction is as follows Figure 4 As shown, the left and right figures are the radiation patterns of the antenna xoz plane (E plane) and yoz plane (H plane) at 5.5GHz, respectively. The red line is co-polarization, the blue dotted line is cross-polarization, and the radiation direction is as follows Figure 5 The left and right figures show the radiation patterns of the antenna's xoz (E-plane) and yoz (H-plane) planes at 5.6 GHz, respectively. The red line represents co-polarization, and the blue dot-dashed line represents cross-polarization. Within the operating frequency band, the leaky-wave antenna's beam pointing direction remains essentially unchanged with frequency, and its beam shape exhibits minimal change, demonstrating excellent beam pointing stability.

[0023] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A fixed-beam end-fire leaky-wave antenna, characterized in that: The invention comprises a dielectric substrate (1) and parallel double wires (3) located on the upper and lower surfaces of the dielectric substrate (1); resonant cavities are provided on the left and right sides of the parallel double wires (3); feeders (2) with a cross structure are provided at the upper and lower ends of the parallel double wires (3); a short-circuit spike (6) is provided at the center line of the parallel double wires (3), and the short-circuit spike (6) is connected to the parallel double wires (3) at the upper and lower sides respectively.

2. The fixed-beam end-fire leaky-wave antenna according to claim 1, characterized in that: The parallel double wires (3), the short-circuit nail (6) and the resonant cavities on both sides of the short-circuit nail (6) together constitute a periodic unit of the leaky-wave antenna.

3. The fixed-beam end-fire leaky-wave antenna according to claim 1, wherein: The resonant cavity comprises a metal patch (4) on the surface of a dielectric substrate (1), a cavity (5) connected to the metal patch (4) in upper and lower directions, and an inner wall of the cavity (5) is covered with a metal layer.

4. The fixed-beam end-fire leaky-wave antenna according to claim 1, wherein: The length of the parallel double line (3) is determined by the period number m of the periodic unit, where m>3.

5. The fixed-beam end-fire leaky-wave antenna according to claim 1, wherein: N short-circuit spikes (6) are equidistantly distributed on the center line of the parallel double wire (3), where n>1.

6. The fixed beam end-fire leaky wave antenna according to claim 1, characterized in that , the length of the resonant cavity is one quarter of the wavelength.

7. The fixed-beam end-fire leaky-wave antenna according to claim 1, wherein: The relative distance between the short-circuit nail (6) and the center of the resonant cavity in the z-axis direction is within a period range.

8. The fixed-beam end-fire leaky-wave antenna according to claim 1, wherein: The dielectric substrate (1) and the resonant cavity are both rectangular.

Images