Small-size high-gain microstrip yagi antenna

Abstract

The invention discloses a small-size high-gain microstrip yagi antenna, and relates to the technical field of microwave communication, in particular to the microstrip antenna technology, which comprises a top metal patch layer, a middle dielectric substrate layer and a bottom metal grounding layer. The top metal patch layer comprises two rectangular reflection patches, a rectangular radiation patch and two rectangular guide patches, the two rectangular reflection patches are symmetrically distributed on the two sides of the microstrip line, and the radiation patch is connected with the feed network through the microstrip line; the radiation patch is provided with two rectangular grooves which are the same in size and are symmetrical, and the two rectangular guide patches are reduced in sequence. According to the design scheme of the application, the principles of the microstrip patch antenna and the yagi antenna are applied, and the antenna has high gain while keeping a small size, so that high-precision measurement of a target in a narrow space is realized.

Description

Technical Field

[0001] This application relates to the field of microwave communication technology, and in particular to a small-size, high-gain microstrip Yagi antenna. Background Technology

[0002] With the rapid development of microwave communication technology, the requirements for antennas, as one of its most basic components, have increased in certain applications. For example, some highly directional local positioning systems, wireless sensor networks, and certain scenarios in mobile communication technologies, which are now widely used, all require antennas with strong directivity and compact or small dimensions. Microstrip Yagi antennas, due to their high gain, directivity, low profile, and ease of integration, are very suitable for such applications.

[0003] Typically, a microstrip Yagi antenna consists of a dielectric substrate, a reflective patch, a radiating patch, a directing patch, and a ground plane. The dielectric substrate is usually much thinner than the antenna wavelength, providing a propagation path for electromagnetic waves. The substrate thickness and dielectric constant affect the sidelobes and front-to-back ratio of the radiation pattern. The radiating patch, also called the excitation patch, is usually composed of a conductive metal layer, and its size often depends on the antenna frequency and wavelength. The ground plane, also made of conductive metal, is usually placed on the bottom of the dielectric substrate and reflects electromagnetic waves. Existing microstrip Yagi antennas, such as the patent with publication number CN111786131B, design a multilayer antenna consisting of a top metal structure, a second metal structure, a third metal structure, a bottom metal structure, a first dielectric substrate, a second dielectric substrate, and a coaxial cable, with a gain range of 8.6-10.9 dBi within the frequency band; and the patent with publication number CN111740230B, which consists of a double-sided microstrip quasi-Yagi antenna and a director loaded on the double-sided microstrip quasi-Yagi antenna, maintaining a gain of 4.5 dBi across the entire impedance bandwidth of 5.3-6.0 GHz. Considering the current microstrip Yagi antennas, when performing high-precision measurements on targets in confined spaces, there is a problem: antennas with high gain are too large, while smaller antennas have low gain. Summary of the Invention

[0004] The main objective of this application is to provide a small-size, high-gain microstrip Yagi antenna, which further improves the gain of the microstrip Yagi antenna and reduces its size, thereby improving the antenna's performance and enabling high-precision measurement of targets in confined spaces.

[0005] To achieve the above objectives, according to one aspect of a specific embodiment of this application, a small-size, high-gain microstrip Yagi antenna is provided, comprising, from bottom to top, a bottom metal layer, a dielectric substrate layer, and a top metal patch layer. The metal patch layer 2 comprises, from one side to the other, a first reflective patch T1 and a second reflective patch T2, a radiating patch R1, a first guiding patch D1 and a second guiding patch D2. The radiating patch R1 is connected to a feed network via a microstrip line. The first reflective patch and the second reflective patch are symmetrically distributed on both sides of the microstrip line.

[0006] The microstrip Yagi antenna radiating patch has two identical and symmetrical rectangular slots.

[0007] The two rectangular reflective patches of the microstrip Yagi antenna are symmetrically distributed on both sides of the microstrip line and are the same size.

[0008] The two rectangular guide patches of the top metal patch layer decrease in size sequentially.

[0009] The size of the reflective patch is smaller than that of the radiating patch, and the size of the radiating patch is smaller than that of the first directional patch but larger than that of the second directional patch.

[0010] There are certain gaps between the reflective patch, the radiating patch, and the directing patch.

[0011] The two rectangular guide patches and two rectangular reflective patches of the top metal patch layer are distributed sequentially along the axial direction of the dielectric substrate.

[0012] The beneficial effects of this invention are: 1. The radiating patch R1 has two identical and symmetrical rectangular slots, introducing an additional resonator and increasing the antenna bandwidth. The slots also disturb the surface current, altering the equivalent circuit parameters and facilitating impedance matching. The first reflective patch T1 and the second reflective patch T2 are symmetrically distributed on both sides of the microstrip line W, improving the symmetry of the radiation pattern. The symmetrical placement of the two reflective patches ensures a balanced influence on the electromagnetic field at the edges of the microstrip line, contributing to good impedance matching. Adding the first reflective patch T1 and the second reflective patch T2 behind the radiating patch R1, with the reflective patches smaller than the radiating patch, causes their phase to lag behind, resulting in destructive interference and reducing back radiation, thus suppressing the antenna beam energy from radiating backward.

[0013] 2. Add a first guide patch D1 and a second guide patch D2 in front of the radiating patch R1 (i.e., on the side of the main radiation direction). The first guide patch D1 is larger than the radiating patch R1, so that its phase leads the radiating patch R1. This phase lead makes the radiation field of the guide patch and the radiation field in front of the radiating patch R1 and the radiation field of the radiating patch R1 itself nearly in phase, producing constructive interference, attracting energy to propagate forward and making it more concentrated, significantly improving the forward gain and directivity of the antenna.

[0014] 3. There is a certain gap between each patch. The gap makes each patch an independent resonant unit, avoiding frequency aliasing caused by direct short circuit. The gap modulates the phase of electromagnetic waves through near-field coupling. The gap blocks the direct current path between patches, suppresses surface wave propagation, and reduces mutual coupling and surface wave loss.

[0015] 4. The radiating patch R1, the first guiding patch D1, and the second guiding patch D2 of the metal patch layer 2 are distributed sequentially along the axial direction of the dielectric substrate. The axial arrangement of the patches forms a beam propagation chain, which enables electromagnetic waves to propagate along the axial direction, suppresses lateral radiation, forms a highly efficient end-firing beam, and significantly improves forward gain.

[0016] 5. Increasing the number of directors can further improve gain and directivity, but adding too many director patches will narrow the bandwidth, increase structural complexity, and make the size too large. This invention adds only two director patches and two reflector patches to the antenna structure, achieving good front-side radiation characteristics and high gain while maintaining a small size. This solves the problems of insufficient gain in small-sized antennas and excessively large size in high-gain antennas when performing high-precision target measurements in confined spaces. Furthermore, the manufacturing process is compatible with existing microstrip Yagi antennas, is technologically mature, and has low production costs, enabling it to meet the requirements for high-precision target measurements in confined spaces. Attached Figure Description

[0017] Figure 1 This is a front view of an embodiment of the present invention; Figure 2 This is a schematic diagram of the rear structure of an embodiment of the present invention; Figure 3 This is an S11 curve diagram of an embodiment of the present invention; Figure 4 This is an E-plane radiation pattern according to an embodiment of the present invention; Figure 5 This is an H-plane radiation pattern according to an embodiment of the present invention.

[0018] 1. Dielectric substrate layer; 2. Top metal patch layer; 3. Bottom metal patch layer; T1, First reflective patch; T2, Second reflective patch; R1, Radiation patch; D1, First directional patch; D2, Second directional patch. Detailed Implementation

[0019] The specific embodiments of this application will be further explained below with reference to the accompanying drawings.

[0020] The small-size, high-gain microstrip Yagi antenna of this application utilizes the principle of microstrip Yagi antennas by adding specially structured patches to the antenna and removing redundant structures from conventional microstrip Yagi antennas, thereby achieving the purpose of reducing antenna size and increasing antenna gain.

[0021] The small-size, high-gain microstrip Yagi antenna of this application, such as Figure 1 and Figure 2 As shown, it includes a dielectric substrate layer 1, a top metal patch layer 2, and a bottom metal layer 3. The metal patch layer includes a rectangular radiating patch R1, a first reflective patch T1, a second reflective patch T2, a first guiding patch D1, and a second guiding patch D2. The radiating patch R1 is connected to the feed network through a microstrip line, and the first reflective patch T1 and the second reflective patch T2 are symmetrically distributed on both sides of the microstrip line.

[0022] The phase of the coupling field between the first reflective patch T1 and the second reflective patch T2 leads the phase of the field of the radiating patch R1, causing the main lobe of the radiation pattern to be biased towards the radiating patch R1, forming a side-firing characteristic. The phase of the coupling field of the first guiding patch D1 lags the phase of the field of the radiating patch R1, playing a guiding role. The second guiding patch D2 is smaller than the first guiding patch D1, causing its coupling field phase to lag behind the coupling field phase of the first guiding patch D1, concentrating more radiated energy in the main lobe direction and improving the antenna gain. Since the beam energy of the radiating patch R1 is concentrated in the side-firing direction, and less energy is radiated in the end-firing direction, the energy obtained by the coupling between the first guiding patch D1 and the second guiding patch D2 is also less. To enhance the coupling between the radiating patch R1 and the guiding patch, the spacing between the patches needs to be small enough, slightly smaller than the thickness of the dielectric substrate.

[0023] like Figure 1 As shown, the first reflective patch T1 and the second reflective patch T2 are symmetrically distributed on both sides of the microstrip line. By adjusting the size and position of the first reflective patch T1 and the second reflective patch T2, the energy radiated backward by the antenna can be reduced, thus changing the front-to-back ratio of the antenna. The first guide patch D1 and the second guide patch D2 are arranged sequentially along the axis of the dielectric substrate 1, with the size of the two patches decreasing sequentially. Appropriately increasing the size of the first guide patch D1 and the second guide patch D2 can improve the main lobe gain of the antenna. However, when the guide patch is too large, it will significantly increase the side lobes, thereby affecting the main lobe and reducing the antenna gain. Due to the coupling relationship between the patches, the distance between them should not exceed the thickness of the dielectric substrate.

[0024] Obtained through simulation Figure 3 The result is that Figure 3 It can be seen that the center frequency of this antenna is 23.9 GHz, the bandwidth is 4.6%, and the return loss is -53 dB. Figure 4 and Figure 5It can be seen that the antenna has good front-side radiation characteristics, with a beam pointing at -60°. 0°, and the maximum gain is 8.4 dBi. In summary, by adding a specially structured reflective patch and removing redundant radiating patches to a traditional microstrip Yagi antenna, the antenna can be reduced in size while increasing gain, achieving the goal of high-precision measurement of targets in confined spaces.

[0025] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0026] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A small-size, high-gain microstrip Yagi antenna, characterized in that, From bottom to top, it includes a bottom metal grounding layer 3, a middle dielectric substrate layer 1, and a top metal patch layer 2. The metal patch layer 2 includes a first reflective patch T1 and a second reflective patch T2, a radiating patch R1, a first guiding patch D1 and a second guiding patch D2, and the radiating patch R1 is connected to the feed network through a microstrip line. The radiating patch R1 has two rectangular slots of the same size and symmetrical. The first reflective patch T1 and the second reflective patch T2 are symmetrically distributed on both sides of the microstrip line; The dimensions of the first guide patch D1 and the second guide patch D2 decrease sequentially.

2. The antenna according to claim 1, characterized in that, The dimensions of the first reflective patch T1 and the second reflective patch T2 are smaller than those of the radiating patch R1. The dimensions of the radiating patch R1 are smaller than those of the first guiding patch D1 and larger than those of the second guiding patch D2.

3. The antenna according to claim 1, characterized in that, There are certain gaps between the first reflective patch T1, the second reflective patch T2, the radiating patch R1, the first guiding patch D1, and the second guiding patch D2.

4. The antenna according to claim 1, characterized in that, The radiating patch R1, the first guiding patch D1, and the second guiding patch D2 of the metal patch layer 2 are distributed sequentially along the axial direction of the dielectric substrate.

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