KR102123976B1 - An antenna apparatus with 1-d ebg ground structures - Google Patents

Abstract

Provided is an antenna apparatus providing a one-dimensional electromagnetic bandgap grounding structure. The antenna apparatus includes a substrate, a ground layer at least partially formed on the substrate, and a planar inverted-L-type radiator (ILA) disposed on one side of the ground layer. The one-dimensional electromagnetic bandgap grounding structure is mounted at the edge of the planar radiator side of the ground layer. Accordingly, the one-dimensional electromagnetic bandgap grounding structure can be integrated into the ILA and a high-performance single antenna device in a small space without an additional circuit due to a high-impedance surface characteristic exhibiting a low-speed wave behavior in a dual direction. In addition, the antenna apparatus can be utilized in a small array antenna based on platforms of various materials characterized by wide bandwidth, high gain, and a wide scan angle.

Description

AN ANTENNA APPARATUS WITH 1-D EBG GROUND STRUCTURES

The present invention relates to an antenna device, and more specifically, a high-performance single antenna device integrated with an inverted-L type radiator without an additional circuit by providing a one-dimensional electromagnetic bandgap grounding structure having a high impedance surface characteristic exhibiting low-speed wave behavior in a dual direction. It is about.

There is an urgent need for small flat antennas featuring broadband and high gain for high-speed and high-capacity communications, beyond the physical critical characteristics of active RF devices in microwave and millimeter wave applications. In particular, there is an urgent need for element antenna technology of a small array antenna having a wide angle scan range. For example, flat array antennas are used as a representative type of small antennas based on their excellent performance. These antennas are required to have small form factor, wide bandwidth, high gain, wide angle scan range, low cost, simple manufacturing and wide compatibility with various platform environments.

Korea Registered Publication No. 10-1172812 ("One-dimensional electromagnetic band gap structure and flat antenna having the structure", Gwangju Institute of Science and Technology)

An object of the present invention for solving the above-mentioned problems is to integrate a one-dimensional electromagnetic bandgap grounding structure having a high impedance surface characteristic exhibiting a low-speed wave behavior in a dual direction with a planar inverse-L-type emitter and thus to perform broadband and horizontal polarization without additional circuits. , To provide a small antenna device capable of providing longitudinal directional radiation.

However, the problem to be solved of the present invention is not limited to this, and may be variously extended in a radio wave extreme environment within a range not deviating from the spirit and scope of the present invention.

An antenna device according to an embodiment of the present invention for solving the above-described problem, according to one aspect, a one-dimensional electromagnetic band gap (EBG) ground structure and a beam deflector integrated radiation pattern capable of improving the radiation pattern-L antenna (ILA ). Such an antenna device may have longitudinal directional radiation in horizontal polarization. An antenna device according to an embodiment of the present invention, a one-dimensional electromagnetic bandgap (1-D EBG) ground structures, and a two-stage beam deflector to convert the radiation pattern using a reverse-L antenna (ILA) topology It may be implemented as a small antenna having a. The antenna can be fed through a coaxial connector and transmission line line (eg, microstrip line), and the one-dimensional EBG structures can be embedded at the ground plane edge of the microstrip line located close to the plane ILA. The one-dimensional EBG ground structure can operate as a high impedance surface with a slow wave behavior that controls both the surface wave in the horizontal direction of the ground plane edge and the reflection phase under plane wave illumination. Through the unique electromagnetic characteristics of this one-dimensional EBG ground structure, a small antenna size of 0.22 λ ₀ Х 0.34 λ ₀ is possible, and a wide impedance bandwidth of 810 MHz between 2.24 GHz and 3.11 GHz is possible. Furthermore, the radiation pattern of the ILA integrated with the one-dimensional EBG and beam deflector can be improved without any additional circuitry. By using the distinct response characteristics of the one-dimensional EBG and the deflector, the antenna according to an embodiment of the present invention can provide horizontally-polarized end-fire radiation. The longitudinal radiation performance within the horizontal polarization of the implemented antenna can be improved without the need for a separate additional circuit by integrating the one-dimensional EBG structures and placing the beam deflectors in a small space. In terms of radiation pattern enhancement, the difference in radiation intensity between the horizontal polarization longitudinal gain of 4.0 dBi and the same polarization direction and cross polarization direction of 14.0 dB can be experimentally confirmed. To verify the characteristics of the one-dimensional EBG ground structure in the antenna, reflection coefficient, radiation pattern and field distribution can be reviewed using various antenna types. The ultra-thin, ultra-compact, one-dimensional EBG ground structure can function as a high-impedance surface with low-speed waves. A two-stage beam deflector can be additionally inserted in front of the ILA to enhance the polarization conversion capability.

An antenna device having a one-dimensional electromagnetic band gap ground structure according to an embodiment of the present invention for achieving the above object, the substrate; A ground layer at least partially formed on the substrate; And a planar inverse-L type radiator disposed on one side of the ground layer, wherein a one-dimensional electromagnetic bandgap grounding structure may be built in an edge of the plane radiator side of the ground layer.

According to one aspect, the one-dimensional electromagnetic bandgap ground structure includes a plurality of periodic one-dimensional unit cells, and the plurality of periodic one-dimensional unit cells form one column at the edge of the planar emitter of the ground layer. Can be.

According to one aspect, the one-dimensional electromagnetic bandgap grounding structure operates as a higher impedance surface having a slower wave behavior, compared to an antenna device without the one-dimensional electromagnetic bandgap grounding structure, and further increases according to frequency fluctuations. It can represent a steep change in reflection phase.

According to an aspect, the antenna device may be configured to control a plane wave with a steep reflection phase change at a frequency of 2.4 GHz.

According to one aspect, the one-dimensional electromagnetic bandgap grounding structure operates as a higher impedance surface having a slower wave behavior, as compared to an asymmetric transmission line device without the one-dimensional electromagnetic bandgap grounding structure, resulting in large group delay. By this, the low-speed wave behavior can be exhibited.

According to one aspect, the asymmetric transmission line device may be configured to control a surface wave flowing at a ground plane edge with a large group delay at a frequency of 2.4 GHz. According to one aspect, the radiator is a reversing-L antenna (ILA ), and the antenna device may be configured to secure an impedance bandwidth of a predetermined size or more without an additional circuit by providing the one-dimensional electromagnetic bandgap ground structure and the ILA.

According to one aspect, the antenna device may be configured to form a wave impedance change based on the impedance surfaces of the one-dimensional electromagnetic bandgap ground structure periodically arranged within a predetermined space to further control surface wave control.

According to one aspect, the one-dimensional electromagnetic bandgap ground structure can operate simultaneously as a reflector and a high impedance surface for the emitter.

According to one aspect, the one-dimensional unit cell may include a strip line, a metal patch having a plurality of slit patterns, and a capacitor by spacing between the plurality of unit cells.

According to one aspect, the radiator may be fed through a coaxial connector and a microstrip line.

According to one aspect, the beam deflector may further include a beam deflector disposed on the opposite side of the ground layer and configured to mitigate mutual interference between the radiator and the one-dimensional electromagnetic bandgap ground structure.

According to one aspect, the beam deflector may include a first stage beam deflector disposed on the radiator side and a second stage beam deflector disposed on the opposite side of the radiator.

The disclosed technology can have the following effects. However, since the specific embodiment does not mean that all of the following effects should be included or only the following effects are included, the scope of rights of the disclosed technology should not be understood as being limited thereby.

According to the antenna device according to an embodiment of the present invention described above, by providing a one-dimensional electromagnetic bandgap ground structure, it is possible to control the surface wave and the plane wave at the same time, characterized by broadband and high gain for high-speed and high-capacity communication, For example, a small antenna device capable of improving radiation patterns and providing longitudinal radiation and horizontal polarization without a separate additional circuit such as a balun or a ground plane can be provided. More specifically, it is equipped with a one-dimensional EBG grounding structure with a high-impedance surface characteristic exhibiting low-speed wave behavior in a dual direction, enabling a small antenna size of 0.22 λ ₀ Х 0.34 λ ₀ , and 810 MHz between 2.24 GHz and 3.11 GHz. It can enable a wide impedance bandwidth. Furthermore, the radiation pattern of the ILA integrated with the one-dimensional EBG and beam deflector can be improved without any additional circuitry. By using the distinct response characteristics of the one-dimensional EBG and the deflector, the antenna according to an embodiment of the present invention can provide horizontally-polarized end-fire radiation.

FIG. 1 shows the configuration of a planar ILA having one-dimensional EBG grounding structures, more specifically FIG. 1A shows the overall view of the fabricated antenna and one-dimensional EBG structures and its unit cells, and FIG. 1B shows one-dimensional EBG grounding structures 1A shows the front view of the plane ILA and FIG. 1C shows the rear view of the plane ILA having one-dimensional EBG ground structures.
2 shows the reflection phase of each of the partially grounded FR-4 substrates with or without a one-dimensional EBG structure.
3 shows a configuration for obtaining a group delay of an asymmetric transmission line having a one-dimensional EBG structure.
4 shows group delay of asymmetric transmission lines with or without a one-dimensional EBG structure of impedance characteristics of 50-Ω and 100-Ω transmission lines. Specifically, FIG. 4A shows a group delay of a transmission line of 50-Ω impedance characteristic, and FIG. 4B shows a 100-Ω impedance characteristic.
5 shows the measured reflection coefficients of the antennas.
Figure 6 shows the measured radiation pattern of the antennas at the operating frequency, specifically, Figure 6a is xy-cut (θ = 90°) @ Ephi-polarization, Figure 6b is zx-cut (φ = 0°) @ Ephi-polarization, FIG. 6C shows xy-cut (θ = 90°) @ Etheta-polarization, and FIG. 6D shows zx-cut (φ = 0°) @ Etheta-polarization.
7 shows the electric field distribution of the antennas. More specifically, FIG. 7A is contour plots of antennas, and FIG. 7B shows normalized field distribution across the AB, CD and EF lines of FIG. 7A.
8 shows the configuration of various planar monopole antennas having a one-dimensional EBG structure, specifically, FIG. 8A shows antennas of type #1, and FIG. 8B shows antennas of type #2.
9 shows measured reflection coefficients of various monopole antennas having a fixed one-dimensional EBG structure, and specifically, FIG. 9A shows antennas of type #1 and FIG. 9B shows antennas of type #2.
FIG. 10 shows the measured radiation pattern of the antennas at the operating frequency, specifically, FIG. 10A shows the xy-cut (θ=90°) @ Ephi-polarization of the type #1 antenna, and FIG. 10B shows the type #1 antenna zx-cut (φ = 0°) @ Ephi-polarization, FIG. 10c shows the xy-cut of type #2 antenna (θ = 90°) @ Ephi-polarization, FIG. 10d shows the type #2 antenna's zx-cut ( φ = 0°) @ Ephi-polarization.
11 shows the configuration of a planar ILA having a one-dimensional EBG structure and a deflector. More specifically, FIG. 11A shows a one-stage deflector, FIG. 11B shows a two-stage deflector, FIG. 11C is a front view of a plane ILA having a one-dimensional EBG structure and a two-stage deflector, and FIG. 11D is a one-dimensional EBG structure and two-stage This is a photograph of the back of a flat ILA with a deflector of.
12 shows the measured reflection coefficient of an ILA with a one-dimensional EBG structure and beam deflectors.
13 shows the measured radiation pattern of an ILA with a one-dimensional EBG structure and beam deflectors at operating frequency, specifically, FIG. 13A shows xy-cut (θ = 90°) @ Ephi-polarization, FIG. 13B shows zx -cut (φ = 0°) @ Ephi-polarization, Figure 13c shows xy-cut (θ = 90°) @ Etheta-polarization, Figure 13d shows zx-cut (φ = 0°) @ Etheta-polarization .
14 is a table showing performance comparison of antennas.
15 is a table showing performance comparison of flat antennas having a one-dimensional EBG structure.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may be referred to as a first component. The term and/or includes a combination of a plurality of related described items or any one of a plurality of related described items.

When an element is said to be "connected" or "connected" to another component, it is understood that other components may be directly connected to or connected to the other component, but there may be other components in between. It should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the overall understanding in describing the present invention, the same reference numerals are used for the same components in the drawings, and duplicate descriptions for the same components are omitted.

As previously noted, a small flat antenna featuring broadband and high gain for high-speed and high-capacity communication is urgently needed to overcome the physical threshold characteristics of active RF devices in microwave and millimeter wave applications. In particular, there is an urgent need for element antenna technology of a small array antenna having a wide angle scan range. For example, flat array antennas are used as a representative type of small antennas based on their excellent performance. These antennas are required to have small form factor, wide bandwidth, high gain, wide angle scan range, low cost, simple manufacturing and wide compatibility with various platform environments.

In particular, in 5G applications, a universal antenna design method for adapting to extreme radio environments such as antenna-in-package (AiP), antenna-on-display (AoD), and antenna-on-chip (AoC) They have been known recently. When AiP is implemented on low temperature co-fired ceramics (LTCC) or multi-layer PCBs, three-dimensional cross-loss, a via hole on a feasible scale, is a very decisive issue in antenna performance. On the other hand, the low conductivity metal coated on the display panel in AoD platforms degrades the radiation performance of the antenna despite solving the limited antenna space for mobile platforms. In addition, the concept of AoC based on Si CMOS has a performance problem due to the low resistivity of Si. Accordingly, there is a need for improvements to the general antenna design according to easily accessible manufacturing processes.

Meanwhile, an electromagnetic bandgap (EBG) structure composed of periodic unit cells has been considered in a conventional study of a small antenna. The two main characteristics of EBG structures in antenna applications can be used to artificially adjust the surface impedance and improve antenna performance. One approach is that EBG structures can control surface current or surface wave, so-called surface wave bandgaps, flowing on the ground plane within a specific frequency band due to their high impedance surface. By controlling the surface wave on the ground plane, the slow wave behavior of the EBG structure can minimize the spacing between antenna elements and reduce mutual coupling. Furthermore, the EBG structures in the surface wave bandgap show in-phase reflection characteristics and can reduce the space between the antenna and the EBG structures using slow wave behavior. When the antenna impedance is matched to a specific frequency at which the EBG exhibits a 90° quadratic reflection phase, the antenna with the EBG shows optimum impedance matching and high radiation efficiency. At a 90° reflection phase, the EBG structure also provides overlapping electromagnetic properties between the surface wave bandgap and the input impedance matching frequency bandwidth.

The one-dimensional EBG structure with longitudinal radiation and horizontal polarization can be applied to implement a flat antenna manufactured through a simple PCB process. Since the dipole antenna with a microstrip balun is manufactured for balanced feeding to the radiator, the overall physical length of the antenna is 0.82 λ ₀ or more, and the antenna impedance bandwidth depends on the operating frequency of the balun. The one-dimensional EBG and SRR structures can be inserted between two straight monopole antennas placed in close proximity. The overall physical length of one antenna element is 0.49 λ ₀ , and the antenna impedance bandwidth is limited by the grounding characteristic mode. Furthermore, in order to achieve a robust array performance in which mutual coupling is suppressed within the element shape, it is required that the space between elements is 0.5 λ _{0 or} more. If an auxiliary circuit that limits the antenna impedance bandwidth is not used, additional miniaturization of the antenna element to implement a robust flat array antenna having a wide bandwidth, high gain, and wide scan angle is impossible, and a general antenna design in an extreme radio wave environment is not possible. Cannot be implemented.

The antenna device according to an embodiment of the present invention may be implemented as an inverted-L antenna (ILA) capable of improving radiation patterns integrated with a one-dimensional electromagnetic bandgap (EBG) ground structure and a beam deflector, according to one aspect. Such an antenna device may have longitudinal directional radiation in horizontal polarization. An antenna device according to an embodiment of the present invention, a one-dimensional electromagnetic bandgap (1-D EBG) ground structures, and a two-stage beam deflector to convert the radiation pattern using a reverse-L antenna (ILA) topology It may be implemented as a small antenna having a. The antenna can be fed through a coaxial connector and transmission line line (eg, microstrip line), and the one-dimensional EBG structures can be embedded at the ground plane edge of the microstrip line located close to the plane ILA. The one-dimensional EBG ground structure can operate as a high impedance surface with a slow wave behavior that controls both the surface wave in the horizontal direction of the ground plane edge and the reflection phase under plane wave illumination. Through the unique electromagnetic characteristics of this one-dimensional EBG ground structure, a small antenna size of 0.22 λ ₀ Х 0.34 λ ₀ is possible, and a wide impedance bandwidth of 810 MHz between 2.24 GHz and 3.11 GHz is possible. For example, the one-dimensional electromagnetic bandgap grounding structure according to an aspect of the present invention operates simultaneously as a high-impedance surface having a double-speed low-speed wave behavior, so that the radiator and the one-dimensional electromagnetic bandgap grounding structure are λ ₀ /30 (λ ₀ is spaced apart from each other by a distance equal to or less than the wavelength in the free space, and the total length of the ground having the one-dimensional electromagnetic bandgap structure may be configured within λ ₀ /3.

Furthermore, the antenna device according to an aspect of the present invention may be configured to secure an impedance bandwidth of a predetermined size or more without an additional circuit by having a one-dimensional electromagnetic bandgap grounding structure and an ILA. The radiation pattern of the ILA integrated with the one-dimensional EBG and beam deflector can be improved without any additional circuitry. By using the distinct response characteristics of the one-dimensional EBG and the deflector, the antenna according to an embodiment of the present invention can provide horizontally-polarized end-fire radiation. The longitudinal radiation performance within the horizontal polarization of the implemented antenna can be improved without the need for a separate additional circuit by integrating the one-dimensional EBG structures and placing the beam deflectors in a small space. In terms of radiation pattern conversion, the difference in radiation intensity between the horizontal polarization longitudinal gain of 4.0 dBi and the same polarization direction and cross polarization direction of 14.0 dB can be experimentally confirmed. To verify the characteristics of the one-dimensional EBG ground structure in the antenna, reflection coefficient, radiation pattern and field distribution can be reviewed using various antenna types. The ultra-thin, ultra-compact, one-dimensional EBG ground structure can function as a high-impedance surface with low-speed waves. A two-stage beam deflector can be additionally inserted in front of the ILA to enhance the polarization conversion capability.

In the antenna device according to an aspect of the present invention, the one-dimensional EBG ground structure may be embedded on the ground plane edge of the microstrip line close to the plane ILA to implement radiation pattern transformation. The space between the ILA and the one-dimensional EBG can be arranged within 0.03 λ ₀ , and the one-dimensional EBG ground structure can operate as a high impedance surface with low-speed wave behavior that controls the 90° reflection phase for impedance matching. Since these characteristics of the one-dimensional EBG ground structure can replace additional circuits that can limit the antenna impedance bandwidth, an ILA topology with a one-dimensional EBG ground structure can exhibit a wide bandwidth. To confirm such antenna performance, reflection coefficients and radiation patterns can be compared using various antennas such as ILA without one-dimensional EBG and PIFA without one-dimensional EBG. By examining the near-field distribution, the antenna's one-dimensional EBG ground structure according to one aspect of the present invention can also operate as a high impedance surface exhibiting slow wave behavior controlling surface waves on the ground plane. The antenna performance of various planar monopole configurations can be considered to minimize the interaction between the monopole emitter and the EGB ground structure. Two stages of parasitic rods can be inserted prior to the ILA to improve the high longitudinal radiation gain per electrical unit volume and minimize the offset interference between the EBG and ILA.

One-dimensional EBG ground structure and its electromagnetic characteristics

1 shows the configuration of a planar ILA with one-dimensional EBG ground structures. FIG. 1A shows the overall view of the fabricated antenna and one-dimensional EBG structures and their unit cells, FIG. 1B shows the front view of a planar ILA with one-dimensional EBG grounding structures, and FIG. 1C shows the rear of a planar ILA with one-dimensional EBG grounding structures. Fig. For example, in FIG. 1, w1 = 1.5 mm, w2 = 4 mm, w3 = 3 mm, w4 = 2 mm, w5 = 1.5 mm, L1 = 15 mm, L2 = 3.3 mm, g (slit width & edge-to -edge spacing between EBG cells) = 0.1 mm).

As shown in FIG. 1, an antenna device having a one-dimensional electromagnetic bandgap ground structure according to an embodiment of the present invention includes a substrate 30 and a ground layer 10 formed at least partially on the substrate 30 ) And a planar radiator 20 disposed on one side of the ground layer 10. Here, the one-dimensional electromagnetic bandgap grounding structure 110 may be embedded in an edge of the plane radiator 20 side of the ground layer 10.

According to one aspect, the antenna can be fed through a coaxial connector and a transmission line line (eg, a microstrip line), and the one-dimensional EBG structure 110 is of 4.4 as shown in FIG. 1, for example. It can be embedded in the edge of the partially grounded front 10 of the FR-4 substrate 30 having a relative permittivity and a size of 70 mm x 40 mm x 1 mm.

The one-dimensional electromagnetic bandgap grounding structure 110 includes a plurality of periodic one-dimensional unit cells (eg, 110-1), and the plurality of periodic one-dimensional unit cells are on the plane emitter side edge of the ground layer 10. One column can be formed. A one-dimensional EBG structure 110 having seven periodic cells, including, for example, cells 110-1, for example on the front (radiator side) edge of the ground plane 10 adjacent to the plane ILA 20, It can be included and patterned in one column to operate as a high impedance surface with slow wave behavior. The one-dimensional EBG unit cell 110-1 includes a narrow gap capacitor, which is a capacitor formed by a strip line, a metal patch having a plurality of slender slit patterns, and a gap between the plurality of EBG unit cells. It can contain. Due to PCB manufacturing limitations, the gap between the EBG cells and the width of the slit may be configured to have a minimum value of 0.1 mm.

To examine the effect of a one-dimensional EBG ground structure, the reflection phase of a partially grounded FR-4 substrate can be calculated using a high frequency structure simulation (HFSS) package and simulation strategy.

The one-dimensional electromagnetic bandgap grounding structure 110 according to one aspect of the present invention operates as a higher impedance surface having a slower wave behavior, compared to an antenna device without a one-dimensional electromagnetic bandgap grounding structure, thereby fluctuating frequency. It may represent a steeper change in the reflection phase. In connection, FIG. 2 shows the reflection phase of each of the partially grounded FR-4 substrates with or without a one-dimensional EBG structure. As shown in Figure 2, a substrate comprising a one-dimensional EBG ground structure provides a 90° reflection phase at 2.4 GHz. Substrates that do not have a one-dimensional EBG grounding structure exhibit a 90° reflection phase beyond 3 GHz. When comparing a substrate having a one-dimensional EBG ground structure and a substrate having no one-dimensional EBG ground structure, the calculated reflection phase shows a relatively steeper phase change due to the influence of the one-dimensional EBG ground structure.

For example, within the same size scale of 20 mmХ40 mm, the EBG ground structure can induce a relatively steep phase change due to slow wave behavior at a 90° (quadratic) reflection phase in a plane wave. Optimization of the monopole length (L1 = 15 mm) can be performed according to the -10 dB reflection coefficient criterion for matching of antenna impedance operating at 2.4 GHz where the EBG ground structure exhibits quadratic reflection phase. Therefore, the antenna device according to an aspect of the present invention may be configured to perform plane wave control by operating at a frequency of 2.4 GHz.

는 하기의 수학식 1 과 같이 정의될 수 있다. 3 shows a configuration for obtaining a group delay of an asymmetric transmission line having a one-dimensional EBG structure. As shown in Fig. 3, the slow wave behavior in the horizontal direction of the ground plane edge due to the one-dimensional EBG structure can be verified by the calculated group delay rather than by dispersion analysis. Since the one-dimensional EBG structure is arranged toward one direction in the ground plane edge, the radiation boundary based on the simulation method is more suitable than the unit cell simulation for analysis of variance. Due to the finite one-dimensional array structure in the ground plane, this simulation method is not easy to obtain variance analysis. Alternatively, an ACPS (Asymmetry CoPlanar Strip) Transmission Line (TL) may be disposed on the right side of the ground plane edge to make the wave direction the same as the surface wave of FIG. 1. By using the 2-port S parameter results in this simulation scenario, the group delay according to Equation 1 below can be calculated. The slow wave behavior controlling the surface wave on the ground plane edge can be demonstrated by comparing group delays with or without a one-dimensional EBG structure. Military delay

Can be defined as in Equation 1 below.

는 S₂₁ (또는 S₁₂) 의 위상이고, f 는 주파수를 나타낸다. here,

Is the phase of S ₂₁ (or S ₁₂ ), and f represents the frequency.

For ACPS TL without a one-dimensional EBG grounding structure, the impedance characteristics are designed as 50-Ω and 100-Ω. The ideal port impedance is assigned to the same impedance characteristic of ACPS TL. For the 50-Ω impedance characteristic of ACPS TL, the entire ACPS TL structure is composed of W ₆ of 4 mm and S ₁ of 0.2 mm. In the impedance characteristic of 100-Ω, W ₆ and S ₁ are 3 mm and 1 mm, respectively.

4 shows group delay of asymmetric transmission lines with or without a one-dimensional EBG structure of impedance characteristics of 50-Ω and 100-Ω transmission lines. Specifically, FIG. 4A shows a group delay of a transmission line of 50-Ω impedance characteristic, and FIG. 4B shows a 100-Ω impedance characteristic. As illustrated in FIG. 4, group delays in two impedance characteristics of ACPS TL with or without a one-dimensional EBG grounding structure may be calculated. For both 50-Ω and 100-Ω impedance characteristics, the group delay of ACPS TL without a one-dimensional EBG grounding structure is almost equal to 0.2 ns within the frequency range of 1 GHz to 4 GHz. The group delay of ACPS TL with a one-dimensional EBG ground structure in each impedance characteristic differs depending on the inherent surface impedance of the one-dimensional EBG structure. Nevertheless, the slow wave behavior due to one-dimensional EBG structures can be explained through large group delays.

One-dimensional EBG ground structure and beam Deflector Small size ILA

Reflection coefficient and radiation pattern

5 shows the measured reflection coefficients of the antennas. As shown in FIG. 5, an inverted-L type antenna (ILA) having a one-dimensional EBG ground structure can operate at a frequency of 2.4 GHz. As shown in FIG. 5, ILA without a one-dimensional EBG ground structure and PIFA (planar inverted-F antenna) without a one-dimensional EBG ground structure have the same physical length (L1) to examine the effect of the one-dimensional EBG ground structure. ).

Since the ground planes having no one-dimensional EBG ground structure exhibit a 90° reflection phase after 3 GHz, the ILA without the one-dimensional EBG ground structure operates near 3 GHz. In PIFAs that do not have a one-dimensional EBG grounding structure, due to the fact that both have the same monopole length, the antenna can operate at the same frequency as the ILA with the one-dimensional EBG grounding structure. The ILA with a one-dimensional EBG grounding structure exhibits a reflection coefficient lower than -10 dB, that is, from 2.24 to 3.11 GHz. Despite the relatively steep phase change as shown in Figure 2, the impedance bandwidth of -10 dB of the ILA with a one-dimensional EBG ground structure is wider than that of the other antennas of Figure 3. Thus, an ILA topology having a one-dimensional EBG grounding structure may not have additional circuits that can limit the antenna impedance bandwidth, such as via holes of PIFA, and thus will be an optimal antenna unit element for a wide array antenna. You can. For example, an antenna device according to an aspect of the present invention is provided with a one-dimensional EBG grounding structure and an ILA, thereby further than a PIFA with a shorting pin or a dipole antenna with a balun, without an additional circuit to limit the impedance bandwidth. It can be configured to enable broadband operation.

Figure 6 shows the measured radiation pattern of the antennas at the operating frequency, specifically, Figure 6a is xy-cut (θ = 90°) @ Ephi-polarization, Figure 6b is zx-cut (φ = 0°) @ Ephi-polarization, FIG. 6C shows xy-cut (θ = 90°) @ Etheta-polarization, and FIG. 6D shows zx-cut (φ = 0°) @ Etheta-polarization.

6A and 6B, the radiation pattern in an ILA with a one-dimensional EBG ground structure shows a maximum gain of 2.0 dBi in E _{phi -polarization} considered as horizontal polarization. The antenna according to one aspect of the present invention can achieve high directional patterns in the E _{phi -polarization} toward the end-fire direction (+ x direction) due to the 90° reflection phase of the EBG structure. The radiation pattern of an ILA with a one-dimensional EBG grounding structure exhibits higher directivity than that of other antennas in the longitudinal direction in E _{phi -polarization} . On the other hand, as shown for E _theta -polarization in FIGS. 6C and 6D, the radiation pattern of the ILA having a one-dimensional EBG ground structure is further reduced compared to that of other antennas. The one-dimensional EBG ground structure can help the ILA radiation pattern conversion to occur without additional circuits. ILA with one-dimensional EBG ground structures can provide improved end-fire radiation in horizontal polarization.

Field distribution

The low-speed wave behavior of a one-dimensional EBG ground structure in a small-sized ground plane can be confirmed in the near field distribution using HFSS. Three types of antennas can be activated through a 50-Ω coaxial connector to obtain a near field distribution. To identify the near field within the transverse plane, contour plots (XY-plane) of total electric field distribution located 0.5 mm higher than the patterned ground structures can be observed.

FIG. 7 shows the electric field distribution of the antennas, more specifically, FIG. 7A is the contour plots of the antennas, and FIG. 7B shows the normalized field distribution across the AB, CD and EF lines of FIG. 7A. As shown in FIGS. 7A and 7B, at an operating frequency, an ILA having a one-dimensional EBG grounding structure is rapidly intensive in the AB line, which is a virtual line, than in a virtual line (CD or EF line) of other antennas. ) Contour lines. It can be seen that the wave impedance change at the edge of the ground plane is rapidly formed due to the fact that the high impedance surface at the edge of the one-dimensional EBG ground structure is periodically arranged within a small space. Thus, the one-dimensional EBG ground structure in the near field distribution can be considered as a high impedance surface with slow wave behavior to control the surface wave. That is, the antenna device according to an aspect of the present invention may be configured to form a wave impedance change based on which the impedance surface of the one-dimensional electromagnetic bandgap ground structure is periodically arranged within a predetermined space to perform surface wave control further. have.

A variety of fixed one-dimensional EBG ground structures Monopole Antennas

Various monopole types of ILA samples with fixed one-dimensional EBG ground structures can be fabricated and evaluated in order to design an optimized antenna form with the most efficient performance by placing one-dimensional EBG ground structures behind. Various ILA monopoles can be investigated to change the input impedance of the antenna within a range that does not impair the inherent characteristics of EBGs having the same space between the EBG and the monopole, and can be compared with the antenna according to one aspect of the present invention. Can be.

8 shows the configuration of various planar monopole antennas having a one-dimensional EBG structure, specifically, FIG. 8A shows antennas of type #1, and FIG. 8B shows antennas of type #2. 8A and 8B, type #1 (reverse-"C") and type #2 (rotated "Z") can be compared within a fixed emitter length (L1).

9 shows measured reflection coefficients of various monopole antennas having a fixed one-dimensional EBG structure, more specifically FIG. 9A shows antennas of type #1, and FIG. 9B shows antennas of type #2. Despite the different impedance matching conditions of designed antennas derived from different monopole configurations, the operating frequency of the one-dimensional EBG ground structure within 90±45° reflection phase is still at 2.4 GHz, as shown in FIGS. 9A and 9B. exist. It can be observed that rather than the interaction between the monopole and the EBG, the interaction between the monopole and the ground plane makes the other resonant frequencies near 3.5 GHz stronger.

10 shows the measured radiation pattern of antennas at the operating frequency. Specifically, FIG. 10A shows xy-cut (θ = 90°) @ Ephi-polarization of type #1 antennas, and FIG. 10B shows zx-cut (φ = 0°) @ Ephi-polarization of type #1 antennas, FIG. 10c shows xy-cut (θ = 90°) @ Etheta-polarization of type #2 antennas, and FIG. 10d shows zx-cut (φ = 0°) @ Etheta-polarization of type #2 antennas. At 2.4 GHz in FIGS. 10A-10D, gain fluctuations in the main lobe toward the +x direction due to the interaction between the one-dimensional EBG ground structure and different monopole emitters appear. The one-dimensional EBG ground structure still acts as a high impedance surface and at the same time acts as a reflector, so that the back lobe of the emitter patterns does not fluctuate much. Thus, an ILA with a one-dimensional EBG ground structure according to one aspect of the present invention can achieve an optimized antenna form for efficient antenna performance such as longitudinal radiation and impedance bandwidth in horizontal polarization.

One-dimensional EBG ground structure and beam Deflector Equipped high gain antenna

In the case of a specific array antenna formed in a small space, reduction of mutual coupling between elements of radiators and deflectors is an essential issue for improving the gain of the array antenna. Furthermore, in order to achieve a higher gain of horizontal polarization within a small length (0.34 λ ₀ ) of the antenna and enhance radiation pattern conversion, beam deflectors 911, 913 prior to ILA as shown in FIG. Can be inserted. 11 shows the configuration of a plane ILA having a one-dimensional EBG structure and a deflector, more specifically FIG. 11A shows a one-stage deflector, FIG. 11B shows a two-stage deflector, and FIG. 11C shows a one-dimensional EBG structure and a two-stage deflector The branch is a front view of the planar ILA, and FIG. 11D is a rear view of the planar ILA having a one-dimensional EBG structure and two-stage deflectors.

11A, the antenna device according to an aspect of the present invention is disposed on the opposite side of the ground layer 10 of the radiator 20, and the radiator 20 and the one-dimensional electromagnetic bandgap grounding structure 110 It may further include a beam deflector 911 configured to mitigate mutual interference. According to one aspect, the beam deflector can be a parastic rod. 11B, the beam deflector includes a first stage beam deflector 911 disposed on the side of the emitter 20 and a second stage beam deflector 913 disposed on the opposite side of the emitter 20. can do.

The ILA with a one-dimensional EBG grounding structure has a small volume, and thus can be designed to achieve a high gain per electrical unit volume without involving negative interference between the ILA and the EBG using a beam deflector. According to one aspect, the optimization is characterized by a wide width (W ₇ = 0.05 λ ₀ ), a short length (L ₃ = 0.3 λ ₀ ), and a small spacing (S ₂ = 0.13 λ ₀ ) between the emitter and the beam deflector. Two stages of planar rods can be used as miniature beam deflectors associated with a one dimensional EBG ground structure. The beam deflector may be configured as a parasitic flat bar type having a predetermined space and structure shape provided in an antenna length within λ ₀ /3.

12 shows the measured reflection coefficient of an ILA with a one-dimensional EBG structure and beam deflectors. As illustrated in FIG. 12, the impedance bandwidth of -10 dB of an ILA having a one-dimensional EBG ground structure and two-stage beam deflectors may be relatively reduced than that of an ILA having a one-dimensional EBG ground structure. Despite the mutual effect between the antenna (radiator) and the beam deflectors, the operating frequency can be very finely shifted from 2.4 GHz to 2.36 GHz.

13 shows the measured radiation pattern of an ILA with one-dimensional EBG structure and beam deflectors at operating frequency. Specifically, FIG. 13A shows xy-cut (θ = 90°) @ Ephi-polarization, FIG. 13B shows zx-cut (φ = 0°) @ Ephi-polarization, and FIG. 13C shows xy-cut (θ = 90°). ) @ Etheta-polarization, FIG. 13D shows zx-cut (φ = 0°) @ Etheta-polarization. As shown in FIG. 13, the measured maximum gain at E _{phi -polarization} is 3.4 dBi for an antenna with a first stage deflector and 4.0 dBi for an antenna with a second stage deflector. The radiation patterns show a higher gain in the horizontal polarization toward the longitudinal direction. Thus, the radiation pattern in Etheta-polarization hardly changes due to the weak response of the beam deflectors, while the antenna with the beam deflectors achieves a more desirable radiation pattern transformation towards the end-fire directioin. can do.

Performance Comparison

14 is a table showing performance comparison of antennas. TABLE 1 of FIG. 14 lists the performance of the designed antennas. Despite the reduction in bandwidth due to having two stages of beam deflectors within a small volume, the proposed antenna according to one aspect of the invention provides a wide impedance bandwidth of 530 MHz. The difference in radiation intensity in the co-polarization and cross-polarization directions, which can be used as a reference for radiation pattern conversion, is 14.0 dB or more in the longitudinal direction. With beam deflectors and reflectors operating in a distinct response under polarization, the ILA with a one-dimensional EBG ground structure and two stages of beam deflectors exhibits radiation pattern transformation with broadband characteristics.

15 is a table showing performance comparison of flat antennas having a one-dimensional EBG structure. TABLE II of FIG. 15 provides a performance comparison of flat antennas having a one-dimensional EBG ground structure according to the prior art. A flat ILA having a one-dimensional EBG grounding structure according to an aspect of the present invention may not have any auxiliary circuits that can limit antenna performance, and thus flat antennas having a one-dimensional EBG grounding structure according to the prior art It shows much improved performance compared to. Thus, the antenna according to one aspect of the present invention can be easily applied to various antenna platforms due to small planar configurations that do not include any auxiliary circuits. In addition, the antenna according to an aspect of the present invention can provide high performance such as wide bandwidth, small form factor, and high antenna efficiency.

That is, according to one aspect of the present invention, a small antenna device including a planar ILA in which a radiation pattern can be converted by a one-dimensional EBG ground structure and unique electromagnetic characteristics of a beam deflector can be provided. The electromagnetic properties of the one-dimensional EBG ground structure, characterized by high impedance surfaces with low-speed wave behavior controlling both surface and plane waves, were confirmed by the antenna's performance as previously mentioned. ILA with one-dimensional EBG grounding structure is 0.22 λ ₀ Х 0.34 λ ₀ It can be implemented with a magnitude of 2.0, and it shows a longitudinal gain of 2.0 dBi and a -10 dB impedance matching bandwidth of 870 MHz from 2.24 GHz to 3.11 GHz. By adding two stages of beam deflectors, the ILA with a one-dimensional EBG grounding structure has a longitudinal gain of 4.0 dBi and a co-polarization and cross-polarization direction of 14.0 dB toward the longitudinal direction. polarization). The antenna device according to one aspect of the present invention can be configured to perform higher gain longitudinal radiation, as compared to an antenna device without a beam deflector, by having a beam deflector.

The ILA with a one-dimensional EBG grounding structure and a beam deflector has desirable performance while having a small volume, so the antenna according to one aspect of the present invention is a platform of various materials featuring wide bandwidth, high gain and wide scan angle. It can be utilized in a small array antenna based on. Furthermore, by using the unique characteristics of a one-dimensional EBG grounding structure, it can be applied to a MIMO antenna concept 5G non-standalone (NSA) full-display metal handset featuring small size and wide bandwidth.

Although described above with reference to the drawings and examples, the scope of protection of the present invention is not meant to be limited by the drawings or examples, and those skilled in the art of the present invention described in the claims below It will be understood that various modifications and changes can be made to the present invention without departing from the spirit and scope.

The present invention described above has been described based on a series of functional blocks, but is not limited by the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes without departing from the spirit of the present invention. It will be apparent to those skilled in the art that the present invention is possible.

Combinations of the above-described embodiments are not limited to the above-described embodiments, and various forms of combinations may be provided as well as the above-described embodiments according to implementation and/or needs.

In the above-described embodiments, the methods are described based on a flowchart as a series of steps or blocks, but the present invention is not limited to the order of steps, and some steps may occur in a different order than the steps described above or simultaneously. have. In addition, those of ordinary skill in the art are aware that the steps shown in the flowcharts are not exclusive, other steps may be included, or one or more steps in the flowcharts may be deleted without affecting the scope of the present invention. You will understand.

The above-described embodiments include examples of various aspects. It is not possible to describe all possible combinations for representing various aspects, but a person skilled in the art will appreciate that other combinations are possible. Accordingly, the present invention will be said to include all other replacements, modifications and changes that fall within the scope of the following claims.

Claims (11)

An antenna device having a one-dimensional electromagnetic band gap ground structure,
Board;
A ground layer at least partially formed on the substrate; And
Including a planar inverted-L-type radiator (ILA) disposed on one side of the ground layer,
The plane radiator side edge of the ground layer has a one-dimensional electromagnetic bandgap grounding structure built-in, which can replace a power supply additional circuit in which impedance bandwidth is limited, and a PIFA (Planar Inverted-F Antenna) with a shorting pin Alternatively, the antenna is configured as the planar inverse-L type radiator (ILA) to enable wider driving than a dipole antenna with a balun.
The one-dimensional electromagnetic bandgap ground structure includes a plurality of periodic one-dimensional unit cells, and the plurality of periodic one-dimensional unit cells form one column at the edge of the plane emitter of the ground layer,
The one-dimensional unit cell, the antenna device, each comprising a narrow gap capacitor (narrow gap capacitor) formed by the gap between the plurality of unit cells and a plurality of slits and a metal patch having a plurality of thin slit patterns formed inside the patch .
delete According to claim 1,
The one-dimensional electromagnetic band gap ground structure,
Compared to the antenna device without the one-dimensional electromagnetic bandgap grounding structure, it operates as a higher impedance surface having a slower wave behavior, thereby inducing a steeper reflection phase change according to frequency fluctuation and performing plane wave control. Configured, antenna device.
delete The method of claim 3,
The antenna device operates in a horizontal direction of the edge of the one-dimensional electromagnetic bandgap ground structure, and operates as a higher impedance surface having a slower wave behavior compared to an antenna device having no one-dimensional electromagnetic bandgap ground structure, thereby controlling surface wave control. An antenna device, configured to be performable.
The method of claim 5,
The one-dimensional electromagnetic band gap ground structure,
Simultaneously acting as a high-impedance surface with double-direction low-speed wave behavior, the radiator and the one-dimensional electromagnetic bandgap ground structure are spaced apart from each other by a distance of λ ₀ /30 (λ ₀ is the wavelength in free space), and the one-dimensional electromagnetic band An antenna device in which the total length of a grounding material having a gap structure is within λ ₀ /3.
delete According to claim 1,
The emitter,
The one-dimensional electromagnetic band gap ground structure is built-in, and the antenna device is fed through a coaxial connector and a microstrip transmission line line without a feeding part additional circuit.
According to claim 1,
And a beam deflector disposed on the opposite side of the radiator and the ground layer and configured to mitigate mutual interference between the radiator and the one-dimensional electromagnetic bandgap ground structure.
The method of claim 9,
The antenna device is configured to perform higher gain longitudinal radiation in comparison to an antenna device without the beam deflector by having the beam deflector.
The method of claim 10,
The beam deflector includes a first stage beam deflector disposed on the radiator side and a second stage beam deflector disposed on the opposite side of the radiator, and a predetermined space and structure shape provided in an antenna length within λ ₀ /3 The antenna device, consisting of a parasitic flat bar type.

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