L-band Small-Size Stacked Microstrip Antenna for Missile-Borne Applications

Abstract

The present invention provides an L-band small-size stacked microstrip antenna for missile-borne applications, belonging to the technical field of microwave communication. It solves the technical problems of relatively high profile height and too large planar size existing in the design of existing microstrip antennas applied to missiles. The technical solution is as follows: It includes a thin substrate and a thick substrate, a circular metal main patch located on the thin substrate respectively, U-shaped parasitic metal patches arranged in a distributed manner and U-shaped parasitic metal patches, rectangular parasitic metal patches and rectangular parasitic metal patches respectively arranged on the top of the thick substrate. The circular metal main patch is close to one side of the U-shaped parasitic metal patch, and a coaxial probe feed is provided on the lower surface of the thin substrate, and a metal floor is provided on the lower surface of the thin substrate. The beneficial effect of the present invention is that the present invention is applicable to an L-band small-size stacked microstrip antenna for missile-borne applications covering the L-band of 1.45 GHz - 1.55 GHz.

Description

Technical Field

[0001] The present invention relates to the field of microwave communication technology, and particularly to an L-band small-sized stacked microstrip antenna for missile-borne applications. Background Art

[0002] In recent years, the continuous improvement of the requirements for missile performance in modern high-tech wars has prompted missile-borne antennas to face higher design requirements. For example, in order to reduce the influence of the antenna shape on the missile's air resistance and improve the stability of the antenna during the missile flight, the missile-borne antenna is required to have as small an area as possible, with a planar size ≤ 0.2×0.2λ 1 2 , where λ 1 is the wavelength in air at the center operating frequency of the antenna, and the profile is thin, with a profile height ≤ 0.04λ 1 . At the same time, it is required that the antenna can be embedded in the missile body to achieve conformal with the missile body, and the periphery of the antenna is the metal boundary of the missile body. Due to its advantages such as low cost, low profile, easy planar integration, and easy conformal, the microstrip patch antenna is widely used in industries such as aerospace and communication, and is an excellent choice for realizing missile-borne antennas. Currently, under the above harsh limiting conditions, that is, the planar size ≤ 0.2×0.2λ 1 2 , the profile height ≤ 0.04λ 1 , and the periphery of the antenna is the metal boundary of the missile body, there is no effective solution in the industry for the broadband design of missile-borne microstrip antennas with a relative bandwidth > 5%. Traditional broadband microstrip antenna designs generally face the following problems more or less: 1. The size is too large, ≥ 0.2×0.2λ 1 2 ; 2. The profile height is relatively high, ≥ 0.04λ 1 ; 3. It does not meet the metal boundary conditions around the antenna. In a high-dynamic and complex electromagnetic environment, a low-profile, small-sized missile-borne antenna embedded in a metal missile body is an important component for realizing information interaction between high-speed flight targets and ground control consoles, and its performance directly affects the success or failure of communication links and wireless controls. Therefore, the research on the broadband design of missile-borne antennas that meet the above limiting conditions has both important theoretical significance and high engineering application value.

[0003] Currently, the proposed microstrip antennas mainly face the technical problems of too large size (≥ 0.2×0.2λ 1 2 ) and relatively high profile height (≥ 0.04λ 1 ), and most of the existing designs do not consider using metal walls around to simulate the missile-borne environment, so the existing technologies cannot solve the actual application problems of current missile-borne antennas. Summary of the Invention

[0004] The object of the present invention is to provide an L-band small-sized stacked microstrip antenna for missile-borne applications, which is applicable to the L-band small-sized stacked microstrip antenna for missile-borne applications covering the L-band of 1.45 GHz - 1.55 GHz.

[0005] The inventive concept of the present invention is as follows: The present invention proposes an L-band small-sized stacked microstrip antenna for missile-borne applications. The antenna design of the present invention mainly solves the problems existing in the design of microstrip antennas applied to missiles, such as relatively high profile height and too large planar size. First, a thin substrate is placed on a metal floor, and a circular microstrip patch antenna is designed on the thin substrate to provide the first resonance point within the target frequency band. Secondly, two U-shaped parasitic metal patches are introduced on one side of the original circular metal main patch, bringing the second resonance point within the target frequency band. Then, a thick substrate is added directly above the thin substrate, and two U-shaped parasitic metal patches arranged distributively are placed on the top of the thick substrate. The two U-shaped parasitic metal patches together provide two resonance modes, the single circular metal main patch provides the fourth resonance mode, and the combination of the two circular metal main patches generates the third resonance mode. It should be noted that simulating the missile-borne embedded environment, the entire antenna structure is wrapped by a copper box, and the bottom radiation patch cannot radiate energy from all around, and the energy can only be radiated from the top path, which results in a strong coupling between the bottom patch and the top patch. In this design, by greatly increasing the thickness ratio of the top substrate to the bottom substrate to 10:1, a good weak coupling between the top mode and the bottom mode is achieved. In addition, a U-shaped slot is introduced on each of the main patch and a rectangular parasitic metal patch at the top to further tune the antenna impedance matching, achieving an improvement in bandwidth.

[0006] To achieve the above-mentioned invention object, the technical solution adopted by the present invention is specifically as follows: An L-band small-sized stacked microstrip antenna for missile-borne applications, comprising a thin substrate, a thick substrate located above the thin substrate, a circular metal main patch and distributively arranged U-shaped parasitic metal patches located on the thin substrate respectively, rectangular parasitic metal patches and rectangular parasitic metal patches respectively arranged on the top of the thick substrate, the circular metal main patch being close to one side of the U-shaped parasitic metal patch and having a coaxial probe feed provided on the lower surface of the thin substrate, and a metal floor provided on the lower surface of the thin substrate;

[0007] It further includes a metal wall located outside the thin substrate and the thick substrate for simulating the missile-borne environment.

[0008] Furthermore, the radio frequency excitation signal is fed into the antenna from the bottom, and the antenna structure located thereon is fed through the coaxial probe feed.

[0009] Furthermore, the antenna is arranged with two layers of ceramic substrates, namely the first layer of ceramic substrate and the second layer of ceramic substrate. The first layer of ceramic substrate is a thin substrate, and a circular metal main patch is placed on the top of the thin substrate as the main patch to generate the first resonance point. Two U-shaped parasitic metal patches and the U-shaped parasitic metal patch introduced on one side of the circular main patch located on the thin substrate constitute the second resonance point.

[0010] Furthermore, the second layer of ceramic substrate is a thick substrate. The thick substrate is located directly above the thin substrate, and two rectangular parasitic metal patches and the rectangular parasitic metal patch arranged distributively are placed on its top. The two rectangular parasitic metal patches and the rectangular parasitic metal patch provide two resonance modes, and a single rectangular parasitic metal patch or the rectangular parasitic metal patch provides the fourth resonance mode. The two rectangular parasitic metal patches and the rectangular parasitic metal patch in combination constitute the third resonance mode. A U-shaped groove is etched on the circular metal main patch and the top rectangular parasitic metal patch as inductive loading to cancel the antenna capacitance reactance to obtain better impedance matching.

[0011] Furthermore, the thickness ratio of the thick substrate to the thin substrate is 10:1.

[0012] Furthermore, two U-shaped parasitic metal patches and the U-shaped parasitic metal patch and the circular metal main patch are introduced on the thin substrate; two rectangular parasitic metal patches and the rectangular parasitic metal patch are introduced on the thick substrate to construct four resonance modes, and the broadband coverage of the target frequency band is achieved by regulating the coupling between the modes.

[0013] Furthermore, a U-shaped groove is etched on the circular metal main patch on the thin substrate and a rectangular parasitic metal patch on the top thick substrate as inductive loading to cancel the antenna capacitance reactance and obtain a matched impedance.

[0014] Furthermore, the overall height of the antenna is 0.0345λ 1 ; the unit planar size is 0.175λ 1 ×0.175λ 1 2 , where λ 1 is the wavelength in free space at 1.5 GHz.

[0015] The present invention adopts a scheme of coupling an additional resonator to introduce a new mode. The entire antenna is wrapped by a peripheral metal wall to simulate the missile-borne environment. This design arranges two layers of substrates. The first layer of ceramic substrate is a thin substrate, and three radiation patches are placed on its top. Among them, the annular metal main patch serves as the main patch, generating the first resonance point at 1.44 GHz. Two U-shaped parasitic metal patches on one side of the main patch provide the second resonance point at 1.46 GHz. The second layer of substrate is a thick substrate, which is located directly above the thin substrate. Two rectangular parasitic metal patches arranged distributively are placed on the top of the thick substrate. The two U-shaped parasitic metal patches together provide two resonance modes, and a single rectangular parasitic metal patch provides the fourth resonance mode. The combination of the two rectangular parasitic metal patches generates the third resonance mode, which are 1.5 GHz and 1.54 GHz respectively. In addition, U-shaped slots are etched on the main patch and the top rectangular parasitic metal patch as inductive loading to cancel the antenna capacitive reactance to obtain better impedance matching. Finally, the present invention has an extremely small planar size ≤ 0.2×0.2λ 1 2 and an extremely low profile height ≤ 0.04λ 1 Under such conditions, the stacked multi-patch technology is introduced. Three patches are introduced at the bottom layer and two patches are introduced at the top layer to construct four resonance modes, realizing broadband coverage in the target frequency band of 1.45 GHz - 1.55 GHz.

[0016] The present invention adopts a design scheme of a broadband microstrip antenna realized by coupling multiple parasitic structures. The structure is compact and has a small planar size of the radiation unit. The planar size of the radiation unit is 35 mm × 35 mm (0.175λ 1 × 0.175λ 1 2 ~λ 1 @1.5 GHz), and the profile height is 6.9 mm (0.0345λ 1 ~λ 1 @1.5 GHz). Under this structure, the proposed antenna design has the advantages of simple structure, small size, low profile, and easy and flexible adjustment of each frequency point.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The existing traditional missile-borne antenna technology often results in an overly large planar size (≥ 0.2×0.2λ 1 2 ) and a relatively high profile height (≥ 0.04λ 1) Technical problems such as narrow bandwidth (≤5%); the design of the present invention can effectively make up for the defects in the above technologies, and provide a design method for a microstrip missile-borne antenna with both small planar size and low profile. Four modes are introduced within 1.45 GHz - 1.55 GHz to achieve the coverage of the target frequency band; the overall profile height of the antenna of the present invention is only 6.9 mm (~0.0345λ 1 @1.5 GHz); the unit planar size is 35 mm × 35 mm (0.175λ 1 ×0.175λ 1 ~λ 1 @1.5 GHz).

[0019] 2. In the design of the present invention, within an extremely small planar size (≤0.2 × 0.2λ 1 2 ) and an extremely low profile height (≤0.04λ 1 ), the stacked multi-patch technology is introduced. Three patches are introduced at the bottom layer and two patches are introduced at the top layer to construct four resonant modes, achieving broadband coverage of the target frequency band.

[0020] 3. In the design of the present invention, the entire antenna is surrounded by the metal structure of the missile body. The bottom radiation patch cannot radiate energy to the surroundings, and the energy can only be radiated from the top path, which results in a strong coupling between the bottom patch and the top patch. In this design, by greatly increasing the thickness ratio of the top substrate to the bottom substrate to about 10:1, good weak coupling between the top mode and the bottom mode is achieved.

[0021] 4. In the present invention, an etched U-shaped groove is used as inductive loading on the main patch on the thin bottom substrate and a rectangular patch on the thick top substrate to cancel the antenna capacitive reactance to obtain better impedance matching.

[0022] 5. The antenna design of the present invention can cover the frequency band of 1.45 GHz - 1.55 GHz, but is not limited to the frequency band of 1.45 GHz - 1.55 GHz. This design technology can be applied to other frequency bands in the L band. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention.

[0024] Figure 1 FIG. is a schematic structural diagram of an L-band small-size stacked microstrip antenna for missile-borne applications of the present invention.

[0025] Figure 2 FIG. is a curve graph of the simulated results of |S11| and gain of the antenna unit of the present invention.

[0026] Figure 3 This is the curve graph of the input impedance simulation result of the antenna unit of the present invention.

[0027] Figure 4 This is the two-dimensional simulation radiation pattern of this antenna unit;

[0028] Among them, (a) is the simulation radiation pattern at 1.44 GHz; (b) is the simulation radiation pattern at 1.46 GHz; (c) is the simulation radiation pattern at 1.5 GHz; (d) is the simulation radiation pattern at 1.54 GHz. Detailed implementation manners

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Embodiment 1

[0031] Refer to Figures 1 to 4 , the technical solution provided in this embodiment is a small-sized stacked microstrip antenna in the L band for missile-borne applications. A small-sized stacked microstrip antenna in the L band for missile-borne applications is characterized by including a thin substrate 9, a thick substrate 3 located above the thin substrate 9, a circular metal main patch 8, U-shaped parasitic metal patches 5 and U-shaped parasitic metal patches 6 arranged distributively on the thin substrate 9, a rectangular parasitic metal patch 1 and a rectangular parasitic metal patch 2 respectively arranged on the top of the thick substrate 3. The circular metal main patch 8 is close to one side of the U-shaped parasitic metal patch 6, and a coaxial probe feed 7 is arranged on the lower surface of the thin substrate 9, and a metal floor 10 is arranged on the lower surface of the thin substrate 9;

[0032] It further includes a metal wall 4 located outside the thin substrate 9 and the thick substrate 3 for simulating the missile-borne environment.

[0033] Further, the radio frequency excitation signal is fed into the antenna from the bottom, and the antenna structure located thereon is fed through the coaxial probe feed 7.

[0034] Further, the antenna is respectively arranged with two layers of ceramic substrates, namely the first layer of ceramic substrate and the second layer of ceramic substrate. The first layer of ceramic substrate is the thin substrate 9. A circular metal main patch 8 is placed on the top of the thin substrate 9 as the main patch to generate the first resonance point. Two U-shaped parasitic metal patches 5 and U-shaped parasitic metal patches 6 introduced on one side of the circular main patch 8 located on the thin substrate 9 constitute the second resonance point.

[0035] Further, the second-layer ceramic substrate is a thick substrate 3, which is located directly above the thin substrate 9. Two rectangular parasitic metal patches 1 and 2 arranged distributively are placed on its top. The two rectangular parasitic metal patches 1 and 2 provide two resonance modes, a single rectangular parasitic metal patch 1 or 2 provides the fourth resonance mode, and the combination of the two rectangular parasitic metal patches 1 and 2 constitutes the third resonance mode. A U-shaped groove is etched on the annular metal main patch 8 and the top rectangular parasitic metal patch 2 as inductive loading to cancel the antenna capacitance reactance to obtain better impedance matching.

[0036] Further, the thickness ratio of the thick substrate 3 to the thin substrate 9 is 10:1.

[0037] Further, two U-shaped parasitic metal patches 5 and 6 and an annular metal main patch 8 are introduced on the thin substrate 9; two rectangular parasitic metal patches 1 and 2 are introduced on the thick substrate 3 to construct four resonance modes, and the broadband coverage of the target frequency band is achieved by regulating the coupling between the modes.

[0038] Further, a U-shaped groove is etched on the annular metal main patch 8 on the thin substrate 9 and a rectangular parasitic metal patch 2 on the top-layer thick substrate 3 as inductive loading to cancel the antenna capacitance reactance and obtain a matched impedance.

[0039] Further, the overall height of the antenna is 0.0345λ 1 ; the unit planar size is 0.175λ 1 ×0.175λ 1 2 where λ 1 is the wavelength in free space at 1.5 GHz.

[0040] Embodiment 2

[0041] Based on Embodiment 1, this embodiment provides a small-sized stacked microstrip antenna for missile-borne applications. The simulation software used is HFSS. Its antenna structure is as Figure 1 shown. The dielectric constant of the dielectric substrate used in this embodiment is 25, and the loss tangent is 0.005; the overall profile height is 6.9 mm (~0.0345λ 1 ~λ 1 @1.5 GHz); the unit planar size is 35 mm × 35 mm (0.175λ 1 ×0.175λ 1 ~λ 1 @1.5 GHz); λ 1is the wavelength in free space at 1.5 GHz; the reflection coefficient and gain of the antenna element are as Figure 2 shown, with |S 11 | ≤ -10 dB as the standard, the impedance bandwidth ranges from 1.45 GHz to 1.55 GHz (relative bandwidth is 6.7%), achieving the coverage of the target frequency band within the L band. Figure 3 is the input impedance of the antenna element. Figure 4 is the two-dimensional simulation radiation pattern of this antenna element. Among them, (a) is the simulation radiation pattern at 1.44 GHz, (b) is the simulation radiation pattern at 1.46 GHz, (c) is the simulation radiation pattern at 1.5 GHz, and (d) is the simulation radiation pattern at 1.54 GHz.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An L-band small-size stacked microstrip antenna for missile-borne applications, characterized in that: It comprises a thin substrate (9), a thick substrate (3) located above the thin substrate (9), an annular metal main patch (8) located on the thin substrate (9) and a U-shaped parasitic metal patch (5) and a U-shaped parasitic metal patch (6) arranged in a distributed manner, a rectangular parasitic metal patch (1) and a rectangular parasitic metal patch (2) respectively arranged on the top of the thick substrate (3), the annular metal main patch (8) being close to one side of the groove of the U-shaped parasitic metal patch (6), a coaxial probe feed (7) being provided on the lower surface of the thin substrate (9), and a metal floor (10) being provided on the lower surface of the thin substrate (9); It also includes a metal wall (4) located on the periphery of the thin substrate (9) and the thick substrate (3) and used for simulating a missile-carrying environment.

2. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 1, characterized in that: The radio frequency excitation signal is fed into the bottom of the antenna and the antenna structure located thereon is fed through the coaxial probe feed (7).

3. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 1, characterized in that: The antenna is provided with two layers of ceramic substrates, namely a first layer of ceramic substrate and a second layer of ceramic substrate, wherein the first layer of ceramic substrate is a thin substrate (9), a ring-shaped metal main patch (8) is placed on the top of the thin substrate (9) as a main patch, generating a first resonance point, and two U-shaped parasitic metal patches (5) and (6) introduced on one side of the ring-shaped main patch (8) on the thin substrate (9) constitute a second resonance point.

4. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 3, characterized in that: The second ceramic substrate is a thick substrate (3), and the thick substrate (3) is located directly above the thin substrate (9). Two distributedly arranged rectangular parasitic metal patches (1) and (2) are placed on the top of the thick substrate. The two rectangular parasitic metal patches (1) and (2) provide two resonance modes. A single rectangular parasitic metal patch (1) or a rectangular parasitic metal patch (2) provides a fourth resonance mode. The combination of the two rectangular parasitic metal patches (1) and (2) constitutes a third resonance mode. U-shaped grooves are etched on the annular metal main patch (8) and the rectangular parasitic metal patch (2) on the top as inductive loads to offset the antenna capacitive reactance to obtain better impedance matching.

5. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 4, characterized in that: The thickness ratio of the thick substrate (3) to the thin substrate (9) is 10:

1.

6. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 5, characterized in that: Two U-shaped parasitic metal patches (5) and (6) as well as a ring-shaped metal main patch (8) are introduced on the thin substrate (9); two rectangular parasitic metal patches (1) and (2) are introduced on the thick substrate (3), so as to construct four resonant modes, and the coupling between the modes is regulated to achieve broadband coverage of the target frequency band.

7. The L-band small-size stacked microstrip antenna for missile-borne applications according to claim 1, characterized in that: The overall height of the antenna is 0.0345λ1; the unit plane size is 0.175λ1×0.175λ1 2 , λ1 is the wavelength in free space at 1.5 GHz.

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