An airborne dual-frequency blade antenna

Abstract

The present invention provides an airborne dual-frequency blade-shaped antenna in the field of aviation airborne antenna technology, comprising a blade-shaped radome; a radiator PCB is inserted into the cavity of the radome, a metal base plate is provided at the bottom, a radio frequency connector is connected to the metal base plate, and the radiator PCB, the metal base plate and the radio frequency connector are grounded together through a grounding lug; a first radiator unit and a second radiator unit of different resonant frequencies are engraved on the surface of the radiator PCB, and the combined input ports of the frequency signals of the two radiator units share a radio frequency connector through a connecting line. The present invention adopts distributed parameters and introduces a microstrip inductor structure on an antenna radiator circuit board, adopts a specific antenna shape and arrangement, realizes two different resonant units and impedance matching, and shares a radio frequency port, thereby improving the performance reliability of the airborne antenna and reducing the weight and construction difficulty of the on-board installation.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation airborne antennas, and more specifically, relates to an airborne dual-frequency blade-shaped antenna. Background Art

[0002] The Emergency Locator Transmitter (ELT) system is mainly composed of a transmitter device and an airborne antenna. The transmitter device is installed in the aircraft cabin, and the 406MHz and 121.5MHz radio frequency signals are manually or automatically triggered when the aircraft is in distress. The airborne antenna is installed on the top of the aircraft fuselage. After a hole is opened in the fuselage, it is connected to the transmitter in the cabin through an RF cable. After being stimulated by the signal from the transmitter, the upper hemisphere transmits a 406MHz radio signal toward the COSPAS communication satellite, and transmits a 121.5MHz radio signal omnidirectionally in the form of broadcasting.

[0003] The ELT antenna is an airborne antenna used for emergency positioning. It is a passive dual-frequency knife-shaped structure. In addition to meeting the general airworthiness requirements for airborne equipment, it should also have the characteristics of high reliability and distress survivability.

[0004] The existing airborne multi-frequency blade antenna technology has at least the following problems:

[0005] The airborne multi-frequency antenna contains multiple radiating poles. Due to the size limitation of the blade-shaped antenna, previous cases have added resistors, capacitors, and inductors to multiple radiating poles in the antenna circuit, and used matching circuits to reduce the antenna's resonant frequency and achieve impedance matching at the antenna feeder port. This antenna pole design uses resistors, capacitors, and inductors, which reduces performance reliability and survivability in the complex environment where airborne antennas are installed and used.

[0006] Similarly, in the improved airborne multi-frequency antenna of the prior art, although the use of RC inductor electronic devices is reduced in the radiating pole circuit design, the radiating pole units of different frequencies do not have a physical common circuit structure in the circuit design, which results in each radiating pole being provided with an RF connection port. The airborne antenna is installed on the outside of the fuselage, and the use of two or more RF connectors will increase the number of openings in the fuselage, thereby damaging the fuselage structure and increasing the difficulty of construction. In addition, two or more RF cables must be arranged between the transmitter or receiver and the airborne antenna, which will increase the weight of the aircraft and the complexity of wiring. Summary of the invention

[0007] The purpose of the present invention is to address the above shortcomings and provide an airborne dual-frequency blade-shaped antenna, which realizes two resonant units and impedance matching of two different frequencies and shares a radio frequency port; improves the performance reliability of the airborne antenna and reduces the weight and construction difficulty of installation on the aircraft.

[0008] To achieve the above object, the present invention is implemented by the following technical solutions:

[0009] The invention discloses an airborne dual-frequency blade-shaped antenna, comprising a blade-shaped antenna cover;

[0010] A radiator PCB is inserted into the cavity of the antenna cover, a metal base plate is provided at the bottom, a radio frequency connector is connected to the metal base plate, and the radiator PCB, the metal base plate and the radio frequency connector are grounded together through a grounding ear piece;

[0011] The surface of the radiating pole PCB is engraved with a first radiating pole unit and a second radiating pole unit with different resonance frequencies, and the combined input ports of the frequency signals of the two radiating pole units share a radio frequency connector through a connecting line.

[0012] Furthermore, foam material is filled between the antenna cover and the radiation pole PCB.

[0013] Furthermore, the metal base plate is fixedly connected to the bottom of the radiating pole PCB.

[0014] Furthermore, the first radiating pole unit includes a main radiating pole and a strip microstrip line and a rectangular microstrip line connected in parallel to the main radiating pole; a first radiating unit tuning slot is arranged above the main radiating pole; the first radiating pole unit modulates its resonant frequency by changing the size of the first radiating unit tuning slot, and realizes impedance matching by changing the size of the strip microstrip line and the rectangular microstrip line; the second radiating pole unit includes a main radiating pole, a second microstrip line and a second radiating pole branch connected in series; the second radiating pole unit modulates its resonant frequency by changing the size of the second microstrip line and the second radiating pole branch, and realizes impedance matching by changing the size of the second microstrip line, the strip microstrip line and the rectangular microstrip line.

[0015] Furthermore, the main radiation pole and the second radiation pole branch are respectively engraved on the lower part and the upper part of the same surface of the radiation pole PCB, and the first radiation unit tuning gap is located between the main radiation pole and the second radiation pole branch.

[0016] Furthermore, the main radiating pole is arranged along the side of the lower part of the radiating pole PCB, the strip microstrip line is on the same plane as the main radiating pole and is connected to the side of the main radiating pole away from the antenna cover; the rectangular microstrip line is engraved on the side of the radiating pole PCB opposite to the main radiating pole, and is connected to the main radiating pole through a micro-through hole.

[0017] Furthermore, the second radiating pole branch is arranged along the edge of the upper part and the top of the radiating pole PCB, and extends inwardly in the form of a bending line structure.

[0018] Furthermore, the second microstrip line is a serpentine line, which is engraved on the side of the radiating pole PCB opposite to the main radiating pole, and is connected to the main radiating pole and the second radiating pole branch through a micro-through hole.

[0019] Furthermore, one end of the grounding ear piece is embedded in the RF connector, and the upper surface of the other end is electrically overlapped with the radiating pole PCB, and the lower surface is electrically overlapped with the metal base plate.

[0020] Furthermore, the radiating pole PCB is a high-frequency epoxy board with double-sided copper cladding.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention adopts distributed parameters and introduces a microstrip inductor structure on an antenna radiation pole circuit board, adopts a specific antenna shape and arrangement, realizes two different resonant units and impedance matching, and shares a radio frequency port, thereby improving the performance reliability of the airborne antenna and reducing the weight and construction difficulty of the on-board installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A front view of an airborne dual-frequency blade antenna provided by an embodiment of the present invention;

[0024] Figure 2 A rear view of an airborne dual-band blade antenna provided by an embodiment of the present invention;

[0025] Figure 3 A voltage standing wave ratio diagram of a simulated airborne dual-frequency blade antenna according to an embodiment;

[0026] Figure 4 A first radiation pole unit pattern of the simulated airborne dual-frequency blade antenna described in the embodiment;

[0027] Figure 5 A second radiation pole unit pattern of the simulated airborne dual-frequency blade antenna described in the embodiment;

[0028] In the figure: 1. Antenna cover; 2. Foam; 3. Radiating pole PCB; 4. Metal base plate; 5. RF connector; 6. Connecting line; 7. Main radiating pole; 8. First radiating unit tuning gap; 9. Second microstrip line; 10. Second radiating pole branch; 11. Grounding ear; 12. Strip microstrip line; 13. Rectangular microstrip line. DETAILED DESCRIPTION

[0029] Traditional airborne dual-band or multi-band antennas, when multiple radiating pole units share a radio frequency input port, usually use resistors, capacitors, and inductors to build a centimeter network circuit to perform tuning and impedance matching between different frequencies. This solution requires soldering more electronic components on the circuit board, and the process is relatively cumbersome, which also has a certain impact on the environmental applicability and performance reliability of the airborne antenna.

[0030] The present invention abandons the traditional design concept of airborne dual-frequency or multi-frequency antennas, adopts distributed parameters on an antenna radiation pole circuit board (in the microwave frequency band, with the difference of signal operating frequency, each position of the signal transmission line will present different parasitic inductance, parasitic capacitance and parasitic resistance effects.) and introduces a microstrip inductor structure. After special antenna shape processing, two different resonant units and impedance matching are realized, and a radio frequency port is shared; the performance reliability of the airborne antenna is improved, and the weight and construction difficulty of the on-board installation are reduced.

[0031] The preferred embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings and specific examples.

[0032] Example 1

[0033] The present invention provides an airborne dual-frequency blade antenna, such as Figure 1 As shown, it includes a radome 1, foam 2, a radiating pole PCB (printed circuit board) 3, a metal base plate 4 and a radio frequency connector 5.

[0034] like Figure 1 As shown, in this embodiment, the external antenna cover 1 is a knife-shaped structure, forming a cavity inside. The antenna cover 1 is installed outside the antenna to protect the internal antenna structure and reduce wind resistance; the radiating pole PCB 3 is inserted into the cavity of the antenna cover 1, and the flexible foam 2 is filled between the antenna cover 1 and the radiating pole PCB 3. The covering structure limits the spatial freedom of the radiating pole PCB 3, and the flexible filler also plays an anti-impact and vibration reduction role, thereby improving the stability of antenna transmission.

[0035] In this embodiment, the metal base plate 4 is installed at the bottom of the antenna to support and fix the radiating pole PCB 3, so that the PCB board remains upright and inserted into the antenna cover 1, further improving the stability of the antenna transmission direction.

[0036] In this embodiment, the RF connector 5 is attached to the metal base plate 4 by means of nuts, the upper surface of the embedded grounding ear piece 11 is electrically overlapped with the radiating pole PCB 3, and the lower surface is electrically overlapped with the metal base plate 4, so that the antenna circuit signal ground and the antenna housing ground are shared, and the induced voltage generated by the lightning effect and high-speed electrostatic friction is discharged to the surface of the fuselage, thereby improving the reliability of the antenna performance and the environmental applicability.

[0037] The size of the radiating poles is different for different resonant frequencies. In order to reduce the size of the blade-shaped antenna structure, compactly utilize the internal space, and avoid the use of RLC electronic components, the present invention engraves a radiating pole circuit with two frequencies on a circuit board, namely a first radiating pole unit and a second radiating pole unit. The combined input ports of the frequency signals of the two radiating pole units share a radio frequency connector 5 through a connecting line 6. The radiating pole PCB 3 is a high-frequency epoxy board with double-sided copper cladding. The radiating pole layout adopts an inverted F type. The wiring size of the radiating pole is limited by 1 / 4 wavelength of the resonant frequency. For the low-frequency resonant pole, a bending line is used to effectively reduce the structural size inside and outside the antenna.

[0038] Example 2

[0039] This embodiment provides an airborne dual-frequency blade-shaped antenna. Based on Embodiment 1, the technical solution is further refined to improve the technical effect. For contents not fully described in this embodiment, please refer to Embodiment 1.

[0040] like Figure 1 and Figure 2 As shown, in this embodiment, the first radiating pole unit includes a main radiating pole 7 and a strip microstrip line 12 and a rectangular microstrip line 13 connected in parallel to the main radiating pole 7; the second radiating pole unit includes a main radiating pole 7, a second microstrip line 9 and a second radiating pole branch 10 connected in series.

[0041] Specifically, in the present embodiment, a main radiating pole 7 is engraved along the side of the lower portion of the front side of the radiating pole PCB 3, a strip microstrip line 12 is connected in parallel on the right side of the main radiating pole 7, and a rectangular microstrip line 13 passing through a micro-through hole to the back side, and a first radiating unit tuning slot 8 is arranged obliquely above the main radiating pole 7. The resonant frequency of the first radiating pole unit is modulated by changing the length and width of the first radiating unit tuning slot 8 so that it operates at a high frequency, and impedance matching is achieved by changing the length and width of the strip microstrip line 12 and the rectangular microstrip line 13.

[0042] Specifically, in this embodiment, the second radiating pole branch 10 is engraved on the upper part of the front of the radiating pole PCB 3, arranged along the upper and top edges of the radiating pole PCB, and extends inward in the form of a meander line structure, so as to extend the current path of the RF signal and make its operating frequency low. The second radiating pole branch 10 is a resonant branch derived from the main radiating pole 7, and a second microstrip line 9 is connected in series between the main radiating pole 7 and the second radiating pole branch 10. The second microstrip line 9 is engraved on the back of the radiating pole PCB 3. Through the serpentine routing, on the one hand, the length of the second radiating pole unit is greatly increased, thereby shortening the pole arm and reducing the resonant frequency; on the other hand, it is equivalent to a low-pass inductance, so that the low-frequency signal derived from the main radiating pole 7 passes through, and the high-frequency signal generated by the first radiating pole unit does not pass through, so that the two frequency signals work on separate resonant units respectively. The second radiating pole unit completes the tuning of the second resonant frequency by changing the length and width of the second microstrip line 9 , and realizes impedance matching by changing the length and width of the second microstrip line 9 , the strip microstrip line 12 and the rectangular microstrip line 13 .

[0043] In this embodiment, the main radiating pole 7 is a physical common combining structure of the first radiating pole unit and the second radiating pole unit, and the impedance matching of the two frequency signals is achieved respectively by adjusting the length and width of the strip microstrip line 12 connected in parallel in the main radiating pole 7 and the rectangular microstrip line 13 from the micro-through hole to the back, and the length and width structure of the serpentine second microstrip line 9 connected in series in the second radiating pole branch 10. The combined input ports of the two signals share the RF connector 5 through the connecting line 6.

[0044] This embodiment performs a model simulation on the designed airborne dual-frequency blade antenna, and the simulation results are as follows: Figure 3 , Figure 4 and Figure 5 shown. Figure 3 It is the standing wave ratio diagram. The simulation results show that the standing wave ratios of the two radiating units are less than 1.5:1, which meets the standing wave ratio requirements of this antenna. Figure 4 It is the directivity diagram of the first radiating unit. Within the plane angle range of 0-360° at three typical elevation angles of 30°, 40°, and 50°, the antenna gain value is within the range of 0-5dB, meeting the gain requirements of the first radiating unit of the antenna; Figure 5 It is the directivity diagram of the second radiating unit. In the plane angle range of 0-360° at three typical elevation angles of 0°, 10°, and 20°, the antenna gain value is in the range of -2-2dB, which meets the gain requirements of the second radiating unit of the antenna. The above results show that the VSWR (voltage standing wave ratio) and direction of the two radiating pole units at the target resonant frequency meet the performance requirements of the airborne antenna.

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0047] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Without departing from the scope and technical principles of the described embodiments, many modifications and changes are obvious to those of ordinary skill in the art, and these modifications and changes should also be regarded as the scope of protection of the present invention.

Claims

1. An airborne dual-frequency blade antenna, characterized in that: A radome (1) comprising a knife-shaped structure; A radiator PCB (3) is inserted into the cavity of the antenna cover (1), a metal base plate (4) is provided at the bottom, a radio frequency connector (5) is connected to the metal base plate (4), and the radiator PCB (3), the metal base plate (4) and the radio frequency connector (5) are grounded via a grounding lug (11); A first radiating pole unit and a second radiating pole unit with different resonance frequencies are engraved on the surface of the radiating pole PCB (3); the combined input ports of the frequency signals of the two radiating pole units share a radio frequency connector (5) via a connecting line (6).

2. The airborne dual-frequency blade antenna according to claim 1, characterized in that: Foam material (2) is filled between the radome (1) and the radiating pole PCB (3).

3. The airborne dual-frequency blade antenna according to claim 1, characterized in that: The metal bottom plate (4) is fixedly connected to the bottom of the radiating pole PCB (3).

4. The airborne dual-frequency blade antenna according to claim 1, characterized in that: The first radiating pole unit comprises a main radiating pole (7) and a strip microstrip line (12) and a rectangular microstrip line (13) connected in parallel to the main radiating pole (7); a first radiating unit tuning slot (8) is arranged above the main radiating pole (7); the first radiating pole unit modulates the resonant frequency by changing the size of the first radiating unit tuning slot (8), and achieves impedance matching by changing the size of the strip microstrip line (12) and the rectangular microstrip line (13); The second radiating pole unit comprises a main radiating pole (7), a second microstrip line (9) and a second radiating pole branch (10) connected in series; the second radiating pole unit modulates its resonant frequency by changing the sizes of the second microstrip line (9) and the second radiating pole branch (10), and achieves impedance matching by changing the sizes of the second microstrip line (9), the strip microstrip line (12) and the rectangular microstrip line (13).

5. The airborne dual-frequency blade antenna according to claim 4, characterized in that: The main radiating pole (7) and the second radiating pole branch (10) are respectively engraved on the lower part and the upper part of the same surface of the radiating pole PCB (3); and the first radiating unit tuning slot (8) is located between the main radiating pole (7) and the second radiating pole branch (10).

6. The airborne dual-frequency blade antenna according to claim 5, characterized in that: The main radiating pole (7) is arranged along the side edge of the lower part of the radiating pole PCB (3); the strip microstrip line (12) is coplanar with the main radiating pole (7) and connected to a side of the main radiating pole (7) away from the radome (1); The rectangular microstrip line (13) is engraved on a side of the radiating pole PCB (3) opposite to the main radiating pole (7), and is connected to the main radiating pole (7) via a micro-through hole.

7. The airborne dual-frequency blade antenna according to claim 5, characterized in that: The second radiating pole branch (10) is arranged along the edge of the upper part and the top of the radiating pole PCB (3), and extends inwardly in the form of a bending line structure.

8. The airborne dual-frequency blade antenna according to claim 5, characterized in that: The second microstrip line (9) is a serpentine line, engraved on a side of the radiating pole PCB (3) opposite to the main radiating pole (7), and connected to the main radiating pole (7) and the second radiating pole branch (10) via a micro-through hole.

9. The airborne dual-frequency blade antenna according to claim 1, characterized in that: One end of the grounding ear piece (11) is embedded in the radio frequency connector (5), and the upper surface of the other end is electrically overlapped with the radiating pole PCB (3), and the lower surface is electrically overlapped with the metal bottom plate (4).

10. The airborne dual-frequency blade antenna according to claim 1, characterized in that: The radiating pole PCB (3) is a high-frequency epoxy board with copper cladding on both sides.

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