A broadband matching network and antenna

Abstract

The embodiment of the present application discloses an antenna and a broadband matching network, the broadband matching network comprises: a passive impedance matching circuit and a non-Foster impedance matching circuit. The passive impedance matching circuit has a first port and a second port; the second port is connected with a coaxial port. The non-Foster impedance matching circuit has an input end and an output end; the input end is connected with the first port, and the output end is connected with a feed end of the antenna. The passive impedance matching circuit comprises at least one capacitor and at least one inductor which are connected with each other; and the non-Foster impedance matching circuit comprises at least one transistor and at least one capacitor, inductor or resistor which are connected with each other. The antenna of the embodiment of the present application realizes impedance matching between a coaxial cable and the feed end of the antenna by using the broadband matching network, realizes the broadband design of the antenna, and provides convenience for the miniaturization of the antenna.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a broadband matching network and antenna. Background Technology

[0002] As an omnidirectional antenna, the monopole antenna possesses excellent radiation performance and is widely used in many communication devices. Ground radios, vehicle-mounted radios, soldier backpacks, ships, and aircraft are all equipped with various types of monopole antennas. In the VHF / UHF bands, omnidirectional monopole antennas are generally quite large, which is not conducive to antenna concealment during installation. For airborne blade antennas, their aerodynamic shape also limits their performance. Therefore, broadband miniaturization of monopole antennas is necessary. Simultaneously achieving broadband, miniaturized, and high-gain monopole antennas is challenging. Reconciling these three conflicting goals and designing the optimal antenna structure and performance is the key issue in designing broadband miniaturized monopole antennas. Summary of the Invention

[0003] In view of the above problems, the purpose of this invention is to provide an antenna and a broadband matching network, thereby achieving broadband, miniaturization and high gain of the antenna.

[0004] According to one aspect of the present invention, a broadband matching network is provided, comprising:

[0005] A passive impedance matching circuit has a first port and a second port; the second port is connected to a coaxial port.

[0006] A non-Foster impedance matching circuit has an input terminal and an output terminal; the input terminal is connected to the first port, and the output terminal is connected to the feed terminal of the antenna;

[0007] The passive impedance matching circuit includes at least one capacitor and at least one inductor connected to each other; the non-Foster impedance matching circuit includes at least one transistor and at least one capacitor, inductor or resistor connected to each other.

[0008] Preferably, the non-Foster impedance matching circuit includes:

[0009] A first resistor, a second resistor, a first inductor, and a first capacitor are connected in series between the antenna feed terminal and the first port of the passive impedance matching circuit.

[0010] A first circuit unit and a second circuit unit; both the first and second circuit units include a transistor, a third resistor and a fourth resistor connected in series between a voltage source and ground, a second inductor connected between the junction of the third and fourth resistors and the base of the transistor, a third inductor connected between the collector of the transistor and the voltage source, and a fourth inductor connected between the emitter of the transistor and ground; wherein, the first circuit unit further includes a fourth capacitor connected between the base of the transistor and the feed terminal of the antenna, and a fifth capacitor connected between the junction of the second resistor and the first inductor and the emitter of the transistor; the second circuit unit further includes a sixth capacitor connected between the collector of the transistor and the first port of the passive impedance matching circuit, and a seventh capacitor connected between the junction of the first and second resistors and the emitter of the transistor; and

[0011] The eighth capacitor is connected between the collector of the transistor in the first circuit unit and the base of the transistor in the second circuit unit.

[0012] Preferably, both the first circuit unit and the second circuit unit further include a fifth resistor; the fifth resistor and the second inductor are connected in series between the connection point of the third resistor and the fourth resistor and the base of the transistor.

[0013] Preferably, both the first circuit unit and the second circuit unit further include a third capacitor connected between the connection point of the voltage source and the third inductor and ground.

[0014] Preferably, the passive impedance matching circuit includes:

[0015] A ninth capacitor and a fifth inductor are connected in series between the first port and the second port;

[0016] The tenth capacitor is connected between the first port and ground;

[0017] The eleventh capacitor is connected between the second port and ground;

[0018] The sixth inductor is connected between the junction of the ninth capacitor and the fifth inductor and ground.

[0019] According to another aspect of the present invention, an antenna is provided, comprising:

[0020] Flooring;

[0021] The top loading plate is positioned face-to-face with the grounding plate.

[0022] A radiator is connected between the top loading plate and the grounding plate, and the radiator includes a power supply terminal.

[0023] Based on the broadband matching network described above.

[0024] Preferably, the top loading plate is circular or elliptical in shape.

[0025] Preferably, the top loading plate is arranged parallel to the grounding plate.

[0026] Preferably, the radiator includes a connecting portion connected to the top loading plate, a first gradient portion, and a second gradient portion connected to the grounding plate, wherein the first gradient portion is located between the connecting portion and the second gradient portion;

[0027] The length of the end of the first gradient portion near the top loading plate is greater than the length of the end of the first gradient portion away from the top loading plate; the length of the end of the second gradient portion away from the ground plate is greater than the length of the end of the second gradient portion near the ground plate.

[0028] Preferably, the length change rate of the second gradient portion from the end near the ground plate to the end away from the ground plate is greater than the length change rate of the first gradient portion from the end away from the top loading plate to the end near the top loading plate.

[0029] The antenna and broadband matching network provided by this invention utilizes a non-Foster impedance matching circuit and a passive impedance matching circuit connected in series between the output port of the coaxial cable and the feed terminal of the antenna to optimize the impedance matching of the antenna feed input, reduce the voltage standing wave ratio of the antenna, improve the antenna performance, and realize the broadband and miniaturization of the antenna.

[0030] The design incorporates an elliptical top loading plate to further extend the antenna bandwidth and improve its miniaturization. Attached Figure Description

[0031] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0032] Figure 1 A front view of an antenna according to an embodiment of the present invention is shown;

[0033] Figure 2 A three-dimensional structural schematic diagram of an antenna according to an embodiment of the present invention is shown;

[0034] Figure 3 A schematic diagram of the structure of a broadband matching network according to an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram of a passive impedance matching circuit according to an embodiment of the present invention is shown;

[0036] Figure 5 The voltage standing wave ratio (VSWR) of an antenna without a broadband matching network according to an embodiment of the present invention is shown.

[0037] Figure 6 The voltage standing wave ratio (VSWR) of an antenna with a loaded broadband matching network according to an embodiment of the present invention is shown.

[0038] Figure 7A , Figure 7B , Figure 7C and Figure 7D The gain curve of an antenna with a loaded broadband matching network according to an embodiment of the present invention is shown as a function of frequency. Detailed Implementation

[0039] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0040] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0041] Figure 1 A front view of an antenna 100 according to an embodiment of the present invention is shown. Figure 2 A three-dimensional structural schematic diagram of an antenna 100 according to an embodiment of the present invention is shown. In this embodiment, the antenna 100 is a monopole antenna.

[0042] Please also refer to Figure 1 and Figure 2 The antenna 100 of this embodiment includes: a ground plane 110, a feed terminal 120, a radiator 130, and a top loading plate 140. The top loading plate 140 and the ground plane 110 are arranged face-to-face. The radiator 130 is connected between the top loading plate 140 and the ground plane 110, and the radiator 130 includes the feed terminal 120. In this embodiment, both the radiator 130 and the top loading plate 140 are all-metal structures.

[0043] In this embodiment, the top loading plate 140 is circular or elliptical in shape.

[0044] In this embodiment, the top loading plate 140 is arranged parallel to the grounding plate 110.

[0045] The radiator 130 is preferably a left-right symmetrical structure, and the feed point connecting the feed end 120 and the radiator 130 is located at the middle of the bottom end of the radiator 130.

[0046] A through hole is provided at the center of the grounding plate 110 so that the power supply terminal 120 passes through the through hole and connects to the radiator 130 to provide power supply information.

[0047] Specifically, the radiator 130 includes a connecting portion connected to the top loading plate 140, a first gradient portion, and a second gradient portion connected to the grounding plate 110, wherein the first gradient portion is located between the connecting portion and the second gradient portion.

[0048] The length W4 of the end of the first gradient portion near the top loading plate 140 is greater than the length W3 of the end of the first gradient portion away from the top loading plate 140; the length W3 of the end of the second gradient portion away from the ground plate 110 is greater than the length W2 of the end of the second gradient portion near the ground plate 110.

[0049] The rate of change of length of the second gradient section from the end closest to the ground plane to the end furthest from the ground plane is greater than the rate of change of length of the first gradient section from the end furthest from the top loading plate to the end closest to the top loading plate. Both the lengths of the first and second gradient sections are linearly gradients.

[0050] The radiator 120 is a plate-shaped structure that stands upright on the grounding plate 110. Its width gradually increases from bottom to top (with the orientation of the grounding plate 110 in the attached figure as an illustrative reference). It includes three width nodes, with the widths W2, W3, and W4 increasing sequentially. The bottom width W2 of the radiator 120 can be selected from 15 mm to 17 mm, the middle width W3 of the radiator 120 can be selected from 59 mm to 61 mm, and the top width W4 of the radiator 120 can be selected from 79 mm to 80 mm.

[0051] The connecting part of the radiator 120 is rectangular, and the overall width of the connecting part is consistent with W4. The thickness of the radiator 120 can be selected from 1 mm to 2 mm.

[0052] In this embodiment of the invention, the top loading plate 140 is connected to the top end of the radiator 120. The top loading plate 140 can be elliptical in shape, with its major axis length L being 115 mm to 122 mm, its minor axis length W1 being 58 mm to 60 mm, and its thickness H4 being 1 mm to 2 mm.

[0053] In the radiator 130, the height H1 from the top of the second tapered section to the ground plane 110 can be selected as 29 mm to 31 mm, the height H2 from the top of the first tapered section to the ground plane 110 can be selected as 49 mm to 51 mm, and the distance H3 from the top surface of the ground plane 110 to the bottom surface of the top loading plate 140 can be selected as 68 mm to 70 mm. The overall height of the antenna 100 is H3 + H4 = 0.056λ0, the length is the major axis length L of the top loading plate 140 = 0.096λ0, and the width is the minor axis length W1 of the top loading plate 140 = 0.048λ0, where λ0 is the electromagnetic wave wavelength corresponding to the lowest operating frequency of the antenna 100. The thickness of the radiator 130 and the top loading plate 140 can be the same, and the material can be a conductive metal.

[0054] Figure 3 A schematic diagram of the structure of a broadband matching network 200 according to an embodiment of the present invention is shown. Figure 3 As shown, the broadband matching network 200 of this embodiment is designed based on a non-Foster impedance matching circuit. The broadband matching network 200 includes a passive impedance matching circuit and a non-Foster impedance matching circuit. The passive impedance matching circuit has a first port and a second port, the second port being connected to a coaxial port. The non-Foster impedance matching circuit has an input terminal and an output terminal; the input terminal of the non-Foster impedance matching circuit is connected to the first port, and the output terminal of the non-Foster impedance matching circuit is connected to the feed terminal of the antenna.

[0055] The passive impedance matching circuit includes at least one capacitor and at least one inductor connected to each other; the non-Foster impedance matching circuit includes at least one transistor and at least one capacitor, inductor or resistor connected to each other.

[0056] In this embodiment, the coaxial port is a 50-ohm coaxial port.

[0057] The passive impedance matching circuit achieves impedance matching through at least one capacitor and at least one inductor.

[0058] The non-Foster impedance matching circuit achieves impedance matching through at least one transistor and at least one capacitor, inductor, or resistor.

[0059] Specifically, the non-Foster impedance matching circuit includes: resistor R1, resistor R2, inductor L1, and capacitor C1 connected in series between the antenna feed terminal and the first port of the passive impedance matching circuit; a first circuit unit 210, a second circuit unit 220, and capacitor C4.

[0060] The first circuit unit 210 includes resistors R13 and R12 connected in series between the voltage source Vdc and ground; inductor L12 connected between the voltage source Vdc and the collector of transistor M1; inductor L11 and resistor R11 connected in series between the base of transistor M1 and the connection point of resistors R12 and R13; capacitor C11 connected between the connection point of voltage source Vdc and inductor L12 and ground; capacitor C12 connected between the base of transistor M1 and the antenna feed terminal 202; inductor L13 connected between the emitter of transistor M1 and ground; and capacitor C15 connected between the emitter of transistor M1 and the connection point of resistor R2 and inductor L1.

[0061] The second circuit unit 220 includes resistors R23 and R22 connected in series between the voltage source Vdc and ground, inductor L22 connected between the voltage source Vdc and the collector of transistor M2, inductor L21 and resistor R21 connected in series between the base of transistor M2 and the connection point of resistors R22 and R23, capacitor C21 connected between the connection point of voltage source Vdc and inductor L22 and ground, inductor L23 connected between the emitter of transistor M2 and ground, capacitor C25 connected between the emitter of transistor M2 and the connection point of resistors R2 and R1, and capacitor C26 connected between the collector of transistor M2 and the input terminal 321 of passive impedance matching circuit 230.

[0062] Capacitor C4 is connected between the collector of transistor M1 and the base of transistor M2.

[0063] Figure 4 A schematic diagram of a passive impedance matching circuit according to an embodiment of the present invention is shown. As shown, the passive impedance matching circuit 230 of the present invention includes a capacitor C31 and an inductor L31 connected in series between a first port 231 and a second port 232, a capacitor C32 connected between the first port 231 and ground, a capacitor C33 connected between the second port 232 and ground, and an inductor L32 connected between the connection point of capacitor C31 and inductor L31 and ground.

[0064] The impedance of the final feed terminal 120 is 50Ω.

[0065] Figure 5 The voltage standing wave ratio (VSWR) of an antenna 100 without a broadband matching network 200 according to an embodiment of the present invention is shown. The horizontal axis represents wavelength, flow represents the lowest radiation frequency of the antenna 100, fhigh represents the highest radiation frequency of the antenna 100, f1 to f6 represent intermediate frequency points with sequentially increasing frequencies, and the vertical axis represents the VSWR, where fhigh:flow = 4:1. As shown in the figure, the VSWR of the antenna 100 without a broadband matching network 200 according to the embodiment of the present invention is much greater than 2, making it impractical.

[0066] Figure 6 The voltage standing wave ratio (VSWR) of an antenna 100 equipped with a broadband matching network 200 according to an embodiment of the present invention is shown. As shown in the figure, the VSWR of the antenna 100 equipped with the broadband matching network 200 according to the embodiment of the present invention is less than 2 across the entire frequency band, and the ratio of the highest frequency fhigh to the lowest frequency flow is equal to 4, which can meet the requirements of shortwave and ultra-shortwave communication and has good performance.

[0067] Figure 7A , Figure 7B , Figure 7C and Figure 7DThe diagram illustrates the gain of an antenna 100 equipped with a broadband matching network 200 according to an embodiment of the present invention, as a function of frequency. Figure 7A For θ = 60°, Antenna full-band gain in the direction of the direction, Figure 7B For θ = 60°, Antenna full-band gain in the direction of the direction, Figure 7C For θ = 90°, Antenna full-band gain in the direction of the direction, Figure 7D For θ = 90°, The antenna gain across the entire frequency band in the direction of the signal. As shown in the figure, the antenna 100 with the loaded broadband matching network 200 in this embodiment of the invention gradually increases in gain from low frequency to high frequency, and at θ = 60°, Direction and θ = 60° The full-band gain in the directional direction is between -18dB and 2dB, at θ = 90°. Direction and θ = 90° The full-band gain in the directional direction is between -18dB and -4dB. Therefore, the antenna 100 of this invention has good gain across the entire frequency band, meeting the design requirements. θ is the angle on the horizontal plane. The angle is the vertical angle.

[0068] The antenna of this invention employs a non-Foster impedance matching circuit as the basis for designing a broadband matching network. The input of this broadband matching network is connected to a 50Ω coaxial port, and the output is connected to the antenna's feed terminal. This broadband matching network achieves impedance matching between the antenna's feed terminal and the 50Ω coaxial port, thereby realizing the antenna's wide bandwidth. The broadband matching network of this invention also incorporates a passive impedance matching circuit to further improve impedance matching performance, while simultaneously reducing energy consumption, lowering the antenna's voltage standing wave ratio (VSWR), and optimizing antenna performance.

[0069] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A broadband matching network, characterized in that, include: A passive impedance matching circuit having a first port and a second port; The second port is connected to the coaxial port; A non-Foster impedance matching circuit has an input terminal and an output terminal; the input terminal is connected to the first port, and the output terminal is connected to the feed terminal of the antenna; The passive impedance matching circuit includes at least one capacitor and at least one inductor connected to each other, and the non-Foster impedance matching circuit includes at least one transistor and at least one capacitor, inductor, or resistor connected to each other. The non-Foster impedance matching circuit includes: A first resistor, a second resistor, a first inductor, and a first capacitor are connected in series between the antenna feed terminal and the first port of the passive impedance matching circuit. First circuit unit and second circuit unit; both the first circuit unit and the second circuit unit include a transistor, a third resistor and a fourth resistor connected in series between the voltage source and ground, a second inductor connected between the connection point of the third resistor and the fourth resistor and the base of the transistor, a third inductor connected between the collector of the transistor and the voltage source, and a fourth inductor connected between the emitter of the transistor and ground. The eighth capacitor is connected between the collector of the transistor in the first circuit unit and the base of the transistor in the second circuit unit.

2. The broadband matching network according to claim 1, wherein, The first circuit unit further includes a fourth capacitor connected between the base of the transistor and the feed terminal of the antenna, and a fifth capacitor connected between the connection point of the second resistor and the first inductor and the emitter of the transistor; the second circuit unit further includes a sixth capacitor connected between the collector of the transistor and the first port of the passive impedance matching circuit, and a seventh capacitor connected between the connection point of the first resistor and the second resistor and the emitter of the transistor.

3. The broadband matching network according to claim 2, characterized in that, The first circuit unit and the second circuit unit also include a fifth resistor; the fifth resistor and the second inductor are connected in series between the connection point of the third resistor and the fourth resistor and the base of the transistor.

4. The broadband matching network according to claim 3, characterized in that, The first circuit unit and the second circuit unit also include a third capacitor connected between the connection point of the voltage source and the third inductor and ground.

5. The broadband matching network according to claim 1 or 2, wherein, The passive impedance matching circuit includes: A ninth capacitor and a fifth inductor are connected in series between the first port and the second port; The tenth capacitor is connected between the first port and ground; The eleventh capacitor is connected between the second port and ground; The sixth inductor is connected between the junction of the ninth capacitor and the fifth inductor and ground.

6. An antenna, characterized in that, include: Flooring; The top loading plate is positioned face-to-face with the grounding plate. A radiator is connected between the top loading plate and the grounding plate, and the radiator includes a power supply terminal. The broadband matching network according to any one of claims 1 to 5.

7. The antenna according to claim 6, characterized in that: The top loading plate is circular or elliptical in shape.

8. The antenna according to claim 6, characterized in that: The top loading plate is arranged parallel to the grounding plate.

9. The antenna according to claim 6, characterized in that: The radiator includes a connecting portion connected to the top loading plate, a first gradient portion, and a second gradient portion connected to the ground plate, wherein the first gradient portion is located between the connecting portion and the second gradient portion; The length of the end of the first gradient portion near the top loading plate is greater than the length of the end of the first gradient portion away from the top loading plate; the length of the end of the second gradient portion away from the ground plate is greater than the length of the end of the second gradient portion near the ground plate.

10. The antenna according to claim 9, characterized in that: The rate of change of length of the second gradient section from the end near the ground plate to the end away from the ground plate is greater than the rate of change of length of the first gradient section from the end away from the top loading plate to the end near the top loading plate.

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