An extremely wideband frequency-independent antenna and a method of operating the same

Abstract

The application discloses an extremely ultra-wideband frequency-independent antenna and a working method thereof. The antenna comprises a monopole radiator, a special-shaped gradually-changing curved surface mode converter and a TEM mode resonator. The TEM mode resonator comprises an inner core and an outer core. The inner core is sleeved in the outer core and coaxial with the outer core. A gap between the inner core and the outer core is filled with a non-conductive medium. The special-shaped gradually-changing curved surface mode converter is a curved surface body structure obtained by radially stretching a special-shaped gradually-changing curved surface with a preset thickness. The special-shaped gradually-changing curved surface is formed by rotating and scanning an axis of the monopole radiator around a special-shaped gradually-changing curve. The monopole radiator is electrically connected with the inner core of the TEM mode resonator. The outer core of the TEM mode resonator is electrically connected with a narrow aperture of the special-shaped gradually-changing curved surface mode converter. The application has the advantages that a receiving antenna with extremely ultra-wideband, frequency-independent response characteristics and an omnidirectional difference beam pattern is provided.

Description

Technical Field

[0001] This invention relates to the field of communication antenna technology, specifically to an ultra-wideband frequency-independent antenna and its operating method. Background Technology

[0002] Antennas are key devices in the field of communications for transmitting and receiving electromagnetic wave signals. Modern communication systems are developing towards ultra-wideband and anti-interference capabilities, placing high demands on antennas in terms of frequency bandwidth and anti-interference performance. Ultra-wideband (UWB) frequency-independent antennas offer advantages such as wide bandwidth, high data transmission rate, strong anti-interference capability, good data security, high positioning accuracy, and low power consumption. They can also address the spectrum shortage problem in today's high-speed wireless communications, improving spectrum utilization. UWB antennas have already found considerable application in modern civilian communication equipment and play an irreplaceable role in military radar and electronic countermeasures systems. Due to the various advantages of UWB antennas, their commercial application prospects are promising, and the actual demand is quite urgent; therefore, the academic community continues to promote the rapid development of UWB antenna technology.

[0003] Since most existing global, intercontinental, and regional communication systems rely on geostationary satellites, the antenna beams of terrestrial communication systems must be pointed towards these satellites. Geostationary satellites are located directly above the equator, and the antenna beams of communication systems at different latitudes in both the Northern and Southern Hemispheres must point upwards towards the equator, with the angle between the beam and the ground decreasing gradually with increasing latitude. To meet the communication coverage requirements of mid-latitude regions, the antenna elevation pattern needs a null point in the normal direction and a certain differential slope, with the maximum beam value pointing towards the high-angle region, and the azimuth pattern being an omnidirectional beam.

[0004] In summary, an ultra-wideband frequency-independent antenna is particularly important in modern communication systems, military radar systems, or electronic countermeasures systems. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to provide a receiving antenna with ultra-wideband, frequency-independent response characteristics, and omnidirectional differential beam pattern.

[0006] This invention solves the above-mentioned technical problems through the following technical means: an ultra-wideband frequency-independent antenna, comprising a monopole radiator, an irregularly shaped gradient surface mode converter, and a TEM mode resonator. The TEM mode resonator includes an inner core and an outer core, with the inner core nested inside the outer core and the two coaxial. The gap between the inner core and the outer core is filled with a non-conductive dielectric. The irregularly shaped gradient surface mode converter is a curved surface structure obtained by radially stretching an irregularly shaped gradient surface to a predetermined thickness. The irregularly shaped gradient surface is formed by rotating and scanning an irregularly shaped gradient curve around the axial direction of the monopole radiator. The monopole radiator is electrically connected to the inner core of the TEM mode resonator, and the outer core of the TEM mode resonator is electrically connected to the narrow aperture of the irregularly shaped gradient surface mode converter.

[0007] Furthermore, the materials of the monopole radiator, the irregularly shaped gradient surface mode converter, and the TEM mode resonator are all conductive materials.

[0008] Furthermore, the shape of the monopolar radiator can be a cylinder, a square column, a polygonal column, a stepped cylinder, a stepped square column, or a stepped polygonal column.

[0009] Furthermore, the irregular gradient curve is an exponential curve, a parabola, a cut elliptic curve, or a cut hyperbola.

[0010] Furthermore, the trajectory of the irregular gradient curve rotating around the axis of the monopolar radiator is circular, square, or polygonal, and the upper and lower aperture shapes formed after scanning are circular, square, or polygonal.

[0011] Furthermore, the inner core of the TEM mode resonator has the same envelope shape as the outer core, but different dimensions. The envelope shape of the inner core and the outer core can be cylindrical, square, polygonal, stepped cylindrical, stepped square, or stepped polygonal. The outer core of the TEM mode resonator is a hollow column, and the shape of the hollow region inside the outer core can be cylindrical, square, polygonal, stepped cylindrical, stepped square, or stepped polygonal.

[0012] Furthermore, the cross-sectional dimensions of the inner core and the outer core satisfy the following relationship:

[0013]

[0014] Among them, R in R represents a dimension of the cross-sectional shape of the inner core. out Z0 represents a certain dimension of the cross-sectional shape of the outer core, Z0 represents the characteristic impedance of the TEM mode resonator, and ε represents the characteristic impedance of the TEM mode resonator. rIt represents the relative permittivity of the non-conductive medium filling the gap between the inner and outer cores.

[0015] Furthermore, the non-conductive medium is one or more of air, foam, polytetrafluoroethylene, and honeycomb.

[0016] Furthermore, the electrical connection between the monopole radiator and the inner core of the TEM mode resonator, and the electrical connection between the outer core of the TEM mode resonator and the narrow aperture of the irregularly shaped gradually curved surface mode converter, are smooth, closed, and continuous.

[0017] This invention also provides a method for operating an ultra-wideband frequency-independent antenna. Electromagnetic waves enter a TEM mode resonator via an RF connector. Electromagnetic resonance occurs in the TEM mode resonator to generate TEM mode electromagnetic waves, which are then transmitted along the TEM mode resonator axis to the narrow aperture surface of a gradient surface mode converter. In the TEM mode resonator, the electric field direction always points radially towards the outer core. When the electromagnetic wave begins to propagate along the axis of the monopole radiator from the narrow aperture surface of the gradient surface mode converter, the electric field direction changes from the monopole radiator to the gradient surface mode converter, and the electric field line cluster diverges into free space. Thus, the electromagnetic wave is transformed from a guided electromagnetic wave into a free-space radiated electromagnetic wave.

[0018] The advantages of this invention are:

[0019] (1) Since the TEM mode resonator has no cutoff frequency, by introducing the irregularly shaped, gradually curved surface mode converter, the TEM mode electromagnetic field in the TEM mode resonator is transmitted to the monopole radiator without loss and continuously, eliminating the upper limit of the frequency response and realizing ultra-wideband frequency characteristics. Increasing the aperture size of the irregularly shaped, gradually curved surface mode converter can further expand the lower limit of the frequency response, thereby achieving approximately frequency-independent response characteristics. The monopole radiator has a radiation null point in the axial direction, but radiates electromagnetic waves omnidirectionally in a plane perpendicular to the axial direction, thus enabling the acquisition of an omnidirectional beam pattern.

[0020] (2) The radial distance between the irregularly shaped, gradually changing curved surface mode converter and the monopole radiator satisfies the requirement of a gradually changing and continuous irregular curve, causing the maximum value of the omnidirectional beam pattern to tilt upwards, away from the plane perpendicular to the axis, and forming a certain angle with it. When this angle has a fixed linear relationship with the latitude angle of the mid-latitude regions globally, an ultra-wideband frequency-independent antenna can receive signals transmitted by geostationary satellites to the maximum extent. This antenna has a broad application prospect in the field of geostationary satellite receiving antennas in the mid-latitude regions globally. Attached Figure Description

[0021] Figure 1 This is a front view of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0022] Figure 2 This is a top view of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0023] Figure 3 This is an overall view of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention in one direction;

[0024] Figure 4 This is an overall view of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention from another direction;

[0025] Figure 5 This is a perspective view of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0026] Figure 6 This is a top view of the electric field distribution of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0027] Figure 7 This is a perspective view of the electric field distribution of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0028] Figure 8 This is an overall view of the electric field distribution of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0029] Figure 9 The standing wave diagram of an ultra-wideband frequency-independent antenna disclosed in an embodiment of the present invention;

[0030] Figures 10 to 14 The images show the 3D radiation patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at frequency points of 6.8 GHz, 15.5 GHz, 25 GHz, 40 GHz, and 60 GHz.

[0031] Figures 15(a) and 15(b) are the azimuth and elevation plane patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at a frequency of 6.8 GHz, respectively.

[0032] Figures 16(a) and 16(b) are the azimuth and elevation plane patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at a frequency of 15.5 GHz, respectively.

[0033] Figures 17(a) and 17(b) are respectively the azimuth and elevation patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at a frequency of 25 GHz.

[0034] Figures 18(a) and 18(b) are respectively the azimuth and elevation plane patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at a frequency of 40 GHz.

[0035] Figures 19(a) and 19(b) are the azimuth and elevation plane patterns of an ultra-wideband frequency-independent antenna disclosed in the embodiments of the present invention at a frequency of 60 GHz, respectively. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Comprehensive reference Figures 1 to 5 An ultra-wideband frequency-independent antenna includes a monopole radiator 10, an irregularly shaped gradient surface mode converter 20, and a TEM mode resonator 30.

[0038] The monopolar radiator 10 is made of a conductive material. The monopolar radiator 10 is columnar in shape, which can be a cylindrical shape, a square column shape, a polygonal column shape, or a stepped cylindrical shape, a stepped square column shape, or a stepped polygonal column shape.

[0039] The irregularly shaped gradient surface mode converter 20 is made of a conductive material. The irregularly shaped gradient surface mode converter 20 has a curved body structure. This curved body structure is obtained by stretching an irregularly shaped gradient surface radially to a certain thickness. The irregularly shaped gradient surface is formed by rotating and scanning an irregularly shaped gradient curve around the axis of the monopolar radiator 10. After scanning, the resulting irregularly shaped gradient surface mode converter 20 forms two apertures along the axis of the monopolar radiator 10. The two apertures have different sizes; the smaller one is called the narrow aperture, and the larger one is called the wide aperture. Between the two apertures is a curved body structure. The irregularly shaped gradient curve can be an exponential curve, a parabola, a diced elliptic curve, or a diced hyperbola.

[0040] As a further improved technical solution, the trajectory of the irregular gradient curve rotating around the axis of the monopolar radiator 10 can be a circle, a square, a polygon, etc., and the upper and lower aperture shapes formed are a circle, a square, a polygon, etc.

[0041] The TEM mode resonator 30 includes an inner core 301 and an outer core 302. The inner core 301 is fitted inside the outer core 302, and the two are concentric and coaxial. The inner core 301 and the outer core 302 of the TEM mode resonator 30 must be made of conductive materials.

[0042] The inner core 301 of the TEM mode resonator 30 is cylindrical. The cylindrical shape of the inner core 301 of the TEM mode resonator 30 can be a cylinder, a square column, a polygonal column, or a stepped cylinder, a stepped square column, or a stepped polygonal column.

[0043] The outer core 302 of the TEM mode resonator 30 is a hollow column. The overall shape of the outer core 302 of the TEM mode resonator 30 can be a cylinder, a square column, a polygonal column, or a stepped cylinder, a stepped square column, or a stepped polygonal column.

[0044] The hollow region inside the outer core 302 of the TEM mode resonator 30 can be cylindrical, square, or polygonal, or it can be stepped cylindrical, stepped square, or stepped polygonal.

[0045] The hollow structure of the outer core 302 of the TEM mode resonator 30 needs to be filled with a non-conductive medium. The medium type can be air, foam, polytetrafluoroethylene, honeycomb, or other non-conductive materials. In this embodiment, the inner core 301 is fitted inside the outer core 302, so that the hollow gap between the inner core 301 and the outer core 302 is filled with the aforementioned medium.

[0046] As a further improved technical solution, the inner core 301 of the TEM mode resonator 30 has the same envelope shape as the outer core 302, but different dimensions. The cross-sectional dimension R of the inner core 301 of the TEM mode resonator 30 is... in With the outer core 302 cross-sectional dimension R out Satisfying certain relationships:

[0047]

[0048] Among them, R in R represents a dimension of the cross-sectional shape of the inner core 301 of the TEM mode resonator 30, such as the length or width of a rectangle, the radius of a circle, etc. out Z0 represents a certain dimension of the cross-sectional shape of the outer core 302 of the TEM mode resonator 30, such as the length or width of a rectangle, the radius of a circle, etc., and ε represents the characteristic impedance of the TEM mode resonator 30. r This represents the relative permittivity of the dielectric material filled in the hollow structure of the outer core 302 of the TEM mode resonator 30.

[0049] The monopole radiator 10 is electrically connected to the inner core 301 of the TEM mode resonator 30, and the connection is smooth, closed, and continuous. The outer core 302 of the TEM mode resonator 30 is electrically connected to the narrow aperture of the irregularly shaped gradient curved surface mode converter 20, and the connection is smooth, closed, and continuous, with the same dimensions.

[0050] The working process and principle of this invention are as follows: Electromagnetic waves enter the TEM mode resonator 30 from the RF connector at the input end of the TEM mode resonator 30, where electromagnetic resonance occurs to generate a TEM mode, which is then transmitted axially along the TEM mode resonator 30 to the narrow aperture surface of the irregularly shaped, gradually curved surface mode converter 20. The electric field direction in the TEM mode resonator 30 always points radially towards the outer core 302. When the electromagnetic wave begins to propagate axially along the monopole radiator 10 from the narrow aperture surface of the irregularly shaped, gradually curved surface mode converter 20, as... Figures 6 to 8As shown, the electric field direction points from the monopole radiator 10 to the irregularly shaped gradient surface mode converter 20, and the electric field line clusters diverge into free space. Thus, the electromagnetic wave is transformed from a guided electromagnetic wave into a free-space radiated electromagnetic wave. Since the TEM mode resonator 30 has no cutoff frequency, it can transmit guided electromagnetic waves of any frequency without frequency bandwidth limitations. When the irregularly shaped gradient surface mode converter 20 is introduced, the TEM mode electromagnetic field in the TEM mode resonator 30 is transmitted losslessly and continuously between the monopole radiator 10 and the irregularly shaped gradient surface mode converter 20, eliminating the upper limit of the frequency response and achieving ultra-wideband frequency characteristics. Increasing the aperture size of the irregularly shaped gradient surface mode converter 20 can further expand the lower limit of the frequency response, thereby achieving approximately frequency-independent response characteristics. The monopole radiator 10 has a radiation null point in the axial direction, but radiates electromagnetic waves omnidirectionally in a plane perpendicular to the axial direction, thus obtaining an omnidirectional beam pattern. The radial distance between the irregularly shaped, gradually curved surface mode converter 20 and the monopole radiator 10 satisfies the requirement of a gradually changing and continuous irregular curve, causing the maximum value of the omnidirectional beam pattern to rise upwards, away from the plane perpendicular to the axis, and forming a certain angle with it. When this angle has a fixed linear relationship with the latitude angle of the mid-latitude region globally, an ultra-wideband frequency-independent antenna can receive signals transmitted by geostationary satellites to the maximum extent. It should be noted that the axis refers to the axis of the monopole radiator 10 and the TEM mode resonator 30, and the radial direction refers to the direction perpendicular to the axis. Regarding the electric field direction, the following explanation is made: the electric field of space electromagnetic waves and guided electromagnetic waves must have a starting point and an ending point. The TEM mode resonator 30 propagates TEM electromagnetic waves, which are characterized by the absence of electric and magnetic fields along their axis, with the electric and magnetic fields being mutually perpendicular and distributed radially. Therefore, the electric field direction initially points towards the radial direction of the outer core 302. The irregularly shaped, gradually curved surface mode converter 20 is connected to the outer core 302, designed with a continuous, smooth transition, forming an open, continuous structure. When the guided electromagnetic wave enters free space, the electric field still needs to point from the inner core 301 to the outer conductor, which is the irregularly shaped, gradually curved surface mode converter 20. The inner core 301 is electrically connected to the monopole radiator 10, therefore the electric field direction is from the monopole radiator 10 to the irregularly shaped, gradually curved surface mode converter 20. Furthermore, since the transmission mode is TEM mode, the electromagnetic wave propagation direction in TEM mode is radial, and the electric field direction must be perpendicular to the electromagnetic wave propagation direction.

[0051] like Figure 9 This is a standing wave diagram of an embodiment of the present invention. Figures 10 to 14Figures 15(a) and 15(b) show the azimuth and elevation beam patterns at 6.8 GHz, 15.5 GHz, 25 GHz, 40 GHz, and 60 GHz, respectively. Figures 16(a) and 16(b) show the azimuth and elevation beam patterns at 15.5 GHz, 17(a) and 17(b) show the azimuth and elevation beam patterns at 25 GHz, 18(a) and 18(b) show the azimuth and elevation beam patterns at 40 GHz, and 19(a) and 19(b) show the azimuth and elevation beam patterns at 60 GHz. Since electromagnetic waves are radiated omnidirectionally in a plane perpendicular to the axis, an omnidirectional beam pattern is obtained. The distance between the irregularly shaped, gradually curved surface mode converter 20 and the monopole radiator 10 satisfies the requirement of a gradually changing and continuous irregular curve. This causes the maximum value of the omnidirectional beam pattern to curve upwards, away from the plane perpendicular to the axis, and to form a certain angle with it. When this angle has a fixed linear relationship with the latitude angle of mid-latitude regions globally, an ultra-wideband frequency-independent antenna can maximize the reception of signals transmitted by geostationary satellites. This antenna has broad application prospects in the field of geostationary satellite receiving antennas in mid-latitude regions globally.

[0052] Through the above technical solutions, the TEM mode resonator 30 of the present invention has no cutoff frequency. By introducing the irregularly shaped, gradually curved surface mode converter 20, the TEM mode electromagnetic field in the TEM mode resonator 30 is transmitted to the monopole radiator 10 without loss and continuously, eliminating the upper limit of the frequency response and realizing ultra-wideband frequency characteristics. By increasing the aperture size of the irregularly shaped, gradually curved surface mode converter 20 within a certain range, the lower limit of the frequency response can be further expanded, thereby realizing frequency-independent response characteristics. The monopole radiator 10 has a radiation null point in the axial direction, and radiates electromagnetic waves omnidirectionally in the plane perpendicular to the axial direction, thus obtaining an omnidirectional beam pattern. The distance between the irregularly shaped, gradually curved surface mode converter 20 and the monopole radiator 10 satisfies the requirement of a gradually changing and continuous irregular curve, causing the maximum value of the omnidirectional beam pattern to rise upwards, away from the plane perpendicular to the axial direction, and forming a certain angle with it. When this angle has a fixed linear relationship with the latitude angle of the mid-latitude region of the world, an ultra-wideband frequency-independent antenna can receive signals transmitted by geostationary satellites to the maximum extent. This antenna has broad application prospects in the field of geostationary satellite receiving antennas in the mid-latitude regions of the world.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-wideband frequency-independent antenna, characterized in that, The system includes a monopole radiator, a shaped gradient surface mode converter, and a TEM mode resonator. The TEM mode resonator includes an inner core and an outer core, with the inner core nested inside the outer core and the two coaxial. The gap between the inner and outer cores is filled with a non-conductive dielectric. The shaped gradient surface mode converter is a curved surface structure obtained by radially stretching a shaped gradient surface to a predetermined thickness. The shaped gradient surface is formed by rotating and scanning a shaped gradient curve around the axial direction of the monopole radiator. The monopole radiator is electrically connected to the inner core of the TEM mode resonator, and the outer core of the TEM mode resonator is electrically connected to the narrow aperture of the shaped gradient surface mode converter. Electromagnetic waves enter the TEM mode resonator via the RF connector. Electromagnetic resonance occurs in the TEM mode resonator, generating TEM mode electromagnetic waves. These waves are then transmitted along the TEM mode resonator axis to the narrow aperture surface of the irregularly shaped gradually curved surface mode converter. Within the TEM mode resonator, the electric field direction always points radially towards the outer core. When the electromagnetic wave begins to propagate along the axis of the monopole radiator from the narrow aperture surface of the irregularly shaped gradually curved surface mode converter, the electric field direction changes from the monopole radiator to the irregularly shaped gradually curved surface mode converter, and the electric field line cluster diverges into free space. At this point, the electromagnetic wave is transformed from a guided electromagnetic wave into a free-space radiated electromagnetic wave.

2. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The materials used for the monopole radiator, the irregularly shaped gradient surface mode converter, and the TEM mode resonator are all conductive materials.

3. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The shape of the monopolar radiator can be cylindrical, square, polygonal, stepped cylindrical, stepped square, or stepped polygonal.

4. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The irregular gradient curve can be an exponential curve, a parabola, a cut elliptic curve, or a cut hyperbola.

5. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The trajectory of the irregularly shaped gradient curve rotating around the axis of the monopolar radiator is circular, square, or polygonal, and the upper and lower aperture shapes formed after scanning are circular, square, or polygonal.

6. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The inner core of the TEM mode resonator has the same envelope shape as the outer core, but different dimensions. The inner core and outer core envelope shapes can be cylindrical, square, polygonal, stepped cylindrical, stepped square, or stepped polygonal. The outer core of the TEM mode resonator is a hollow column, and the shape of the hollow region inside the outer core can be a cylinder, a square column, a polygonal column, a stepped cylinder, a stepped square column, or a stepped polygonal column.

7. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The cross-sectional dimensions of the inner core and the outer core satisfy the following relationship: Among them, R in R represents a dimension of the cross-sectional shape of the inner core. out Z0 represents a certain dimension of the cross-sectional shape of the outer core, Z0 represents the characteristic impedance of the TEM mode resonator, and ε represents the characteristic impedance of the TEM mode resonator. r It represents the relative permittivity of the non-conductive medium filling the gap between the inner and outer cores.

8. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The non-conductive medium is one or more of air, foam, polytetrafluoroethylene, and honeycomb.

9. The ultra-wideband frequency-independent antenna according to claim 1, characterized in that, The electrical connection between the monopole radiator and the inner core of the TEM mode resonator, as well as the electrical connection between the outer core of the TEM mode resonator and the narrow aperture of the irregularly shaped, gradually curved surface mode converter, are smooth, closed, and continuous.

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