Terahertz multi-beam frequency scanning antenna based on dielectric lens

Abstract

The invention discloses a terahertz multi-beam frequency scanning antenna based on a dielectric lens, and the antenna comprises a feed array which comprises a metal substrate and a rectangular waveguide feed array disposed on the metal substrate; the right trapezoid metal cavity comprises a right-angle waist side and an inclined waist side; the frequency shift dielectric lens comprises a dielectric substrate and a dielectric shaping lens located above the dielectric substrate; the dielectric forming lens comprises N * M forming units distributed in the transverse direction and the longitudinal direction of the dielectric substrate, the length and the width of each forming unit are equal, and the height of each forming unit is specifically calculated. According to the invention, fusion of time-domain wave beam scanning and frequency-domain wave beam scanning is realized in a mode of integrating the feed array and the frequency-shift dielectric lens, and the antenna has the advantages of time-frequency fusion two-dimensional scanning and high wave beam resolution; and the frequency shift dielectric lens is adopted to realize offset and radiation ends, so that the antenna has the advantages of random gain expansion, no grating lobe and large working bandwidth.

Description

Technical Field

[0001] The present invention relates to the field of terahertz antennas, and in particular to a terahertz multi-beam frequency-sweeping antenna based on a dielectric lens. Background Art

[0002] In RF integrated systems, in order to achieve functions such as dynamic communication, point cloud imaging and scanning radar, it is often necessary to conduct all-round scanning and detection of the target area. Therefore, antennas with beam scanning functions have important application value. Traditional beam scanning antennas are often implemented using electrically controlled phased arrays or mechanical scanning antennas. The electrically controlled phased arrays need to integrate thousands of antenna units and tuning devices, which are not only costly and difficult to integrate, but also have problems such as large heat dissipation loss and complex beam control. At the same time, in high-frequency bands such as millimeter waves / terahertz, due to the immaturity of high-frequency varactor diodes and PIN switch technologies, terahertz phased arrays are far from being able to be used in practice. Mechanical scanning antennas also have problems such as large size, slow scanning speed and high cost. Therefore, it is of great significance to study a beam scanning antenna with low cost, simple structure and wide applicable frequency band.

[0003] Frequency scanning antenna is an antenna whose electromagnetic beam direction changes with frequency. This type of antenna can not only realize electrically controlled beam scanning by changing the frequency of the signal source, but also realize simultaneous large-range coverage by using wide-band signals. It has the advantages of low cost and frequency domain beam scanning. At present, frequency scanning antennas are mainly realized based on waveguide slot antennas, artificial electromagnetic metamaterials, gradient feeding networks and offset feed arrays. Among them, the frequency scanning antenna based on waveguide slot antenna has a simple structure and a wide applicable frequency band, but a small scanning range and a narrow working bandwidth; the frequency scanning antenna based on artificial electromagnetic metamaterial has a large scanning range, but is only applicable to low frequency bands and has a complex structure; the frequency scanning antenna based on gradient feeding network has a wide applicable frequency band, a large scanning range, and is easy to realize two-dimensional scanning, but it is large in size and has high processing cost; the frequency scanning antenna based on offset feed array has a wide applicable frequency band and a small size, but a small scanning range and cannot perform two-dimensional scanning.

[0004] In summary, the existing various frequency scanning antennas still have some problems and cannot meet the application requirements of current high-frequency band communications, radar and imaging systems such as terahertz. Therefore, it is of great significance to develop a small-volume, low-cost, two-dimensionally scannable terahertz frequency scanning antenna. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a terahertz multi-beam frequency-scanning antenna based on a dielectric lens.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A first aspect of the present invention provides a terahertz multi-beam frequency-scanning antenna based on a dielectric lens, comprising:

[0008] A feeding array comprises a metal substrate and a rectangular waveguide feeding array provided on the metal substrate;

[0009] A right-angled trapezoidal metal cavity, comprising a right-angled waist side and an oblique waist side; the right-angled waist side of the right-angled trapezoidal metal cavity is connected to the feed-out side of the rectangular waveguide feed array;

[0010] The frequency-shift dielectric lens comprises a dielectric substrate and a dielectric shaped lens located above the dielectric substrate; the dielectric substrate is connected to the oblique waist side of the right-angle trapezoidal metal cavity; the dielectric shaped lens comprises N*M shaped units distributed in the horizontal and vertical directions along the dielectric substrate, the length and width of each shaped unit are equal, and the height of each shaped unit is calculated in the following manner:

[0011] Taking the center position of the frequency-shift dielectric lens as the coordinate origin, the phase distribution of each shaping unit of the frequency-shift dielectric lens is ij Satisfy the formula:

[0012]

[0013] According to the phase distribution φ ij , calculate the height distribution of each shaping unit:

[0014] In the formula, λ 0 is the vacuum wavelength corresponding to the central operating frequency, F is the focal length of the frequency-shifting dielectric lens, (Fcosα,0,Fsinα) is the coordinate of the center position of the feed array, α is the oblique waist bottom angle of the right-angle trapezoidal metal cavity, (x ij ,y i ) is the center coordinate of the corresponding shaping unit located on the plane where the dielectric substrate is located, is the beam pointing direction of the antenna center operating frequency, ε r is the dielectric constant of the dielectric material used in the frequency-shifting dielectric lens.

[0015] Furthermore, each rectangular waveguide in the rectangular waveguide feeding array is arranged transversely and is completely identical, and the size of the rectangular waveguide is an international standard waveguide size, and the corresponding rectangular waveguide size is selected according to the central operating frequency of the antenna;

[0016] The arrangement period of the rectangular waveguide feeding array must be greater than the width of the rectangular waveguide.

[0017] Furthermore, the median line of the right-angled trapezoidal metal cavity is equal to the focal length of the frequency-shifting dielectric lens, the height of the right-angled trapezoidal metal cavity is equal to the height of the metal substrate, and the width of the right-angled trapezoidal metal cavity is equal to the width of the metal substrate.

[0018] Furthermore, the metal substrate and the outer shell of the right-angle trapezoidal metal cavity are made of one of aluminum, copper, silver, nickel and gold;

[0019] The dielectric substrate and the dielectric shaping lens are made of one of photosensitive resin, high molecular polymer, silicon and quartz materials.

[0020] Furthermore, the length and width of the shaping unit need to be less than or equal to 1 / 2 of the working wavelength.

[0021] Furthermore, the oblique waist bottom angle α of the right-angled trapezoidal metal cavity is less than 90°.

[0022] The beneficial effects of the present invention are:

[0023] In an exemplary embodiment of the present invention, the fusion of time domain beam scanning and frequency domain beam scanning is realized by integrating a feeding array and a frequency-shifting dielectric lens, which has the advantages of time-frequency fusion two-dimensional scanning and high beam resolution; and by using a frequency-shifting dielectric lens to realize the offset and the radiation end, it has the advantages of arbitrary gain expansion, no grating lobes, and a large working bandwidth; by using a multi-port feeding array, it has the advantages of a large beam scanning range and the scan range can be modified and expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of a terahertz multi-beam frequency-sweeping antenna based on a dielectric lens provided in an exemplary embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the structure of a frequency-shifting dielectric lens provided in an exemplary embodiment of the present invention

[0026] Figure 3 A lateral time-domain beam scanning pattern at 150 GHz of a terahertz multi-beam frequency-sweeping antenna based on a dielectric lens provided in an exemplary embodiment of the present invention;

[0027] Figure 4 A longitudinal frequency domain beam scanning pattern of a terahertz multi-beam frequency-sweeping antenna based on a dielectric lens provided in an exemplary embodiment of the present invention at 120 to 170 GHz;

[0028] In the figure, 1-feeding array, 101-metal substrate, 102-rectangular waveguide feeding array, 2-right-angle trapezoidal metal cavity, 3-frequency-shifting dielectric lens, 301-dielectric substrate, 302-dielectric shaping lens. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are directions or positional relationships based on the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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, "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "installation", "connection" and "connection" 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 according to specific circumstances.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] See also Figure 1 , Figure 1 A terahertz multi-beam frequency-sweeping antenna based on a dielectric lens provided in an exemplary embodiment of the present invention is shown, comprising:

[0034] The feed array 1 comprises a metal substrate 101 and a rectangular waveguide feed array 102 opened on the metal substrate 101;

[0035] The right-angled trapezoidal metal cavity 2 comprises a right-angled waist side and an oblique waist side; the right-angled waist side of the right-angled trapezoidal metal cavity 2 is connected to the feed side of the rectangular waveguide feed array 102;

[0036] like Figure 2As shown, the frequency-shift dielectric lens 3 includes a dielectric substrate 301 and a dielectric shaped lens 302 located above the dielectric substrate 301; the dielectric substrate 301 is connected to the oblique waist side of the right-angle trapezoidal metal cavity 2; the dielectric shaped lens 302 includes N*M shaped units distributed horizontally and vertically along the dielectric substrate 301, the length and width of each shaped unit are equal, and the height of each shaped unit is calculated in the following manner:

[0037] Taking the center position of the frequency-shift dielectric lens 302 as the coordinate origin, the phase distribution φ of each shaping unit of the frequency-shift dielectric lens 302 is ij Satisfy the formula:

[0038]

[0039] According to the phase distribution φ ij , calculate the height distribution of each shaping unit:

[0040] In the formula, λ 0 is the vacuum wavelength corresponding to the central operating frequency, F is the focal length of the frequency-shifting dielectric lens, (Fcosα,0,Fsinα) is the coordinate of the center position of the feed array, α is the oblique waist bottom angle of the right-angle trapezoidal metal cavity, (x ij ,y i ) is the center coordinate of the corresponding shaping unit located on the plane where the dielectric substrate is located, is the beam pointing direction of the antenna center operating frequency, ε r is the dielectric constant of the dielectric material used in the frequency-shifting dielectric lens.

[0041] Specifically, in this exemplary embodiment, the terahertz wave is fed from the feeding side of the feeding array 1, passes through the right-angle trapezoidal metal cavity 2, and enters the frequency-shifting dielectric lens 3. By accurately shaping the structure of the frequency-shifting dielectric lens 3, the frequency domain scanning of the terahertz wave incident at any angle can be realized. At the same time, by switching the ports in the feeding array 1, high-gain, large-angle time-frequency fusion two-dimensional beam scanning of the terahertz wave can be achieved. Moreover, in this exemplary embodiment, the shaping method of the frequency-shifting dielectric lens 3 structure is disclosed. The time domain beam scanning in the X direction is realized by the feeding switching of the feeding array 1; the frequency domain scanning is realized by generating the path difference through the offset feeding lens.

[0042] In summary, in this exemplary embodiment, the fusion of time domain beam scanning and frequency domain beam scanning is realized by integrating the feeding array and the frequency-shifting dielectric lens, which has the advantages of time-frequency fusion two-dimensional scanning and high beam resolution; and by adopting the frequency-shifting dielectric lens to realize the offset and the radiation end, it has the advantages of arbitrary gain expansion, no grating lobes, and a large working bandwidth; by adopting a multi-port feeding array, it has the advantages of a large beam scanning range and the scanning range can be modified and expanded.

[0043] The following content will describe in detail the preferred exemplary embodiments of each structure:

[0044] More preferably, in an exemplary embodiment, each rectangular waveguide in the rectangular waveguide feed array 102 is arranged transversely and is identical, and the size of the rectangular waveguide is an international standard waveguide size, and the corresponding rectangular waveguide size is selected according to the central operating frequency of the antenna;

[0045] The arrangement period of the rectangular waveguide feeding array 102 needs to be greater than the width of the rectangular waveguide.

[0046] Specifically, in this exemplary embodiment, the rectangular waveguide feed array 102 is described in detail: the thickness of the metal substrate 101 is consistent with the thickness of the rectangular waveguide array 102, and the height and width of the metal substrate 101 must be greater than the rectangular waveguide feed array 102. At the same time, each rectangular waveguide in the rectangular waveguide feed array 102 is arranged horizontally and is exactly the same, and the size of the rectangular waveguide is the international standard waveguide size, and the corresponding rectangular waveguide size is selected according to the central operating frequency of the antenna; the arrangement period of the rectangular waveguide feed array 102 must be greater than the width of the rectangular waveguide.

[0047] The central operating frequency f of the terahertz multi-beam frequency-sweeping antenna is 150 GHz, and the operating wavelength λ 0 For example, the frequency belongs to D waveguide, and the corresponding standard rectangular waveguide has a height of 0.83 mm and a width of 1.65 mm. Therefore, in this exemplary embodiment, the thickness (Z direction), width (X direction) and height (Y direction) of the metal substrate 101 are 2 mm, 10.4 mm and 7.47 mm respectively; the number of feeding ports of the rectangular waveguide feeding array 102 is 7, and the length (Z direction), width (X direction) and height (Y direction) of each feeding port are 2 mm, 0.83 mm and 1.65 mm respectively; the lateral period (X direction) of the rectangular waveguide feeding array 102 is 1.5 mm.

[0048] More preferably, in an exemplary embodiment, the midline of the right-angled trapezoidal metal cavity 2 is equal to the focal length of the frequency-shifting dielectric lens 3 , the height of the right-angled trapezoidal metal cavity 2 is equal to the height of the metal substrate 101 , and the width of the right-angled trapezoidal metal cavity 2 is equal to the width of the metal substrate 101 .

[0049] Specifically, in this exemplary embodiment, the right-angled trapezoidal metal cavity 2 is described in detail: the midline length (Z direction) of the cavity in the right-angled trapezoidal metal cavity 2 is equal to the focal length of the frequency-shifting dielectric lens 3, which is 6 mm, the width is 10 mm, and the height of the right-angle waist is 7.07 mm; the angle between the oblique waist and the ZOX plane in the right-angled trapezoidal metal cavity 2 (oblique waist bottom angle) α=45° (preferably), and the length of the oblique waist is 10 mm. The midline length (Z direction), width, right-angle waist height, and oblique waist length of the metal shell in the right-angled trapezoidal metal cavity 2 are 6 mm, 10.4 mm, 7.47 mm, and 10.4 mm, respectively.

[0050] It should be additionally explained that, in a preferred exemplary embodiment, the slant waist bottom angle α of the right-angled trapezoidal metal cavity 2 needs to be less than 90° to produce a path difference, and only with a path difference can frequency scanning be achieved; the greater the path difference, the greater the scanning angle, but if the slant waist bottom angle is too small, the beam performance will deteriorate, so an angle of 45° is used.

[0051] Preferably, in an exemplary embodiment, the dielectric substrate 301 and the dielectric shaping lens 302 adopt a dielectric constant ε r =2.739 of photosensitive resin material, wherein the thickness, width and height (along the oblique waist direction) of the dielectric substrate 301 are 0.1 mm, 10.4 mm, and 10.4 mm respectively; the dielectric substrate 301 is parallel to the plane where the oblique waist of the right-angled trapezoidal metal cavity 2 is located, and the angle between the dielectric substrate 301 and the ZOX plane (oblique waist bottom angle) is 45°.

[0052] The dielectric shaping lens 302 includes 100 shaping units, and the lateral and longitudinal widths and periods of each shaping unit (parallel to the plane of the dielectric substrate 301) are equal and 0.5 mm; the 150 GHz pointing θ 0 =90°. Taking the center position of the frequency shift medium lens as the coordinate origin, the center coordinates (x ij ,y ij , 0), the focal length of the frequency-shifting dielectric lens, λ 0 =2mm, dielectric constant ε r =2.739, beam pointing at the center operating frequency (φ 0 ,θ 0 ), using the phase distribution φ ij formula:

[0053]

[0054] The required height of each shaping unit can be calculated

[0055] More preferably, in an exemplary embodiment, the metal substrate 101 and the outer shell of the right-angled trapezoidal metal cavity 2 are made of one of aluminum, copper, silver, nickel and gold.

[0056] Specifically, in this exemplary embodiment, a structure in which a dielectric lens is loaded in an all-metal metal cavity is adopted, which has the advantages of easy processing, small size, and integrated design of the feed array and the lens.

[0057] More preferably, in an exemplary embodiment, the length and width of the shaping unit need to be less than or equal to 1 / 2 of the working wavelength. The smaller the length and width of the shaping unit, the smoother the dielectric shaping lens.

[0058] In summary, all parameters of this example can be obtained, and the feed array 1, the right-angle trapezoidal metal cavity 2 and the frequency-shifting dielectric lens 3 are connected together (by bonding) to form a complete terahertz multi-beam frequency-scanning antenna structure.

[0059] The terahertz multi-beam frequency-sweeping antenna was modeled and simulated using CST three-dimensional electromagnetic field simulation software. Figure 3 The lateral time domain beam scanning simulation results of the terahertz multi-beam frequency-sweeping antenna when switching ports 1 to 7 are shown. The beam pointing is in the theta = 90° plane. The beam pointing of ports 1 and 7 is phi = 56 / 124°, and the beam gain is 13.1dBi; the beam pointing of ports 2 and 6 is phi = 66 / 114°, and the beam gain is 14.3dBi; the beam pointing of ports 3 and 5 is phi = 77 / 103°, and the beam gain is 14.1dBi; the beam pointing of port 4 is phi = 90°, and the beam gain is 15.2dBi.

[0060] like Figure 4 The shown results are the gain normalized longitudinal frequency domain beam scanning simulation results of the terahertz multi-beam frequency-sweeping antenna in the frequency domain of 120 to 170 GHz. The beam pointing is in the phi = 90° plane. The beam pointing at 120 GHz is theta = 63°, and the beam gain is 13 dBi. The beam pointing at 130 GHz is theta = 74°, and the beam gain is 14.7 dBi. The beam pointing at 140 GHz is theta = 84°, and the beam gain is 14.2 dBi. The beam pointing at 150 GHz is theta = 90°, and the beam gain is 15.2 dBi. The beam pointing at 160 GHz is theta = 97°, and the beam gain is 17.7 dBi. The beam pointing at 170 GHz is theta = 100°, and the beam gain is 16.3 dBi.

[0061] The above-mentioned terahertz multi-beam frequency-scanning antenna based on frequency-shifting dielectric lens realizes a two-dimensional time-frequency beam scanning range of 36°×68° by changing the feeding port. The average gain during transverse time domain beam scanning is 14.1dBi; the average gain during longitudinal frequency domain beam scanning is 15.18dBi; the overall size (length×width×height) is approximately: 10.3mm×10.4mm×7.47mm; the terahertz multi-beam frequency-scanning antenna can realize frequency domain scanning and time domain scanning at the same time, and has the advantages of large two-dimensional beam scanning range, scalable gain, small size and low cost, and is of great value in terahertz communication, radar and imaging applications.

[0062] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A terahertz multi-beam frequency-scanning antenna based on a dielectric lens, characterized in that: include: A feeding array comprises a metal substrate and a rectangular waveguide feeding array provided on the metal substrate; A right-angled trapezoidal metal cavity, comprising a right-angled waist side and an oblique waist side; the right-angled waist side of the right-angled trapezoidal metal cavity is connected to the feed-out side of the rectangular waveguide feed array; The frequency-shift dielectric lens comprises a dielectric substrate and a dielectric shaped lens located above the dielectric substrate; the dielectric substrate is connected to the oblique waist side of the right-angle trapezoidal metal cavity; the dielectric shaped lens comprises N*M shaped units distributed in the horizontal and vertical directions along the dielectric substrate, the length and width of each shaped unit are equal, and the height of each shaped unit is calculated in the following manner: Taking the center position of the frequency-shift dielectric lens as the coordinate origin, the phase distribution of each shaping unit of the frequency-shift dielectric lens is ij Satisfy the formula: According to the phase distribution φ ij , calculate the height distribution of each shaping unit: Where λ0 is the vacuum wavelength corresponding to the central operating frequency, F is the focal length of the frequency-shifting dielectric lens, (Fcosα,0,Fsinα) is the coordinate of the center position of the feed array, α is the bottom angle of the right-angle trapezoidal metal cavity, (x ij ,y i ) is the center coordinate of the corresponding shaping unit located on the plane where the dielectric substrate is located, is the beam pointing direction of the antenna center operating frequency, ε r is the dielectric constant of the dielectric material used in the frequency-shifting dielectric lens.

2. The terahertz multi-beam frequency-scanning antenna based on a dielectric lens according to claim 1, characterized in that: Each rectangular waveguide in the rectangular waveguide feeding array is arranged transversely and is identical, and the size of the rectangular waveguide is the international standard waveguide size, and the corresponding rectangular waveguide size is selected according to the central operating frequency of the antenna; The arrangement period of the rectangular waveguide feeding array is greater than the width of the rectangular waveguide.

3. The terahertz multi-beam frequency-scanning antenna based on a dielectric lens according to claim 1, characterized in that: The median line of the right-angled trapezoidal metal cavity is equal to the focal length of the frequency-shifting dielectric lens, the height of the right-angled trapezoidal metal cavity is equal to the height of the metal substrate, and the width of the right-angled trapezoidal metal cavity is equal to the width of the metal substrate.

4. The terahertz multi-beam frequency-scanning antenna based on a dielectric lens according to claim 1, characterized in that: The metal substrate and the outer shell of the right-angle trapezoidal metal cavity are made of one of aluminum, copper, silver, nickel and gold; The dielectric substrate and the dielectric shaping lens are made of one of photosensitive resin, high molecular polymer, silicon and quartz materials.

5. The terahertz multi-beam frequency-scanning antenna based on a dielectric lens according to claim 1, characterized in that: The length and width of the shaping unit must be less than or equal to 1 / 2 of the working wavelength.

6. The terahertz multi-beam frequency-scanning antenna based on a dielectric lens according to claim 1, characterized in that: The oblique waist bottom angle α of the right-angled trapezoidal metal cavity is less than 90°.

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