CN109994814B - Circularly polarized varactor active metasurface thin lens antenna - Google Patents

Abstract

The invention discloses a circularly polarized varactor active super-surface thin lens antenna which comprises a focusing lens, a circularly polarized array, a gasket, a support pillar, a horn antenna and a base, wherein the focusing lens is arranged on the base; the circularly polarized array is a super-surface; the focusing lens is a thin lens; the circularly polarized array, the focusing lens and the support column are sequentially connected through a gasket, and the horn antenna is fixed on the base; the circularly polarized array is an active super surface of a multilayer varactor, and the layers are separated by a gasket; the super surface of the single-layer varactor consists of metal patterns which are periodically arranged, the metal patterns are formed by nesting an outer rectangular ring into an inner rectangular patch, and the outer ring is connected with the inner patch through a varactor; the polarization mode of the transmitted wave is adjusted by changing the capacitance of the varactor. The gain can be secured while miniaturization is performed.

Description

Circularly polarized varactor active metasurface thin lens antenna

technical field

The invention belongs to the technical field of millimeter wave and terahertz communication, and in particular relates to a circularly polarized varactor active metasurface thin lens antenna.

Background technique

Electromagnetic lens is a lens structure that realizes functions such as convergence and divergence similar to optical lenses in the microwave and millimeter wave frequency bands.

Millimeter waves are electromagnetic waves with a frequency range of 30 to 300 GHz and a wavelength of 10 mm to 1 mm. Terahertz is a frequency band with a frequency range of 300GHz to 3THz, and its wavelength is 1mm to 0.1mm. The millimeter waveband and terahertz frequency band have the characteristics of wide frequency band, high transmission rate, small size of equipment, low attenuation and strong penetrating power, and are suitable for near-field point-to-point communication, satellite communication, etc. The electromagnetic lens antenna applied in the millimeter wave frequency band can better meet the application scenarios, that is, to meet the requirements of high convergence and high gain.

A metasurface is a vertical thickness much smaller than the wavelength, and a horizontal plane periodic structure. By adjusting the structure of the arrangement unit, the phase, amplitude and polarization mode of the reflected wave and the transmitted wave can be adjusted. It is an application of metamaterials in two-dimensional planes.

The present invention adopts an active metasurface to realize circular polarization.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides a circularly polarized varactor active ultra-surface thin lens antenna working in the millimeter wave and terahertz bands, which is used to realize a wide-band, variable-polarization circularly polarized antenna.

The invention is solved by the following technical solutions: a circularly polarized varactor active ultra-surface thin lens antenna, characterized in that it includes a focusing lens, a circularly polarized array, a gasket, a support column, a horn antenna and a base; the The focusing lens is a thin lens, and the circularly polarized array is a metasurface; the circularly polarized array, the focusing lens, and the support column are connected in sequence through a gasket, the support column is fixed on the base, and the horn antenna is fixed on the base. On the base, the horn mouth of the horn antenna faces the focusing lens; the circularly polarized array is a multi-layer varactor active metasurface, and the layers are separated by spacers; the single-layer varactor metasurface is composed of periodically arranged metal The metal pattern is an outer rectangular ring nested with an inner rectangular patch, and the outer ring and the inner patch are connected by a varactor diode; the transmission wave polarization mode is adjusted by changing the capacitance of the varactor.

Further, the antenna is a fully enclosed structure.

Further, the support column is cylindrical, the gasket is annular, the support column and the gasket are made of ABS plastic, and the inner wall of the support column is affixed with a wave absorbing material.

Further, the focusing lens is selected from a hyperbolic dielectric lens or a crescent dielectric lens.

Further, the circularly polarized array adopts a multi-layer varactor active metasurface, each layer includes a dielectric substrate, and the lower surface of the dielectric substrate is etched with periodically arranged metal pattern units, and each metal pattern unit is an outer square. The inner rectangular patch is nested in the ring, and the outer square ring and the inner rectangular patch are connected through two varactor diodes in opposite directions, or through four varactor diodes.

Further, the circularly polarized array adopts a multi-layer varactor active metasurface, each layer contains a dielectric substrate, and the lower surface of the dielectric substrate is etched with periodically arranged metal pattern units, and each metal pattern unit is an outer circle. The ring is nested with the inner circular patch, and the outer circular ring and the inner circular patch are connected by two varactor diodes in opposite directions.

Further, between two adjacent layers of the circularly polarized array is a separation layer filled with air, foam or a dielectric substrate.

Further, the adjacent units of the active metasurface are connected by resistance; the bias line is loaded on one of the units; the transmission wave polarization mode is changed by changing the bias voltage, including left-hand circular polarization and right-hand circular polarization. , and linear polarization.

Compared with the prior art, the advantages of the present invention are:

1. The circularly polarized radome realized by using multi-layer active metasurfaces has the advantage of high bandwidth. By adjusting the bias voltage, the circularly polarized outgoing wave can be realized in a wide bandwidth.

2. By adjusting the bias voltage, the left-hand circularly polarized wave, the right-hand circularly polarized wave and the linearly polarized wave can be output simultaneously by using the same antenna structure, and the switching between the three can be realized by adjusting the bias voltage.

3. In order to achieve higher gain, the focusing lens in the present invention adopts a hyperbolic dielectric lens or a crescent dielectric lens.

4. In order to reduce the loss and have a larger phase shift adjustment range with fewer layers, the unit parameters, the thickness of the dielectric substrate, and the capacitance of the varactor in the circularly polarized varactor active metasurface array in the present invention are in the longitudinal direction. non-uniform distribution.

5. The antenna of the present invention is a fully enclosed structure, which reduces energy loss.

Description of drawings

1 is a schematic structural diagram of a crescent dielectric lens and a hyperbolic dielectric lens of a focusing lens according to a preferred embodiment;

Fig. 2 is the schematic diagram of the active metasurface structure of the circularly polarized varactor according to the preferred embodiment;

3 is a schematic diagram of the structure dimensioning of the active metasurface unit of the circularly polarized varactor according to the preferred embodiment;

4 is a schematic diagram of a focusing lens, a circularly polarized array and a horn antenna in a circularly polarized varactor active ultra-surface thin lens antenna in a preferred embodiment;

5 is a schematic diagram of the relative position dimensioning of the focusing lens, the circularly polarized array and the horn antenna in the circularly polarized varactor active ultra-surface thin lens antenna of the preferred embodiment;

6 is a schematic diagram of the bias line loading scheme of the active metasurface unit of the circularly polarized varactor according to the preferred embodiment;

7 is a schematic diagram of the assembly relationship of a focusing lens, a circularly polarized array, a support column, and a horn antenna in a circularly polarized varactor active metasurface lens antenna in a preferred embodiment;

In the figure: focusing lens 1, circularly polarized array 2, gasket 3, support column 4, horn antenna 5, base 6.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments.

Example 1

A circularly polarized varactor active ultra-surface thin lens antenna provided in this embodiment is characterized in that it includes a focusing lens 1 , a circularly polarized array 2 , a gasket 3 , a support column 4 , a horn antenna 5 and a base 6 Described focusing lens 1 is a thin lens, and described circularly polarized array 2 is a metasurface; Described circularly polarized array 2, focusing lens 1, support column 4 are all connected successively by gasket 3, and described support column 4 is fixed On the base 6, the horn antenna 5 is fixed on the base 6, and the horn mouth of the horn antenna 5 faces the focusing lens 1; the circularly polarized array 2 is a multi-layer varactor active metasurface, and the layers pass through The spacers are separated by 3; the single-layer varactor metasurface is composed of metal patterns arranged periodically, and the metal pattern is an outer rectangular ring nested with an inner rectangular patch, and the outer ring and the inner patch are connected by a varactor diode; The size of the capacitor tube can adjust the polarization mode of the transmitted wave.

Further, the antenna is a fully enclosed structure.

Further, the support column 4 is cylindrical, the gasket 3 is annular, the materials of the support column 4 and the gasket 3 are both ABS plastic, and the inner wall of the support column 4 is affixed with a wave absorbing material. .

Further, the focusing lens 1 is selected from a hyperbolic dielectric lens or a crescent dielectric lens.

Further, the circularly polarized array 2 adopts a multi-layer varactor active metasurface, each layer contains a dielectric substrate, and the lower surface of the dielectric substrate is etched with periodically arranged metal pattern units, and each metal pattern unit is an outer surface. The square ring nests the inner rectangular patch, and the outer square ring and the inner rectangular patch are connected by two varactors in opposite directions, or connected by four varactors.

Further, the circularly polarized array 2 adopts a multi-layer varactor active metasurface, each layer contains a dielectric substrate, and the lower surface of the dielectric substrate is etched with periodically arranged metal pattern units, and each metal pattern unit is an outer surface. The circular ring nests the inner circular patch, and the outer circular ring and the inner circular patch are connected by two varactor diodes in opposite directions.

Further, between two adjacent layers of the circularly polarized array is a separation layer filled with air, foam or a dielectric substrate.

Further, the adjacent units of the active metasurface are connected by resistance; the bias line is loaded on one of the units; the transmission wave polarization mode is changed by changing the bias voltage, including left-hand circular polarization and right-hand circular polarization. , and linear polarization.

Example 2

In a preferred embodiment of the present invention, the circularly polarized varactor active metasurface thin lens antenna operates in the Ka frequency band.

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram of a crescent dielectric lens and a hyperbolic dielectric lens of a focusing lens 1 according to a preferred embodiment of the present invention. The lower surface of the crescent lens is a spherical surface, and the upper surface is an ellipsoid; the lower surface of the hyperbolic lens is an envelope surface formed by the rotation of the hyperbola along the symmetry axis of the lens; the parameters of the upper and lower surfaces of the crescent lens and the hyperbolic lens are determined by the focal length of the lens and the medium interface. The electric constant is uniquely determined. The thin lens changes the phase shift of the transmitted wave through the uneven thickness of the center and the edge. By designing the curved surfaces of the upper and lower surfaces, the phase shift of the transmitted wave compensates for the phase shift difference between the spherical wave and the plane wave to achieve convergence.

Referring to Fig. 2 and Fig. 3, Fig. 2 is a schematic diagram of the active metasurface structure of the circularly polarized array 2 varactors in the preferred embodiment of the present invention; Fig. 3 is the circularly polarized array 2 varactors in the preferred embodiment of the present invention. Schematic diagram of the dimensioning of the active metasurface element structure. Among them, the varactor active metasurface of the circularly polarized array 2 adopts a six-layer structure, and each layer is composed of periodically arranged units. Slice pattern, a metal outer ring with a width of t and a side length of w _o , and a patch with side lengths of w _ia and w _ib are etched on the printed medium board with a period p, and connected between the outer ring and the patch 2 or 4 varactors; in Figure 2(b) and Figure 3(b), the unit adopts an outer circular frame to nest a central circular patch pattern, and the width is t etched on the printed medium board with a period p A metal outer ring with an outer diameter of _wo and a patch with a diameter of _wi , and a varactor diode is connected between the outer ring and the patch. The interlayer is a separation layer, filled with air, with a thickness of g. Define the row direction as the x direction and the column direction as the y direction. By adjusting the bias voltage of the varactor diode to change its equivalent capacitance, the phase shift of the x-direction polarized wave and the y-direction polarized wave passing through the unit is adjusted.

In this preferred embodiment, the size of the varactor active metasurface unit of the circularly polarized array 2 adopts an outer rectangular ring nested inner rectangular patch structure, where p=5.00mm, w _o =4.90mm, w _ia =3.40mm , w _ib =3.40mm, t=0.30mm, g=3.00mm. The substrate adopts Rogers RT5880, the thickness is 0.127mm, and the dielectric constant ε _r =2.2. At the same time, g, _wi and C _p are optimized to make them non-uniformly distributed along the z direction, so as to obtain a larger adjustment range of phase shift.

The present invention changes the phase shift of the x-direction polarized wave and the y-direction polarized wave of the metasurface by changing the loaded bias voltage, so that the phase shift difference between the two is 90° or -90°, so that the two transmitted waves are Synthesize left-handed circularly polarized waves or right-handed circularly polarized waves.

Referring to FIG. 6 , FIG. 6 is the bias line loading scheme of the active metasurface unit of the circularly polarized array 2 varactors in the preferred embodiment of the present invention. Among them, the vertically adjacent metasurface units are connected by resistance, and the bias line is loaded on one of the units; by changing the bias voltage, the transmission wave polarization mode is changed, including left-hand circular polarization, right-hand circular polarization, and line polarization.

Referring to Fig. 4 and Fig. 5, Fig. 5 is a schematic diagram of the relative positional relationship of a circularly polarized varactor active metasurface radome, a focusing lens 1, and a horn antenna 5 in a preferred embodiment of the present invention; Schematic diagram of the relative position dimensioning of the varactor active metasurface radome, focusing lens 1, and horn antenna 5. The diameter of the lens is D=60mm, and the focal length is f=60mm.

Referring to FIG. 7 , FIG. 7 is a schematic diagram of the assembly relationship of the gasket 3 , the support column 4 , and the horn antenna 5 in the varactor active metasurface thin lens antenna according to the preferred embodiment of the present invention. Among them, the circularly polarized array 2 and the focusing lens 1 in the active metasurface radome of the circularly polarized varactor are fixed by the spacer 3 while making a certain thickness of the separation layer, filled with air or other media; the circularly polarized array 2, focusing The lens 1 and the support column 4 are connected in sequence through the gasket 3 , the other end of the support column 4 is fixed on the base 6 , and the horn antenna 5 is also fixed in the center of the base 6 , and the horn of the horn antenna 5 faces the focusing lens 1 . Both the gasket 3 and the support column 4 are made of ABS plastic. The inner wall of the support column 4 is affixed with a wave absorbing material.

Those skilled in the art can easily make various changes and modifications according to the written description, drawings and claims provided by the present invention without departing from the spirit and scope of the present invention defined by the claims. Any modifications and equivalent changes made to the above embodiments according to the technical idea and essence of the present invention fall within the protection scope defined by the claims of the present invention.

Claims (8)

1. a circularly polarized varactor active metasurface thin lens antenna, is characterized in that, comprises focusing lens, circular polarization array, gasket, support column, horn antenna and base; Described focusing lens is a thin lens; The circularly polarized array, the focusing lens, and the support column are connected in sequence through spacers, the support column is fixed on the base, the horn antenna is fixed on the base, and the horn mouth of the horn antenna faces the focusing lens; the The circularly polarized array is a multi-layer varactor active metasurface, and the layers are separated by spacers; a single-layer varactor metasurface is composed of metal patterns arranged periodically, and the metal patterns are outer rectangular rings nested inner rectangular patches. The outer rectangular ring and the inner rectangular patch are connected through a varactor; the transmission wave polarization mode is adjusted by changing the capacitance of the varactor. 2 . The circularly polarized varactor active metasurface thin lens antenna according to claim 1 , wherein the antenna is a fully enclosed structure. 3 . 3. a kind of circularly polarized varactor active metasurface thin lens antenna as claimed in claim 1, is characterized in that, described support column is cylindrical, described gasket is annular, described support Both the column and the gasket are made of ABS plastic, and the inner wall of the support column is affixed with a wave absorbing material. 4 . The circularly polarized varactor active metasurface thin lens antenna according to claim 1 , wherein the focusing lens is selected from a hyperbolic dielectric lens or a crescent dielectric lens. 5 . 5. a kind of circularly polarized varactor active metasurface thin lens antenna as claimed in claim 1, is characterized in that, described circularly polarized array adopts multi-layer metasurface, and each layer comprises dielectric substrate, and the The lower surface is etched with periodically arranged metal pattern units, each metal pattern unit is an outer square ring nested with an inner rectangular patch, and the outer square ring and the inner rectangular patch are connected by two varactor diodes in opposite directions. Or connected through four varactors. 6. a kind of circularly polarized varactor active metasurface thin lens antenna as claimed in claim 1, is characterized in that, described circularly polarized array adopts multilayer varactor active metasurface, and each layer comprises medium Substrate, the lower surface of the dielectric substrate is etched with periodically arranged metal pattern units, each metal pattern unit is an outer circular ring nested with an inner circular patch, and the outer circular ring and the inner circular patch pass through two. A varactor diode in the opposite direction is connected. 7. a kind of circularly polarized varactor active metasurface thin lens antenna as claimed in claim 5 or 6, it is characterised in that the adjacent two layers of the circularly polarized array are separation layers, filled with air, Foam or dielectric substrates. 8. A kind of circularly polarized varactor active metasurface thin lens antenna as claimed in claim 5 or 6, characterized in that, the adjacent units of the active metasurface are connected by resistance; On one of the units; by changing the bias voltage, the polarization mode of the transmitted wave is changed, including circular polarization and linear polarization, and the circular polarization includes left-hand circular polarization and right-hand circular polarization.

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