Radiation Unit

Abstract

The present invention relates to a radiation unit including a lens (10) having a dielectric refractive lens body (12) for transmitting electromagnetic waves, the dielectric refractive lens body (12) having a first relative permittivity εcentre in the center region and a second relative permittivity εperipheraledge in the edge region, the first relative permittivity εcentre and the second relative permittivity εperipheraledge satisfy the relationship εcentre = 1.42√εperipheraledge + 0.58, with a tolerance of 0.2, and satisfying |εperipheraledge - εcentre| > 0.1 and εperipheraledge > 1.5.

Description

[Technical Field]

[0001] The present invention relates to a radiating unit according to the preamble of claim 1 . [Background technology]

[0002] For example, from US Pat. No. 5,649,999, it is known that lenses are made from solid dielectric materials, in which case the refractive index is influenced by drilling holes in the material.

[0003] The material in the center of the lens has a dielectric constant of 2.04, while the outermost ring has a dielectric constant of 1.25. The lens shown has a dielectric constant of less than 1.5 at its edges, with a deviation from the rule from center to edge of approximately 0.02. The lens has at least one waveguide coupled to it so that electromagnetic waves can be transmitted from the waveguide to the lens.

[0004] The cross-sectional area of ​​a waveguide is inversely proportional to the square root of the dielectric constant of the material filling the waveguide. By using a uniform material to couple the waveguide to the lens, the dielectric constant of the lens material can be directly linked to the dielectric constant of the material filling the waveguide. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2014 / 0176377 Summary of the Invention

[0006] It is an object of the present invention to use multiple waveguides attached to a single lens to obtain improved resolution and good focusing properties of the lens.

[0007] This object is achieved by combining the characterizing part of claim 1 with the preamble of claim 1.

[0008] The dependent claims are advantageous embodiments of the invention.

[0009] As is well known in the art, a dielectric refractive lens body has a first dielectric constant, ε center, at the center of the lens and a second dielectric constant, ε peripheral edge, at the edge of the lens.

[0010] According to the present invention, the dielectric constant is distributed over the entire lens body so that the first relative dielectric constant εcenter and the second relative dielectric constant εperipheral edge satisfy the following relationship: εcentre = 1.42(√εperipheral edge) + 0.58, with a tolerance of 0.2, where |εperipheral edge - εcentre| > 0.1 and εperipheral edge > 1.5. Due to the tolerance, the value of εcentre satisfies the relationship 1.42(√εperipheral edge)+ 0.78 > εcentre > 1.42(√εperipheral edge)+ 0.38.

[0011] An edge dielectric constant greater than 1.5 allows coupling to waveguides filled with materials having relatively high dielectric constants, preferably greater than 2.5, more preferably greater than 3, thereby allowing for waveguides with small cross-sectional areas. When using prior art materials, an increase in edge dielectric constant leads to a distribution of dielectric constants within the lens, reducing the beam focusing characteristics and therefore the gain.

[0012] By applying the above relationship, the lens provides a radiating unit with higher gain than a lens body having a relative permittivity distribution that deviates significantly from the relationship εcentre = 1.42√εperipheraledge + 0.58 for a selected εperipheraledge.

[0013] According to this relationship, the second relative permittivity εperipheral edge may be smaller than the first relative permittivity εcentre at the center, or vice versa.

[0014] The idea of ​​the present invention is to increase the permittivity of the dielectric in the edge region of the lens to match the relative permittivity of the substrate integrated waveguide (relative permittivity ≥ 1.5) where it transitions to the connected waveguide, thereby reducing the reflection at the interface, resulting in a very good coupling from the lens to the waveguide, reducing losses, improving radiation efficiency and therefore power consumption.

[0015] With the dielectric constant distribution according to the present invention, the focusing properties of a classical Lüneburg lens can be nearly achieved when the second relative permittivity εperipheral edge is greater than 1.5. Therefore, substantial coupling with the coupled waveguide can be achieved when the dielectric constant of the dielectric material in the waveguide is higher than or close to the second relative permittivity εperipheral edge.

[0016] By increasing or decreasing the permittivity from the second relative permittivity εperipheral edge to the first relative permittivity εcentre, the focusing properties of the lens according to the invention can be made to approach the focusing properties of a classical Luneburg lens.

[0017] The permittivity distribution in the radial direction of the lens varies according to a square function. The radial position r is an element in [0,1], specifically the normalized radius of a sphere or cylinder. Here, the relative permittivity of each point or position with radial coordinate r follows the relationship: εr(r) = εcentre -(εcentre - εperipheral edge)r 2

[0018] Thus, for a given second relative permittivity εperipheral edge, a first relative permittivity εcentre can be selected that ensures an optimum gain of the lens.

[0019] In a preferred embodiment, the distributions are staggered, which results in an annular (ring-shaped) distribution, in particular a concentrically arranged annular (ring-shaped) distribution, and in a further preferred embodiment, the width of the rings is between 1 / 10 and 1 / 15 of the lens radius.

[0020] One way to achieve a step distribution is to introduce holes into the different rings that make up the lens. For each ring, the effective / equivalent permittivity is assumed to be a weighted average of the permittivity of the dielectric body εdielectricBody and the material that makes up the holes εholes (in particular, any material, such as air). The weights given to both quantities are proportional to the proportion of each material in the ring. εring =(Vholes / Vring)εholes + ((Vring - Vholes) / Vring)εdielectricBody εring = (fraction of hole material in the ring) εholes + (fraction of dielectric body in the ring) εdielectricBody

[0021] Another realization is a random distribution of holes that does not follow a predefined ring or area. In this case, the effective permittivity at a given point is considered as a weighted average of the permittivity of the dielectric body εdielectric_body and the material εholes that makes up the holes (in particular, any material, such as air). Here, the weight given to both quantities is proportional to the proportion of each material in the cylindrical area (axis coincident with the axis of the cylindrical lens) centered at the given point, with a radius equal to one-tenth of the cylindrical lens radius, and with a thickness that completely covers the thickness / height of the cylindrical lens. A cylindrical lens can form a fan beam, which allows the evaluation of echoes along a strip cross section. By combining two lenses, one for transmitting and the other for receiving, a grid can be generated.

[0022] Another realization is a random distribution of holes that does not follow a predefined ring or area. In this case, the effective permittivity at a particular point is considered as a weighted average of the permittivity of the dielectric body εdielectricBody and the material εholes that make up the holes (in particular, any material such as air), where the weight given to both quantities is proportional to the share of each material in the spherical area centered at the particular point and having a radius equal to one-tenth of the lens radius in the case of a spherical lens.

[0023] Further advantages, features and potential applications of the present invention can be understood from the following description taken in conjunction with the embodiments illustrated in the drawings.

[0024] These terms and associated reference symbols are used throughout the specification, claims and drawings, as will be apparent from the accompanying list of reference symbols. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view of a lens according to the present invention. [Figure 2] FIG. 2 is a curve showing the relationship between the second relative permittivity εperipheral edge and the first relative permittivity εcentre. [Figure 3] FIG. 3 is a graph showing the function εr(r) for multiple combinations of εcenter / εperipheral edge. DETAILED DESCRIPTION OF THE INVENTION

[0026] FIG. 1 is a perspective view of a lens 10 according to the present invention. The lens 10 of FIG. 1 can be part of a radiation unit. The lens 10 comprises a cylindrical dielectric body 12 coated with a metal layer on its top and bottom surfaces. The lens 10 further comprises holes 14, shown in black, drilled in the dielectric body 12. To ensure the effective / equivalent permittivity at the periphery and center of the lens, the shape and distribution of the holes 14 are selected to satisfy the criterion ε = 1.42√ε + 0.58 (with a tolerance of 0.2). Note that |ε - ε > 0.1 and ε > 1.5 are also satisfied. The holes 14 do not necessarily have to have a circular cross section. Therefore, the value of ε satisfies the following relationship: 1.42√εperipheral edge + 0.78 > εcentre > 1.42√εperipheral edge + 0.38

[0027] The permittivity distribution in the radial direction of the lens body 12 essentially follows the function: εr(r) = εcentre - (εcentre - εperipheral edge) r 2 | r ∈[0,1] where r is the normalized radial coordinate.

[0028] The distributions are staggered, which results in a ring-shaped distribution of the permittivity. The width of the ring is between 1 / 10 and 1 / 15 of the radius. In each ring, the effective / equivalent permittivity is assumed to be a weighted average of the permittivity of the dielectric body εdielectricBody and the material that makes up the holes εholes (in particular, any material, such as air). The weights given to both quantities are proportional to the proportion of each material in the ring. εring =(Vholes / Vring)εholes + ((Vring - Vholes) / Vring)εdielectricBody εring = (fraction of hole material in the ring) εholes + (fraction of dielectric body in the ring) εdielectricBody

[0029] In this case, each ring is made up of an equal width of 1 mm. Naturally, the innermost region is a circle, not a ring.

[0030] Figure 2 is a graph showing εcentre = 1.42√εperipheraledge + 0.58, which shows the optimum relationship between a given edge permittivity εperipheraledge and a center permittivity εcentre.

[0031] Figure 3 shows the relationship between the εr(r) and εperipheral edge combinations: εr(r) = εcentre -(εcentre - εperipheral edge)r 2 This shows the relationship between

[0032] In this case, the graph shows a continuous distribution, but the distribution can also be implemented by regions of equal width, preferably defined to approximate a continuous distribution.

[0033] In this case, the bottom curve has a value of the second relative permittivity εperipheral edge, which is close to the value of 1.5 for air, where εcentre = 2.3.

[0034] The distribution preferably used in this application corresponds to the approximation of the ideal curve 30 shown, which is associated with the combination εcentre=2.9 and εperipheral edge=2.6.

[0035] By providing lenses that correspond to this distribution, it is possible to select a lens that is perfectly suited to the application, thereby obtaining the optimum gain. [Explanation of symbols]

[0036] 10 Lenses 12. Induced body 14 holes 30 curve

Claims

1. A radiation unit comprising a lens (10) having a dielectric refractive lens body (12) transmitting electromagnetic waves, the dielectric refractive lens body (12) has a first relative permittivity εcentre at a center region and a second relative permittivity εperipheraledge at an edge region; The first relative permittivity εcenter and the second relative permittivity εperipheral edge satisfy the relational expression εcenter = 1.42√εperipheral edge + 0.58, the tolerance is 0.2, and |εperipheral edge - εcenter| > 0.1 and εperipheral edge > 1.

5. A radiation unit characterized by satisfying.

2. 2. The radiation unit according to claim 1, The lens (10) comprises at least two regions, each said region comprises a point / location of radial coordinate r corresponding to a relative permittivity value ε(r); Here, εr(r) = εcentre - (εcentre - εperipheral edge)r ２ A radiation unit characterized by:

3. 3. The radiation unit according to claim 1, The lens (10) is a GRIN (gradient index) lens whose permittivity gradually increases or decreases from a first relative permittivity εcenter to a second relative permittivity εperipheral edge.

4. 4. The radiation unit according to claim 3, A radiation unit characterized in that the lens (10) is a generalized Luneburg lens.

5. A radiating unit according to any one of claims 1 to 3, A radiation unit, characterized in that the dielectric refractive lens body (12) is made of a solid dielectric material and has holes (14) to provide the dielectric constant distribution.

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