JP5580437B2 - Corrugated horn - Google Patents

Description

  The present invention relates to a corrugated horn.

  As shown in FIG. 9, the conventional corrugated horn has a plurality of corrugated grooves 30 at regular intervals on the inner wall surface of the horn. A waveguide 7 is arranged at the bottom of the horn. By appropriately designing the pitch and depth of the corrugated groove 30, axial symmetry of the radiation pattern and excellent sidelobe characteristics can be obtained (see Patent Document 1).

  As a method for producing the corrugated horn, there is a method in which space layers and fin layers are alternately stacked and plated. In addition, there are a method of creating a corrugated groove by metal cutting, a method of creating a groove mold by electroforming after forming a groove mold, and all require high dimensional accuracy (see Patent Document 2).

  Further, as a method for producing a horn, there is a method of producing a multilayer structure of a ceramic substrate and a through via (see Patent Document 3).

JP 63-272205 A JP 59-148408 A Japanese Patent No. 3420474

  By the way, in the terahertz band, the wavelength is on the order of submillimeters, so that the depth of the corrugated groove is small and the pitch interval is narrowed. In order to manufacture such a corrugated horn, high dimensional accuracy on the order of several tens of microns is required, and thus it is difficult to manufacture at low cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a corrugated horn that can be manufactured at low cost.

In order to solve the above-described problem, the corrugated horn according to the first aspect of the present invention includes a plurality of dielectric layers in which through holes of different sizes are formed, and a conductor layer is provided on the surface of each dielectric layer, Conductor pillars that penetrate each dielectric layer in the stacking direction are provided, a conductor layer is provided up to the end surface on the through hole side of the dielectric layer in which the through holes are formed, and the size of the through holes is directed from the lower layer to the upper layer greatly to Rukoto every two or more dielectric layers and features.

  For example, the corrugated horn includes a dielectric layer located at one end in the laminating direction or two or more dielectric layers sequentially laminated including the dielectric layer, and a conductor layer provided on each dielectric layer. Instead of this, a metal layer may be provided.

  For example, the distance between the center of each conductor pillar and the end face on the through hole side of the dielectric layer penetrated by the conductor pillar is an odd number of 1/4 of the wavelength corresponding to the center frequency of the electromagnetic wave passing through the through hole. Can be doubled.

  For example, the cross section of the conductor pillar can be an ellipse.

  According to the present invention, a plurality of dielectric layers having through-holes of different sizes are stacked, a conductor layer is provided on the surface of each dielectric layer, and a conductor pillar that penetrates each dielectric layer in the stacking direction is provided. A corrugated horn that can be manufactured at low cost can be provided by providing the conductor layer up to the end face on the through hole side of the dielectric layer in which the through hole is formed. Further, the distance between the center of each conductor pillar and the end face on the through hole side of the dielectric layer penetrated by the conductor pillar is an odd number of 1/4 of the wavelength corresponding to the center frequency of the electromagnetic wave passing through the through hole. By doubling, a corrugated horn suitable for the electromagnetic wave can be provided. In addition, a dielectric layer positioned at one end in the stacking direction or two or more dielectric layers sequentially stacked including the dielectric layer, and a metal layer instead of the conductor layer provided in each dielectric layer By providing, the gain can be flattened (broadband). Moreover, the loss by the influence of electromagnetic wave leakage can be reduced by making the cross section of the said conductor pillar into an ellipse shape.

1 is a plan view of a corrugated horn according to Embodiment 1. FIG. It is an AA arrow directional view of FIG. It is an enlarged view of the part B of FIG. It is a figure which shows the calculation result which computed the characteristic of the corrugated horn which concerns on Example 1 by simulation. 6 is a view showing a cross section of a corrugated horn according to Embodiment 2. FIG. It is an enlarged view of the part C of FIG. It is a figure which shows the shape and arrangement | positioning of the conductor pillar 5 which concern on the modification common to 1st, 2nd Example. 1 is a diagram showing an aspect of mounting a corrugated horn 1; It is a figure which shows the cross section of the conventional corrugated horn.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Example 1]
1 is a plan view of a corrugated horn according to a first embodiment, FIG. 2 is a view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged view of a portion B in FIG.

  The corrugated horn 1 is formed by laminating a plurality of dielectric layers 2 in which through holes 21 having different sizes are formed, and providing a conductor layer 3 (not shown in FIG. 2) on the surface of each dielectric layer 2. Is provided with conductor pillars 5 penetrating through in the stacking direction. By adopting such a configuration, for example, a horn-like and rectangular cavity 6 whose opening gradually widens stepwise is formed. In order to supply power to the corrugated horn 1, a waveguide 7 is disposed at the bottom portion of the cavity 6. For example, an electromagnetic wave transmitted through the waveguide 7 passes through the cavity 6 and is released into free space. Alternatively, the electromagnetic wave received by the cavity 6 is guided to the waveguide 7.

  2 and 3, the size of the through hole 21 is increased every three layers, and the inner wall of the horn is stepped. The size of the through hole 21 may be changed for each layer, two layers, or three or more layers. When one dielectric layer 2 and the conductor layer 3 provided on the dielectric layer 2 are counted as one layer, the total number of layers is, for example, 10 to 40 layers. The greater the number of layers, the longer the horn length and the horn gain can be increased.

  The dielectric layer 2 is a substrate formed of a dielectric, for example, and has a thickness of several tens to several hundreds of microns. The material of the dielectric layer 2 may be a ceramic, a ceramic mixed material mixed with a glass filler, or a polymer material such as polyimide, but a material having a small dielectric loss is desirable. In addition, when using a ceramic material, baking is performed at high temperature after lamination | stacking.

  The conductor layer 3 is formed up to the end face 22 of the dielectric layer 2 in which the through holes 21 having different sizes are formed, and constitutes a fin portion of the corrugated groove. Further, the conductor layer 3 of each layer is electrically connected by the conductor pillar 5. The conductor layer 3 has a thickness of several to several tens of microns and is formed by silk screen printing or subsequent plating. The material of the conductor layer 3 is gold, silver, tungsten, copper or the like.

  A plurality of conductive pillars 5 penetrate one dielectric layer 2 and constitute the bottom of a corrugated groove filled with a dielectric. For example, cylindrical vias are formed around the through holes 21 of the dielectric layer 2 at predetermined intervals, and the vias are filled with metal, which becomes the conductor pillars 5. The shapes of the conductor pillars 5 and vias may be square pillars or the like, and the intervals are not necessarily the same. Part of the electromagnetic wave transmitted through the cavity 6 enters the dielectric layer 2. The conductor column 5 reflects the invading electromagnetic wave to the cavity 6. In order to prevent electromagnetic waves from leaking between the conductor columns 5 without being reflected by the conductor columns 5, the interval between the conductor columns 5 is 1/10 (1/10 wavelength) or less of the wavelength corresponding to the center frequency of the electromagnetic waves. It is desirable that

For the conductor column 5 closest to the end face 22 on the through hole 21 side of the dielectric layer 2, the distance D between the center and the end face 22 is an electromagnetic wave (an electromagnetic wave passing through the through hole 21 (cavity 6)). It is desirable to set it to an odd number (2n + 1: n = 0, 1, 2,...) Times 1/4 of the wavelength corresponding to the center frequency. When the effective dielectric constant of the dielectric layer 2 is ε _eff = (1 + ε _r ) / 2 and the wavelength in the dielectric layer 2 is λ _eff = λ / ε _eff ^0.5 , 125 um corresponds to a quarter wavelength. Actually, the effective reflection point of the electromagnetic wave also depends on the interval between the conductor columns 5 and the diameter of the conductor columns 5, and the optimum distance D is obtained by numerical calculation. For example, when the dielectric constant is 6.8, the thickness of the dielectric layer 2 is 100 μm, the diameter of the conductor pillar 5 is 100 μm, and the center frequency is 300 GHz, the distance D is about 200 μm.

  FIG. 4 is a diagram illustrating a calculation result obtained by calculating the characteristics of the corrugated horn according to the first embodiment by simulation.

  In Example 1, the radiation pattern of the E plane and the radiation pattern of the H plane have good axial symmetry, and the axial symmetry of the radiation pattern, which is a characteristic of the corrugated horn, and excellent sidelobe characteristics can be obtained. Note that the step width L shown in FIG. 3 is a parameter that is appropriately adjusted so that the radiation pattern and band characteristics are desired, and does not necessarily have to be constant in all layers.

[Example 2]
FIG. 5 is a diagram illustrating a cross-section of the corrugated horn according to the second embodiment, and FIG. 6 is an enlarged view of a portion C in FIG.

  The difference from the corrugated horn of the first embodiment is that in FIG. 3, the three dielectric layers 2 having the smallest size of the through holes 21 (including the dielectric layer 2 positioned at one end in the stacking direction are sequentially included). Instead of the three dielectric layers 2) laminated and the conductor layer 3 provided on each dielectric layer 2, a metal layer 8 is provided as shown in FIGS. When one dielectric layer 2 and the conductor layer 3 provided on the dielectric layer 2 are counted as one layer, the three layers are replaced by the metal layer 8. The number of layers is not limited to 3, but may be 1, 2 or 4 or more.

  The metal layer 8 is a metal sheet in which through holes are formed by cutting or etching, for example.

  In the vicinity of the first layer connected to the waveguide 7, the electric field density is high, and the loss due to the leakage of electromagnetic waves from between the conductor columns 5 increases as the frequency of the electromagnetic waves increases. The gap between vias filling the metal as the conductor pillars 5 is several tens of um, which is a manufacturing limit. Therefore, the metal layer 8 is provided in the vicinity of the first layer having a particularly high electric field density. Thereby, the effect of preventing leakage of electromagnetic waves can be enhanced as compared with the first embodiment. Further, the frequency characteristic of loss can be flattened, that is, gain flatness can be improved. The thickness of the metal layer 8 is a matter to be designed as appropriate, and is, for example, about 1/4 of the wavelength. The through hole of the metal layer 8 is preferably tapered. By doing so, it is possible to reduce the influence of reflection due to the discontinuity of impedance caused by the step and the connection with the waveguide 7 as compared with the first embodiment.

(Modification)
As is common to the first and second embodiments, a current is generated in the traveling direction on the long side of the waveguide 7, and the electric field strength increases at the center of the long side. Even in layers other than the first layer connected to the waveguide 7, a loss due to electric field leakage occurs.

  FIG. 7 is a diagram showing the shape and arrangement of the conductor pillars 5 according to a modification common to the first and second embodiments.

  The conductor column 5 of the first and second embodiments has been described as a cylinder or a quadrangular column, but the cross section may be an ellipse. That is, an elliptical slit hole is formed in the dielectric layer 2, and the slit hole is filled with metal in the same manner as the via. Thereby, the conductor pillar 5 whose section is an ellipse is formed. With the conductor pillar 5 having such a shape, it is possible to reduce loss due to the influence of leakage of electromagnetic waves from between the conductor pillars 5. In FIG. 7, the conductor pillar 5 having an oval cross section is arranged in the vicinity of the long side and the short side of the through-hole 21. It is. Further, the columnar conductor pillars 5 may be disposed between the conductor pillars 5 having an oval cross section. With such an arrangement, it is possible to further reduce leakage of electromagnetic waves.

  FIG. 8 is a diagram illustrating one mode of mounting the corrugated horn 1.

  The corrugated horn 1 includes, for example, a plurality of wiring boards 11 (referred to as LTCC board 11A as a whole) stacked to mount a high frequency integrated circuit (MMIC) 10 and a conductor layer (not shown) provided on the surface of each wiring board 11. 1) is configured as the dielectric layer 2 and the conductor layer 3 in FIG.

  The MMIC 10 includes an amplifier or the like used for transmission / reception of electromagnetic waves, and is connected to a coupler 13 configured to couple with the cavity 6 with high efficiency. The MMIC 10 is covered with a lid 14 made of metal or the like. As described above, the MMIC may be mounted on the LTCC substrate and combined with the corrugated horn 1 to form a module.

DESCRIPTION OF SYMBOLS 1 ... Corrugated horn 2 ... Dielectric layer 3 ... Conductor layer 5 ... Conductor pillar 6 ... Cavity 7 ... Waveguide 8 ... Metal layer 10 ... MMIC
DESCRIPTION OF SYMBOLS 11 ... Wiring board 11A ... LTCC board 13 ... Coupler 14 ... Cover 21 ... Through-hole 22 ... End surface 30 ... Corrugated groove

Claims (4)

A plurality of dielectric layers having through holes of different sizes are laminated, a conductor layer is provided on the surface of each dielectric layer, conductor pillars that penetrate each dielectric layer in the lamination direction are provided, and the through holes Provide a conductor layer up to the end face on the through hole side of the formed dielectric layer ,
Corrugated horn characterized by greatly be Rukoto every two or more dielectric layers towards the upper size of the through-hole from the lower layer.   A metal layer is provided in place of the dielectric layer located at one end in the stacking direction or two or more dielectric layers sequentially stacked including the dielectric layer and the conductor layer provided in each dielectric layer. The corrugated horn according to claim 1, wherein:   The distance between the center of each conductor pillar and the end face on the through hole side of the dielectric layer penetrated by the conductor pillar is an odd multiple of 1/4 of the wavelength corresponding to the center frequency of the electromagnetic wave passing through the through hole. The corrugated horn according to claim 1 or 2, wherein   The corrugated horn according to any one of claims 1 to 3, wherein a cross section of the conductor column is an ellipse.

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