Patent Publication Number: US-2023152361-A1

Title: Testing base

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefits of U.S. application Ser. No. 63/279,684, filed on Nov. 16, 2021, and Taiwan application serial no. 111137685, filed on Oct. 4, 2022. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND 
     Technical Field 
     This disclosure relates to a testing base, and in particular to a testing base adapted for antennas. 
     Description of Related Art 
     The radiation pattern of a planar antenna (especially a patch antenna) varies with a feed point, so measurement and verification procedures are usually taken to verify the characteristics of a planar antenna. The conventional test method is to conduct the test through the detection system as shown in  FIG.  1   . 
       FIG.  1    is a schematic diagram of a conventional detection system. Referring to  FIG.  1   , a detection system  10  includes a platform  12 , two probes  14 , and a microscope lens  16 . The platform  12  is configured to carry a component to be tested (e.g., a planar antenna, not shown). The two probes  14  are located above the platform  12  and configured to contact the feed point and a ground point of the component to be tested. The microscope lens  16  is located above the platform  12  and the two probes  14 . However, the radiation pattern of the component to be tested is actually affected by the nearby metal, making it difficult to obtain more realistic test results. 
     SUMMARY 
     The disclosure provides a testing base, capable of helping provide more realistic test results. 
     A testing base of the disclosure includes a housing, a carrier, a wave absorber, and a filler. The housing has an inner surface. The carrier is disposed on the housing. The carrier includes an upper surface, a lower surface, and a groove recessed in the upper surface. The groove is adapted for accommodating a component to be tested. The lower surface and the inner surface of the housing define a cavity body together. The wave absorber is disposed on the inner surface of the housing. The filler is filled the cavity body and contacts the wave absorber and the carrier. A relative permittivity of the filler is less than or equal to 2. 
     In an embodiment of the disclosure, a thickness of the carrier corresponding to the groove is less than 5 mm. 
     In an embodiment of the disclosure, the carrier includes a through hole. The through hole is located in the groove and is connected from the upper surface of the carrier to the lower surface of the carrier. 
     In an embodiment of the disclosure, the wave absorber is further disposed on a part of the lower surface of the carrier corresponding to a part outside the groove. 
     In an embodiment of the disclosure, the lower surface is a plane. 
     In an embodiment of the disclosure, the lower surface is a curved surface. 
     In an embodiment of the disclosure, a diameter or a length of the groove is D cm, a wavelength of a radiation signal of the component to be tested adapted for the testing base is greater than or equal to λ cm, and a depth of the cavity body is greater than or equal to 2D 2 /λ cm. 
     In an embodiment of the disclosure, an equivalent relative permittivity of the filler is between 1.2 and 1.6. 
     In an embodiment of the disclosure, the filler includes multiple filler layers, the filler layers have multiple different relative permittivities, and the relative permittivities of the filler layers are greater along a direction farther away from the carrier. 
     In an embodiment of the disclosure, a material of the filler includes foamed polytetrafluoroethylene (PTFE) or foamed polyethylene (PE) with a foaming degree between 50% and 80%. 
     Based on the above, the lower surface of the carrier of the testing base of the disclosure and the inner surface of the housing define the cavity body together. The wave absorber is disposed on the inner surface of the housing. The filler is filled in the cavity body. The relative permittivity of the filler is less than or equal to 2. The component to be tested is located in the groove recessed in the upper surface of the carrier. The wave absorber is configured to absorb energy radiated downward by the component to be tested (e.g., a planar antenna) to better simulate an open environment. The filler provides support to the carrier, and the relative permittivity of the filler is less than or equal to 2, which is closer to the air environment. The testing base of the disclosure may better simulate the open air environment and help provide more realistic test results. 
     To make the aforementioned more comprehensible, several accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIG.  1    is a schematic diagram of a conventional detection system. 
         FIG.  2 A  is a schematic diagram of a testing base according to an embodiment of the disclosure. 
         FIG.  2 B  is a schematic diagram of a testing base according to another embodiment of the disclosure. 
         FIG.  2 C  is a schematic diagram of a testing base according to another embodiment of the disclosure. 
         FIG.  3 A  is a schematic diagram of a testing base according to another embodiment of the disclosure. 
         FIG.  3 B  is a schematic diagram of a testing base according to another embodiment of the disclosure. 
         FIG.  4    is a schematic diagram of a testing base according to another embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG.  2 A  is a schematic diagram of a testing base according to an embodiment of the disclosure. Referring to  FIG.  2 A , a testing base  100  according to this embodiment may replace a platform of a conventional detection system (e.g., a platform  12  of  FIG.  1   ) to provide better testing conditions. The testing base  100  according to this embodiment includes a housing  110 , a carrier  120 , a wave absorber  140 , and a filler  130 . 
     In this embodiment, the housing  110  is, for example, a box or a hollow cylinder, and a material of the housing  110  may be metallic or non-metallic material. The carrier  120  is, for example, a plate disposed on the housing  110 . A material of the carrier  120  is non-metallic, such as a low-dielectric ceramic material. 
     The carrier  120  includes an upper surface  122 , a lower surface  124 , and a groove RA recessed in the upper surface  122 . The groove RA is adapted for accommodating a component to be tested  200 . In this embodiment, the component to be tested  200  is, for example, a planar antenna (patch antenna), but the type of the component to be tested  200  is not limited thereto. 
     In this embodiment, the upper surface  122  of the carrier  120  is a plane outside the groove RA, and the lower surface  124  of the carrier  120  is a plane. That is, the carrier  120  is substantially equal in thickness outside the groove RA. In this embodiment, a thickness T 1  of a part of the carrier  120  corresponding to the groove RA is less than 5 mm, and a thickness T 2  of a part of the carrier  120  outside the groove RA is greater than 10 mm. The smaller thickness T 1  of the part of the carrier  120  corresponding to the groove RA reduces a chance of the carrier  120  blocking a signal radiated downward by the component to be tested  200 . 
     The wave absorber  140  is disposed on an inner surface  112  of the housing  110 . The wave absorber  140  is configured to absorb energy of a radiation signal and reduce a chance of energy reflection. A material of the wave absorber  140  is, for example, foam sponge, but the material of the wave absorber  140  is not limited thereto. In an embodiment not shown, the wave absorber  140  may have a multi-layer structure, so that the energy of the radiation signal may be rapidly attenuated therein. 
     The lower surface  124  of the carrier  120  and the inner surface  112  of the housing  110  define a cavity body together. The filler  130  is filled in the cavity body, and contacts the wave absorber  140  and the carrier  120  to provide good and stable support. In this embodiment, a relative permittivity of the filler  130  is less than or equal to 2. 
     Specifically, as can be seen from Table 1 below, the relationship between a foaming degree of the filler  130  and an equivalent relative permittivity can be seen from Table 1 below. The smaller the foaming degree, the better the support, but the greater the equivalent relative permittivity. In this embodiment, the filler  130  is intended to be configured to provide support, which requires a certain level of supporting property. However, since the environment inside the cavity body is meant to simulate an air environment, the closer the environment inside the cavity body is to air (the equivalent relative permittivity of 1), the better. Therefore, the equivalent relative permittivity of the filler  130  needs to be balanced with the supporting property. In a preferred embodiment, the equivalent relative permittivity of the filler  130  is between 1.2 and 1.6. A material of the filler  130  includes foamed polytetrafluoroethylene (PTFE) or foamed polyethylene (PE) with a foaming degree between 50% and 80%. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE I 
               
               
                   
                   
               
               
                   
                 foaming degree (%) 
                 equivalent relative permittivity 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 0 
                 2.32 
               
               
                   
                 10 
                 2.16 
               
               
                   
                 20 
                 2.01 
               
               
                   
                 30 
                 1.86 
               
               
                   
                 40 
                 1.72 
               
               
                   
                 50 
                 1.59 
               
               
                   
                 60 
                 1.46 
               
               
                   
                 70 
                 1.34 
               
               
                   
                 80 
                 1.22 
               
               
                   
                 90 
                 1.15 
               
               
                   
                   
               
            
           
         
       
     
     Furthermore, in this embodiment, a depth L of the cavity body is related to a wavelength and a size of the radiation signal of the component to be tested  200 . The size of the component to be tested  200  is close to a diameter D 1  of the groove RA. If the diameter D 1  or a length of the groove RA is D cm, the wavelength of the radiation signal of the component to be tested  200  adapted for the testing base  100  is greater than or equal to λ cm, and the depth L of the cavity body is greater than or equal to 2D 2 /λ cm. 
     For example, a millimeter-wave FR2 frequency band is about 26 GHz to 30 GHz, a corresponding wavelength λ is about 1 cm for 30 GHz, and if the diameter D 1  of the groove RA is 5 cm, it can be seen by bringing in the above formula that when the depth L or a height of the cavity body is about 50 cm, the frequency band below 30 GHz may be satisfied. 
     If the platform  12  of a detection system  10  of  FIG.  1    is replaced by the testing base  100  of this embodiment, the component to be tested  200  radiates downward into the testing base  100 , while the microscope lens  16  probes above the testing base  100 . There is a wave absorber  140  inside the testing base  100 , which absorbs the energy of the radiation signal and makes the reflected energy smaller, and the relative permittivity of the filler  130  is less than or equal to 2, making the testing base  100  similar to the open air environment, closer to the actual use of the state, which helps to get a more realistic test result of antenna characteristics such as S 11  of the component to be tested  200 . Thus, the antenna characteristics obtained by using the testing base  100  of this embodiment to carry the component to be tested  200  may be less affected by the metal above the testing base  100  than in the conventional way. 
     The following is a description of the main differences between the testing bases of other implementations. The identical or similar components are indicated by the same or similar symbols and are not repeated in the following. 
       FIG.  2 B  is a schematic diagram of a testing base according to another embodiment of the disclosure. Referring to  FIG.  2 B , the main difference between a testing base  100   a  of  FIG.  2 B  and the testing base  100  of  FIG.  2 A  is that, in this embodiment, a carrier  120   a  of the testing base  100   a  includes a through hole O 1 , and the through hole O 1  is located in the groove RA and is connected from the upper surface  122  of the carrier  120   a  to the lower surface  124  of the carrier  120   a . The through hole O 1  may help the radiation signal transmission of the component to be tested  200 , and reduce the influence of the testing base material and structure on the characteristics of the component to be tested  200 . 
     In this embodiment, since the carrier  120   a  is provided with a through hole O 1  at the groove RA, a thickness T 1 ′ of a part of the carrier  120   a  corresponding to the groove RA may be greater, for example, 8 mm, to provide good support. 
       FIG.  2 C  is a schematic diagram of a testing base according to another embodiment of the disclosure. Referring to  FIG.  2 C , the main difference between a testing base  100   b  of  FIG.  2 C  and the testing base  100  of  FIG.  2 A  is that, in this embodiment, the testing base  100   b  further includes a wave absorber  141  disposed on a part of the lower surface  124  of the carrier  120   a  corresponding to a part outside the groove RA. That is, in this embodiment, the testing base  100   b  includes a wave absorber  140  disposed on the inner surface  112  of the housing  110  and a wave absorber  141  disposed on a part of the lower surface  124  of the carrier  120   a  corresponding to a part outside the groove RA, and provides better absorbency. 
       FIG.  3 A  is a schematic diagram of a testing base according to another embodiment of the disclosure. Referring to  FIG.  3 A , the main difference between a testing base  100   c  of  FIG.  3 A  and the testing base  100  of  FIG.  2 A  is that, in this embodiment, a lower surface  124   c  of a carrier  120   c  is a curved surface, while making the carrier  120   c  close to an arch structure. 
     The lower surface  124   c  of the carrier  120   c  is designed, for example, along a local shape of a radiation pattern. The reason for this design is that a standard radiation pattern of an antenna is spherical, and if an antenna is placed in the groove RA and radiates towards the bottom of  FIG.  3 A , the signal is weak near the left and right side of the groove RA, which is not the location to be tested. Thus, the lower surface  124   c  of the carrier  120   c  being a curved surface does not affect the test result, and accordingly, the shape of the lower surface  124   c  of the carrier  120   c  may vary. 
     In addition, the design of the lower surface  124   c  of the carrier  120   c  being curved (arch-shaped) may also increase the structural strength. Of course, in other embodiments, the lower surface of the carrier may also be other shapes 
       FIG.  3 B  is a schematic diagram of a testing base according to another embodiment of the disclosure. Referring to  FIG.  3 B , the main difference between a testing base  100   d  of  FIG.  3 B  and the testing base  100   c  in  FIG.  3 A  is that, in this embodiment, the testing base  100   d  further includes a wave absorber  141  disposed on a part of the lower surface  124   c  of the carrier  120   c  corresponding to a part outside the groove RA. That is, in this embodiment, the testing base  100   d  includes a wave absorber  140  disposed on the inner surface  112  of the housing  110  and a wave absorber  141  disposed on a part of the lower surface  124   c  of the carrier  120   c  corresponding to a part outside the groove RA, and provides better absorbency. 
       FIG.  4    is a schematic diagram of a testing base according to another embodiment of the disclosure. Referring to  FIG.  4   , the main difference between a testing base  100   e  of  FIG.  4    and the testing base  100  of  FIG.  2 A  is that, in this embodiment, a filler  130   e  includes multiple filler layers  131 ,  133 , and  135 . The filler layers  131 ,  133 , and  135  have different relative permittivities, and the relative permittivities of the filler layers  131 ,  133 , and  135  are greater along a direction farther away from the carrier  120  (further down). 
     Specifically, the equivalent relative permittivity of the filler layer  131  is 1.22, and the foaming degree is, for example, 80%. The equivalent relative permittivity of the filler layer  133  is 1.34, and the foaming degree is, for example, 70%. The equivalent relative permittivity of the filler layer  135  is 1.46, and the foaming degree is, for example, 60%. In other words, in this embodiment, the farther the filler layers  131 ,  133 , and  135  are from the carrier  120  (the further down), the smaller the foaming degree, and the stronger the support, to provide good support. 
     To sum up, the lower surface of the carrier of the testing base of the disclosure and the inner surface of the housing define the cavity body together. The wave absorber is disposed on the inner surface of the housing. The filler is filled in the cavity body. The relative permittivity of the filler is less than or equal to 2. The component to be tested is located in the groove recessed in the upper surface of the carrier. The wave absorber is configured to absorb energy radiated downward by the component to be tested (e.g., a planar antenna) to better simulate an open environment. The filler provides support to the carrier, and the relative permittivity of the filler is less than or equal to 2, which is closer to the air environment. The testing base of the disclosure may better simulate the open air environment and help provide more realistic test results. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.