Patent Publication Number: US-2022217878-A1

Title: Cable

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a cable, and more particularly to a cable used to transmit high frequency signals. 
     2. Description of Related Arts 
     With the development and popularization of electronic technology products, signal cables are widely used in household appliances, instrumentation, automation equipment, data centers, servers, switches, cloud computing and  5 G as a tool for signal transmission. However, in the signal transmission process, the cable is susceptible to interference from external electromagnetic signals, so it is often necessary to use a shielding structure to eliminate or reduce the interference of the external electromagnetic field and to prevent the leakage of the transmission signal. The traditional shielding layer is made of aluminum-coated PET (polyethylene terephthalate) material. However, the loss factor of PET material is relatively large, which affects signal transmission. 
     Therefore, it is necessary to provide an improved cable with strong anti-interference performance and better shielding effect. 
     SUMMARY OF THE INVENTION 
     A main object of the present invention is to provide a cable, which has good shielding effect and stable signal transmission capability. 
     To achieve the above-mentioned object, a cable comprises: a pair of core wires; a shielding layer covering the core wires; and an outer insulating layer covering the shielding layer; wherein the shielding layer is aluminum coated PP, or aluminum coated PE, or aluminum coated PTFE, or copper coated PP, or copper coated PE, or copper coated PTFE. 
     Compared to prior art, the present invention uses aluminum coated PP, or aluminum coated PE, or aluminum coated PTFE, or copper coated PP, or copper coated PE, or copper coated PTFE, so that the signal attenuation value is small, and the reliability of signal transmission is ensured. Also, the cable of the present invention has the ability to transmit high-speed data signals with a frequency greater than 40 GHz. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is the front view of a cable of the present invention; and 
         FIG. 2  is the test curve of the cable of the present invention and a traditional cable. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , which is a cable  100  of the present invention. The cable  100  includes a pair of core wires  10 , a shielding layer  30  covering the core wires  10 , an outer insulating layer  50  covering the shielding layer  30 , and a ground wire  60  located between the shielding layer  30  and the outer insulating layer  50 . 
     In this embodiment of two core wires  10 , each core wire  10  includes an inner conductor  1  and an inner insulating layer  2  covering the inner conductor  1 . The inner insulating layer  2  of each core wire  10  is extruded and molded to cover the inner conductor  1 . The inner conductor  1  is used for transmitting high-speed signal. The inner insulating layers  2  of the two core wires  10  are in contact with each other. The shielding layer  30  is wrapping around the two core wire  10  in a longitudinal wrapping way or in a spiral winding way. The upper and lower sides between the shielding layer  30  and the two core wires  10  form air gaps  70 . There are two ground wires  60 , and the ground wires  60  are located on the left and right sides of the shielding layer  30 , or located in the corresponding air gaps  70  on the upper and lower sides. The ground wire  60  can be only one. The shielding layer  30  can be one of Aluminum coated with PP (polypropylene), Aluminum coated with PE (polyethylene), Aluminum coated with PTFE (Polytetrafluoroethylene), Copper coated with PP, Copper coated with PE, Copper coated with PTFE. The shielding layer  30  is a PP layer  31  and a metal aluminum layer  32  formed on the PP layer  31 , or a PE layer  31  and a metal aluminum layer  32  formed on the PE layer  31 , or a PTFE layer  31  and a metal aluminum layer  32  formed on the PTFE layer  31 , or a PP layer  31  and a metal copper layer  32  formed on the PP layer  31 , or a PE layer  31  and a metal copper layer  32  formed on the PE layer  31 , or a PTFE layer  31  and a metallic copper layer  32  formed on the PTFE layer  31 . The aluminum layer  32  of the shielding layer  30  faces outward or the copper layer  32  faces outward. The outer insulating layer  50  can be provided as one layer or multiple layers, and its material can be PET (polyethylene terephthalate) tape. The outer insulating layer  50  is wrapped around the shielding layer  30  in a spiral winding way or a longitudinal winding way. 
     Please refer to  FIG. 2 , which is a comparison of the performance test curves of the cable of the present invention and the traditional cable, adopts the cable with the above structure and the wire gauge is  30 . The measured result of the cable with the shielding layer of aluminum-coated PP is curve  1 , and the measured result of the cable with the shielding layer of aluminum coated PET is curve  2 .The abscissa is the frequency, unit in GHz, and the ordinate is the loss, unit in dB. 
       FIG. 2  is the SDD21 (Differential Insertion Loss) curve of the two cables. It can be seen that as the frequency increases, the differential insertion loss has no cliff-like attenuation before 40 GHz, and the attenuation of the cable with aluminum coated PP as the shielding layer is smaller than the attenuation of the cable with aluminum-coated PET as the shielding layer. And as the frequency increases, the gap between the two increases. The attenuation of the cable with aluminum coated PP as the shielding layer is less than −14 dB at 40 GHz. At a frequency of 40 GHz, the cable with aluminum-coated PP has a 2 dB lower attenuation than the cable with aluminum-coated PET. 
     The present invention uses aluminum coated PP, or aluminum coated PE, or aluminum coated PTFE, or copper coated PP, or copper coated PE, or copper coated PTFE as the shielding layer. The loss factor of PP, PE, PTFE material is smaller than that of traditional PET material, so the overall attenuation value of the cable is smaller, which improves the shielding effect. Compared with PET, PP material is lighter in weight and cheaper in price. The cable of the present invention has a high-speed data transmission capability with a signal transmission frequency greater than 40 GHz.