Abstract:
Disclosed is the technology to create connectors based solely on capacitive or inductive coupling that are impervious to ambient moisture giving rise to the idea of waterproof connectors and ultimately to waterproof consumer electronics. NMCs use no conductive tracks for ohmic contacts. The present invention is a waterproof version of a connector conforming to the USB 3.0 standard, which is visually and mechanically similar to current popular USB connectors.

Description:
BACKGROUND 
     The standard connector up until now has been referred to simply as “connector” or in some literature mated connector. By definition, an electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly [ 1 ]. Every connector, then, must “join” electrical circuits by making electrical contact between two electrical contact points. 
     Capacitive coupling can also be used to join ac circuits and simultaneously block dc offsets. This capacitive coupling effect is done without conduction current that standard connectors use to connect two circuit joints. It is done by displacement current. This work focuses on a new type of connector based entirely on this concept called the non-mating connector (NMC). Capacitive and magnetic coupling are not new concepts. 
     But only until now have they been fully integrated into connector applications. There are applications where coupling is used. Some examples could be coupling two circuits or circuit boards together with one conductive track [ 2 ] or capacitive coupled connector for PCB grounding [ 3 ]. The NMC is no different in theory as they are based on the same principles of operation; it&#39;s the application, again, to connectors. 
     NMCs use no conductive tracks for ohmic contacts. In short, there currently is no connector on the market today that is truly non-mating. This work introduces the concept and development of the NMC. 
     The primary vision for NMCs is to create connectors that are impervious to ambient moisture giving rise to the idea of waterproof connectors and ultimately to waterproof consumer electronics. One such application that an NMC can be used for is the USB 3.0 as shown in  FIG. 1   a  (traditional) and  1   b  (NMC concept). 
     This work introduces the developments and design of this connector application. The objective for creating the NMC for the USB 3.0 is the same for every NMC application which is to prevent connector contact corrosion, eliminate the use and need for mechanical latches and ultimately create a connector that is 100% sealed from the environment. 
     Included in this work are both simulated and empirical results obtained for the development of the NMC USB 3.0 which uses two parallel plates for each data line. The technique used to eliminate mechanical latches is one developed by Apple Inc. called MagSafe [ 4 ] that has a movable I/O port and housing that uses a magnet to hold the connector in place. 
     SUMMARY 
     Principles of Operation 
     The physical principals that govern the NMC in  FIG. 2  are based on three fundamental concepts of electromagnetic theory. They are Gauss&#39;s Law, voltage potential and the relationship between voltage, charge and capacitance. Later it will be explained why capacitance matters. Gauss&#39;s Law states in words that the electric flux passing through any closed surface is equal to the total charge enclosed by that surface [ 5 ]. Mathematically, this can be written as:
 
ψ=             D   s   ·dA=             ∈E·dA=∈E             dA=Q   enc  

     Where ψ is the electric flux flowing through the surface of the NMC plates, Ds is the electric flux density and Q enc  is the total change enclosed by the surface of the NMC plates. If the electric flux density is known, the electric field intensity can be found by the auxiliary equation D=∈E. The electric field for a parallel plate therefore is: 
             E   =     Q     ɛ   ⁢           ⁢   A             
Using this concept and definition for voltage potential we get:
 
             V   =       -     ∫     E   ·     ⅆ   I           =       -     ∫       Q     ɛ   ⁢           ⁢   A       ·     ⅆ   I           =         -     Q     ɛ   ⁢           ⁢   A         ⁢     ∫           ⁢     ⅆ   I         =     -       Q   ⁢           ⁢   I       ɛ   ⁢           ⁢   A                     
The relationship between voltage potential, charge and capacitance is:
 
             C   =         (     1   V     )     ⁢   Q     =         ɛ   ⁢           ⁢   A     I     =     k   ⁢           ⁢     A   I                 
Substituting the above relationship into this equation, the capacitance between the two plates finally is:
 
     
       
         
           
             C 
             = 
             
               
                 
                   ( 
                   
                     1 
                     V 
                   
                   ) 
                 
                 ⁢ 
                 Q 
               
               = 
               
                 
                   
                     ɛ 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     A 
                   
                   I 
                 
                 = 
                 
                   k 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     A 
                     I 
                   
                 
               
             
           
         
       
     
     The equation above can and does change depending on which type of geometry is used. In this case, the geometry is for parallel plates. This is exactly the governing principle behind signal transfer for the USB 3.0. 
     According to the USB 3.0 Specification Handbook, the acceptable amount of differential insertion loss in a mated cable assembly is defined by four vertices which are at: (100 MHz, −1.5 dB), (1.25 GHz, −5.0 dB), (2.5 GHz, −7.5 dB), (7.5 GHz, −25 dB). Since the NMC is essentially a parallel plate capacitor the insertion loss for it is directly related to its capacitance value. The claim for the NMC USB 3.0 is that the capacitance value will be within the range of 0.1 nF to 100 nF in order to meet the industry requirement for insertion loss. The simulations for the NMC A-receptacle and B-receptacle are shown in  FIGS. 4   a  and  4   b  respectively which confirm this claim of what is an acceptable capacitance range that yields the acceptable amount of insertion loss with respect to the standard. 
     The principles of operation behind the power NMC are the most fundamental principles of electromagnetics. They are the same governing dynamics behind solenoids, relays, motors, generators and transformers. We know that whenever a time varying current I(t) travels through a wire, a magnetic field B radiates perpendicular to the flow of current flowing through that wire as described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows for USB 3.0 A and B receptacles,  FIG. 1B  shows NMC USB 3.0 A and B receptacles and  FIG. 1C  illustrates the sliding aspect. 
         FIG. 2A  shows a high-level NMC example showing side-view and  FIG. 2B  shows the top-view thereof and sliding action and shows high-level example drawings of a single non-mating connector side view 
         FIG. 3 : insertion loss measurements with Agilent E8361A network analyzer for six different capacitance values 
         FIG. 4A  and  FIG. 4B  show HFSS simulations for differential insertion loss for the NMC USB 3.0 A-receptacle mated pair and B-receptacle mated pair, respectively 
         FIG. 5 : is a front perspective view of the mated pair for the USB 3.0 A-receptacle, the first embodiment of the invention. 
         FIG. 6 : is an unmated, exploded front perspective view of the first embodiment. 
         FIG. 7 : is an exploded clamshell-style perspective view showing internal construction parts in phantom. 
         FIG. 8 : is a cross-sectional view taken of the A-receptacle mated pair on line  4 - 4  of  FIG. 6.1 . 
         FIG. 9 : is a cross-sectional view similar to  FIG. 6.4 , showing the components partially separated. 
         FIG. 10 : is a cross-sectional view with parts broken away, taken on line  6 - 6  of  FIG. 6.5 , although unlike 
         FIG. 11 : is a front perspective view of the mated pair for the USB 3.0 B-receptacle, the second embodiment of the invention. 
         FIG. 12 : is an unmated, exploded front perspective view of the second embodiment. 
         FIG. 13 : is an exploded clamshell-style perspective view showing internal construction parts in phantom. 
         FIG. 14A  and  FIG. 14B  illustrate a demonstration of Ampere&#39;s Law (a) showing how a current I(t) traveling through a wire creates a perpendicular magnetic field B and Faraday&#39;s Law of induction (b) showing how a current I 1 (t) that travels through one wire, which produces an adjacent magnetic field B 1 , can induce a second current I 2 (t) into a second wire, separated by a distance d, resulting in a second magnetic field B 2 . 
         FIG. 15 : Physical illustration of what happens in a coil of wire when a current flows 
         FIG. 16 : High-level (simplified) Power NMC schematic setup. 
     
    
    
     INCORPORATION BY REFERENCE 
     What follows is a cite list of references which are, in addition to those references cited above and below herein, and including that which is described as background, the invention summary, brief description of the drawings, the drawings and the abstract, hereby incorporated by reference into the detailed description of the preferred embodiments below, as disclosing alternative embodiments of elements or features of the preferred embodiments not otherwise set forth in detail below. A single one or a combination of two or more of these references may be consulted to obtain a variation of the preferred embodiments described in the detailed description below. Further patent, patent application and non-patent references are cited in the written description and are also incorporated by reference into the preferred embodiment with the same effect as just described with respect to the following references: 
     Joshua Benjestorf, et al., “Non-mating connector for USB a quality waterproof connection”, 2013 IEEE International Conference on Consumer Electronics (ICCE), 11-14 Jan. 2013 ISSN: 2158-3994, pp. 560-563 
     DETAILED DESCRIPTION 
       FIG. 1  shows both the female A-receptacle and B-receptacle for the USB 3.0 (a) and its NMC equivalents (b). It should be noted that the NMC USB 3.0 uses the same physical dimensions as the current standard USB connector(s). This was a design requirement in order to maintain continuity with the industry. 
       FIGS. 1-13  show USB 3.0 A-receptacle  10  overall non-mating connector invention, showing a mated pair, the first embodiment of the invention. The Male component housing  12  for the A-receptacle. The nonconductive housing mold  13  of component  12 . It is the housing that surrounds the male component of the connector. For connectors, housing is usually called mold and some common mold materials used for connectors are PPC or Teflon. Other materials are possible so long as it is a very good insulator. The female receptacle component housing  14  for the A-receptacle. 
     The nonconductive housing mold  15  of component  14 . It is the housing that surrounds the female component of the connector. Just as in  13 , the female housing can be made from PPC or Teflon unless the application requires it to be different. For NMCs, this typically will not be the case in order to avoid having to use more than one type of material for housing mold. Other materials are possible so long as it is a very good insulator. 
     The ohmic contacts  16  of component  12  can be made from materials such as copper, but are no restricted to only copper. The only requirement is the material that makes up the ohmic contact is a good conductor of electric current. The ohmic contacts  18  of component  14 , just as in  16 , can be made from materials such as copper, but are not restricted to only copper. The only requirement is the material that makes up the ohmic contact is a good conductor of electric current. 
     The insertable portion  20  of component  12 . This insertable portion is the male A-receptacle. The high-k dielectric material  22  of component  12 . The conductive plates  24  of component  12 . The plates are mounted between the mold of  13  and the high-k dielectric layer of  22  of component  12 . This plate is made from a very thin, highly conductive metal. Examples could be, but are not limited to, copper, gold-plated stainless steel, platinum, etc. The opening  25  of component  14 . The high-k dielectric plates  26  of component  14 . The conductive plates  28  of component  14 . The plates are mounted between the mold of  15  and the high-k dielectric layer of  26  of component  14 . This plate is made from a very thin, highly conductive metal. Examples could be, but are not limited to, copper, gold-plated stainless steel, platinum, etc. The magnet  30  of component  12 . It is mounted and secured at the end tip of  12 . The purpose of  30  is for making contact with  32  with the objective of joining, locking and securing  12  and  14  together. The magnet  32  of component  14 . It is mounted and secured at the back of  14 . The purpose of  32  is for making contact with  30  with the objective of joining, locking and securing  12  and  14  together. 
     The USB 3.0 B-receptacle overall non-mating connector invention  40 , showing a mated pair, the second embodiment of the invention. The male component  42  of the second embodiment. The nonconductive housing mold  43  of component  42 . It is the housing that surrounds the male component of the connector. 
     For connectors, housing is usually called mold and some common mold materials used for connectors are PPC or Teflon. Other materials are possible so long as it is a very good insulator. The female receptacle component housing  44  for the B-receptacle. The nonconductive housing mold  45  of component  44 . It is the housing that surrounds the female component of the connector. Just as in  43 , the female housing can be made from PPC or Teflon unless the application requires it to be different. For NMCs, this typically will not be the case in order to avoid having to use more than one type of material for housing mold. 
     Other materials are possible so long as it is a very good insulator. The ohmic contacts  46  of component  42 . They can be made from materials such as copper, but are not restricted to only copper. The only requirement is the material that makes up the ohmic contact is a good conductor of electric current. The ohmic contacts  48  of component  44 . Just as in  46 , they can be made from materials such as copper, but are not restricted to only copper. These must also be good conductors. 
     The insertable portion  50  of component  42  is the male B-receptacle. The high-k dielectrics  52  of component  42  The conductive plates  54  of component  42 . The plates are mounted between the mold of  42  and the high-k dielectric layer of  52  of component  42 . This plate is made from a very thin, highly conductive metal. Examples could be, but are not limited to, copper, gold-plated stainless steel, platinum, etc. The opening  55  of component  44 . 
     The high-k dielectric plates  56  of component  44 . The conductive plates  58  of component  44 . The plates are mounted between the mold of  44  and the high-k dielectric layer of  56  of component  44 . This plate is made from a very thin, highly conductive metal. Examples could be, but are not limited to, copper, gold-plated stainless steel, platinum, etc. 
     Power Connector 
     As outlined above, the principles of operation behind the power NMC are the same governing dynamics behind solenoids, relays, motors, generators and transformers. We know that whenever a time varying current I(t) travels through a wire, a magnetic field B radiates perpendicular to the flow of current flowing through that wire as shown in  FIG. 14  and by Ampere&#39;s circular law. 
       FIG. 2A  depicts the inductive power connector, in connected configuration. Conductors  109 ,  110 ,  119 ,  129  supply power and ground to male coil  111  and female coil  112 . Permanent magnets  107  and  108  hold the connected assembly together, in much the same way discussed previously for the magnetic plates used in the capacitive connector.  FIG. 2   b  depicts the inductive power connector, in unconnected configuration. Housings  101  and  102  seal the unit from its environment, extending across in front of the coils  111  and  112   
     The mathematical derivation that describes the relationship between current density J and the magnetic field H is Ampere&#39;s circular law: 
               ∇     ×   H       =     J   +       ∂   D       ∂   t               
Where H is the magnetic field intensity, J is the density of current and D is the electric flux density. The density of the magnetic field B and its intensity H are interrelated by the permeability of free space μ 0 . The auxiliary equation relates the two: B=μ 0 H. Applying Stokes Theorem to equation (1) we can find a relationship between the magnetic field B and the current I.
 
     
       
         
           
             
               
                 
                   
                     
                       ∫ 
                       S 
                     
                     ⁢ 
                     
                       
                         ( 
                         
                           ∇ 
                           
                             × 
                             B 
                           
                         
                         ) 
                       
                       · 
                       
                         ⅆ 
                         S 
                       
                     
                   
                   = 
                   
                     
                       ∮ 
                       C 
                     
                     ⁢ 
                     
                       B 
                       · 
                       
                         ⅆ 
                         l 
                       
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       ∫ 
                       S 
                     
                     ⁢ 
                     
                       
                         ( 
                         
                           J 
                           + 
                           
                             
                               ∂ 
                               D 
                             
                             
                               ∂ 
                               t 
                             
                           
                         
                         ) 
                       
                       · 
                       
                         ⅆ 
                         S 
                       
                     
                   
                   = 
                   
                     
                       
                         μ 
                         0 
                       
                       ⁢ 
                       
                         ∫ 
                         
                           
                             ∫ 
                             S 
                             
                                 
                             
                           
                           ⁢ 
                           
                             J 
                             · 
                             
                               ⅆ 
                               S 
                             
                           
                         
                       
                     
                     = 
                     
                       
                         μ 
                         0 
                       
                       ⁢ 
                       
                         I 
                         enc 
                       
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     From equations (2) and (3) we can easily see the relationship between the magnetic field B and the current I:
 
             c   B·dl=μ   0   I   enc   (4)
 
What equation (4) says is that the magnetic field B circulating the contour is equal to the enclosed current I that is moving through it, which is exactly what  FIGS. 14   a  and  14   b  illustrate.

     For the power NMC, wire conductors simple will not cut it. The magnetic field that travels through an insulating material will have to be much stronger than the field generated by I enc . For this reason the wires are wound into a coil resulting in a magnification of the magnetic field as shown in  FIG. 15 , which provides a physical illustration of what happens in a coil of wire when a current flows through it. The magnetic lines of force from the magnetic field reinforce each other in proportion to the number of turns in the coil. The power NMC uses two coils: the M-Coil  111  (L 2 ) and F-Coil  112  (L 1 ). 
     As already mentioned, the number of turns N that a coil has can be thought of as the magnification factor of the magnetic field, which is solidly responsible for signal transfer. For example, if the strength of the magnetic field around a coil that has one turn is X, then the strength of the same coil with three turns will be 3X. The power NMC uses this concept.  FIG. 16  shows the power NMC connected to a time varying source V S , representing the signal being transmitted T X , and the receiving source T R . The F-Coil is on the transmitting side, T X , which is L 1  and the M-Coil is on the receiving side, T L , which is L 2  as shown in the figure. 
     As  FIG. 16  also shows, the ideas behind the setup of the power NMC is nothing more than an RLC resonance tank circuit which means both the transmitting and receiving sides will have to be tuned for resonance for maximum power transfer, or efficiency. Both the M and F-Coils (L 1  and L 2 ) will also need the highest Q-factor possible for optimal efficiency which is dependent on the values chosen for R S,L , L 1,2  and C S,L  according to equation (5). 
     
       
         
           
             
               
                 
                   Q 
                   = 
                   
                     
                       1 
                       R 
                     
                     ⁢ 
                     
                       
                         L 
                         C 
                       
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
     Since each power NMC has two inductive, there are two Q-factors, one for each coil called Q L1  and Q L2 .The optimal efficiency, η opt , for the entire power NMC can be found after each of the two Q-factors have been found as well as the coupling coefficient, k. This coefficient is the fraction of flux of L 1  from the transmission side that permeates through to the receiving side and into L 2  of  FIG. 16 . The optimal efficiency, be found by (6). 
     
       
         
           
             
               
                 
                   
                     η 
                     opt 
                   
                   = 
                   
                     
                       
                         k 
                         2 
                       
                       ⁡ 
                       
                         ( 
                         
                           
                             Q 
                             
                               L 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               1 
                             
                           
                           ⁢ 
                           
                             Q 
                             
                               L 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               2 
                             
                           
                         
                         ) 
                       
                     
                     
                       
                         ( 
                         
                           1 
                           + 
                           
                             
                               1 
                               + 
                               
                                 
                                   k 
                                   2 
                                 
                                 ⁢ 
                                 
                                   Q 
                                   
                                     L 
                                     ⁢ 
                                     
                                         
                                     
                                     ⁢ 
                                     1 
                                   
                                 
                                 ⁢ 
                                 
                                   Q 
                                   
                                     L 
                                     ⁢ 
                                     
                                         
                                     
                                     ⁢ 
                                     2 
                                   
                                 
                               
                             
                           
                         
                         ) 
                       
                       2 
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
     In addition to the Q-factors for each NMC inductive coil, there is the resonate frequency for optimal performance. Resonance takes place when both the capacitive reactance X C  and inductive reactance X L  for both T X  and T R  are equal and opposite. This frequency can be found by (7). 
     
       
         
           
             
               
                 
                   
                     f 
                     0 
                   
                   = 
                   
                     
                       0 
                       
                         2 
                         ⁢ 
                         π 
                       
                     
                     = 
                     
                       1 
                       
                         2 
                         ⁢ 
                         π 
                         ⁢ 
                         
                           
                             L 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             C 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
           
         
       
     
     And finally, it should be mentioned that the distance separating the two coils must be as small as possible in order to maintain optimal signal transfer. Also, the insulating material, or mold, between the two NMC receptacles need to be taken into account since the material will have an effect on how well the magnetic energy transfers from T X  to T R . For this reason, each material chosen for a particular NMC power application must have a reasonable tan(δ) which is the loss coefficient. 
     The above-description is developed on various embodiments in accordance with the present invention. It is to be noted that the scope of the present invention is not limited by the embodiments. For example, an embodiment obtained by combining arrangements or constructions included in two or more of the above-described embodiments as required also falls within the scope of the present invention.