Patent Publication Number: US-2016249157-A1

Title: Adaptable coil-nfc antenna for powered and unpowered applications

Description:
BACKGROUND 
     Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. 
     Near Field Communication (NFC) technology may be employed with portable devices to enable short-range wireless communication when the portable device is within a predefined range of another device or transmitter. Active NFC may be enabled when an NFC antenna is connected with an external power supply, such as a battery of a portable device. In some portable devices, such as smartphones, passive NFC systems may not function because additional shielding caused by elements of the smartphone, such as the battery and other metal layers, may prevent the NFC antenna from receiving enough power to operate. Since the NFC antenna incorporated with smartphones needs power to operate, contactless systems and applications, such as a contactless payment system may not be usable if the battery of the smartphone is uncharged. Wireless Power Transfer (WPT) technology may enable a smartphone to be wirelessly charged employing a WPT antenna installed on the smartphone, in addition to the NFC antenna. However, even with widespread WPT technology, portable devices may become uncharged, inhibiting the ability to use contactless systems installed on the portable devices. 
     SUMMARY 
     According to some examples, methods are described to provide adaptable near field communication (NFC) for powered and unpowered applications in a portable device. The method may include receiving a wireless signal; determining whether the received wireless signal is a wireless power transfer (WPT) signal; in response to a determination that the received wireless signal is the WPT signal, charging a battery of the portable device; and in response to a determination that the received wireless signal is not the WPT signal, modifying a configuration of an antenna on the portable device to support NFC. The method may also include determining whether a power level of the portable device is sufficient to support active NFC and in response to a determination that the power level of the portable device is insufficient to support active NFC, enabling passive NFC through the modified configuration antenna, where the passive NFC relies on power derived from the received wireless signal through the modified configuration antenna. 
     According to other examples, a portable device capable to support adaptable near field communication (NFC) for powered and unpowered applications is described. The portable device may include a processing block, a portable power source, a switchable antenna configured to support wireless power transfer (WPT) in a first configuration and NFC in a second configuration and to receive a wireless signal, and a secure element (SE) coupled to the switchable antenna. The SE may be configured to determine whether the received wireless signal is a WPT signal; in response to a determination that the received wireless signal is the WPT signal, charge a battery of the portable device; in response to a determination that the received wireless signal is not the WPT signal, modify a configuration of the antenna to the second configuration; determine whether a power level of the portable device is sufficient to support active NFC; in response to a determination that the power level of the portable device is insufficient to support active NFC, enable passive NFC through the antenna in the second configuration, where the passive NFC relies on power derived from the received wireless signal through the antenna in the second configuration; and in response to a determination that the power level of the portable device is sufficient to support active NFC, enable active NFC through the antenna in the second configuration, where the active NFC relies on power derived from the battery of the portable device. 
     According to further examples, a near field communication (NFC) module capable to support powered and unpowered applications is described. The NFC module may include a switchable antenna configured to support wireless power transfer (WPT) in a first configuration and NFC in a second configuration and to receive a wireless signal; and a secure element (SE) coupled to the switchable antenna. The SE may be configured to determine whether the received wireless signal is a WPT signal; in response to a determination that the received wireless signal is the WPT signal, charge a battery of a portable device that hosts the NFC module; in response to a determination that the received wireless signal is not the WPT signal, modify a configuration of the antenna to the second configuration; determine whether a power level of the portable device that hosts the NFC module is sufficient to support active NFC; in response to a determination that the power level of the portable device is insufficient to support active NFC, enable passive NFC through the antenna in the second configuration, where the passive NFC relies on power derived from the received wireless signal through the antenna in the second configuration; in response to a determination that the power level of the portable device is sufficient to support active NFC, enable active NFC through the antenna in the second configuration, where the active NFC relies on power derived from the battery of the portable device; and upon detection of a completion of the passive NFC or the active NFC, switch the antenna to the first configuration. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of this disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which: 
         FIG. 1  illustrates mounting of a secure element (SE) integrated circuit (IC) in a smartcard; 
         FIG. 2  illustrates a conceptual diagram of a subscriber identity module (SIM)-centric vision of how to use an SE chip for a payment application on a smartphone; 
         FIG. 3  illustrates an example comparison of power versus frequency distributions for NFC and wireless power transfer (WPT) communications; 
         FIG. 4  illustrates an example switchable NFC/WPT antenna circuit and implementation of NFC and power connections on a charger pack of a smartphone; 
         FIG. 5  illustrates a conceptual diagram of a portable device operational blocks implementing a switchable NFC/WPT antenna; 
         FIG. 6  illustrates a general purpose computing device, which may be used to implement adaptable coil-NFC antenna systems for powered and unpowered applications; 
         FIG. 7  is a flow diagram illustrating an example process to implement adaptable coil-NFC antenna systems for powered and unpowered applications that may be performed by a computing device such as the computing device in  FIG. 6 ; and 
         FIG. 8  illustrates a block diagram of an example computer program product, all arranged in accordance with at least some embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. The aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. 
     Briefly stated, technologies are generally described to provide adaptable near field communication (NFC) in portable devices to enable a portable device to provide wireless power transfer (WPT) functionality and NFC functionality. According to some examples, a wireless power antenna installed on the portable device may be configured to function as a WPT antenna and as an NFC antenna. For example, the wireless power antenna may be a coil, which may be modified to adjust a quality factor (Q) by incorporation of a switchable resistor element. The modified coil may function as a wireless power receiver/transmitter with a high Q value when the resistor element is not added and as an active NFC antenna with a low Q value when the resistor is added. Additionally, the modified coil may further enable the portable device to function as a passive NFC antenna when the portable device is unpowered. 
       FIG. 1  illustrates mounting of a secure element (SE) integrated circuit (IC) in a smartcard, arranged in accordance with at least some embodiments described herein. 
     A diagram  100  shows an example SE chip  110  mounted within a smartcard  102  to enable secure NFC between portable devices. A cross section view  122  illustrates the SE chip  110  mounted within the smartcard  102 . An example smartcard  102  may be a subscriber identity module (SIM) card associated with a portable device. As shown in the cross section view  122 , the SE chip  110  may be embedded within a substrate  106  with an active side  118  of the SE chip  110  in contact with an encapsulation portion  116  of the smartcard  102 . One or more bond wires  108  may electrically connect electrical contacts  112  on the surface of the smartcard  102  with the SE chip  110 . The substrate  106  including the SE chip  110  may be adhered to the smartcard  102  employing a thermoplastic adhesive  114  such as hot-melt. A top view  120  illustrates an example configuration of the electrical contacts  112  associated with the SE chip  110  on the surface of the smartcard  102 . 
     In a system according to embodiments, the SE chip  110  may be incorporated with the smartcard  102  and/or a SIM card associated with a portable device equipped with NFC capabilities. The SIM card may provide identification, authentication, data storage and application processing to enable the portable device to execute secure transactions employing NFC. The SE chip  110  of the smartcard  102  may store sensitive data such as credentials, keys, passwords, instructions and other secure information to enable the secure NFC. The sensitive data may be stored encrypted within the SE chip  110  and may be decrypted by processors of the SE chip  110 . The SE chip  110  may also be configured to detect chip tampering and to erase the secure information if tampering is detected. In some examples, the SE chip  110  may be covered in a wire mesh configured to hide the chip visually and electrically, and if the mesh is removed and/or otherwise tampered with, the SE chip  110  may stop functioning and may erase the secure information. 
     An example secure transaction employing NFC may include a contactless payment system using a portable device provisioned with a payment application and payment account information. An SE chip incorporated with the portable device may store and encrypt the secure payment account information, such as a credit card number and credentials. The portable device may use NFC to enable the payment information to be wirelessly exchanged between the portable device and a point of sale terminal when the portable device is placed within a predefined range of the point of sale terminal. 
     Active NFC as described herein may be powered by a battery of the portable device. The battery may be wirelessly charged employing WPT when a WPT antenna is incorporated with the portable device and the portable device is placed within a predefined range of a power transmitter. Some portable devices may include both an NFC antenna and a WPT antenna to enable both NFC and WPT functionality. In some embodiments as described herein, an installed WPT antenna may be configured to function also as an NFC antenna to eliminate the need for two separate antennas. Additionally, the WPT antenna may enable the NFC antenna to function when the portable device is unpowered such as when the battery is uncharged, which may enable applications, such as the contactless payment system, to operate when the portable device is unpowered. 
       FIG. 2  illustrates a conceptual diagram  200  of a subscriber identity module (SIM)-centric vision of how to use an SE chip for a payment application on a smartphone, arranged in accordance with at least some embodiments described herein. 
     As described herein, a portable device  202  such as a smartphone may be equipped with near field communication (NFC)  206  capabilities to enable contactless payment with a point of sale (POS) terminal  208 . The portable device  202  may implement a SIM card  216 , or a Universal Integrated Circuit Card (UICC), as the NFC payment card. In example embodiments, the SIM card  216  may be and/or may include an SE chip configured to store and encrypt secure information. The SE chip may be illustrated by contacts  227  in the diagram  200 . 
     As also illustrated in the diagram  200 , a contactless payment application associated with the portable device  202  may include one or more software components. The software components may be executed on a processor  204  of the portable device  202  and/or on a processor of the SIM card  216 . Example software components may include a user application  214 , which may operate on the processor  204  of the portable device  202 , and at least one SE applet (for example, applets  220 A- 220 D) which may operate on the SIM card  216  processor. The SE applet(s) may be responsible for high security tasks such as providing information for NFC  206  with the POS terminal  208 . In some examples, secure numbers and information stored on the SIM card  216  may be used to calculate other information, which may be shared by the SIM card  216 . 
     In example embodiments, the SIM card  216  may be configured to host one or more different secure services or applications. Example applications may include a Mobile Network Operator (MNO) service  218  including an associated MNO applet  220 A and MNO authentication data  222  for mobile network authentication, a ticketing and public transportation service  224 , which may include a payment applet  220 B, and a credit or debit card payment service  226  and associated payment applets  220 C,  220 D. The described applications are not intended to be limiting, and other applications may also be hosted, such as authentication and signature verification systems, corporate badges and electronic identification systems, loyalty programs, a secure facility access application, a non-monetary resource access application, and an identification application, and others. Each of the services maintained on the SIM card  216  may be protected by a firewall  229  from the other services. 
     In an example embodiment, the applets (for example, applets  220 A- 220 D) of the SIM card  216  may communicate over a secure channel  215  with less secure software operating on the main processor  204  of the portable device  202  and may be responsible for security sensitive tasks, such as storing sensitive information of the associated service and communication  212  with the POS terminal  208  through a contactless front end (CLF)  210  of the portable device  202 . The CLF  210  may include radio hardware such as an antenna  240  configured to enable NFC for contactless payment and other contactless functionality. 
     In an example scenario illustrated in the diagram  200 , data and applets of the SIM card  216  may be controlled by an MNO server  230 , such as a mobile network service provider, via a secure data connection over a cellular modem network  228 . The MNO server  230  may enable remote installation and updating of payment cards and account information on the SIM card  216  of the portable device  202  over the cellular modem network  228 . Additionally, because of increased security demands of the SIM card  216 , software to be installed on the SIM card  216  may need to be approved by a trusted service manager (TSM)  232 . The TSM  232  may be a third party that verifies software to be loaded on the SIM card  216 . In some examples, a card issuer  234  such as a financial institution may coordinate with the TSM  232  in order to load payment information associated with a particular card associated with the card issuer  234  on the portable device  202 . 
     In other example embodiments, an SE chip may be installed directly within the hardware of the portable device  202  rather than on the SIM card  216  such that the portable device  202  may be provided with an NFC antenna and including a built-in SE chip. In this scenario, a portable device manufacturer may be responsible for installation of payment information and payment cards on the portable device  202  via firmware downloads and installation. In yet other scenarios, a physical SE chip may not be installed, and a Host Card Emulation (HCE) technology may be employed which may emulate an SE chip in software operating on the portable device processor. In such a scenario employing HCE technology, the card issuer  234  may not have to negotiate with another entity, such as the TSM  232 , in order to manage payment cards. 
     As previously described, the antenna  240  to enable NFC may be installed at the CLF  210  of the portable device  202 . The antenna  240  may operate according to ISO/IEC 14443, which is an international standard that specifies transmission and communication protocols. Based on the standard, the antenna  240  may operate at a frequency around 13.56 MHz. The antenna  240  may be configured to enable NFC for contactless payment while the portable device  202  is charged and has power. However, if the battery of the portable device  202  is uncharged, the antenna  240  may not be able to function to enable contactless payment. 
     In a system according to embodiments, WPT may also be incorporated with the portable device  202  to enable wireless power transmission for charging the portable device without requiring the portable device  202  to be plugged into a power source. WPT may include a WPT antenna configured to enable power to be wirelessly exchanged when the portable device  202  is placed within a predefined range of a power source. An example range may be up to several meters. Without modification, a WPT antenna as described herein may not be able to function as an NFC antenna, and the portable device may need to include both a WPT antenna and an NFC antenna to enable wireless power exchange and near field communication concurrently. Inclusion of both the WPT antenna and the NFC antenna on the portable device  202  may necessitate more physical space, more working parts of the portable device  202 , and additional expense. 
       FIG. 3  illustrates an example comparison of power versus frequency distributions for NFC and WPT communications, arranged in accordance with at least some embodiments described herein. 
     A diagram  300  shows a plot  302  of example amplitudes versus frequency distributions of a WPT antenna  308  and an NFC antenna  306  in response to an excitation, which may illustrate that a WPT antenna without additional modification may not function as an NFC antenna. The curves in the plot  302  are normalized to a maximum of 1, although the maximum amplitude due to WPT may be larger than for NFC without normalization. 
     An example NFC antenna as previously described herein may have an operating frequency around 13.56 MHz  304 . A resonant WPT antenna may also have an operating frequency around 13.56 MHz  304 . The 13.56 MHz frequency may be chosen as the operating frequencies for the antennas based on the international communication standard ISO/IEC 14443. In other example embodiments, inductive WPT antennas may also be used, however, inductive WPT antennas may have a resonant frequency in a range from 100 to 250 kHz, which does not overlap with the NFC antenna frequency around 13.56 MHz. Since resonant WPT antennas have an operating frequency similar or substantially the same as the NFC operating frequency, a resonant WPT antenna may be able to function as an NFC antenna in some scenarios. 
     As shown in the plot  302  of the diagram  300 , the NFC antenna  306  has a low quality factor (Q) of about 10. Because the NFC antenna  306  follows the ISO/IEC 14443 communication standard, which operates over a wide bandwidth, the NFC antenna  306  may transmit information in sidebands  310  centered at 12.71 and 14.41 MHz, where the sidebands may represent NFC smartcard sidebands. As also shown in the plot  302 , the WPT antenna  308  may have a narrow resonance curve, centered at 13.56 MHz, and may have a high Q value of around 1000, which may enable the WPT antenna  308  to transmit power efficiently. The WPT antenna  308  may behave as a narrow frequency filter and may remove information from an NFC signal, which may make it unacceptable as an NFC antenna. 
     The curves shown in the plot  302  of the diagram  300  may be derived from the Universal Resonance Curve given by: 
     
       
         
           
             
               I 
                
               
                 ( 
                 
                   f 
                   , 
                   Q 
                 
                 ) 
               
             
             = 
             
               1 
               
                 
                   1 
                   + 
                   
                     
                       
                         Q 
                         2 
                       
                        
                       
                         ( 
                         
                           
                             f 
                             
                               f 
                               0 
                             
                           
                           - 
                           
                             
                               f 
                               0 
                             
                             f 
                           
                         
                         ) 
                       
                     
                     2 
                   
                 
               
             
           
         
       
     
     In the above formula, f 0  may be the resonance frequency, which is 13.56 MHz in the case of both the NFC antenna  306  and the WPT antenna  308 , as previously discussed. The importance of the Q value may be shown by figure of merit, U, given by: 
       U=k√{square root over (Q T , Q R )},
 
     where Q R  and Q T  are quality factors of transmit and receive circuits, and k is a magnetic coupling which decreases with distance. 
     The optimum power transfer efficiency may be given by: 
     
       
         
           
             
               η 
               Opt 
             
             = 
             
               
                 U 
                 2 
               
               
                 
                   ( 
                   
                     1 
                     + 
                     
                       
                         1 
                         + 
                         
                           U 
                           2 
                         
                       
                     
                   
                   ) 
                 
                 2 
               
             
           
         
       
     
     illustrating that reducing the Q value from 1000 to 10 may decrease a power transfer efficiency up to a factor of 100, which may demonstrate why a WPT antenna may not function as an NFC antenna, and vice versa. For example, a low Q value of 10 may cause the WPT antenna to be inefficient and/or inoperable as a power transmitter and receiver. 
     In a system according to embodiments, the WPT antenna  308  may be modified to enable the WPT antenna  308  to function as an NFC antenna by incorporating a switchable resistor with the WPT antenna  308 . The switchable resistor may enable the Q value of the WPT antenna  308  to be reduced from 1000 to 10, which may support NFC functionality. 
       FIG. 4  illustrates an example switchable NFC/WPT antenna circuit and implementation of NFC and power connections on a charger pack of a smartphone, arranged in accordance with at least some embodiments described herein. 
     A diagram  400  shows a circuit of an example switchable NFC/WPT antenna, which may be a WPT antenna circuit modified to enable NFC functionality as described herein. The circuit for the switchable NFC/WPT antenna may include an inductor  404 , a capacitor  402 , a switch  408 , and a resistor  406 , where the inductor  404 , the capacitor  402 , and the resistor  406  may be connected in series. The switch  408  and the resistor  406  may be additional elements added to the WPT antenna that may enable the WPT antenna to function as an NFC antenna. In the example circuit for the WPT antenna, Q may be given by: 
         Q= 2 πf L/R,    
     where f is the frequency, L is the inductance and R is the total resistance of the circuit. In the case of the WPT antenna, the components of the circuit may be selected to produce an initial Q value around 1000. Opening the switch  408  may add a resistance, R 1 , of the resistor  406  to the circuit, which may have the effect of reducing the Q value as illustrated by: 
     
       
         
           
             
               Q 
               NFC 
             
             = 
             
               
                 2 
                  
                 π 
                  
                 
                     
                 
                  
                 fL 
               
               
                 ( 
                 
                   R 
                   + 
                   
                     R 
                      
                     
                         
                     
                      
                     1 
                   
                 
                 ) 
               
             
           
         
       
     
     In an example embodiment, the resistance value of the resistor  406  may be selected to reduce the Q from 1000 to 10. As a result, when the switch is closed, the antenna may function as a WPT antenna with a Q value around 1000. When the switch is opened, the resistance, R 1 , may be added to reduce the Q value by a factor of 100 to around 10, and the antenna may function as an NFC antenna. 
     In a system according to embodiments, a switchable NFC/WPT antenna  452  including the modified circuit may enable at least three distinct functions when the switchable NFC/WPT antenna  452  is installed on a portable device  456  as shown in a diagram  450 . Firstly, the NFC/WPT antenna  452  may enable wireless transmission of power between the portable device  456  and an external power source. Secondly, the NFC/WPT antenna  452  may enable active NFC when the portable device  456  is powered. Additionally, the NFC/WPT antenna  452  may enable passive NFC when the portable device  456  is unpowered. A controller or control circuit integrated with the NFC/WPT antenna  452  on the portable device may detect a power supply  454  on the portable device  456  and may switch between the at least three functions depending on the detected power levels of a power source of the portable device  456 . 
       FIG. 5  illustrates a conceptual diagram of a portable device operational blocks implementing a switchable NFC/WPT antenna, arranged in accordance with at least some embodiments described herein. 
     As illustrated in a diagram  500 , an NFC/WPT antenna  506  may be integrated with a portable device  502  such as a smartphone. The NFC/WPT antenna  506  may be an LC circuit  508  including an inductor and a capacitor connected in series as described previously, and may also include a switch  510  and a resistor  512 , where the resistor  512  may also be connected in series with the capacitor and the inductor. The values for the capacitor (C) and the inductor (L) may be chosen such that a resonant frequency, f 0 , of the NFC/WPT antenna  506  is 13.56 MHz, where f 0  is given by: 
     
       
         
           
             
               f 
               0 
             
             = 
             
               1 
               
                 2 
                  
                 π 
                  
                 
                   LC 
                 
               
             
           
         
       
     
     When the switch  510  is closed, a small resistance of the circuit elements may produce a Q value for the NFC/WPT antenna  506  of around 1000, where Q is given by: 
         Q= 2 πf L/R    
     In the scenario when the switch  510  is closed, the NFC/WPT antenna  506  may function as a WPT antenna for wireless transmission of power. When the switch  510  is open, a resistance, R 1 , of the added resistor  512  is added to give Q a new value given by: 
     
       
         
           
             
               Q 
               NFC 
             
             = 
             
               
                 2 
                  
                 π 
                  
                 
                     
                 
                  
                 fL 
               
               
                 ( 
                 
                   R 
                   + 
                   
                     R 
                      
                     
                         
                     
                      
                     1 
                   
                 
                 ) 
               
             
           
         
       
     
     The value of the resistor  512 , R 1 , may be selected so that Q NFC  may be around 10, which may allow enough radio frequency (RF) bandwidth to be transmitted via a contactless front end (CLF)  504  of the portable device  502  to enable NFC. In this case, the NFC/WPT antenna  506  may function as an active NFC antenna. When functioning as an active NFC antenna, the NFC may be powered by a battery  520  of the portable device  502 . 
     In a system according to embodiments, when the switch  510  is open and/or closed, the NFC/WPT antenna  506  output may pass through a rectifier  514 , which may convert the output to a DC current  516  in each described scenario. The DC current  516  may vary in magnitude based on the functionality, where the DC current  516  may be small in an NFC mode and large in the case of a WPT mode. A controller or a control circuit integrated with the portable device  502  may measure the DC current  516  and compare the DC current  516  to a threshold current, I L . I L  may be set less than WPT charging currents, which may be about 1 A and more than induced NFC currents, which may be in a range from about 10 mA to about 100 mA. For example, I L  may be 100 mA. If the DC current  516  is larger than the I L , then the control circuit may switch the NFC/WPT antenna  506  to the WPT mode. In the WPT mode, the switch  510  may be turned on for high Q efficiency, and the DC current  516  may be routed to charge  519  the battery  520 . If the DC current  516  is less than the I L , then the control circuit may switch the NFC/WPT antenna  506  to the NFC mode where the Q value is low. 
     In an example embodiment, after switching to the NFC mode, a voltage of the battery  520  may be measured  522 . If the measured voltage is larger than a threshold voltage, V L , (where V L  may be in a range from about 2.8 to about 3.2 V for the Li-Ion batteries often used in smartphones) required to power the portable device  502 , then an active NFC mode may be initiated, where the battery  520  may employed to power NFC. In the active NFC mode, a SIM card  540  of the portable device  502  may also be powered by the battery  520  and may communicate with the CLF  504  over a single wire protocol (SWP) wire as described herein to enable NFC with one or more installed payment systems of the SIM card  540 . 
     If the measured voltage is less than the V L  required to power the portable device  502 , then a passive NFC mode may be initiated. The passive NFC mode may rely on radio frequency (RF) power derived from the small DC current or signal received through NFC/WPT antenna  506  in the NFC mode. For example, the small DC current  516  may be directed  524  to power an embedded SE chip  526  as part of a backup payment system  528  integrated with the portable device  502  and also to power the CLF  504 . In the passive NFC mode, the SIM card  540  of the portable device  502  may be unpowered and may not respond to NFC signals. The backup payment system  528  may be implemented to enable payment when the battery  520  is uncharged, employing one or more backup payment applets  530  integrated with the backup payment system  528 . The example current and voltage values provided herein are for illustration purposes and may vary depending on circuit and device configurations. 
     Table 1 below illustrates different modes of the NFC/WPT antenna  506  based on detected DC current  516  of the NFC/WPT antenna  506  and a measured voltage of the battery  520  of the portable device  502 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 At least three potential modes of an NFC/WPT antenna based on detected 
               
               
                 current and battery voltage - 1) WPT 2) Active or powered NFC 3) 
               
               
                 Passive or unpowered NFC. 
               
            
           
           
               
               
               
            
               
                 Rectifier Current I &gt; I L   
                 Battery Voltage V &gt; V L   
                 Function/Mode 
               
               
                   
               
               
                 No 
                 No 
                 Passive NFC 
               
               
                 No 
                 Yes 
                 Active NFC 
               
               
                 Yes 
                 No 
                 WPT 
               
               
                 Yes 
                 Yes 
                 WPT 
               
               
                   
               
            
           
         
       
     
     In a further embodiment, the backup payment system may be installed directly on the SIM card  540 , rather than integrated with the NFC/WPT antenna  506 . When the passive NFC mode is entered, the DC current  516  may be directed to power the backup payment system on the SIM card  540 . This example implementation may enable the payment system to function in a SIM-centric mode described previously with SIM software loaded by a mobile network operator. While the contactless backup payment system is described as a function enabled by the passive NFC mode, other contactless systems and applications may also be installed and powered by the NFC/WPT antenna  506  in the passive mode when the portable device is unpowered. 
       FIG. 6  illustrates a general purpose computing device  600 , which may be used to implement adaptable coil-NFC antenna systems for powered and unpowered applications, arranged in accordance with at least some embodiments described herein. 
     For example, the computing device  600  may be used to implement modification of a wireless power coil to enable active and passive NFC antenna functionality in portable devices as described herein. In an example basic configuration  602 , the computing device  600  may include one or more processors  604  and a system memory  606 . A memory bus  608  may be used to communicate between the processor  604  and the system memory  606 . The basic configuration  602  is illustrated in  FIG. 6  by those components within the inner dashed line. 
     Depending on the desired configuration, the processor  604  may be of any type, including but not limited to a microprocessor (μP), a microcontroller (μC), a digital signal processor (DSP), or any combination thereof. The processor  604  may include one more levels of caching, such as a level cache memory  612 , a processor core  614 , and registers  616 . The example processor core  614  may include an arithmetic logic unit (ALU), a floating point unit (FRU), a digital signal processing core (DSP Core), or any combination thereof. An example memory controller  618  may also be used with the processor  604 , or in some implementations, the memory controller  618  may be an internal part of the processor  604 . 
     Depending on the desired configuration, the system memory  606  may be of any type including but not limited to volatile memory (such as RAM), non-volatile memory (such as ROM, flash memory, etc.) or any combination thereof. The system memory  606  may include an operating system  620 , a communication management application  622 , a power control module  626 , and program data  624 , which may include power data  628 . The communication management application  622  may together with the power control module  626  determine a power sufficiency of a portable device and may activate a switchable resistor to modify a Q value of an NFC/WPT antenna to enable wireless power transfer and active and passive NFC antenna functionality as described herein. 
     The computing device  600  may have additional features or functionality, and additional interfaces to facilitate communications between the basic configuration  602  and any desired devices and interfaces. For example, a bus/interface controller  630  may be used to facilitate communications between the basic configuration  602  and one or more data storage devices  632  via a storage interface bus  634 . The data storage devices  632  may be one or more removable storage devices  636 , one or more non-removable storage devices  638 , or a combination thereof. Examples of the removable storage and the non-removable storage devices include magnetic disk devices such as flexible disk drives and hard-disk drives (HDDs), optical disk drives such as compact disk (CD) drives or digital versatile disk (DVD) drives, solid state drives (SSDs), and tape drives to name a few. Example computer storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. 
     The system memory  606 , the removable storage devices  636  and the non-removable storage devices  638  are examples of computer storage media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVDs), solid state drives, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information and which may be accessed by the computing device  600 . Any such computer storage media may be part of the computing device  600 . 
     The computing device  600  may also include an interface bus  640  for facilitating communication from various interface devices (for example, one or more output devices  642 , one or more peripheral interfaces  644 , and one or more communication devices  646 ) to the basic configuration  602  via the bus/interface controller  630 . Some of the example output devices  642  include a graphics processing unit  648  and an audio processing unit  650 , which may be configured to communicate to various external devices such as a display or speakers via one or more A/V ports  652 . One or more example peripheral interfaces  644  may include a serial interface controller  654  or a parallel interface controller  656 , which may be configured to communicate with external devices such as input devices (for example, keyboard, mouse, pen, voice input device, touch input device, etc.) or other peripheral devices (far example, printer, scanner, etc.) via one or more I/O ports  658 . An example communication device  646  includes a network controller  660 , which may be arranged to facilitate communications with one or more other computing devices  662  over a network communication link via one or more communication ports  664 . 
     The network communication link may be one example of a communication media. Communication media may be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and may include any information delivery media. A “modulated data signal” may be a signal that has one or more of its characteristics set of changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), microwave, infrared (IR) and other wireless media. The term computer readable media as used herein may include both storage media and communication media. 
     The computing device  600  may be implemented as a part of a general purpose or specialized server, mainframe, or similar computer that includes any of the above functions. The computing device  600  may also be implemented as a personal computer including both laptop computer and non-laptop computer configurations. 
       FIG. 7  is a flow diagram illustrating an example process to implement adaptable coil-NFC antenna systems for powered and unpowered applications that may be performed by a computing device such as the computing device in  FIG. 6 , arranged in accordance with at least some embodiments described herein. 
     Example methods may include one or more operations, functions or actions as illustrated by one or more of blocks  722 ,  724 ,  726 ,  728 ,  730 ,  732 ,  734 , and/or  736 , and may in some embodiments be performed by a computing device such as the computing device  600  in  FIG. 6 . The operations described in the blocks  722 - 736  may also be stored as computer-executable instructions in a computer-readable medium such as a computer-readable medium  720  of a computing device  710 . 
     An example process to implement adaptable coil-NFC antenna systems for powered and unpowered applications may begin with block  722 , “RECEIVE WIRELESS SIGNAL,” where a portable device with NFC and WPT capabilities may receive a wireless signal. The signal may be communications signal for NFC or power transfer signal for WPT. 
     Block  722  may be followed by decision block  724 , “RECEIVED WIRELESS SIGNAL A WPT SIGNAL?” where a control circuit integrated with an NFC/WPT antenna on the portable device may determine whether the received signal is for NFC or WPT. The controller may accomplish this by comparing a current derived from the received signal to a threshold current value. If the derived current is higher than the threshold, the signal may be classified as WPT by the controller, otherwise as NFC. 
     Decision block  724  may be followed by block  726 , “CHARGE BATTERY OF THE PORTABLE DEVICE,” where in response to an affirmative decision at the decision block  724 , a battery of the portable device may be charged by a charging circuitry of the portable device using the current derived from the received wireless signal. 
     Decision block  724  may be followed by block  728 , “MODIFY CONFIGURATION OF ANTENNA TO SUPPORT NFC”, where in response to a negative decision at the decision block  724 , an antenna circuit of the portable device may be modified to accommodate NFC. In some examples, WPT may be the default configuration of the antenna circuit, and the antenna circuit may be modified (e.g., by adding a resistor in series with an inductor and a capacitor) to switch from a WPT mode to an NFC mode reducing a Q value of the antenna circuit. The controller may perform the modification operations or instruct a processor on the portable device to modify the antenna. 
     Block  728  may be followed by decision block  730 , “POWER LEVEL OF A BATTERY SUFFICIENT TO SUPPORT ACTIVE NFC?” where the controller integrated with the portable device may detect a voltage level of the battery of the portable device. If the voltage is less than a threshold voltage, then the power level of the portable device may be determined to be insufficient to support active NFC, as described above. 
     Decision block  730  may be followed by block  732 , “ENABLE ACTIVE NFC,” where in response to an affirmative decision at the decision block  730 , the controller may enable near field communications with the source of the received wireless signal using a battery power of the portable device. 
     Decision block  730  may be followed by block  734 , “ENABLE PASSIVE NFC”, where in response to a negative decision at the decision block  724 , the controller may enable near field communications with the source of the received wireless signal using power derived from the received wireless signal through the low-Q configuration antenna circuit of the portable device. 
     Blocks  732  and  734  may be followed by optional block  736 , “UPON DETECTION OF COMPLETION OF THE NFC MODIFY THE ANTENNA TO SUPPORT WPT” where upon completion of the near field communication session, the controller may modify the antenna to its default WPT configuration e.g., by removing the resistor). In other embodiments, the default mode of the antenna circuit may be NFC and switched to WPT upon detection of a WPT signal. In such configurations, it may be easier to detect a difference between the WPT and the NFC signals. 
       FIG. 8  illustrates a block diagram of an example computer program product, arranged in accordance with at least some embodiments described herein. 
     In some examples, as shown in  FIG. 8 , a computer program product  800  may include a signal bearing medium  802  that may also include one or more machine readable instructions  804  that, when executed by, for example, a processor may provide the functionality described herein. Thus, for example, referring to the processor  604  in  FIG. 6 , the communication management application  622  in conjunction with the power control module  626  may undertake one or more of the tasks shown in  FIG. 8  in response to the instructions  804  conveyed to the processor  604  by the medium  802  to perform actions associated with implementation of adaptable NFC antennas to enable wireless power transfer and passive and/or active NFC functionality as described herein. Some of those instructions may include, for example, instructions to receive a wireless signal; determine whether the received wireless signal is a WPT signal; if the received wireless signal is the WPT signal, charge a battery of the portable device; if the received wireless signal is not the WPT signal, modify a configuration of an antenna on the portable device to support NFC determine whether a power level of the portable device is sufficient to support active NFC; if the power level of the portable device is insufficient to support active NFC, enable passive NFC through the modified configuration antenna; and/or if the power level of the portable device is sufficient to support active NFC, enable active NFC through the modified configuration antenna according to some embodiments described herein. 
     In some implementations, the signal bearing media  802  depicted in  FIG. 8  may encompass computer-readable media  806 , such as, but not limited to, a hard disk drive, a solid state drive, a Compact Disk (CD), a Digital Versatile Disk (DVD), a digital tape, memory, etc. In some implementations, the signal bearing media  802  may encompass recordable media  808 , such as, but not limited to, memory, read/write (R/W) CDs, R/W DVDs, etc. In some implementations, the signal bearing media  802  may encompass communications media  810 , such as, but not limited to, a digital and/or an analog communication medium (for example, a fiber optic cable, a waveguide, a wired communications link, a wireless communication link, etc.). Thus, for example, the program product  800  may be conveyed to one or more modules of the processor  604  by an RF signal bearing medium, where the signal bearing media  802  is conveyed by the wireless communications media  810  (for example, a wireless communications medium conforming with the IEEE 802.11 standard). 
     According to some examples, methods are described to provide adaptable near field communication (NFC) for powered and unpowered applications in a portable device. The method may include receiving a wireless signal; determining whether the received wireless signal is a wireless power transfer (WPT) signal; in response to a determination that the received wireless signal is the WPT signal, charging a battery of the portable device; and in response to a determination that the received wireless signal is not the WPT signal, modifying a configuration of an antenna on the portable device to support NFC. The method may also include determining whether a power level of the portable device is sufficient to support active NFC and in response to a determination that the power level of the portable device is insufficient to support active NFC, enabling passive NFC through the modified configuration antenna, where the passive NFC relies on power derived from the received wireless signal through the modified configuration antenna. 
     According to other examples, the method may further include in response to a determination that the power level of the portable device is sufficient to support active NFC, enabling active NFC through the modified configuration antenna, where the active NFC relies on power derived from the battery of the portable device. Modifying the configuration of the antenna to support NFC may include reducing a Q value of the antenna. Reducing the Q value of the antenna may include coupling a series resistor circuit between a capacitor circuit and an inductor circuit, wherein the capacitor circuit and the inductor circuit are coupled in series. Reducing the Q value of the antenna may also include reducing the Q value by a factor of about 100 or more. 
     According to further examples, determining whether the received wireless signal is the WPT signal may include deriving a current from the received wireless signal; comparing the derived current to a threshold current; and in response to a determination that the derived current is higher than the threshold current, determining the received wireless signal to be the WPT signal. The method may further include determining a completion of the passive NFC and modifying the configuration of the antenna to support WPT to the portable device. The configuration of the antenna to support WPT may be a default configuration. Modifying the configuration of the antenna to support WPT may include increasing a Q value of the antenna. Increasing the Q value of the antenna may include removing a series resistor circuit between a capacitor circuit and an inductor circuit. Increasing the Q value of the antenna may also include increasing the Q value by a factor of about 100 or more. 
     According to other examples, a portable device capable to support adaptable near field communication (NFC) for powered and unpowered applications is described. The portable device may include a processing block, a portable power source, a switchable antenna configured to support wireless power transfer (WPT) in a first configuration and NFC in a second configuration and to receive a wireless signal, and a secure element (SE) coupled to the switchable antenna. The SE may be configured to determine whether the received wireless signal is a WPT signal; in response to a determination that the received wireless signal is the WPT signal, charge a battery of the portable device; in response to a determination that the received wireless signal is not the WPT signal, modify a configuration of the antenna to the second configuration; determine whether a power level of the portable device is sufficient to support active NFC; in response to a determination that the power level of the portable device is insufficient to support active NFC, enable passive NFC through the antenna in the second configuration, where the passive NFC relies on power derived from the received wireless signal through the antenna in the second configuration; and in response to a determination that the power level of the portable device is sufficient to support active NFC, enable active NFC through the antenna in the second configuration, where the active NFC relies on power derived from the battery of the portable device. 
     According to some examples, the SE may be further configured to upon detection of a completion of the passive NFC or the active NFC, switch the antenna to the first configuration. The portable device may be a smartphone, a personal digital assistant (PDA), a tablet computer, a wearable computer, or a vehicle mount computer. The SE may be attached to a subscriber identity module (SIM) of the portable device, attached to an NFC module of the portable device that includes the antenna, or emulated through one or more applications executed by the processing block of the portable device. The first configuration and the second configuration of the antenna may include a high-Q mode and a low-Q mode of the antenna, respectively. The high-Q mode may include a capacitor circuit and an inductor circuit coupled in series, and the low-Q mode may include the capacitor circuit, the inductor circuit and a resistor circuit coupled in series. The SE may be further configured to employ the passive NFC for one or more of a payment application, a secure facility access application, a non-monetary resource access application, and an identification application. 
     According to further examples, a near field communication (NFC) module capable to support powered and unpowered applications is described. The NFC module array include a switchable antenna configured to support wireless power transfer (WPT) in a first configuration and NFC in a second configuration and to receive a wireless signal; and a secure element (SE) coupled to the switchable antenna. The SE may be configured to determine whether the received wireless signal is a WPT signal; in response to a determination that the received wireless signal is the WPT signal, charge a battery of a portable device that hosts the NFC module; in response to a determination that the received wireless signal is not the WPT signal, modify a configuration of the antenna to the second configuration; determine whether a power level of the portable device that hosts the NFC module is sufficient to support active NFC; in response to a determination that the power level of the portable device is insufficient to support active NFC, enable passive NFC through the antenna in the second configuration, where the passive NFC relies on power derived from the received wireless signal through the antenna in the second configuration; in response to a determination that the power level of the portable device is sufficient to support active NFC, enable active NFC through the antenna in the second configuration, where the active NFC relies on power derived from the battery of the portable device; and upon detection of a completion of the passive NFC or the active NFC, switch the antenna to the first configuration. 
     According to yet other examples, the NFC module may further include a rectifier circuit configured to provide a rectifier current, and the SE may be further configured to detect a battery voltage of the portable device and the rectifier current; in response to a determination that the rectifier current is lower than a current threshold and the battery voltage is lower than a voltage threshold, enable the passive NFC through the antenna in the second configuration; in response to a determination that the rectifier current is lower than the current threshold and the battery voltage is higher than the voltage threshold, enable the active NFC through the antenna in the second configuration; in response to a determination that the rectifier current is higher than the current threshold and the battery voltage is lower than the voltage threshold, enable the WPT through the antenna in the first configuration; and in response to a determination that the rectifier current is higher than the current threshold and the battery voltage is higher than the voltage threshold, enable the WPT through the antenna in the first configuration. 
     According to some examples, the first configuration and the second configuration of the antenna may include a high-Q mode and a low-Q mode of the antenna, respectively. The SE may be configured to enable the passive NFC communication for one or more of a payment application, a secure facility access application, a non-monetary resource access application, and an identification application executed on a subscriber identity module (SIM) of the portable device. 
     Various embodiments may be implemented in hardware, software, or combination of both hardware and software (or other computer-readable instructions stored on a non-transitory computer-readable storage medium and executable by one or more processors); the use of hardware or software is generally (but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost vs. efficiency tradeoffs. There are various vehicles by which processes and/or systems and/or other technologies described herein may be effected (for example, hardware, software, and/or firmware), and the preferred vehicle will vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and/or firmware vehicle; if flexibility is paramount, the implementer may opt for a mainly software implementation; or, yet again alternatively, the implementer may opt for some combination of hardware, software, and/or firmware. 
     The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, each function and/or operation within such block diagrams, flowcharts, or examples may be implemented, individually, and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs executing on one or more computers (for example, as one or more programs executing on one or more computer systems), as one or more programs executing on one or more processors (for example, as one or more programs executing on one or more microprocessors), as firmware, or as virtually any combination thereof, and designing the circuitry and/or writing the code for the software and or firmware are possible in light of this disclosure. 
     The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, are possible from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. 
     In addition, the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Versatile Disk (DVD), a digital tape, a computer memory, a solid state drive, etc.; and a transmission type medium such as a digital and/or an analog communication medium (for example, a fiber optic cable, a waveguide, wired communications link, a wireless communication link, etc.). 
     Those skilled in the art will recognize that it is common within the art to describe devices and/or processes in the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. A data processing system may include one or more of a system unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and/or control systems including feedback loops and control motors (for example, feedback for sensing position and/or velocity of gantry systems; control motors to move and/or adjust components and/or quantities). 
     A data processing system may be implemented utilizing any suitable commercially available components, such as those found in data computing/communication and/or network computing/communication systems. The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. Such depicted architectures are merely exemplary, and in fact many other architectures may be implemented which achieve the same or substantially similar functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermediate components. Likewise, any two components so associated may also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality, and any two components capable of being on associated may also be viewed as being “operably comparable”, to each other to achieve the desired functionality. Specific examples of operably comparable include but are not limited to physically connectable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or interactable components. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (for example, bodies of the appended claims) are generally intended as “open” terms (for example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (for example, “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of “two recitations,” without other modifiers, means at least two recitations, or two or more recitations). 
     Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” 
     As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth. 
     While various aspects and embodiments have been disclosed herein, other aspects and embodiments are possible. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.