Patent Publication Number: US-11652293-B2

Title: Tunable antenna system for Bluetooth and Wi-Fi bands with electronically-reconfigurable and mechanically-identical antennas

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present disclosure is a national stage application of PCT Application No. PCT/US19/32370, with an international filing date of May 15, 2019, and with a priority date of May 22, 2018, which claimed priority to U.S. patent application Ser. No. 15/985,827, filed May 22, 2018, the contents of each are incorporated by reference in their entirety. 
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to a wireless antenna system. More particularly, the present disclosure relates to a tunable antenna system for Bluetooth and Wi-Fi bands with electronically-reconfigurable and mechanically-identical antennas. 
     BACKGROUND OF THE DISCLOSURE 
     Various devices utilize antennas for wireless communication, such as wireless Access Points (APs), streaming media devices, laptops, tablets, and the like (collectively “wireless devices”). Further, the design trend for such devices is focused on aesthetics, compact form factors, etc. These wireless devices require communication utilizing Wi-Fi and Bluetooth. Wi-Fi requires support for two bands—2.4 GHz and 5 GHz, and Bluetooth requires support for the 2.4 GHz band. Conventional approaches utilize different antennas for these different bands. Of course, this increases the size, cost, complexity, etc. It would be advantageous to provide a radio system that supports tunability (for single 2.4 GHz band, single 5 GHz band, or dual 2.4 GHz/5 GHz operation) and antenna diversity (multiple different antennas) in a manner that minimizes switches, footprint, etc. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     In an embodiment, a radio system supporting 2.4 GHz operation, 5 GHz operation, and dual simultaneous 2.4 GHz/5 GHz operation one or more radios; and a plurality of antenna systems connected to the one or more radios via a plurality of switches, wherein each of the plurality of antenna systems includes: an antenna element including a first end and a second end; a terminating network connecting the first end to ground; and a matching network connecting the second end to an antenna port which is communicatively coupled to one or more radios, wherein the antenna element operates as one of a quarter wave, a half wave, based on first settings in the terminating network and the matching network, and wherein the one or more radios are selectively connected to the plurality of antenna systems based on second settings of the plurality of switches. The antenna system can operate as one of a quarter wave, a half wave, and simultaneous operation as half and quarter wave, based on settings in the terminating network and the matching network. The quarter wave can support the 2.4 GHz operation, the half-wave supports the 5 GHz operation, and the half and quarter wave supports the dual simultaneous 2.4 GHz/5 GHz operation. 
     The terminating network can include a first switch (TN) and the matching network can include a second switch (MN 1 ) and a third switch (MN 2 ), wherein each of the first switch, the second switch, and the third switch select between at least two of open, a bypass, an inductor, and a capacitor. The quarter wave can operate with the TN set to open or through the inductor, with the MN 1  set through the capacitor, and with the MN 2  set to open; the half wave can operate with the TN set through the capacitor or bypass, with the MN 1  set to bypass, and the MN 2  set to open, and the half and quarter wave can operate with the TN set through the capacitor, with the MN 1  set to bypass, and with the MN 2  set through the inductor. The one or more radios can be configured to electronically configure the first settings and the second settings. The first settings can be adjusted to select a band, and the second settings are adjusted to select an appropriate antenna system based on any of diversity, condition number, and pattern. The first settings can be adjusted to select a band, and the second settings are adjusted to select a Multiple-Input and Multiple-Output (MIMO) dimension. The first settings and the second settings can be implemented with a converged mode and Tx/Rx select switch. The antenna element can include a first vertical side with the first end, a second vertical side with the second end, and a horizontal portion between the first vertical side and the second vertical side at an end of each of the first vertical side and the second vertical side opposite of the first end and the second end. 
     In another embodiment, a configurable dual and single band antenna system includes an antenna element including a first end and a second end; a terminating network connecting the first end to ground; a matching network connecting the second end to an antenna port which is communicatively coupled to one or more radios, wherein the antenna element operates as one of a quarter wave, a half wave, and simultaneous operation as half and quarter wave based on settings in the terminating network and the matching network. The quarter wave can support 2.4 GHz operation, the half-wave can support 5 GHz operation, and the half and quarter wave can support dual simultaneous 2.4 GHz/5 GHz operation. The terminating network can include a first switch (TN) and the matching network can include a second switch (MN 1 ) and a third switch (MN 2 ), wherein each of the first switch, the second switch, and the third switch select between at least two of open, a bypass, an inductor, and a capacitor. 
     The quarter wave can operate with the TN set to open or through the inductor, with the MN 1  set through the capacitor, and with the MN 2  set to open; the half wave can operate with the TN set through the capacitor or bypass, with the MN 1  set to bypass, and the MN 2  set to open, and the half and quarter wave can operate with the TN set through the capacitor, with the MN 1  set to bypass, and with the MN 2  set through the inductor. The one or more radios can be configured to electronically configure the settings. The antenna element can include a first vertical side with the first end, a second vertical side with the second end, and a horizontal portion between the first vertical side and the second vertical side at an end of each of the first vertical side and the second vertical side opposite of the first end and the second end. The antenna element can be tuned for the quarter wave, the half wave, and the simultaneous operation as half and quarter wave based on elements in the terminating network and the matching network. 
     In a further embodiment, a method of operating a radio system supporting 2.4 GHz operation, 5 GHz operation, and dual simultaneous 2.4 GHz/5 GHz operation includes selectively connecting one or more radios to a plurality of antenna systems via setting first settings on a plurality of switches, wherein each of the plurality of antenna systems includes an antenna element including a first end and a second end; a terminating network connecting the first end to ground; and a matching network connecting the second end to an antenna port which is communicatively coupled to one or more radios; and causing operation of the antenna element for one or more of the plurality of antenna systems as one of a quarter wave, a half wave, and simultaneous operation as half and quarter wave based on second settings in the terminating network and the matching network. The quarter wave can support the 2.4 GHz operation, the half-wave can support the 5 GHz operation, and the half and quarter wave can support the dual simultaneous 2.4 GHz/5 GHz operation. The method can further include changing an antenna element system for one of the one or more radios based on any of diversity, condition number, and pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which: 
         FIG.  1    is a schematic diagram of the radio system which is a converged switch acting as an antenna mode selector and Tx/Rx switch; 
         FIG.  2    is a schematic diagram of the radio system which is a converged switch acting as an antenna mode selector, Tx/Rx switch, and diversity switch; 
         FIG.  3    is a schematic diagram of the radio system with two radios capable of 2×2 Multiple-Input and Multiple-Output (MIMO) 2.4 GHz/5 GHz operation or 4×4 MIMO 5 GHz operation; 
         FIG.  4    is a block diagram of functional components of a wireless access point as an example wireless device implementing the radio system described herein; 
         FIG.  5    is a perspective diagram of a physical form factor for the wireless access point of  FIG.  4   ; 
         FIG.  6    is a perspective diagram of the access point of  FIG.  4    and the form factor with a top portion removed; 
         FIG.  7    is a top view of the access point of  FIG.  4    and the form factor with the top portion removed; 
         FIG.  8    is a perspective diagram of a portion of the access point illustrating a single antenna system and physical connectivity to the associated configurable antenna; 
         FIG.  9    is a diagram of an element view of the single antenna system; 
         FIG.  10    is a schematic diagram of the single antenna system in  FIG.  8    illustrating circuit connectivity; 
         FIG.  11    is a schematic diagram of the single antenna system in  FIG.  8    illustrating circuit connectivity in a 2.4 GHz configuration; 
         FIG.  12    is a schematic diagram of the single antenna system in  FIG.  11    illustrating circuit connectivity with the terminating network (TN) connected through the inductor in a 2.4 GHz configuration; 
         FIG.  13    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating the effect of the inductor in a 2.4 GHz configuration; 
         FIG.  14    is a schematic diagram of the current flow in the schematic diagram of  FIG.  12    in a 2.4 GHz configuration; 
         FIG.  15    is a schematic diagram of the single antenna system in  FIG.  8    illustrating circuit connectivity in a 5 GHz configuration along with the associated current flow; 
         FIG.  16    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating the effect of the capacitor in a 5 GHz configuration; 
         FIG.  17    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating matching resonance at 5 GHz with different values of inductance in a 5 GHz configuration; 
         FIG.  18    is a schematic diagram of the single antenna system in  FIG.  8    illustrating circuit connectivity in a dual 2.4 GHz and 5 GHz configuration along with the associated current flow; 
         FIG.  19    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating operating in a 2.4 GHz configuration, a 5 GHz configuration, and a dual simultaneous 2.4 GHz/5 GHz configuration for the antenna system; 
         FIG.  20    is a graph which illustrates the efficiency versus frequency illustrating operating in a 2.4 GHz configuration, a 5 GHz configuration, and a dual simultaneous 2.4 GHz/5 GHz configuration for the antenna system; and 
         FIG.  21    is various diagrams of an exemplary implementation of the antenna described herein utilizing stamping and Surface Mount Technology (SMT). 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     In various embodiments, the present disclosure relates to a tunable antenna system for Bluetooth and Wi-Fi bands with electronically-reconfigurable and mechanically-identical antennas. The antenna element system includes a tunable, dual-band (2.4 GHz and 5 GHz) antenna. The antenna can be tunable between single and dual-band, supporting 2.4 GHz operation, 5 GHz operation, and dual simultaneous 2.4 GHz/5 GHz operation. The tuning can be dynamic and electronic (i.e., no physical changes to the antenna element). The tuning is based on conversion from quarter wave to half wave and a mode which operates simultaneously as half and quarter wave, supporting both 2.4 GHz and 5 GHz bands. 
     A radio system supporting 2.4 GHz operation, 5 GHz operation, and dual simultaneous 2.4 GHz/5 GHz operation includes one or more radios; and a plurality of antenna systems connected to the one or more radios via a plurality of switches, wherein each of the plurality of antenna systems includes an antenna element including a first end and a second end; a terminating network connecting the first end to ground; and a matching network connecting the second end to an antenna port which is communicatively coupled to one or more radios, wherein the antenna element operates as one of a quarter wave, a half wave, and simultaneous operation as half and quarter wave based on first settings in the terminating network and the matching network, and wherein the one or more radios are selectively connected to the plurality of antenna systems based on second settings of the plurality of switches. 
     Radio System 
       FIGS.  1 ,  2 , and  3    are schematic diagrams of radio systems  10 ,  12 ,  14 .  FIG.  1    is a schematic diagram of the radio system  10  which is a converged switch acting as an antenna mode selector and Tx/Rx switch.  FIG.  2    is a schematic diagram of the radio system  12  which is a converged switch acting as an antenna mode selector, Tx/Rx switch, and diversity switch.  FIG.  3    is a schematic diagram of the radio system  14  with two radios  16 ,  20  capable of 2×2 Multiple-Input and Multiple-Output (MIMO) 2.4 GHz/5 GHz operation or 4×4 MIMO 5 GHz operation. The radio system  10 ,  12  include two radios  16 ,  18 , a configurable antenna  20 , mode select switches  22  connected to the configurable antenna  20 , and a converged mode select and Tx/Rx select switch  24 . The radio system  12  further utilizes the switches  24  as diversity switches between different configurable antennas  20 . 
     Radio systems have Radio Frequency (RF) switches that serve as transmit/receive (Tx/Rx) switches, band select switches, diversity switches, or other functions. The transmit/receive switches are used to connect the configurable antenna  20  to either the receiving portion of the radios  16 ,  18 , or the transmitting portion of the radios  16 ,  18 . The radios  16 ,  18  can operate in a time domain duplex mode, rather than the full-duplex mode, so the radio  16 ,  18  is either transmitting or receiving at any given time, but not both at once. It is often desirable to isolate the transmitter circuitry from the receive circuitry in the radios  16 ,  18 . This may help provide good matching and tuning to the respective circuits which could not be achieved if both sets of circuits were tied to the same transmission line. Transmitters tend to put out very high-power levels, which can actually sometimes be damaging to the more sensitive receive circuits. Using the switch  24  that connects to only one of the transmitter or receiver at a time can help with these issues. 
     Diversity switches are used to select one of several antennas  20  for use by the transmitter or receiver. Having multiple antennas  20 , at different physical locations and potentially different polarizations, provides diversity gain. If the signal is poor in one location (on one of the antennas  20 ), the signal may be stronger or better on another antenna  20 . If the radio  16 ,  18  can select either antenna  20 , it can potentially improve its performance by selecting the better performing of the antennas  20  for the exact spot the radio  16 ,  18  is in. Typically, RF switches are used to select which antenna is connected to the Tx or Rx port of the radio at any given time. 
     Band select switches, such as the mode select switches  22 , choose between radios  16 ,  18  that are operating in different bands. Some radios  16 ,  18  can make use of a dual-band antenna, such that the same antenna can be used for either 2.4 GHz or 5 GHz signals. However, while the antenna is able to operate in both bands simultaneously, the radios  16 ,  18  themselves are separate circuits designed specifically for one of the bands. As with the Tx/Rx case described earlier, it may be undesirable to have radios  16 ,  18  in both of the bands attached to the antenna  20  at the same time. It can be difficult to get the correct tuning/matching of the radios  16 ,  18  if the 2.4 GHz and 5 GHz radios are connected to each other, and the transmission line that goes to the antenna  20 . Again, a set of RF switches that connects only one of the radios  16 ,  18  at a time is helpful. The mode select switches  22  can switch between a capacitor, an inductor, bypass (short), and open. 
     The configurable antenna disclosed herein uses RF switches  22 ,  24  within the antenna structure to select its mode of operation and select proper tuning elements for the antenna  20  to work efficiently. The switches  22 ,  24  that are part of the configurable antenna  20  would end up in series with the switches in the radios  16 ,  18  that are acting as Tx/Rx, diversity, or band select antennas. There are disadvantages with cascading switches in series. First, there is added cost to having multiple sets of switches. Second, there is loss going through each switch, and when placed in series both losses occur, doubling the loss of a single switch. 
     It is possible to combine the two switches that would be in series into a single switch that has more connections within it. For example, rather than cascading two one pole two throw switches, utilizing a single one pole four throw switch. While the switch with more connections is incrementally more complicated, it will still have a lower total cost than two separate switches and will have a lower loss as well. 
     The radio systems  10 ,  12 ,  14  include combining switches that are part of the antenna operation such that they provide multiple functions. In  FIG.  1   , the radio system  10  combines the antenna mode/tuning switches with the Tx/Rx switch functionality within the radio  16 ,  18 . As shown in  FIG.  1   , by correctly choosing the 1P4T (1 pole, 4 terminal) switch (i.e., the converged mode select and Tx/Rx select switch  24  is a 1P4T switch), Tx versus Rx, as well as 5 Gb/s vs. 2.4 Gb/s can be selected for both the radio  16 ,  18  and the antenna  20 . In  FIG.  2   , the radio system  12  extends this concept to antenna diversity as well. Here, there are two antennas  20 , each with a 1P4T switch for the converged mode select and Tx/Rx select switch  24 . By properly setting these switches, either antenna  20  can be connected to the Tx or Rx, of either of the 2.4 GHz or 5 GHz radios. A single set of switches therefore act as the antenna mode selector, the band select switch, the Tx/Rx switch, and as an antenna diversity switch. 
     In  FIG.  3   , the radio system  14  includes four antenna systems  30  (labeled as  30 A- 30 D) connected via 1P4T switches  32 ,  34  to the radios  16 ,  18 .  FIG.  3    illustrates the antenna system  30 A in detail. Note, the antenna systems  30 B,  30 C,  30 D are identical even though omitted from the illustration. The antenna system  30  connects to one of the switches  32  via an antenna port  36 . The antenna system  30  includes the configurable antenna  20  connected to a terminating switch  38  and tuning/matching network switches  40 . The terminating switch  38  is a 1P3T switch with the three terminals connected to ground directly, via a capacitor, and via an inductor. Similarly, the tuning/matching network switches  40  includes a terminating switch  42  which is a 1P3T switch with the three terminals connected to ground directly, via a capacitor, and via an inductor. Collectively, the terminating switches  38 ,  42  are set to set a mode of the antenna  20 . The tuning/matching network switches  40  includes a switch  44  which is a 1P3T switch with the three terminals connected to the antenna port  36  directly, via a capacitor, and via an inductor. 
     The combinations of the switches  32 ,  34 ,  38 ,  40  are used for the radios  16 ,  18  to connect to the antennas  20  (i.e., the antenna  20  in each of the antenna systems  30 A,  30 B,  30 C,  30 D) as well as to select the band. For example, the radio  16  can support 2×2 MIMO operation in the 2.4 GHz band or 2×2 MIMO operation in the 5 GHz band, at one time, and the radio  18  can support 2×2 operation in the 5 GHz band. Accordingly, any system utilizing the radio system  14  can support 2×2 MIMO 2.4 GHz operation and 2×2 MIMO 5 GHz operation or 4×4 MIMO 5 GHz operation based on the switch configuration. Each of the radios  16 ,  18  include two chains  46 ,  48  which selectively connect to the antenna systems  30 A,  30 B,  30 C,  30 D via the switches  32 ,  34 . 
     The radio system  14  is an exemplary embodiment of how the reconfigurable antennas  20  allow the radios  16 ,  18  to be optimized for 2.4 GHz, 5 GHz, and dual simultaneous 2.4 GHz/5 GHz operation. The radio  16  has two chains  46 ,  48  for supporting 2.4 GHz or 5 GHz operation and the radio  18  has two chains  46 ,  48  for supporting 5 GHz operation. Thus, the radio system  14  can support a 4 chain 5 GHz system (4×4 MIMO) or a 2 chain 2.4 GHz system and a 2 chain 5 GHz system. In the 4 chain 5 GHz system, the radios  16 ,  18  can pick any of the antenna systems  30 A,  30 B,  30 C,  30 D as needed or required. Also, in any configuration, the radios  16 ,  18  can select any of the antenna systems  30 A,  30 B,  30 C,  30 D needed. This allows for the radios  16 ,  18  to pick up antennas on different location in a product. 
     Example Wireless Device 
       FIG.  4    is a block diagram of functional components of a wireless access point  50  as an example wireless device implementing the radio system  14  described herein.  FIG.  5    is a perspective diagram of a physical form factor  52  for the wireless access point  50 . The access point  50  includes the physical form factor  50  which contains a processor  54 , a plurality of radios  56 , a local interface  58 , a data store  60 , a network interface  62 , and power  64 . It should be appreciated by those of ordinary skill in the art that  FIG.  4    depicts the access point  50  in an oversimplified manner, and a practical embodiment may include additional components and suitably configured processing logic to support features described herein or known or conventional operating features that are not described in detail herein. 
     In an exemplary embodiment, the form factor  52  is a compact physical implementation where the access point  50  directly plugs into an electrical socket and is physically supported by the electrical plug connected to the electrical socket. This compact physical implementation is ideal for a large number of access points  50  distributed throughout a location. The processor  54  is a hardware device for executing software instructions. The processor  54  can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors, a semiconductor-based microprocessor (in the form of a microchip or chip set), or generally any device for executing software instructions. When the access point  50  is in operation, the processor  54  is configured to execute software stored within memory or the data store  60 , to communicate data to and from the memory or the data store  40 , and to generally control operations of the access point  50  pursuant to the software instructions. In an exemplary embodiment, the processor  54  may include a mobile-optimized processor such as optimized for power consumption and mobile applications. 
     The radios  56  enable wireless communication. The radios  56  can operate according to the IEEE 802.11 standard and variants thereof. The radios  56  include address, control, and/or data connections to enable appropriate communications on a Wi-Fi system. As described herein, the access point  50  includes the radios  16 ,  18  to support different links, i.e., backhaul links and client links. In an exemplary embodiment, the access point  50  can support dual-band operation simultaneously operating 2.4 GHz and 5 GHz 2×2/4×4 MIMO 802.11b/g/n/ac radios having operating bandwidths of 20/40 MHz for 2.4 GHz and 20/40/80 MHz for 5 GHz. For example, the access point  50  can support IEEE 802.11AC1200 gigabit Wi-Fi (300+867 Mbps). Also, the radios  56  can include a Bluetooth interface as well for local access, control, onboarding, etc. The radios  36  contemplate using the radio systems  10 ,  12 ,  14  described herein. 
     The local interface  58  is configured for local communication to the access point  50  and can be either a wired connection or wireless connection such as Bluetooth or the like. Since the access point  50  can be configured via the cloud, an onboarding process is required to first establish connectivity for a newly turned on access point  50 . In an exemplary embodiment, the access point  50  can also include the local interface  58  allowing connectivity to a user device for onboarding to a Wi-Fi system such as through an app on the user device. The data store  60  is used to store data. The data store  60  may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, and the like), and combinations thereof. Moreover, the data store  60  may incorporate electronic, magnetic, optical, and/or other types of storage media. 
     The network interface  62  provides wired connectivity to the access point  50 . The network interface  62  may be used to enable the access point  50  communicate to a modem/router. Also, the network interface  62  can be used to provide local connectivity to a user device. For example, wiring in a device to an access point  50  can provide network access to a device which does not support Wi-Fi. The network interface  62  may include, for example, an Ethernet card or adapter (e.g., 10BaseT, Fast Ethernet, Gigabit Ethernet, 10 GbE). The network interface  62  may include address, control, and/or data connections to enable appropriate communications on the network. The processor  54  and the data store  60  can include software and/or firmware which essentially controls the operation of the access point  50 , data gathering and measurement control, data management, memory management, and communication and control interfaces with the cloud. 
     Physical Implementation 
       FIG.  6    is a perspective diagram of the access point  50  and the form factor  52  with a top portion  70  removed.  FIG.  7    is a top view of the access point  50  and the form factor  52  with the top portion  70  removed. The access point  50  can utilize the radio system  14  with four of the antenna systems  30 A,  30 B,  30 C,  30 D. Specifically, the access point  50  can include support Wi-Fi and Bluetooth with the antenna systems  30 A,  30 B,  30 C,  30 D. The antenna systems  30 A,  30 B,  30 C,  30 D are identical elements for covering the Bluetooth 2.4 GHz band, the Wi-Fi 2.4 GHz band, and the Wi-Fi 5 GHz band, individually or simultaneously. The access point  50  can support the radios  16 ,  18  selecting the chains  46 ,  48  and allocating to desired bands. Advantageously, the design presented herein includes one radio system  30  implementation which can be reproduced and used in combination to make “different” antennas supporting the Wi-Fi and Bluetooth bands. 
     In  FIGS.  6  and  7   , the access point  50  includes four identical configurable antennas  20 A,  20 B,  20 C,  20 D part of the antenna systems  30 A,  30 B,  30 C,  30 D. The access point  50  includes an RF Printed Circuit Board (PCB)  100  for the antenna systems  30 A,  30 B,  30 C,  30 D and their associated radio systems  14 , an RF shield  102  over the radio system  14  which includes the antenna systems  30 A,  30 B,  30 C,  30 D, and a heatsink  104 . 
     Advantageously, all the antenna systems  30 A,  30 B,  30 C,  30 D is physically and mechanically identical (except for location) in the access point  50 . This provides efficiency in manufacturing, cost, etc. The access point  50  and the radios  16 ,  18  can select the best antenna systems  30 A,  30 B,  30 C,  30 D as needed for system performance, e.g., based on the position of the access point  50  in deployment and other factors. 
     Antenna System 
       FIG.  8    is a perspective diagram of a portion of the access point  50  illustrating a single antenna system  30  and physical connectivity to the associated configurable antenna  20 .  FIG.  9    is a diagram of an element view of the single antenna system  30 . The RF PCB  100  includes a cleared ground  110 . The configurable antenna  20  is supported on the cleared ground  110  via feet  112 ,  114 . The tuning/matching network switch  40  on the RF PCB  100  connects to the configurable antenna  20  at the foot  114  and the antenna port  36  connects to the tuning/matching network switch  40  and provides a connection to the radios  16 ,  18  inside of the RF shield  102 . The terminating switch  38  connects to the configurable antenna  20  at the foot  112  and to a ground connector  116  such as a screw which grounds the RF PCB  100  to a metallic enclosure of the heatsink  104 .  FIG.  9    illustrates the element view of the single antenna system  30  in  FIG.  8    illustrating circuit connectivity. The configurable antenna  20  is shaped with two vertical sides and a horizontal portion interconnecting the two vertical sides. The length overall of the two vertical sides and the horizontal portion is about λ/4 at 2.4 GHz. 
       FIG.  10    is a schematic diagram of the single antenna system  30  in  FIG.  8    illustrating circuit connectivity. The switch  38  is a terminating network and is denoted as TN and the tuning/matching network switch  40  includes the switches  42 ,  44  each is a matching network and the switch  42  is denoted as MN 2  and the switch  44  is denoted as MN 1 . Each of the switches  38 ,  42 ,  44  are a 1P3T switch with connectively direct, via a capacitor, and via an inductor. Each of the TN, MN 1 , and MN 2  can be (1) open, (2) terminated with an inductor, and (3) terminated with a capacitor. 
       FIG.  11    is a schematic diagram of the single antenna system  30  in  FIG.  8    illustrating circuit connectivity in a 2.4 GHz configuration. In the 2.4 GHz configuration, the TN is open (not connected to any of the terminals), the MN 2  is open (not connected to any of the terminals), and the MN 2  is set through the capacitor. The effective circuit is similar to a folded inverted F antenna (IFA) or planar IFA (PIFA). The capacitor in the MN 2  can be set to between 0.3 to 1 pF and this capacitor is in series to compensate for the “over-inductiveness” of the antenna  20 . There is a capacitor shown in dotted line between the TN and ground to reflect parasitic capacitance due to the foot  112 . The parasitic capacitance is between the support foot  112  and ground  110  on the PCB  100 . This parasitic capacitance will naturally tune the antenna  20  low when the antenna  20  is in the 2.4 GHz mode. This Cp is inherent or build in due to implementation antenna  20  on the PCB  100  by the Surface Mount Technology (SMT) process. 
       FIG.  12    is a schematic diagram of the single antenna system  30  in  FIG.  11    illustrating circuit connectivity with the terminating network (TN) connected through the inductor.  FIG.  13    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating the effect of the inductor.  FIG.  14    is a schematic diagram of the current flow in the schematic diagram of  FIG.  12   . Terminating the TN through the inductor tunes the antenna  20  higher by counteracting the parasitic capacitance that the antenna feet  112 ,  114  add between the antenna  20  and the heat sink at termination. Thus, the inductor acts as a tuning know for fine tuning resonance in the 2.4 GHz band. The capacitor in the MN 1  is a matching know minimizing the reflected input power and typically ranges between about 0.3 to 1.5 pF. The graph in  FIG.  14    illustrates different values for the TN inductor. Note, the size (length) of the arrows is used to indicate current intensity. In this configuration, L is high value at 2.4 GHz and 5 GHz making this section almost open. Some inductance is still needed to compensate for Parasitic Capacitance Cp. L is tuning knob around 2.5 GHz when element in 2.4 GHz mode. The terminating element with L is highly counter intuitive because one would think it would “break” the quarter wavelength requirement for IFA/PIFA element in 2.4 HzG mode. In reality, it does not break this requirement because L is neutralized by the parasitic capacitance. 
       FIG.  15    is a schematic diagram of the single antenna system  30  in  FIG.  8    illustrating circuit connectivity in a 5 GHz configuration along with the associated current flow.  FIG.  16    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating the effect of the capacitor.  FIG.  17    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating matching resonance at 5 GHz with different values of inductance. For the 5 GHz configuration, the TN (switch  38 ) is configured through the capacitor, the MN 2  (switch  42 ) is open, and the MN 1  (switch  44 ) is shorted for an effective length L of about λ/2 for the antenna  20 . Here, the antenna system  30  operates as a loop/slot antenna with the current flow. In this configuration, the capacitor C in TN is acting as a semi-block at 2.4 GHz but as semi-short at 5 GHz. Increasing C adds up to parasitic capacitance and tunes the loop/slot resonance lower in the 5 GHz band. In the graph of  FIG.  16   , different capacitance values are shown for tuning the antenna  20  lower to adjust to the effective length L of about λ/2. Here, the capacitor C in the TN is a tuning knob for fine tuning resonance into the band.  FIG.  17    illustrates different inductance values on the MN 2  for the foot  114 . Here, the inductor L in MN 1  is a matching knob minimizing reflected input power. 
       FIG.  18    is a schematic diagram of the single antenna system  30  in  FIG.  8    illustrating circuit connectivity in a dual 2.4 GHz and 5 GHz configuration along with the associated current flow. In this configuration, the TN (switch  38 ) is configured through the capacitor, the MN 2  (switch  42 ) is configured through the inductor, and the MN 1  (switch  44 ) is short. The antenna  20  here operates as a combined loop/slot and IFA antenna. The current flow illustrates the 2.4 GHz and 5 GHz currents. The capacitor in the TN appears open at 2.4 GHz (blocked) and the inductor in the MN 2  appears open at 5 GHz (choked). Again, the size (length) of the arrows is used to indicate current intensity. In this configuration, the capacity C in the TN is high enough to present itself as short for 5 GHz and low enough to present itself as open to 2 GHz. In this configuration, the inductor L in MN 2  is high enough to present itself as open for 5 GHz and inductive to 2.4 GHz. 
       FIG.  19    is a graph which illustrates the scattering parameter S 11  versus frequency illustrating operating in a 2.4 GHz configuration, a 5 GHz configuration, and a dual simultaneous 2.4 GHz/5 GHz configuration for the antenna system  30 .  FIG.  20    is a graph which illustrates the efficiency versus frequency illustrating operating in a 2.4 GHz configuration, a 5 GHz configuration, and a dual simultaneous 2.4 GHz/5 GHz configuration for the antenna system  30 . The configuration of the switches  38 ,  42 ,  44  (TN, MN 2 , MN 1 ) is as follows: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 2.4 GHz only 
                 TN (switch 38) - OPEN or through the inductor 
               
               
                 (quarter wave) 
                 (about 8 to 15 nH) 
               
               
                   
                 MN1 (switch 44) - through capacitor 
               
               
                   
                 MN2 (switch 42) - OPEN 
               
               
                 5 GHz only 
                 TN (switch 38) - short (bypass) or through 
               
               
                 (half wave) 
                 capacitor (about 0.5 to 2.5 pF) 
               
               
                   
                 MN1 (switch 44) - short (bypass) or through 
               
               
                   
                 the inductor 
               
               
                   
                 MN2 (switch 42) - OPEN 
               
               
                 2.4 GH + 5 GHz 
                 TN (switch 38) - through capacitor (about 
               
               
                 (half and quarter wave) 
                 0.5 to 2.5 pF) 
               
               
                   
                 MN1 (switch 44) - short (bypass) 
               
               
                   
                 MN2 (switch 42) - through inductor 
               
               
                   
               
            
           
         
       
     
     Advantageously, the radios  16 ,  18  can be configured to selectively use any of the antenna systems  30 A,  30 B,  30 C,  30 D such as to avoid nulls and steer the beam. The radios  16 ,  18  can use 2 chains  46 ,  48  in 2 GHz and 2 chains  46 ,  48  in 5 GHz or 4 chains  46 ,  48  in 5 GHz. 
     The antenna systems  30 A,  30 B,  30 C,  30 D can be controlled by the radios  16 ,  18  for tuning and band configuration. In a dual-band configuration (2.4 GHz/5 GHz), the antenna system  30  operates simultaneously as half and quarter wave in the different bands. The antenna system  30  has better isolation and efficiency when operating in a single band (2.4 GHz or 5 GHz). The antenna system  30  can be tuned dynamically and electronically which no physical changes to the antenna  20  or to the hardware (except for switch changes). 
     The antenna system  30  tuning converts the antenna  20  from quarter wave to half wave including a mode for simultaneous operation as half and quarter wave, specifically for 2.4 GHz and 5 GHz band as these are both Wi-Fi and are almost 2:1 in frequency. The antenna  20  includes the switches  38 ,  42 ,  44  on each end for tuning. 
     The inductor can be used get better open in the 2.4 GHz mode, compensating for the capacitance of the feet  112 ,  114  on the RF PCB  100  (relates to manufacturability). The capacitance at the end gets a bigger loop (change effective length) in the 5 GHz loop mode. The inductor in shunt at the source is to match in the dual mode operation with the capacitance at the end. 
     The wireless access point  50  can use the radios  16 ,  18  to reconfigure the antenna systems  30 A,  30 B,  30 C,  30 D to support reconfigurable MIMO dimensions without requiring a larger number of antennas  20 . The radios  16 ,  18  can be configured for antenna swapping for diversity (fading), condition number (MIMO channel dimension), antenna pattern (directional gain pattern selection), etc. 
     A single antenna system  30  can serve as 2.4 GHz, 5 GHz, or dual-band, with just different tuning elements or different states of the tuning on the board. The advantages of this approach are economy of tooling, volume, inventory, etc. 
     Antenna Implementation 
       FIG.  21    is various diagrams of an exemplary implementation of the antenna  20  utilizing stamping and Surface Mount Technology (SMT). Advantageously, the antenna  20  used in the antenna system  30  is cost effective to produce, designed for mechanical stability, and designed with minimal parasitic capacitance (C e ). The parasitic capacitance can severely impact radiation efficiency. The antenna  20  is formed through a stamping process ( 200 ). In  FIG.  21   , the antenna  20  is shown installed on the ground  110  as shown in more detail in  FIG.  8   , after stamping where the feet  112 ,  114  and the body of the antenna  20  are formed. The antenna  20  includes a first vertical side  210  with the foot  112  at an end, a second vertical side  212  with the foot  114  at an end, and a horizontal portion  214  between the first vertical side  210  and the second vertical side  212  opposite of the feet  112 ,  114 . Those skilled in the art will recognize “horizontal” and “vertical” are used for logical and relative purposes and in a practical deployment of the antenna  20  may be any physical orientation. The antenna  20  can also include an alignment pin  220  which is inserted into the PCB  100  ( FIG.  8   ). After stamping, the feet  112 ,  114  are folded ( 202 ) such as in opposite directions from one another for better mechanical stability and for less parasitic capacitance. The parasitic capacitance gets distributed from the feet  112 ,  114  on several small patches (instead of one big patch). The alignment pin  220  is used during the SMT process. The antenna  20  is shown installed on the ground  100  ( 204 ). 
     It will be appreciated that some embodiments described herein may include one or more generic or specialized processors (“one or more processors”) such as microprocessors; Central Processing Units (CPUs); Digital Signal Processors (DSPs): customized processors such as Network Processors (NPs) or Network Processing Units (NPUs), Graphics Processing Units (GPUs), or the like; Field Programmable Gate Arrays (FPGAs); and the like along with unique stored program instructions (including both software and firmware) for control thereof to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more Application Specific Integrated Circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic or circuitry. Of course, a combination of the aforementioned approaches may be used. For some of the embodiments described herein, a corresponding device in hardware and optionally with software, firmware, and a combination thereof can be referred to as “circuitry configured or adapted to,” “logic configured or adapted to,” etc. perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. on digital and/or analog signals as described herein for the various embodiments. 
     Moreover, some embodiments may include a non-transitory computer-readable storage medium having computer readable code stored thereon for programming a computer, server, appliance, device, processor, circuit, etc. each of which may include a processor to perform functions as described and claimed herein. Examples of such computer-readable storage mediums include, but are not limited to, a hard disk, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), Flash memory, and the like. When stored in the non-transitory computer-readable medium, software can include instructions executable by a processor or device (e.g., any type of programmable circuitry or logic) that, in response to such execution, cause a processor or the device to perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for the various embodiments. 
     Although the present disclosure has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following claims.