Multi-band network node having selectable backhaul/fronthaul configurations

A multi-band network node has selectable backhaul/fronthaul configurations. Network nodes provide multi-band operation to take advantage of higher Internet speeds and to support lower latency (>2 Gbps, <4 ms latency) applications. A greater Wi-Fi device count (capacity) is supported by implementing communication over additional bands. Increased bandwidth is made available between connected nodes by selectively combining backhaul throughputs. Hardware quality-of-service (QoS) is provided by splitting traffic flows for low latency and data applications. Network coverage is extended by dynamic assignment of backhaul connections and by configuring unused backhauls as fronthauls.

FIELD

Various of the disclosed embodiments concern a multi-band network node having selectable backhaul/fronthaul configurations.

BACKGROUND

The data transfer speed of the Internet is continually increasing, making more bandwidth available to end users for their home networks. At the same time, the use of low latency applications over home networks is also increasing, especially for gaming and with the use of conference calls for people who work from home. For example, conference calls take place in real time, and the lag— or the maximum latency allowed—is about 150 to 200 milliseconds. As such, user applications increasingly operate in real time; such applications are very sensitive to latency. There are also many people who trade from home. When they do such trading, they want to sell or buy in a few milliseconds time. Thus, it is important that data is delivered across the home network with maximum throughput and very low latency.

Further, in the past a home network may have had twenty clients, but today, a typical client load in a home network is 40 to 50 clients. As such, adding additional bandwidth over the home network would help to increase the network's capacity.

Finally, the home network itself has grown from a single access point to a network of interconnected nodes. Currently, such networks must both handle traffic and coordinate their interoperation.

There are many challenges to be met in the home network to accommodate both the increase in data transfer speed and bandwidth provided by the Internet and the number of applications now in use in home networks that are sensitive to network latency.

SUMMARY

A multi-band network node has selectable backhaul/fronthaul configurations. Network nodes provide multi-band operation to take advantage of higher Internet speeds and to support lower latency (>2 Gbps, <4 ms latency) applications. A greater Wi-Fi device count (capacity) is supported by implementing communication over additional bands. Increased bandwidth is made available between connected nodes by selectively combining backhaul throughputs. Hardware quality-of-service (QoS) is provided by splitting traffic flows for low latency and data applications. Network coverage is extended by dynamic assignment of backhaul connections and by configuring unused backhauls as fronthauls.

DETAILED DESCRIPTION

Various of the disclosed embodiments concern a multi-band network node having selectable backhaul/fronthaul configurations.FIG.1is an example of a multi-band spectrum according to an embodiment of the invention. InFIG.1, there are five bands: a 2.4 GHz band; a 5 GHz band or 5 GHz low band; a 5 GHz high band; a 6 GHz low band; and a 6 GHz high band.FIG.1shows the frequencies of each band (2400.0 MHz to 2483.5 MHz, etc.) the respective bandwidth of each band (83.5 MHz, 100 MHz, 100 MHz, and so on). Some of the bands are segregated with dynamic frequency selection (DFS), some of bands the request an automatic frequency coordination (AFC), and some of the bands implement a contention-based protocol (CBP) mechanism.

Embodiments include a feature referred to as adaptivity. Adaptivity concerns how a given radio coexists with another radio in the same location/medium. A radio with adaptivity includes a Listen Before Talk (LBT) algorithm with backoff mechanism to avoid collision.

InFIG.1, Band-1may be used as a backup backhaul and Band-2and Band-3may be operated as a backhaul and/or a fronthaul. Spectrum is provided by different regulatory boards across different regions, such as USA-FCC, CANADA-IC, and Europe-ETSI, etc. U-NII (Unlicensed National Information Infrastructure) bands mostly used by WiFi. Typically, WiFi is operated in U-NII-1, 2A, 2C, 3, 4, 5, 6, 7 & 8 bands.

In embodiments, multi-band network nodes, used as network nodes, provide multi-band operation to take advantage of higher Internet speeds and to support lower latency (>2 Gbps, <4 ms latency) applications. A greater Wi-Fi device count (capacity) is supported by implementing communication over additional bands. Increased bandwidth is made available between connected nodes by selectively combining backhaul throughputs. Hardware quality-of-service (QoS) is provided by splitting traffic flows for low latency and data applications. Network coverage is extended by dynamic assignment of backhaul connections and by configuring unused backhauls as fronthauls.

The herein disclosed multi-band network node having selectable backhaul/fronthaul configurations offers several advantages, which are categorized as three primary modes of multi-band network node operation.

One mode of operation is a high-performance mode which provides high performance between any connected network nodes. For example, in an embodiment having a minimum of two backhauls it is possible to aggregate both backhauls from each of the nodes. If each backhaul provides 2 Gbps of throughput, then the aggregate throughput provided is 4 Gbps. This mode of operation provides the highest performance.

For highest performance, embodiments replace the bandwidth of either 320 MHz or 160 MHz. Higher bandwidth provides maximum performance for short distances but is more prone to wireless interference. Every time bandwidth is double receiver sensitivity is reduced by half (3 dB). For highest performance 320/160 MHz bandwidth is considered with limitations. Those are the bandwidths available in Wi-Fi. When using high-performance mode, the nodes are very close links, e.g. the nodes are spaced, for example, twenty feet apart. Thus, it is necessary to reduce the fronthaul power to low power. Fronthaul transmit power is dynamically controlled in 1 dB Steps to have 3-6 dB overall between node fronthauls so that the nodes do not overlap when they are operating in fronthaul, i.e. so they do not interfere with each other.

In the high-performance mode, there is concurrent multi-band operation, selective backhaul and fronthaul, and hardware QoS. In such mode, operational bandwidth is 320 MHz>>>160 MHz, the fronthaul supports link budget control (TPC) (see, for example, IEEE 802.11, 802.15) and the transmitter operates in a low TX power.

In mid-performance mode selective backhaul and fronthaul are available. An application for selective backhaul and fronthaul concerns situations where 4 Gbps performance is not necessary and 2 Gbps performance is adequate. A node using one radio as a backhaul can provide 2 Gbps. In this case, the remaining backhaul can be used as a fronthaul. This keeps the network performance at mid-performance, but it extends the network coverage. In this mode of operation, the operational bandwidth can from 320 MHz to 160 MHz. For fronthaul transmission, the TX power is reduced to medium power. Fronthaul transmit power is dynamically controlled in 1 dB Steps to have 3-6 dB overall between node fronthauls. The high-performance mode requires low power because the nodes are close to each other. In the medium performance mode the nodes are spaced, for example, 40 feet apart, and the TX power is set to medium.

In the mid-performance mode, there is selective backhaul and fronthaul, but operational bandwidth is 320 MHz>>>160 MHz>>>80 MHz, the fronthaul supports link budget control (TPC), and the transmitter operates at medium TX power.

In a coverage extension mode, the network is optimized for maximum range. Throughput may be reduced from 4 Gbps to 2 Gbps, but the node-to-node distance is more than 60 to 70 feet, and the TX power is set to high.

In the coverage extension mode, there is selective backhaul and fronthaul, but operational bandwidth is 80 MHz>>>40 MHz>>>20 MHz, the fronthaul supports link budget control (TPC), and the transmitter operates at high Tx power.

Multi-Band Network Node Having Selectable Backhaul/Fronthaul Configurations—Hardware Design

FIG.2shows a block diagram of a multi-band network node having selectable backhaul/fronthaul configurations. The I/O interface20includes, for example, power, reset, WAN-1, WAN-2and LAN, USB, etc. The network processing unit (NPU)21is connected to five radios22-26, one radio for each of the five bands, via a PCIe bus. Those skilled in the art will appreciate that embodiments of the invention may encompass any number of radios operating over any number of bands. Further, embodiments of the invention do not require a PCIe bus.

In embodiments of the invention each radio has a corresponding RF front end27-30that includes a power amplifier, low noise amplifier, and band pass filters. To reduce the complexity of the number of antennas, a diplexer is used for the 2.4 GHz band and the 5 GHz low band to combine the two bands to use one set of antennas31for both bands; the other bands have independent antennas32-34.

Because embodiments of the invention include, e.g. five radios, there are several design challenges when operating five 36 dBm (4 watts) effective isotropic radiated power (EIRP) radios in proximity. For example there is an isolation requirement:
Isolation=Tx Power+abs(Receiver Sensitivity)
Isolation(Typical)=36+abs(−95)=131 dB

In embodiments, the following techniques are used to achieve multi-band operation. Each technique gives 10-50 dB of isolation. These techniques include, for example, an isolated radio module design, isolated heatsinks, isolated power supply, use of high selectivity filters, use of a narrow band receive low noise amplifier, use of a narrow band transmit power amplifier, and isolated antenna cable routing.

FIG.3shows perspective and side views of a multi-band network node having selectable backhaul/fronthaul configurations having isolated radios and heatsinks.

In embodiments of the invention, five radios are packaged in one network node. Consider that five radios operate at 36 dBm (4 watts). Four watts of power from each radio means that it is very challenging when the radios are situated near each other in a single package to make the radios all work concurrently without impacting each other. How this is achieved is a key aspect of the invention hardware design.

One aspect of the invention isolates the radio module design. Not every radio is put on the main system circuit board35. There is a lot of crosstalk in such arrangement. Instead, each module is preferably mounted separately and is connected to the main system circuit board through a connector. Thus, each radio is isolated as a separate module. The radios do not crosstalk with each other because there is a ground plain in common between each of the radios.

Embodiments of the invention also employ isolated heatsinks. When a heatsink is put on any radio component or power amplifier, there is always leakage between the power amplifier to the heatsink. There is more than enough leakage to couple energy into the heatsink or even a shield cover. In such case the heatsink becomes an RF radiator. That is, it is not just radiating heat, it is also radiating perfectly for any frequency of operation. To counter this, in embodiments the heatsinks36-39are placed on opposite sides of the respective radio module circuit boards in a staggered fashion to avoid the possibility of energy radiated by one radio's heatsink interfering with the operation of another radio.

FIG.4is a schematic representation of a multi-band network node having selectable backhaul/fronthaul configurations and incorporating isolated power supplies for each radio. When there are multiple bands operating, if the same firewall is used to separate each radio, radio-to-radio isolation is reduced because each transmitter outputs 30 dBm power. This dBm power to the power arrays is only 20 or 30 dB lower, that means 0 dBm on the power array. That power goes back into the other radio and causes interference. With 0 dBm considered, the other radios have minus 90 dBm, 0 dBm is 90 dB low sensitivity level. Cross coupling between radios through the radio power supply section is more detrimental to the radios' concurrent operation. For example, with Radio-1transmitting at 30 dBm the leakage transmit power through the DC power supply is only 20-30 dB lower. This means Radio-2is subjected to Radio-1transmit noise with a 0 dBm level with a traditional non-isolated power supply. This greatly reduces the performance of Radio-2and vice versa to an extent of 90˜100 dB. To address this, embodiments of the invention incorporate an isolated power supply for each radio. Accordingly, each radio22-26has its own respective power supply41-50connected to a common power source40but operating separately therefrom.

FIG.5is a block diagram representation of a multi-band network node having selectable backhaul/fronthaul configurations and having a narrow band PA, LNA, filter, and antenna. The isolation requirement is 36 dBm−xdB to achieve a resistance of −95 dBm, for the Rx sensitivity. As such, it is desirable to have 131 dB of isolation. As discussed, embodiments of the invention start with an isolated radio module, an isolated power supply, and an isolated heatsink. Embodiments of the invention also use a highly selective filter52. Thus, each component, i.e. module placement, heatsink and power supply isolation, and filtering, adds 50 dB or 10 dB or 20 dB of isolation, which all adds to 131 dB of isolation.

In embodiments, it is not sufficient to provide only a filter. It is important to make sure that the system is operating with a narrow bandwidth. For example, the 5 GHz band starts at 5 GHz and goes to 7 GHz. If the system operates in that band, it is not possible to reject other bands. Accordingly, embodiments of the invention provide tuned circuits54,56in the power amplifier55path and tuned circuits60,58in low noise amplifier59path. These filters and tuned circuits are provided in the signal path for each band to effect additional rejection within the bands. A narrow band antenna53is also provided.

FIG.6shows front, back, and respective 3D views of isolated antenna cable routing in a multi-band network node having selectable backhaul/fronthaul configurations. In an antenna, it is not just the antenna element alone that radiates RF energy; the antenna cable, which is a part of the antenna, also radiates RF energy. Because the antenna cable carries significant current to the antenna, the antenna cable outer shield becomes a part of the antenna. For multiple bands where the antenna cables pinch each other as they are routed to their respective antennas, there is poor isolation because the cables couple the signals that they carry between each other. Embodiments of the invention isolate every cable as much as possible to get the maximum output. Thus, the antenna cables65-68for each of the radios61-64are positioned away from the cables for each of the other radios.

A further isolation feature is a software feature, referred to as a coexistence bus. In embodiments, there is coexistence for pre-wired coexistence versus a serial interface bus. The system transmits to all the radio rows, when one radio is transmitting, the other does not transmit, it receives. This typically used for Bluetooth and Wi-Fi coexistence, not for Wi-Fi-to-Wi-Fi coexistence. In multi-band WiFi systems all radios can transmit at the same time, all radios can receive at the same time, and some radios can transmit and receive at the same time, which is contrast to Bluetooth+WiFi operation where either only the Bluetooth or WiFi radio is transmitting or receiving at any given time.

Embodiments

FIG.7shows an embodiment of the invention that provides concurrent multi-band operation in a STAR network configuration where the throughput TPUT=TPUT1+TPUT2. This embodiment increases the throughput, i.e. it provides maximum throughput. Between any two nodes there are two backhauls operating simultaneously. Each backhaul provides 2 Gpbs throughput. When the backhauls are aggregated there is 4 Gpbs throughput. InFIG.7, Node1(83), Node2(84), and Node3(85) each have three fronthauls80and two backhauls81,82that together provide a combined 4 Gpbs throughput.

FIG.8shows an embodiment of the invention that provides concurrent multi-band operation in a DAISY network configuration where throughput TPUT=TPUT1+TPUT2. InFIG.8, Node1(93), Node2(94), and Node3(95) each have three fronthauls90and two backhauls91,92that together provide two throughputs, i.e. 2+2 Gpbs between any of the nodes.

FIG.9shows an embodiment of the invention that provides a QoS based backhaul in a STAR network configuration. There are two backhauls going to a spreading node (103); the backhauls are split where one of the backhauls is used for low latency applications to other backhauls and the other backhaul is used for DATA applications. InFIG.9, Node1(103), Node2(104), and Node3(105) each have three fronthauls100and two backhauls101,102, one of which (101) is dedicated to low latency applications and the other of which (102) is dedicated to DATA applications.

FIG.10shows an embodiment of the invention that provides a QoS based backhaul in a DAISY network configuration. One backhaul is used for the lower latency applications throughout the network chain, while another backhaul is used for DATA applications throughout the network chain. InFIG.10, Node1(113), Node2(114), and Node3(115) each have three fronthauls110and two backhauls111,112, one of which (111) is dedicated to low latency applications and the other of which (112) is dedicated to DATA applications.

FIG.11shows an embodiment of the invention that provides selective backhaul in a STAR network configured for coverage. In a Node1, one backhaul communicates with one of the nodes and the other backhaul communicates with the other node. At the same time, Node2and Node3use only one backhaul each to communicate with Node1; the unused backhaul of each of Node2and Node3is used as a fronthaul. As a result, more devices can be added to each of Node2and Node3. InFIG.11, Node1(123), Node2(124), and Node3(125) each have three fronthauls120and two backhauls121,122. Because Node2and Node3do not use all their respective backhauls, Node2has an additional fronthaul127and Node3has an additional fronthaul128.

FIG.12shows an embodiment of the invention that provides selective backhaul in a DAISY network configured for coverage. As in the DAISY chain embodiment above, each of the nodes has a STAR configuration fronthaul available. In Figure, 12 Node1(133), Node2(134), and Node3(135) each have three fronthauls130and two backhauls131,132. Additionally, Node1has one fronthaul137, Node2has two fronthauls138,139, and Node3has one fronthaul140.

In embodiments, for selective backhaul traffic routing in a multi-band network node:Classify fronthaul traffic type, e.g. low latency applications or DATA applications, using any of Mirror Stream Classification Service (MSCS), Type of Service (TOS) field in IP packet headers/Diffserv Code Point (DSCP), Deep Packet Inspection (DPI);Based on satellite placement scenarios (High Performance, Mid Performance, Coverage Extension) to adapt to different control mechanisms;Control system wide parameters (operating system, switch, NPU, Wi-Fi ICs) to route traffic into different backhauls with priority.

Embodiments of the invention include different ICs and software that runs on the ICs. In embodiments, the operating system comprises an embedded Linux OS having settings that can be tuned, such as TCP window and buffer size, to allocate bandwidth on usage. An exemplary switch comprises an Ethernet switch that is embedded in SoC and the provides registers for configuring, e.g. buffer queue, traffic classification, and traffic routing. An exemplary NPU (Network Processor Unit) is embedded in SoC and controls traffic routing between different hardware elements, e.g. Wi-Fi, switch, Bluetooth, powerline, Bluetooth, etc. The NPU provides control on priorities between different hardware elements and traffic shaping. Exemplary Wi-Fi ICs include WMM settings, TWT handling, and Airtime Fairness.

In embodiments, incoming packets are subjected to a deep packet inspection that determines whether the packet is from a real time application or a DATA application. If the packet is from a DATA application it is routed to one of the backhauls, e.g. a backhaul that is dedicated to DATA transfer, if the packet is from a real time application it is routed to another one of the backhauls, e.g. a backhaul that is dedicated to low latency applications. When the nodes are close to each other maximum throughput can be selected and each packet goes through both backhauls at the same time. There is no segregation of data.

Multi-band traffic routing is shown in Table 1 below, which provides a summary of traffic dispatching scenarios.

As can be seen from Table 1, multi-band traffic routing provides three traffic dispatching scenarios:

High Performance, in which:Both backhauls are available and aggregated;Traffic is either equally dispatched or based on selective traffic flow between two backhauls;Low latency packets are routed with priority and assured to avoid packets getting dropped; andData packets are routed with allowing random packet dropping when resources limited or congested.

Mid Performance, in which:Both backhauls are available, where one backhaul is dedicated for low latency packets and the other backhaul is dedicated for data packets.

Coverage Extension, in which:Only one selective backhaul is available;Low latency packets are routed with priority and assured to avoid packets being dropped;Data packets are routed with allowing random packet dropping when resources limited or congested.

FIG.13shows an embodiment of the invention that provides a QoS based backhaul in a STAR network configuration.

InFIG.13, Node1(143), Node2(144), and Node3(145) each have three fronthauls140and two backhauls141,142that together provide two throughputs. One backhaul (141) is dedicated to handling packets for to low latency applications; the other backhaul (142) is dedicated to handling packets for DATA applications. In this STAR network configuration, two of the nodes144,145handle traffic for Client1(151), Client2(152), Client3(153), and Client4(154), where packets for low latency applications are handled via a first fronthaul146and packets for data applications are handled via a second fronthaul147.

Table 2 below provides a summary of QoS based backhaul in a STAR network configuration showing designated routing paths.

FIG.14shows an embodiment of the invention that provides a QoS based backhaul in a DAISY network configuration. InFIG.14, Node1(163), Node2(164), and Node3(165) each have three fronthauls160and two backhauls161,162that together provide two throughputs. One backhaul (161) is dedicated to handling packets for to low latency applications; the other backhaul (162) is dedicated to handling packets for DATA applications. In this DAISY architecture, two of the nodes164,165handle traffic for Client1(171), Client2(172), Client3(173), and Client4(174), where packets for low latency applications are handled via a first fronthaul166and packets for data applications are handled via a second fronthaul167. Note that in this embodiment Node2provide backhaul connections to both of Node1and Node3.

Table 3 below provides a summary of QoS based backhaul in a DAISY network configuration showing designated routing paths.

FIGS.15A and15Bshow side views and top views of antenna placement in a multi-band node, the antennas having a same polarization antenna configuration (FIG.15A) or an orthogonally polarized antenna configuration (FIG.15B). In an embodiment, the dimensions of the device are 160 mm (diameter)×250 mm (height). An exemplary multi-band node has four antenna arrays including a four element 5GH antenna (62) at 21 mm (height); a four element 6GL antenna (63) 21 mm (height); a four element 6GH antenna (63) at 21 mm (height); and a four element 2.4G/5GL antenna (61) at 43 mm (height). The antennas are of a narrow band design and have frequency ranges of 5GH (5490˜5925 MHz); 6GL (5925˜6425 MHz); 6GH (6585˜7125 MHz); 5GL (5170˜5330 MHz); and 2.4G (2400˜2500 MHz).

Typically, vertical polarization is used for arrangements having sixteen antennas. The antenna, for example a dipole antenna, which has a donut shaped radiation pattern is normally used. Usually, better isolation results depend on the spacing between any of the respective antennas. To get the maximum isolation between any same band antenna, the antenna elements can be arranged orthogonal to each other. In the parallel arrangement, the donut shaped radiation pattern of each antenna overlaps, which means that the antennas couple to each other and result in a poor isolation. In the orthogonal arrangement, the antennas are in optimal polarization and the peak point of the radiation pattern of one antenna coexists with the null point, maybe 10 dB or 20 dB lower, of the other antenna. The antennas do not couple to each other, which gives additional isolation on the network.

Embodiments of the invention provide a coupling feed unbalance dipole antenna which has narrow bandwidth. The signal feeds in the shorter L-shaped strip couple to the top straight strip. The longer L-shaped strip is the negative electrode of the signal. The resonated frequency is controlled with the parameters “L1” and “L2.” Impedance matching of the antenna is optimized with the parameters “F” and “G”, resulting in narrow bandwidth.

The traditional dipole antenna without coupling feed has a wideband result and cannot be used for the desired band. In embodiments of the invention, a narrow bandwidth is achieved by designing the coupling feed instead. In this way, the antenna can be made more selective with the desire frequency. According to a simulated result, a narrow bandwidth antenna is presented and each antenna is designed in the desired band (5GH/6GL/6GH/2.4G_5GL).

InFIG.15A, an exemplary same polarization antenna system has the following specifications:

InFIG.15Ban exemplary orthogonally polarized antenna configuration has the following specifications;

Orthogonal polarization placement provides for better isolation (>25).

FIGS.16A and16Bshow a perspective view of same (FIG.16B) and orthogonal (FIG.16A) antenna polarizations.

With orthogonal polarization (FIG.16A), less volume height for the antennas180a,181ais needed in the device (106 mm vs. 124 mm), better isolation is achieved when all antennas placed have orthogonally polarization, and better coverage of radiation pattern with 4× tilted (45 degree) antenna for each MIMO radio. However, the space of the PCB/heatsink might be limited due to antenna tilt inside the device.

With same polarization (FIG.16B), the PCB/heatsink has more space due to antenna180b,181bfit on the inner wall of the device. However, more volume height is occupied for antennas in the device (124 mm V.S. 106 mm), there is worse isolation with all antennas placed under same polarization, and worse coverage of radiation pattern with 4× parallel antennas for each MIMO radio

FIG.17shows a perspective view (left side ofFIG.17) and plane view (right side ofFIG.17) of a 5 GHz— high band antenna190. The antenna is a narrow band antenna, in an embodiment made of FR4 with a size of 6×23×0.8 mm. The antenna is a high efficiency antenna having an omnidirectional radiation pattern.

FIG.18shows graphic representations of 5 GHz— high band antenna performance. Return loss and efficiency is graphed and the radiation pattern of the antenna is shown in the X-Y plane, Y-Z plane, and X-Y plane, all at 5700 MHz

FIG.19shows a perspective view (left side ofFIG.19) and plane view (right side ofFIG.19) of a 6 GHz— low band antenna200. The antenna is a narrow band antenna, in an embodiment made of FR4 with a size of 6×23×0.8 mm. The antenna is a high efficiency antenna having an omnidirectional radiation pattern.

FIG.20shows graphic representations of 6 GHz— low band antenna performance. Return loss and efficiency is graphed and the radiation pattern of the antenna is shown in the X-Y plane, Y-Z plane, and X-Y plane, all at 6175 MHz

FIG.21shows a perspective view (left side ofFIG.21) and plane view (right side ofFIG.21) of a 6 GHz— high band antenna210. The antenna is a narrow band antenna, in an embodiment made of FR4 with a size of 6×23×0.8 mm. The antenna is a high efficiency antenna having an omnidirectional radiation pattern.

FIG.22shows graphic representations of 6 GHz— high band antenna performance. InFIG.22, return loss and efficiency are graphed, and the radiation pattern of the antenna is shown in the X-Y plane, Y-Z plane, and X-Y plane, all at 6855 MHz

FIG.23shows a perspective view (left side ofFIG.23) and plane view (right side ofFIG.23) of a 2.4 GHz+5 GHz— low band dual band antenna220. The antenna is a narrow band antenna, in an embodiment made of FR4 with a size of 9×53×0.8 mm. The antenna is a high efficiency antenna having an omnidirectional radiation pattern.

FIG.24shows graphic representations of 2.4 GHz+5 GHz— low band dual band antenna performance. InFIG.24, return loss and efficiency are graphed, and the radiation pattern of the antenna is shown in the X-Y plane, Y-Z plane, and X-Y plane, at both 2440 MHz and 5250 MHz

FIG.25shows an antenna return loss comparison for a prior art tube antenna, a 2.4 GHz+5 GHz— low band dual band antenna, a 5 GHz— high band antenna, a 6 GHz— low band antenna, and a 6 GHz— high band antenna.

FIG.26shows coupling feed unbalance in a dipole antenna in accordance with embodiments of the invention. The parameter of “F” and “G” can control the impedance matching and the bandwidth of the antenna. The parameter of “L1” and “L2” can control the resonated frequency of the antenna.