1. Field of the Invention
The present invention generally relates to wireless communications. More specifically, the present invention relates to dual polarization antenna antennas with mountable antenna elements.
2. Description of the Related Art
In wireless communications systems, there is an ever-increasing demand for higher data throughput and reduced interference that can disrupt data communications. A wireless link in an Institute of Electrical and Electronic Engineers (IEEE) 802.11 network may be susceptible to interference from other access points and stations, other radio transmitting devices, and changes or disturbances in the wireless link environment between an access point and remote receiving node. The interference may degrade the wireless link thereby forcing communication at a lower data rate. The interference may, in some instances, be sufficiently strong as to disrupt the wireless link altogether.
In one particular example, the wireless device 100 may be a handheld device that receives input through an input mechanism configured to be used by a user. The wireless device 100 may process the input and generate a corresponding RF signal, as may be appropriate. The generated RF signal may then be transmitted to one or more receiving nodes 110-140 via wireless links. Nodes 120-140 may receive data, transmit data, or transmit and receive data (i.e., a transceiver).
Wireless device 100 may also be an access point for communicating with one or more remote receiving nodes over a wireless link as might occur in an 802.11 wireless network. The wireless device 100 may receive data as a part of a data signal from a router connected to the Internet (not shown) or a wired network. The wireless device 100 may then convert and wirelessly transmit the data to one or more remote receiving nodes (e.g., receiving nodes 110-140). The wireless device 100 may also receive a wireless transmission of data from one or more of nodes 110-140, convert the received data, and allow for transmission of that converted data over the Internet via the aforementioned router or some other wired device. The wireless device 100 may also form a part of a wireless local area network (LAN) that allows for communications among two or more of nodes 110-140.
For example, node 110 may be a mobile device with WiFi capability. Node 110 (mobile device) may communicate with node 120, which may be a laptop computer including a WiFi card or wireless chipset. Communications by and between node 110 and node 120 may be routed through the wireless device 100, which creates the wireless LAN environment through the emission of RF and 802.11 compliant signals.
Efficient manufacturing of wireless device 100 is important to provide a competitive product in the market place. Manufacture of a wireless device 100 typically includes construction of one or more circuit boards and one or more antenna elements. The antenna elements can be built into the circuit board or manually mounted to the wireless device. When mounted manually, the antenna elements are attached to the surface of the circuit board and typically soldered although those elements may be attached by other means.
When surface-mounted antenna elements are used in a wireless device, a ground layer of a circuit board within the device is coupled to the antenna elements. Coupling the surface-mounted antenna elements to a ground layer with a large area is required for proper operation of the antenna elements. Dipole antenna elements that are built into a circuit board do not operate very well when positioned close proximity to a ground layer. Hence, when a large ground layer is used to accommodate surface-mounted antenna elements in a wireless device, the presence of the ground layer affects the performance of any dipole antenna elements embedded within the circuit board and usually precludes their use within such a device. A smaller ground layer may result in better performance of embedded dipole antennas but would reduce the efficiency of a surface mounted antenna element. Because of this tradeoff, wireless devices with both surface-mount antenna elements and embedded dipole antenna elements do not provide efficient dual polarization operation.
In a claimed embodiment, a wireless device for transmitting a radiation signal may include a circuit board, an antenna array and a radio modulator/demodulator. The circuit board may receive a mountable antenna element for radiating at a first frequency. The antenna array may be coupled to the circuit board. The radio modulator/demodulator may provide a radio frequency (RF) signal to the first mountable antenna and the antenna array.
In another claimed embodiment, a circuit board for transmitting a radiation signal may include a coupling element, a coupling element, a stub, and a radio modulator/demodulator. The coupling element may couple to a mountable antenna element. The stub may be positioned proximate to the antenna array and generate an impedance in the antenna array. The radio modulator/demodulator may provide a RF signal to the first mountable antenna and the antenna array.
In another claimed embodiment, wireless device for transmitting a radiation signal may include communication circuitry, a plurality of antenna elements, a mountable antenna coupling element, and a switching network. The communication circuitry is located within the circuit board and generates a RF signal. The plurality of antenna elements are arranged proximate the edges of the circuit board. Each antenna element may form a radiation pattern when coupled to the communication circuitry and receives a generated impedance. The mountable antenna coupling element is configured on the circuit board and couples a mountable antenna element to the circuit board. The switching network selectively couples one or more of the plurality of antenna elements and the mountable antenna coupling element to the communication circuitry.
Embodiments of the present invention allow for the use of a wireless device having a mountable antenna element and an antenna array that operate simultaneously and efficiently on a circuit board within a wireless device. The mountable antenna element may be coupled to a ground layer of the circuit board. The antenna array may include dipole antennas incorporated within the circuit board and positioned within a close proximity to the ground layer. One or more stubs may be implemented on the circuit board near the dipole antenna array. Each antenna stub may create an impedance in the dipole elements which enable the elements to operate efficiently while positioned in close proximity to the circuit board ground layer.
A stub may be coupled to or constructed as an extension of a circuit board ground layer. The stub may extend alongside a dipole antenna element or ground portion and generate a high impedance at a point along the dipole antenna element. The high impedance point enables the antenna dipole to operate without any adverse radiation effects caused from the ground plane. Without the stub, the ground plane would terminate the radiation field of the antenna element in close proximity to the ground plane. The stub enables the antenna element to radiate as if the ground plane were not present or “invisible” to the energy radiated from the antenna element.
The mountable antenna element may be constructed as a single element or object from a single piece of material, can be configured to transmit and receive RF signals, achieve optimized impedance values, and operate in a concurrent dual-band system. The mountable antenna element may have one or more legs, an RF signal feed, and one or more impedance matching elements. The legs and RF signal feed can be coupled to a circuit board. The mountable antenna can also include one or more antenna stubs that enable it for use in concurrent dual band operation with the wireless device.
A reflector may also be mounted to a circuit board having a mountable antenna element. The reflector can reflect radiation emitted by the antenna element. The reflector can be constructed as an element or object from a single piece of material and mounted to the circuit board in a position appropriate for reflecting radiation emitted from the antenna element.
Wireless device may include communication circuitry to generate and direct an RF signal to antenna array 240. The data I/O module 205 of
The antenna selector 215 of
Antenna array 240 can include an antenna element array, a mountable antenna element and reflectors. The antenna element array can include a horizontal antenna array with two or more antenna elements. The antenna elements can be configured to operate at frequencies of 2.4 GHZ and 5.0 GHz. Antenna array 240 can also include a reflector/controller array. Each mountable antenna may be configured to radiate at a particular frequency, such as 2.4 GHz or 5.0 GHz. The mountable antenna element and reflectors can be located at various locales on the circuit board of a wireless device, including at about the center of the board.
The antenna array incorporated into the circuit board includes radio frequency feed port 310 selectively coupled to antenna elements 320, 330, 340, 350, 360, and 370. Although six antenna elements are depicted in
Also within the circuit board, depicted as dashed lines in
Each antenna element 320, 330, 340, 350, 360, and 370 and corresponding ground portion may be about the same length. As shown in
To minimize or reduce the size of the antenna array, each of the modified dipoles (e.g., the antenna element 320 and the portion 325 of the ground component) may incorporate one or more loading structures 390. For clarity of illustration, only the loading structures 390 for the modified dipole formed from antenna element 320 and portion 325 are numbered in
Antenna selector 215 of
A series of control signals can be used to bias each PIN diode. With the PIN diode forward biased and conducting a DC current, the PIN diode switch is on, and the corresponding antenna element is selected. With the diode reverse biased, the PIN diode switch is off. In this embodiment, the radio frequency feed port 310 and the PIN diodes of the antenna element selector are on the side of the substrate with the antenna elements 320-370, however, other embodiments separate the radio frequency feed port 310, the antenna element selector, and the antenna elements 320-370.
One or more light emitting diodes (LED) (not shown) can be coupled to the antenna element selector. The LEDs function as a visual indicator of which of the antenna elements 320-370 is on or off. In one embodiment, an LED is placed in circuit with the PIN diode so that the LED is lit when the corresponding antenna element is selected.
A mountable antenna element can be coupled to the circuit board 300 using coupling elements such as for example coupling pads 380 and 382. Reflectors for reflecting or directing the radiation of a mounted antenna element can be coupled to the circuit board at coupling pads 384. A coupling pad is a pad connected to circuit board circuitry (for example a switch or ground) and to which the antenna element can be connected, for example via solder. The antenna element can include a coupling plate having a surface that, when mounted to the circuit board, is roughly parallel and in contact with the circuit board coupling pads 380 and 382. Reflectors may include a coupling plate for coupling the reflector to coupling pads 384. A coupling plate is an antenna element surface (e.g., a surface at the end of an antenna element leg) that may be used to connect the antenna element to a coupling pad. Antenna elements having a coupling plate (e.g., coupling plate 670) are illustrated in
Coupling pads 380 and 384 can be connected to ground and coupling pad 382 can be connected to a radio modulator/demodulator 220 through a diode switch (e.g., diode switch 230). Coupling pads 380, 382 and 384 can include one or more coupling pad holes for receiving an antenna element pin to help the secure antenna element to the circuit board. Mountable antenna elements, reflectors, and circuit boards circuit boards configured to receive the elements and reflectors are described in more detail in U.S. patent application Ser. No. 12/545,758, filed on Aug. 21, 2009, and titled “Mountable Antenna Elements for Dual Band Antenna,” the disclosure of which is incorporated herein by reference.
The antenna components (e.g., the antenna elements 320-370, the ground components 325-375, a mountable antenna element, and any reflector/directors for the antenna elements and mountable antenna element) are formed from RF conductive material. For example, the antenna elements 320-370 and the ground components 325-375 can be formed from metal or other RF conducting material. Rather than being provided on opposing sides of the substrate as shown in
The antenna components can be conformally mounted to a housing. The antenna element selector comprises a separate structure (not shown) from the antenna elements 320-370 in such an embodiment. The antenna element selector can be mounted on a relatively small PCB, and the PCB can be electrically coupled to the antenna elements 320-370. In some embodiments, a switch PCB is soldered directly to the antenna elements 320-370.
Antenna elements 320-370 can be selected to produce a radiation pattern that is less directional than the radiation pattern of a single antenna element. For example, selecting all of the antenna elements 320-370 results in a substantially omnidirectional radiation pattern that has less directionality than the directional radiation pattern of a single antenna element. Similarly, selecting two or more antenna elements may result in a substantially omnidirectional radiation pattern. In this fashion, selecting a subset of the antenna elements 320-370, or substantially all of the antenna elements 320-370, may result in a substantially omnidirectional radiation pattern for the antenna array.
Reflector/directors may further be implemented in circuit board 300 to constrain the directional radiation pattern of one or more of the antenna elements 320-370 in azimuth. Other benefits with respect to selectable configurations are disclosed in U.S. patent application Ser. No. 11/041,145 filed Jan. 21, 2005 and entitled “System and Method for a Minimized Antenna Apparatus with Selectable Elements,” the disclosure of which is incorporated herein by reference.
The stubs create a high impedance point at a position within an antenna element or ground element. The high impedance point results in no current in the corresponding antenna element or ground element. For example, for ground portion 325, the high impedance point may be generated at a point about half way within the ground portion 325, extruding away from antenna element 320, or at a point on the ground portion 325 between the two middle loading structures. The high impedance point allows the ground plane 420 to be in close proximity to the dipole without affecting the radiation of the dipole.
By creating the high impedance point, the stub allows an antenna element to be positioned in close proximity to ground plane 420 without affecting operation (i.e., radiation) of the antenna element. This overcomes problems associated with ground planes that terminate the radiation field of a dipole when the ground plane is too close to a dipole antenna element and corresponding ground portion. The stub enables a larger ground plane for use in a circuit board with dipoles and mountable antenna elements, which is desirable as the larger ground plane is needed for proper operation of a mountable antenna element.
The length of a stub may be selected based on the design of the circuit in which the stub is implemented. The stub may be positioned a distance of one quarter wavelength from the ground plane, wherein the wavelength may be derived from the dipole antenna element radiating frequency. The length of the stub may be selected based on where in an antenna element or ground element the impedance point should be generated. For a circuit having an antenna array that radiates at 2.4 GHz, the stub may have a length of about 595 mils (thousandths of an inch) and a slot width (the width of the slot between the ground plane 420 and the stub) of about 20 mils. With this configuration, the dipole can be within about 300 mils of the ground plane. The stubs, dipoles and loading structures may include extension units for extending their length. For example, an extension unit may include a zero ohm resistor coupled to the end of a stub, dipole or loading structure during manufacturing or testing of the circuit.
The antenna element legs can be used to couple the antenna element to circuit board 300 (
When the antenna element coupling plate 570 is connected to circuit board coupling pad 380 and a switch connecting the coupling pad 380 to radio modulator/demodulator 220 is open, no radiation pattern is transmitted or received by the mounted antenna element. When the switch is closed, the mounted antenna element is connected to radio modulator/demodulator 220 and may transmit and receive RF signals. The length of the side members 550 and 560 can be chosen at time of manufacture based on the frequency of the antenna element from which radiation is being received.
Extending downward from near the center of the top surface 505, 510, 515, 520 are impedance matching elements 525, 530 and 535. Impedance matching elements 525, 530, 535 as illustrated in
Impedance matching elements 525 and 535 extend downward towards a ground layer within circuit board 300 and form a capacitance between the impedance matching element and the ground layer. By forming a capacitance with the ground layer of the circuit board 300, the impedance matching elements achieve impedance matching at a desired frequency of the antenna element. To achieve impedance matching, the length of the impedance matching element and the distance between the circuit board ground layer and the closest edge of the downward positioned impedance matching element can be selected based on the operating frequency of the antenna element. For example, when an antenna element 500 is configured to radiate at about 2.4 GHz, each impedance matching element may be about 8 millimeters long and positioned such that the edge closest to the circuit board is about 2-6 millimeters (e.g., about 3.6 millimeters) from a ground layer within the circuit board.
The mountable antenna element may also include a radio frequency (RF) feed element that extends down from the center of the top surface between impedance matching members 425 and 430 and can be coupled to coupling pad 382 on circuit board 300. The RF feed element includes a plate that can be coupled via solder or some other process for creating a connection between the coupling pad 382 and antenna element 400 through which an RF signal can travel.
Reflector 600 can be constructed as an object formed from a single piece of material, such as tin, similar to the construction of antenna element 500. The reflector 600 can be symmetrical except for the pins 615 and the plate 620. Hence, the material for reflector 600 can be built as a flat and approximately “T” shaped unit with a center portion with arms extending out to either side of the center portion. The flat element can then be bent, for example, down the center of the base such that each arm is of approximately equal size and extends from the other arm at a ninety-degree angle.
The antenna element legs can be used to couple the antenna element to circuit board 300 (
Extending downward from near the center of the top surface are impedance matching elements 725 and 730. A third impedance matching element is positioned opposite to impedance matching element 730 but not visible in the view of
Mountable antenna element 700 may include an RF feed element that extends down towards ground and is positioned opposite to impedance matching element 725 near the center of the top surface of antenna element 700. The RF feed element can be coupled to coupling pad 382 on circuit board 300. The RF feed element can include a coupling plate to be coupled to coupling pad 382 via solder or some other process for creating a connection between the RF source and antenna element 700.
Impedance matching elements 725 and 730 extend downward from the top surface toward a ground layer within circuit board 300 and form a capacitance between the impedance matching element and the ground layer. The impedance matching elements achieve impedance matching at a desired frequency based on the length of the impedance matching element and the distance between the circuit board ground layer and the closest edge of the downward positioned impedance matching element based. For example, when an antenna element 700 is configured to radiate at about 5.0 GHz, each impedance matching element may be about 5 millimeters long and positioned such that the edge closest to the circuit board is between 2-6 millimeters (e.g., about 2.8 millimeters) from a ground layer within the circuit board.
Base 820 includes a mounting plate 825. Mounting plate 825 can be used to couple reflector 800 to circuit board 300 via solder. In addition to mounting plate 825, pins 815 can also be soldered to mounting pad 384. Once the pins 830 are inserted into holes within a coupling pad and coupling plate 825 is in contact with the surface of the mounting pad, the reflector 800 can stand upright without additional support, making installation of the reflectors easer than typical reflectors which do not have mounting pins 830 and a mounting plate 825.
Reflector 800 can be constructed as an object from a single piece of material, such as a piece of tin. The reflector 800 can be symmetrical except for the pins 830 and the plate 825. Hence, the material for reflector 800 can be built as a flat and approximately “T” shaped unit. The flat element can then be bent down the center such that each arm is of approximately equal size and extends from the other arm at a ninety-degree angle.
The present technology may be used with a variety of circuits, circuit boards, and antenna technology, such as the technology described in U.S. patent application Ser. No. 12/212,855 filed Sep. 18, 2008, which is a continuation of U.S. patent application Ser. No. 11/938,240 filed Nov. 9, 2007 and now U.S. Pat. No. 7,646,343, which claims the priority benefit of U.S. provisional application 60/865,148 filed Nov. 9, 2006; U.S. patent application Ser. No. 11/938,240 which is also a continuation-in-part of U.S. patent application Ser. No. 11/413,461 filed Apr. 28, 200, which claims the priority benefit of U.S. provisional application No. 60/694,101 filed Jun. 24, 2005, and the disclosure of each of the aforementioned applications is incorporated herein by reference.
Though a finite number of mountable antenna elements are described herein, other variations of single piece construction mountable antenna elements are considered within the scope of the present technology. For example, an antenna element 400 generally has an outline of a generally square shape with extruding legs and side members as illustrated in
The embodiments disclosed herein are illustrative. Various modifications or adaptations of the structures and methods described herein may become apparent to those skilled in the art. Such modifications, adaptations, and/or variations that rely upon the teachings of the present disclosure and through which these teachings have advanced the art are considered to be within the spirit and scope of the present invention. Hence, the descriptions and drawings herein should be limited by reference to the specific limitations set forth in the claims appended hereto.