Patent Application
20140159982
In mobile devices, the number of supported frequency bands continues to increase with increasing demands for new features and higher data throughput. Some examples of new features include multiple voice/data communication links—GSM, CDMA, WCDMA, LTE, EVDO—each in multiple frequency bands, short range communication links (Bluetooth, UWB), broadcast media reception (MediaFLO, DVB-H), high speed internet access (UMB, HSPA, 802.11, EVDO), and position location technologies (GPS, Galileo). Supporting multiple frequency bands results in increased complexity and design challenges. Often, tradeoffs are made to support multiple frequency bands, at the cost of performance.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
A multiband monopole antenna is disclosed that can be dynamically and programmatically reconfigured to accommodate different frequency bands. In one embodiment, a radiator element is coupled to a feed point through a feed-point switch. The switch can direct current between the feed point and the radiator element using at least two different current paths. The current paths can be of different lengths so as to be optimized for the different frequency bands. Each current path can share a majority of a radiator element so as to save space. By switching the feed-point switch to select one of the current paths, the antenna can be configured. Selection can be controlled from a modem or even user input.
In another embodiment, a parasitic radiator can be coupled to ground through a ground switch. Using the feed-point switch and the ground switch multiple modes of operation can be implemented using a single antenna structure.
Overall performance can, therefore, be improved with minimal additional components.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
A reconfigurable monopole antenna is described which includes a radiator element coupled to a feed point through at least two different current paths. The current paths are of different lengths to accommodate different frequency bands. To change the current paths, a feed-point switch is positioned at the antenna feed point for selectively supplying current along either a first current path or a second current path. The current paths share a majority of the radiator element so that separate radiator elements need not be used.
By supplying an antenna that is designed to tune or switch between different bands, there is no need to supply separate antennas. As a result, the antenna size is reduced given that the same resonator structure acts as radiator element for different frequencies. The space that is saved can be used for other purposes, such as a battery, circuitry or device size reduction. Additionally, antenna performance improves (e.g., higher QoS, lower dropped calls, higher battery life) due to the absence of tradeoffs made in prior multiple band configurations. Additionally, the antenna can be positioned in more aggressive volumes, such as on top of a PCB ground plane, which can have benefits from hand/head detuning effect and the regulated absorption of energy to the human tissue (specific absorption ratio, SAR). Placing the switches close to the feed point (where no high electric fields are present) can minimize the generation of fundamental harmonics, which could assist in passing regulatory testing.
In specific embodiments, an antenna is disclosed that uses several switchable elements within a radiating structure itself. One single-pole-double-throw (SPDT) switch can be utilized to cover two different groups of frequency bands located in a lower frequency spectrum of LTE (e.g., 800 MHz). For example, a short path can allow operation at high frequency bands while a longer path can allow operation at the lower frequencies. An additional single-pole-single-throw (SPST) can be used to provide antenna operation in the group of bands allocated at the high frequency spectrum (e.g., 2 GHz). Thus, the antenna allows each band or groups of bands to be adjusted independently through the use of switches located at the antenna feed point or near the feed point (e.g., within λ/10). The switches can prevent or allow currents on demand depending on the desired frequency of operation.
The illustrated mobile device 100 can include a controller or processor 110 (e.g., signal processor, microprocessor, ASIC, or other control and processing logic circuitry) for performing such tasks as signal coding, data processing, input/output processing, power control, and/or other functions. An operating system 112 can control the allocation and usage of the components 102 and support for one or more application programs 114. The application programs can include common mobile computing applications (e.g., email applications, calendars, contact managers, web browsers, messaging applications), or any other computing application.
The illustrated mobile device 100 can include memory 120. Memory 120 can include non-removable memory 122 and/or removable memory 124. The non-removable memory 122 can include RAM, ROM, flash memory, a hard disk, or other well-known memory storage technologies. The removable memory 124 can include flash memory or a Subscriber Identity Module (SIM) card, which is well known in GSM communication systems, or other well-known memory storage technologies, such as “smart cards.” The memory 120 can be used for storing data and/or code for running the operating system 112 and the applications 114. Example data can include web pages, text, images, sound files, video data, or other data sets to be sent to and/or received from one or more network servers or other devices via one or more wired or wireless networks. The memory 120 can be used to store a subscriber identifier, such as an International Mobile Subscriber Identity (IMSI), and an equipment identifier, such as an International Mobile Equipment Identifier (IMEI). Such identifiers can be transmitted to a network server to identify users and equipment.
The mobile device 100 can support one or more input devices 130, such as a touchscreen 132, microphone 134, camera 136, physical keyboard 138 and/or trackball 140 and one or more output devices 150, such as a speaker 152 and a display 154. Other possible output devices (not shown) can include piezoelectric or other haptic output devices. Some devices can serve more than one input/output function. For example, touchscreen 132 and display 154 can be combined in a single input/output device. The input devices 130 can include a Natural User Interface (NUI). An NUI is any interface technology that enables a user to interact with a device in a “natural” manner, free from artificial constraints imposed by input devices such as mice, keyboards, remote controls, and the like. Examples of NUI methods include those relying on speech recognition, touch and stylus recognition, gesture recognition both on screen and adjacent to the screen, air gestures, head and eye tracking, voice and speech, vision, touch, gestures, and machine intelligence. Other examples of a NUI include motion gesture detection using accelerometers/gyroscopes, facial recognition, 3D displays, head, eye, and gaze tracking, immersive augmented reality and virtual reality systems, all of which provide a more natural interface, as well as technologies for sensing brain activity using electric field sensing electrodes (EEG and related methods). Thus, in one specific example, the operating system 112 or applications 114 can comprise speech-recognition software as part of a voice user interface that allows a user to operate the device 100 via voice commands. Further, the device 100 can comprise input devices and software that allows for user interaction via a user's spatial gestures, such as detecting and interpreting gestures to provide input to a gaming application.
A wireless modem 160 can be coupled to a reconfigurable monopole antenna 170 and can support two-way communications between the processor 110 and external devices, as is well understood in the art. The modem 160 is shown generically and can include a cellular modem for communicating with the mobile communication network 104 and/or other radio-based modems (e.g., Bluetooth 164 or Wi-Fi 162). The wireless modem 160 is typically configured for communication with one or more cellular networks, such as a GSM network for data and voice communications within a single cellular network, between cellular networks, or between the mobile device and a public switched telephone network (PSTN). The one or more modems can communicate (transmit and receive) with the antenna 170 through one or more switches 172 that are used to configure the antenna for multiple frequency bands of operation, as further described below. The switches 172 can be controlled automatically by the modems based on an optimal frequency band to be used, or user input can be received through one of the input devices 130 to select the desired frequency band. In any event, the antenna 170 is selectably and programmatically configurable.
The mobile device can further include at least one input/output port 180, a power supply 182, a satellite navigation system receiver 184, such as a Global Positioning System (GPS) receiver, an accelerometer 186, and/or a physical connector 190, which can be a USB port, IEEE 1394 (FireWire) port, and/or RS-232 port. The illustrated components 102 are not required or all-inclusive, as any components can be deleted and other components can be added.
The feed-point switch 250 is shown as a single pole, double throw (SPDT) switch that is responsive to the control signal to switch the antenna between at least two modes of operation. In a first mode of operation, the longer current path 252 can be used to supply the shared portion of the radiator element 260. In this mode, the antenna 210 can allow operation at low frequencies. In a second mode of operation, the shorter current path 254 can be used to supply the radiator element 260. In this mode, the antenna can allow operation at higher frequencies. Thus, using one SPDT switch, two different groups of frequency bands can be used that are located in the lower frequency spectrum of LTE.
It should be recognized that the antenna configuration 200 can be extended to additional current paths by simply adding another current path having a desired length associated with a frequency band and modifying the switch to be able to handle switching between the different current paths. Thus, three, four, five, etc. current paths can be used.
In the
Thus, using only two switches, at least three different antenna modes of operation can be selected. In a first mode of operation, path 340 is activated (using switch 312) with switch 310 turned on (grounding the parasitic radiator). In a second mode of operation, path 342 is activated with switch 310 turned on (grounding the parasitic radiator). In these first two modes, the parasitic radiator serves the purpose of impedance matching. In a third mode of operation, current path 372 is activated by turning switch 310 off and selecting current path 340 using switch 312. A possible fourth mode of operation can have current path 342 (the shorter path) selected with switch 310 off.
Any of the disclosed methods can have aspects that are implemented as computer-executable instructions stored on one or more computer-readable storage media (e.g., one or more optical media discs, volatile memory components (such as DRAM or SRAM), or nonvolatile memory components (such as flash memory or hard drives)) and executed on a computer (e.g., any commercially available computer, including smart phones or other mobile devices that include computing hardware). As should be readily understood, the term computer-readable storage media does not include communication connections, such as modulated data signals. Any of the computer-executable instructions for implementing the disclosed techniques as well as any data created and used during implementation of the disclosed embodiments can be stored on one or more computer-readable media. The computer-executable instructions can be part of, for example, a dedicated software application or a software application that is accessed or downloaded via a web browser or other software application (such as a remote computing application). Such software can be executed, for example, on a single local computer (e.g., any suitable commercially available computer) or in a network environment (e.g., via the Internet, a wide-area network, a local-area network, a client-server network (such as a cloud computing network), or other such network) using one or more network computers.
It should also be well understood that any functionality described herein can be performed, at least in part, by one or more hardware logic components, instead of software. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Program-specific Integrated Circuits (ASICs), Program-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.
Furthermore, any of the software-based embodiments (comprising, for example, computer-executable instructions for causing a computer to perform any of the disclosed methods) can be uploaded, downloaded, or remotely accessed through a suitable communication means. Such suitable communication means include, for example, the Internet, the World Wide Web, an intranet, software applications, cable (including fiber optic cable), magnetic communications, electromagnetic communications (including RF, microwave, and infrared communications), electronic communications, or other such communication means.
The disclosed methods, apparatus, and systems should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and subcombinations with one another. The disclosed methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed embodiments require that any one or more specific advantages be present or problems be solved.
In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope of these claims.
