Background

[0001] Computing devices can include an antenna to facilitate wireless communication. For example, in a computing device including an antenna tuner, an antenna may be tuned to operate in different frequency bands of interest to the device.

Brief Description of the Drawings

[0002] Figure 1 illustrates an example of a circuit diagram of an antenna tuner according to the disclosure.

[0003] Figure 2 illustrates a flow diagram of an example of a method of bypassing a tunable capacitor of an antenna tuner according to the disclosure.

[0004] Figure 3 illustrates an example of a baseband controller according to the disclosure.

Detailed Description

[0005] As computing device specifications change, space allocation within computing devices may change. For example, mobile and/or portable computing devices (referred to generally herein as "devices") may become smaller, thinner, and/or lighter. Devices can include smartphones, handheld computers, personal digital assistants, carputers, wearable computers, laptops, tablet computers, laptop/tablet hybrids, etc.

[0006] Devices can include an antenna to send and/or receive signals over a wireless network. For example, an antenna can be used to facilitate web access, voice over IP, gaming, high-definition mobile television, video conferencing, etc. As devices become smaller, thinner, and/or lighter, and/or as wireless network standards change, an antenna of a device may be limited to a frequency band in which the antenna's performance may suffer. Some devices may employ an antenna tuner that includes a tunable capacitor to allow the antenna to cover larger frequency bands. However, electrical losses due to the tunable capacitor may lead to a reduction in performance of the antenna.

[0007] Accordingly, the disclosure is directed to devices and methods for bypassing a tunable capacitor of an antenna tuner. For example, bypassing a tunable capacitor of an antenna tuner, as described herein, can include an antenna tuner comprising a reference capacitor, a tunable capacitor, a switch, and a baseband controller to bypass the tunable capacitor by the switch based on an operating frequency for an antenna.

[0008] Figure 1 illustrates an example of a circuit diagram of an antenna tuner 100 according to the disclosure. As illustrated in Figure 1 , the antenna tuner 100 can include a reference capacitor 102, a tunable capacitor 104, a switch 106, and a baseband controller 1 12,

[0009] As illustrated in Figure 1 , the reference capacitor 102 and the tunable capacitor 104 can be connected in parallel. For example, the reference capacitor 102 and the tunable capacitor 104 can be connected such that the same voltage may be applied to reference capacitor 102 and the tunable capacitor 104. As used herein, a capacitor refers to an electrical component that stores electrical energy.

[0010] The reference capacitor 102 may have a fixed capacitance. For example, the reference capacitor 102 may have a fixed capacitance of one picofarad (pF). As used herein, capacitance refers to the ability of a capacitor to store electrical energy.

[0011] Although the reference capacitor 102 is described has having a fixed capacitance of one pF, examples of the disclosure are not so limited. For example, the capacitance of the reference capacitor 102 may be chosen based on a frequency range the antenna 1 10 is intended to cover, as will be further described herein. That is, the capacitance of the reference capacitor 102 can be chosen to be higher than one pF or lower than one pF based on the intended frequency range coverage of the antenna 1 10.

[0012] The tunable capacitor 104 may have a range of capacitances. That is, the capacitance of the tunable capacitor 104 may be modified (e.g., increased or decreased). As used herein, a tunable capacitor refers to a capacitor whose capacitance may be intentionally and repeatedly modified mechanically or electronically. For example, the tunable capacitor 104 may have a capacitance range of two pF to four pF. As another example, the tunable capacitor 104 may have a capacitance range of six pF to eight pF. The capacitance of tunable capacitor 104 may be modified to a capacitance value within the capacitance range.

[0013] Although the tunable capacitor 104 is described has having

capacitance ranges of two pF to four pF and six pF to eight pF, examples of the disclosure are not so limited. For example, the capacitance range of the tunable capacitor 104 may be chosen based on a frequency range the antenna 1 10 is intended to cover, as will be further described herein. That is, the capacitance range of the tunable capacitor 104 can be chosen to be capacitance ranges different from two pF to four pF or six pF to eight pF based on the intended frequency range coverage of the antenna 1 10.

[0014] In some embodiments, the tunable capacitor 104 may be a barium strontium titanate (BST) capacitor, A BST capacitor may handle higher power and a larger signal amplitude than conventional varactor diodes used in other types of tunable capacitors. However, examples of the disclosure are not limited to BST capacitors.

[001 S] The tunable capacitor 104 and the switch 106 may be connected in series. For example, the tunable capacitor 104 and the switch 106 may be connected along a single path (e.g., the same current flows through the tunable capacitor 104 and the switch 106 when the switch 106 is turned on, as will be further described herein). As used herein, a switch may refer to an electrical component capable interrupting, altering a path of, and/or otherwise adjusting the current in the electrical circuit comprising the antenna tuner 100.

[0016] in some embodiments, the switch 106 may be a metal-oxide semiconductor field-effect transistor (MOSFET). For example, the switch 106 can be a MOSFET to bypass the tunable capacitor 104 by switching off, as will be further described herein.

[0017] In some embodiments, the switch 106 may be a complementary metal-oxide semiconductor (CMOS). For example, the switch 106 can be a CMOS to bypass the tunable capacitor 104 by switching off, as will be further described herein.

[0018] As illustrated in Figure 1 , the antenna tuner 100 can connect to an antenna 1 10. The antenna 1 10 can transmit and/or receive signals from a wireless network. As used herein, a wireless network refers to a network using wireless data connections between devices and/or nodes. For example, the antenna 1 10 can wirelessly transmit and/or receive signals in accordance with a long term evolution (LTE) wireless network. Examples of an LTE network may include a worldwide long term evolution (WW-LTE) wireless network or a United States long term evolution (US-LTE) wireless network, although examples of the disclosure are not so limited to WW-LTE and/or US-LTE wireless networks.

[0019] The antenna tuner 100 can include a baseband controller 1 12 to bypass the tunable capacitor 104 by the switch 106 based on an operating frequency for the antenna 1 10, For example, the antenna 1 10 of a device may be operating at a frequency compatible with a US-LTE network; the device may, at a later time, may be operating in a VWV-LTE network that may require the antenna 1 10 to operate at a different frequency corresponding to the WW-LTE network. The antenna tuner 100 can cause the antenna 1 10 to change operating

frequencies to accommodate for the change from the US-LTE network to the WW- LTE network.

[0020] The baseband controller 1 12 can cause the tunable capacitor 104 to be bypassed by the switch 106 when the operating frequency for the antenna 1 10 is greater than a first threshold frequency. For example, when the operating frequency for the antenna 1 10 is greater than a first threshold frequency, the switch 106 can be switched off, causing current to flow through the reference capacitor 102, bypassing the tunable capacitor 104.

[0021] The operating frequency for the antenna 1 10 can be based on the capacitance of the electrical circuit comprising the antenna tuner 100. In some examples, an antenna may need to be operating in a low band frequency range that may include frequencies in a range from 900 megahertz (MHz) to one gigahertz (GHz) or higher. The capacitance corresponding to the frequency range of 900 MHz to one GHz can correspond to the capacitance of the reference capacitor 102 (e.g., one pF). Therefore, to allow the antenna 1 10 to operate in the low band frequency range from 900 MHz to one GHz, the switch 106 can be switched off, resulting in a capacitance of the electrical circuit comprising the antenna tuner 100 being equal to the capacitance of the reference capacitor 102 (e.g., one pF). That is, when the operating frequency for the antenna 1 10 is greater than 900 MHz (e.g., the first threshold frequency), the switch 106 can be switched off, bypassing the tunable capacitor 104, causing the capacitance of the electrical circuit comprising the antenna tuner 100 to be one pF, resulting in the antenna 1 10 operating at a frequency greater than 900 MHz (e.g., the first threshold frequency).

[0022] The baseband controller 1 12 can cause the switch 106 to be switched on when the operating frequency for the antenna is less than a first threshold frequency and greater than a second threshold frequency. In some examples, the antenna may need to be operating in a low band frequency range that may include frequencies in a range from 800 MHz to 900 MHz. To allow the antenna 1 10 to operate in the low band frequency range from 800 MHz to 900 MHz, the switch 106 can be switched on, resulting in the tunable capacitor 104 and the reference capacitor 102 being connected in parallel.

[0023] The capacitance of the electrical circuit comprising the antenna tuner 100 can be equal to the capacitance of the reference capacitor 102 (e.g., one pF) plus the capacitance of the tunable capacitor 104 at a low capacitance (e.g., the tunable capacitor is set to four pF out of a range of four pF to six pF). That is, when the operating frequency for the antenna 1 10 is to be less than 900 MHz (e.g., the first threshold frequency) and greater than 800 MHz (e.g., the second threshold frequency), the switch 106 can be switched on, connecting the reference capacitor 102 and the tunable capacitor 104 in parallel, increasing the capacitance of the electrical circuit comprising the antenna tuner 100 to six pF, and lowering the operating frequency for the antenna 1 10 to be less than the first threshold frequency and greater than the second threshold frequency.

[0024] The baseband controller 1 12 can cause the switch 106 to be switched on when the operating frequency for the antenna is less than a second threshold frequency. In some examples, the antenna may need to be operating in a low band frequency range that may include frequencies in a range from 800 MHz to 700 MHz, or lower. To allow the antenna 1 10 to operate in the low band frequency range from 700 MHz to 800 MHz, the switch 106 can be switched on (e.g., the tunable capacitor 104 and the reference capacitor 102 being connected in parallel) and a capacitance of the tunable capacitor 104 to be modified when the operating frequency for the antenna 1 10 is less than the second threshold frequency (e.g., 800 MHz).

[0025] The capacitance of the electrical circuit comprising the antenna tuner 100 can be equal to the capacitance of the reference capacitor 102 (e.g., one pF) plus the capacitance of the tunable capacitor 104 at a high capacitance (e.g., the tunable capacitor is set to six pF out of a range of four pF to six pF). That is, when the operating frequency for the antenna 1 10 is to be less than 800 MHz (e.g., the second threshold frequency), the switch 106 can be switched on, connecting the reference capacitor 102 and the tunable capacitor 104 in parallel, and the capacitance of the tunable capacitor 104 can be modified (e.g., increased to six pF), increasing the capacitance of the electrical circuit comprising the antenna tuner 100 to seven pF, and lowering the operating frequency for the antenna 1 10 to be less than the second threshold frequency.

[0026] Although the capacitance of the tunable capacitor 104 is described as being increased, examples of the disclosure are not so limited, in some examples, the operating frequency for the antenna 1 10 may need to be increased; the capacitance of the tunable capacitor 104 can be modified (e.g., decreased). That is, as the capacitance of the electrical circuit comprising the antenna tuner 100 is increased, the operating frequency for the antenna 1 10 is decreased. Conversely, as the capacitance of the electrical circuit comprising the antenna tuner 100 is decreased, the operating frequency for the antenna 1 10 is increased.

[0027] Although the frequency ranges described above are described as being 700-800 MHz, 800-900 MHz, and 900 MHz to one GHz, where the corresponding first threshold is described as 900 MHz and the second threshold is described as being 800 MHz, examples of the disclosure are not so limited to the above thresholds and frequency ranges. For example, the switch 106 and the tunable capacitor 104 can be utilized to allow for operation of the antenna 1 10 in other middle band frequency ranges and other high band frequency ranges.

[0028] The capacitance of the reference capacitor 102 can be chosen to allow for operation of the antenna 1 10 in other frequency ranges. For example, although the capacitance of the reference capacitor 102 is described as being one pF, examples of the disclosure are not so limited. In some examples, the capacitance of the reference capacitor 102 can be chosen to be lower than one pF to allow for operation of the antenna 1 10 in higher frequency ranges. In some examples, the capacitance of the reference capacitor 102 can be chosen to be higher than one pF to allow for operation of the antenna 1 10 in lower frequency ranges.

[0029] The capacitance range of the tunable capacitor 104 can be chosen to allow for operation of the antenna 1 10 in other frequency ranges. For example, although the capacitance range of the tunable capacitor 104 is described as being two pF to four pF or six pF to eight pF, examples of the disclosure are not so limited. In some examples, the capacitance range of the tunable capacitor 104 can be chosen to be lower than two pF to four pF to allow for, in conjunction with the reference capacitor 102, operation of the antenna 1 10 in higher frequency ranges. In some examples, the capacitance range of the tunable capacitor 104 can be chosen to be higher than six pF to eight pF to allow for, in conjunction with the reference capacitor 102, operation of the antenna 1 10 in lower frequency ranges.

[0030] As described above, the reference capacitor 102 and the tunable capacitor 104 can be chosen such that the capacitances of the reference capacitor 102 and the tunable capacitor 104 can allow for operation of the antenna 1 10 in various frequency ranges the antenna 1 10 is intended to cover, while providing for acceptable antenna performance for the antenna in an intended operating frequency of interest.

[0031] Figure 2 illustrates a flow diagram of an example of a method 214 of bypassing a tunable capacitor of an antenna tuner according to the disclosure. For example, method 214 may be performed by a baseband controller (e.g., baseband controller 1 12 and/or baseband controller 312, described in connection with Figures 1 and 3, respectively).

[0032] As illustrated at 216, the method 214 can include determining an operating frequency for an antenna. As described above, the baseband controller can determine an operating frequency for an antenna (e.g., antenna 1 10, previously described in connection with Figure 1 ). For example, the baseband controller can utilize a lookup table to determine, based on the wireless network, the operating frequency for the antenna. [0033] As illustrated at 218, the method 214 can include switching a switch connected in series to a tunable capacitor based on the operating frequency for the antenna. As described above, an antenna tuner can include a switch (e.g., switch 106, previously described in connection with Figure 1 ) that is connected in series to a tunable capacitor (e.g., tunable capacitor 104, previously described in connection with Figure 1 ). The tunable capacitor can be connected in parallel to a reference capacitor (e.g., reference capacitor 102, previously described in connection with Figure 1 ).

[0034] The tunable capacitor can be bypassed by the switch when the operating frequency for the antenna is greater than a first threshold frequency. For example, the switch can be switched off, causing current to flow through the reference capacitor, bypassing the tunable capacitor when the operating frequency for the antenna is greater than a first threshold frequency. That is, the switch is switched off to bypass the tunable capacitor when the operating frequency for the antenna is greater than a first threshold frequency.

[0035] The tunable capacitor and the reference capacitor can be connected in parallel when the operating frequency for the antenna is less than the first threshold frequency and greater than a second threshold frequency. For example, the switch can be switched on, causing current to flow through both the reference capacitor and the tunable capacitor when the operating frequency for the antenna is less than the first threshold frequency and greater than the second threshold frequency. That is, the switch is switched on to connect the tunable capacitor and the reference capacitor in parallel when the operating frequency for the antenna is less than the first threshold frequency and greater than the second threshold frequency. The capacitance of the reference capacitor can result in an operating frequency for the antenna being greater than the first threshold frequency.

[0038] The capacitance of the tunable capacitor can be increased in response to the operating frequency for the antenna being less than the second threshold frequency. For example, the switch can be switched on and the capacitance of the tunable capacitor can be increased, causing current to flow through both the reference capacitor and the tunable capacitor when the operating frequency for the antenna is less than the second threshold frequency. That is, the switch is switched on to connect the tunable capacitor and the reference capacitor in parallel and the capacitance of the tunable capacitor can be increased when the operating frequency for the antenna is less than the second threshold frequency. The increase in capacitance by adding the capacitance of the tunable capacitor to the capacitance of the reference capacitor can result in an operating frequency for the antenna being lowered to be less than the second threshold frequency.

[0037] increasing the capacitance of the tunable capacitor can include applying a bias voltage to the tunable capacitor by the baseband controller. For example, the baseband controller can utilize a lookup table to determine, based on the wireless network, an operating frequency for the antenna. Based on the wireless network, the baseband controller can determine the operating frequency for the antenna to be less than the second threshold frequency, and the baseband controller can apply the bias voltage to the tunable capacitor to increase the capacitance of the tunable capacitor. The increase in capacitance of the tunable capacitor along with the capacitance of the reference capacitor can result in an operating frequency for the antenna that is less than the second threshold frequency.

[0038] Figure 3 illustrates an example of a baseband controller according to the disclosure. The baseband controller 312 (e.g., baseband controller 1 12, previously described in connection with Figure 1 ) can include a processing resource 322 in communication with a memory resource 326. The memory resource 326 can include instructions, executable by the processing resource 322 to perform a plurality of functions described herein.

[0039] The baseband controller 312 can utilize software, hardware, firmware, and/or logic to perform a plurality of functions. The baseband controller 312 can include a combination of hardware and program instructions to perform a plurality of functions (e.g., actions). For instance, in some examples the baseband controller 312 can include an application specific integrated circuit (ASIC). The hardware, for example, can include a processing resource 322 and a memory resource 326, such as a machine-readable medium (MRM) and/or other memory resource,

[0040] The memory resource 326 can be infernal and/or external to the baseband controller 312 (e.g., the controller can include an internal memory resource and/or have access to an external memory resource). The program instructions (e.g., machine-readable instructions (MRI)) can include instructions stored on the MRI to implement a particular function. The set of MR! can be executable by the processing resource 322. The memory resource 326 can be coupled to the baseband controller 312 in a wired and/or wireless manner. For example, the memory resource 326 can be an internal memory, a portable memory, a portable disk, and/or a memory associated with another resource (e.g., enabling MRI to be transferred and/or executed across a network such as the Internet).

[0041] Memory resource 326 is non-transitory and can include volatile and/or non-volatile memory. Volatile memory can include memory that depends upon power to store information, such as various types of dynamic random access memory (DRAM) among others. Non-volatile memory can include memory that does not depend upon power to store information. Examples of non-volatile memory can include solid state media such as flash memory, electrically erasable programmable read-only memory (EEPROM), phase change random access memory (PCRAM), magnetic memory such as a hard disk, optical discs, digital versatile discs (DVD), Blu-ray discs (BD), compact discs (CD), and/or a solid state drive (SSD), etc., as well as other types of machine-readable media,

[0042] The processing resource 322 can be coupled to the memory resource 326 via a communication path 324, The communication path 324 can be local or remote to baseband controller 312. Examples of a local communication path 324 can include an electronic bus internal to a machine, where the memory resource 326 can be in communication with the processing resource 322 via the electronic bus. Examples of such electronic buses can include Industry Standard Architecture (ISA), Peripheral Component Interconnect (PCI), Advanced

Technology Attachment (ATA), Small Computer System Interface (SCSI), USB, among other types of electronic buses and variants thereof. The communication path 324 can be such that the memory resource 326 is remote from the processing resource 322, such as in a network connection between the memory resource 326 and the processing resource 322. That is, the communication path 324 can be a network connection. Examples of such a network connection can include local area network (LAN), wide area network (WAN), personal area network (PAN), and the internet, among others.

[0043] As shown in Figure 3, the MRI stored in the memory resource 326 can be segmented into a plurality of engines 328, 330 that when executed by the processing resource 322 can perform a plurality of functions including those described herein. The engines may include a combination of hardware and machine readable instructions that are executable using hardware components such as a processor (e.g., processing resource 322), but at least hardware, to perform actions described herein. The machine readable instructions may be stored in a memory resource such as a non-transitory machine readable medium (e.g., memory resource 326). Also, the plurality of engines may be stored as a hard-wired program, or logic. As used herein, logic" is an additional processing resource to perform a particular action and/or operation, etc., described herein, which includes hardware, such as various forms of transistor logic, and/or application specific integrated circuits (ASICs), among others, as opposed to computer executable instructions, stored in memory and executable by a processor.

[0044] The determine engine 328 may include hardware and/or a

combination of hardware and machine readable instructions, but at least hardware, to determine an operating frequency for an antenna. For example, the determine engine 328 can determine, based on the wireless network, the operating frequency for the antenna. [004S] The switch engine 330 may include hardware and/or a combination of hardware and machine readable instructions, but at least hardware, to cause a switch connected in series to a tunable capacitor to be switched based on the operating frequency for the antenna. In some examples, the tunable capacitor can be bypassed by the switch engine 330 causing the switch to be switched off when the operating frequency is greater than a first threshold frequency. In some examples, the tunable capacitor can be connected in parallel to a reference capacitor by the switch engine 330 causing the switch to be switched on when the operating frequency for the antenna is less than a first threshold frequency and greater than a second threshold frequency.

[0046] In the foregoing detailed description of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration how examples of the disclosure may be practiced. These examples are described in sufficient detail to enable those of ordinary skill in the art to practice the examples of this disclosure, and it is to be understood that other examples may be utilized and that process, electrical, and/or structural changes may be made without departing from the scope of the disclosure.

[0047] The figures herein follow a numbering convention in which the first digit corresponds to the drawing figure number and the remaining digits identify an element or component in the drawing. For example, reference numeral 1 12 may refer to element "12" in Figure 1 and an analogous element may be identified by reference numeral 312 in Figure 3. Elements shown in the various figures herein can be added, exchanged, and/or eliminated so as to provide a plurality of additional examples of the disclosure. In addition, the proportion and the relative scale of the elements provided in the figures are intended to illustrate the examples of the disclosure, and should not be taken in a limiting sense,

[0048] As used herein, "logic" is an alternative or additional processing resource to perform a particular action and/or function, etc., described herein, which includes hardware, e.g., various forms of transistor logic, ASICs, etc., as opposed to computer executable instructions, e.g., software firmware, etc., stored in memory and executable by a processing resource. As used herein, "a plurality of an element and/or feature can refer to one or more of such elements and/or features. It is understood that when an element is referred to as being "on," "connected to", "coupled to", or "coupled with" another element, it can be directly on, connected to, or coupled with the other element or intervening elements may be present.