An example dual-band antenna includes a substrate and a primary radiator disposed on the substrate and connected to a transmission line for driving the primary radiator, where the primary radiator, when driven via the transmission line, has a first resonant frequency. The dual-band antenna also includes a secondary radiator disposed on the substrate and unconnected to the primary radiator, where the primary radiator, when driven via the transmission line, induces a current in the secondary radiator such that the secondary radiator has a second resonant frequency different from the first resonant frequency.

FIELD OF THE DISCLOSURE

BACKGROUND

Options for accessing and listening to digital audio in an out-loud setting were limited until in 2002, when SONOS, Inc. began development of a new type of playback system. Sonos then filed one of its first patent applications in 2003, entitled “Method for Synchronizing Audio Playback between Multiple Networked Devices,” and began offering its first media playback systems for sale in 2005. The Sonos Wireless Home Sound System enables people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a controller (e.g., smartphone, tablet, computer, voice input device), one can play what she wants in any room having a networked playback device. Media content (e.g., songs, podcasts, video sound) can be streamed to playback devices such that each room with a playback device can play back corresponding different media content. In addition, rooms can be grouped together for synchronous playback of the same media content, and/or the same media content can be heard in all rooms synchronously.

The drawings are for the purpose of illustrating example embodiments, but those of ordinary skill in the art will understand that the technology disclosed herein is not limited to the arrangements and/or instrumentality shown in the drawings.

DETAILED DESCRIPTION

Embodiments described herein relate to wireless communications devices in general, and wireless playback devices in a multi-room media playback system specifically. In particular, the embodiments herein discuss an improved dual-band antenna design that may provide increased design flexibility and operational advantages in a wireless communication device, such as a wireless, multimedia playback device.

Dual-band antennas are designed and implemented in a wide variety of consumer hardware devices. This is especially true in consumer electronics that support applications such as multi-band cellular networks, multi-band global positioning protocols (i.e., GPS and GLONASS) and wireless local area network (WLAN) systems, or similar. Industrial design requirements (e.g., aesthetics) and other space constraints have necessitated that an antenna designer use a so-called shared space to provide a single antenna element with a dual-band or multi-band behavior.

In general, the starting point to design said elements is usually a single-band radiator that owes its native characteristics to the structure on which it resides along with the length/size and aspect ratio of what is commonly deemed as the radiating element (i.e. the part of the conductive surface that is excited to produce electromagnetic radiation). To achieve a multi-band resonance behavior, further elements can be added, such as secondary/tertiary arms or radiating elements.

The constraints, however, in having the second resonant element be a part of the first element's footprint will limit the topologies chosen to achieve this dual-resonant behavior. Also, modifying one element's physical characteristic (e.g., its length) will impact the other, and vice-versa, as they are part of the same conductive structure and commonly share a feed-point location from a transmission line.

In the examples herein, dual-band antenna designs are described which, based on their unique topology, mitigate and at times fully avoid a noticeable impact to the principal element. In the following examples, the secondary resonance is achieved by coupling a secondary element to the first element in a parasitic, or capacitive manner (i.e., not in direct contact). By using this dual-band antenna topology, the primary element's characteristics are minimally altered when adding the secondary element, or when manipulating the electrical length of the secondary element using inductive/capacitive components within this secondary element, for example. In some implementations, the secondary element may be arranged as a slot radiator that capacitively couples to the primary element, such as a bent monopole, which may result in a cross-polarization of the low-band and high-band.

Accordingly, a unique dual-band antenna may be provided that is cost-effective, flexible in its design properties, and can be implemented not only in WLAN applications but other similar multi-resonant designs.

In some embodiments, for example, a dual-band antenna is provided including a substrate and a primary radiator disposed on the substrate. The primary radiator is connected to a transmission line for driving the primary radiator. The primary radiator, when driven via the transmission line, has a first resonant frequency. The dual-band antenna also includes a secondary radiator disposed on the substrate and unconnected to the primary radiator. The primary radiator, when driven via the transmission line, induces a current in the secondary radiator such that the secondary radiator has a second resonant frequency different from the first resonant frequency.

In another aspect, a method for driving a dual-band antenna is provided. The method includes driving a primary radiator via a transmission line connected to the primary radiator, where the primary radiator is disposed on a substrate and has a first resonant frequency. The method also includes inducing a current in a secondary radiator via the driven primary radiator, where the secondary radiator is disposed on the substrate and unconnected to the primary radiator, and where the secondary radiator has a second resonant frequency different from the first resonant frequency.

In the FIGS., identical reference numbers identify generally similar, and/or identical, elements. To facilitate the discussion of any particular element, the most significant digit or digits of a reference number refers to the Figure in which that element is first introduced. For example, element110ais first introduced and discussed with reference toFIG. 1A. Many of the details, dimensions, angles and other features shown in the FIGS. are merely illustrative of particular embodiments of the disclosed technology. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the spirit or scope of the disclosure. In addition, those of ordinary skill in the art will appreciate that further embodiments of the various disclosed technologies can be practiced without several of the details described below.

II. Suitable Operating Environment

FIG. 1Ais a partial cutaway view of a media playback system100distributed in an environment101(e.g., a house). The media playback system100comprises one or more playback devices110(identified individually as playback devices110a-n), one or more network microphone devices (“NMDs”),120(identified individually as NMDs120a-c), and one or more control devices130(identified individually as control devices130aand130b).

As used herein the term “playback device” can generally refer to a network device configured to receive, process, and output data of a media playback system. For example, a playback device can be a network device that receives and processes audio content. In some embodiments, a playback device includes one or more transducers or speakers powered by one or more amplifiers. In other embodiments, however, a playback device includes one of (or neither of) the speaker and the amplifier. For instance, a playback device can comprise one or more amplifiers configured to drive one or more speakers external to the playback device via a corresponding wire or cable.

Moreover, as used herein the term NMD (i.e., a “network microphone device”) can generally refer to a network device that is configured for audio detection. In some embodiments, an NMD is a stand-alone device configured primarily for audio detection. In other embodiments, an NMD is incorporated into a playback device (or vice versa).

The term “control device” can generally refer to a network device configured to perform functions relevant to facilitating user access, control, and/or configuration of the media playback system100.

Each of the playback devices110is configured to receive audio signals or data from one or more media sources (e.g., one or more remote servers, one or more local devices) and play back the received audio signals or data as sound. The one or more NMDs120are configured to receive spoken word commands, and the one or more control devices130are configured to receive user input. In response to the received spoken word commands and/or user input, the media playback system100can play back audio via one or more of the playback devices110. In certain embodiments, the playback devices110are configured to commence playback of media content in response to a trigger. For instance, one or more of the playback devices110can be configured to play back a morning playlist upon detection of an associated trigger condition (e.g., presence of a user in a kitchen, detection of a coffee machine operation). In some embodiments, for example, the media playback system100is configured to play back audio from a first playback device (e.g., the playback device100a) in synchrony with a second playback device (e.g., the playback device100b). Interactions between the playback devices110, NMDs120, and/or control devices130of the media playback system100configured in accordance with the various embodiments of the disclosure are described in greater detail below with respect toFIGS. 1B-1H.

In the illustrated embodiment ofFIG. 1A, the environment101comprises a household having several rooms, spaces, and/or playback zones, including (clockwise from upper left) a master bathroom101a, a master bedroom101b, a second bedroom101c, a family room or den101d, an office101e, a living room101f, a dining room101g, a kitchen101h, and an outdoor patio101i. While certain embodiments and examples are described below in the context of a home environment, the technologies described herein may be implemented in other types of environments. In some embodiments, for example, the media playback system100can be implemented in one or more commercial settings (e.g., a restaurant, mall, airport, hotel, a retail or other store), one or more vehicles (e.g., a sports utility vehicle, bus, car, a ship, a boat, an airplane), multiple environments (e.g., a combination of home and vehicle environments), and/or another suitable environment where multi-zone audio may be desirable.

The media playback system100can comprise one or more playback zones, some of which may correspond to the rooms in the environment101. The media playback system100can be established with one or more playback zones, after which additional zones may be added, or removed to form, for example, the configuration shown inFIG. 1A. Each zone may be given a name according to a different room or space such as the office101e, master bathroom101a, master bedroom101b, the second bedroom101c, kitchen101h, dining room101g, living room101f, and/or the balcony101i. In some aspects, a single playback zone may include multiple rooms or spaces. In certain aspects, a single room or space may include multiple playback zones.

In the illustrated embodiment ofFIG. 1A, the master bathroom101a, the second bedroom101c, the office101e, the living room101f, the dining room101g, the kitchen101h, and the outdoor patio101ieach include one playback device110, and the master bedroom101band the den101dinclude a plurality of playback devices110. In the master bedroom101b, the playback devices110land110mmay be configured, for example, to play back audio content in synchrony as individual ones of playback devices110, as a bonded playback zone, as a consolidated playback device, and/or any combination thereof. Similarly, in the den101d, the playback devices110h-jcan be configured, for instance, to play back audio content in synchrony as individual ones of playback devices110, as one or more bonded playback devices, and/or as one or more consolidated playback devices. Additional details regarding bonded and consolidated playback devices are described below with respect toFIGS. 1B and 1E.

In some aspects, one or more of the playback zones in the environment101may each be playing different audio content. For instance, a user may be grilling on the patio101iand listening to hip hop music being played by the playback device110cwhile another user is preparing food in the kitchen101hand listening to classical music played by the playback device110b. In another example, a playback zone may play the same audio content in synchrony with another playback zone. For instance, the user may be in the office101elistening to the playback device110fplaying back the same hip hop music being played back by playback device110con the patio101i. In some aspects, the playback devices110cand110fplay back the hip hop music in synchrony such that the user perceives that the audio content is being played seamlessly (or at least substantially seamlessly) while moving between different playback zones. Additional details regarding audio playback synchronization among playback devices and/or zones can be found, for example, in U.S. Pat. No. 8,234,395 entitled, “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is incorporated herein by reference in its entirety.

a. Suitable Media Playback System

FIG. 1Bis a schematic diagram of the media playback system100and a cloud network102. For ease of illustration, certain devices of the media playback system100and the cloud network102are omitted fromFIG. 1B. One or more communication links103(referred to hereinafter as “the links103”) communicatively couple the media playback system100and the cloud network102.

The links103can comprise, for example, one or more wired networks, one or more wireless networks, one or more wide area networks (WAN), one or more local area networks (LAN), one or more personal area networks (PAN), one or more telecommunication networks (e.g., one or more Global System for Mobiles (GSM) networks, Code Division Multiple Access (CDMA) networks, Long-Term Evolution (LTE) networks, 5G communication network networks, and/or other suitable data transmission protocol networks), etc. The cloud network102is configured to deliver media content (e.g., audio content, video content, photographs, social media content) to the media playback system100in response to a request transmitted from the media playback system100via the links103. In some embodiments, the cloud network102is further configured to receive data (e.g. voice input data) from the media playback system100and correspondingly transmit commands and/or media content to the media playback system100.

The cloud network102comprises computing devices106(identified separately as a first computing device106a, a second computing device106b, and a third computing device106c). The computing devices106can comprise individual computers or servers, such as, for example, a media streaming service server storing audio and/or other media content, a voice service server, a social media server, a media playback system control server, etc. In some embodiments, one or more of the computing devices106comprise modules of a single computer or server. In certain embodiments, one or more of the computing devices106comprise one or more modules, computers, and/or servers. Moreover, while the cloud network102is described above in the context of a single cloud network, in some embodiments the cloud network102comprises a plurality of cloud networks comprising communicatively coupled computing devices. Furthermore, while the cloud network102is shown inFIG. 1Bas having three of the computing devices106, in some embodiments, the cloud network102comprises fewer (or more than) three computing devices106.

The media playback system100is configured to receive media content from the networks102via the links103. The received media content can comprise, for example, a Uniform Resource Identifier (URI) and/or a Uniform Resource Locator (URL). For instance, in some examples, the media playback system100can stream, download, or otherwise obtain data from a URI or a URL corresponding to the received media content. A network104communicatively couples the links103and at least a portion of the devices (e.g., one or more of the playback devices110, NMDs120, and/or control devices130) of the media playback system100. The network104can include, for example, a wireless network (e.g., a WiFi network, a Bluetooth, a Z-Wave network, a ZigBee, and/or other suitable wireless communication protocol network) and/or a wired network (e.g., a network comprising Ethernet, Universal Serial Bus (USB), and/or another suitable wired communication). As those of ordinary skill in the art will appreciate, as used herein, “WiFi” can refer to several different communication protocols including, for example, Institute of Electrical and Electronics Engineers (IEEE) 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ac, 802.11ad, 802.11af, 802.11ah, 802.11ai, 802.11aj, 802.11aq, 802.11ax, 802.11ay, 802.15, etc. transmitted at 2.4 Gigahertz (GHz), 5 GHz, and/or another suitable frequency.

In some embodiments, the network104comprises a dedicated communication network that the media playback system100uses to transmit messages between individual devices and/or to transmit media content to and from media content sources (e.g., one or more of the computing devices106). In certain embodiments, the network104is configured to be accessible only to devices in the media playback system100, thereby reducing interference and competition with other household devices. In other embodiments, however, the network104comprises an existing household communication network (e.g., a household WiFi network). In some embodiments, the links103and the network104comprise one or more of the same networks. In some aspects, for example, the links103and the network104comprise a telecommunication network (e.g., an LTE network, a 5G network). Moreover, in some embodiments, the media playback system100is implemented without the network104, and devices comprising the media playback system100can communicate with each other, for example, via one or more direct connections, PANs, telecommunication networks, and/or other suitable communication links.

In some embodiments, audio content sources may be regularly added or removed from the media playback system100. In some embodiments, for example, the media playback system100performs an indexing of media items when one or more media content sources are updated, added to, and/or removed from the media playback system100. The media playback system100can scan identifiable media items in some or all folders and/or directories accessible to the playback devices110, and generate or update a media content database comprising metadata (e.g., title, artist, album, track length) and other associated information (e.g., URIs, URLs) for each identifiable media item found. In some embodiments, for example, the media content database is stored on one or more of the playback devices110, network microphone devices120, and/or control devices130.

In the illustrated embodiment ofFIG. 1B, the playback devices110land110mcomprise a group107a. The playback devices110land110mcan be positioned in different rooms in a household and be grouped together in the group107aon a temporary or permanent basis based on user input received at the control device130aand/or another control device130in the media playback system100. When arranged in the group107a, the playback devices110land110mcan be configured to play back the same or similar audio content in synchrony from one or more audio content sources. In certain embodiments, for example, the group107acomprises a bonded zone in which the playback devices110land110mcomprise left audio and right audio channels, respectively, of multi-channel audio content, thereby producing or enhancing a stereo effect of the audio content. In some embodiments, the group107aincludes additional playback devices110. In other embodiments, however, the media playback system100omits the group107aand/or other grouped arrangements of the playback devices110.

The media playback system100includes the NMDs120aand120d, each comprising one or more microphones configured to receive voice utterances from a user. In the illustrated embodiment ofFIG. 1B, the NMD120ais a standalone device and the NMD120dis integrated into the playback device110n. The NMD120a, for example, is configured to receive voice input121from a user123. In some embodiments, the NMD120atransmits data associated with the received voice input121to a voice assistant service (VAS) configured to (i) process the received voice input data and (ii) transmit a corresponding command to the media playback system100. In some aspects, for example, the computing device106ccomprises one or more modules and/or servers of a VAS (e.g., a VAS operated by one or more of SONOS®, AMAZON®, GOOGLE® APPLE®, MICROSOFT®). The computing device106ccan receive the voice input data from the NMD120avia the network104and the links103. In response to receiving the voice input data, the computing device106cprocesses the voice input data (i.e., “Play Hey Jude by The Beatles”), and determines that the processed voice input includes a command to play a song (e.g., “Hey Jude”). The computing device106caccordingly transmits commands to the media playback system100to play back “Hey Jude” by the Beatles from a suitable media service (e.g., via one or more of the computing devices106) on one or more of the playback devices110.

b. Suitable Playback Devices

FIG. 1Cis a block diagram of the playback device110acomprising an input/output111. The input/output111can include an analog I/O111a(e.g., one or more wires, cables, and/or other suitable communication links configured to carry analog signals) and/or a digital I/O111b(e.g., one or more wires, cables, or other suitable communication links configured to carry digital signals). In some embodiments, the analog I/O111ais an audio line-in input connection comprising, for example, an auto-detecting 3.5 mm audio line-in connection. In some embodiments, the digital I/O111bcomprises a Sony/Philips Digital Interface Format (S/PDIF) communication interface and/or cable and/or a Toshiba Link (TOSLINK) cable. In some embodiments, the digital I/O111bcomprises an High-Definition Multimedia Interface (HDMI) interface and/or cable. In some embodiments, the digital I/O111bincludes one or more wireless communication links comprising, for example, a radio frequency (RF), infrared, WiFi, Bluetooth, or another suitable communication protocol. In certain embodiments, the analog I/O111aand the digital111bcomprise interfaces (e.g., ports, plugs, jacks) configured to receive connectors of cables transmitting analog and digital signals, respectively, without necessarily including cables.

The playback device110a, for example, can receive media content (e.g., audio content comprising music and/or other sounds) from a local audio source105via the input/output111(e.g., a cable, a wire, a PAN, a Bluetooth connection, an ad hoc wired or wireless communication network, and/or another suitable communication link). The local audio source105can comprise, for example, a mobile device (e.g., a smartphone, a tablet, a laptop computer) or another suitable audio component (e.g., a television, a desktop computer, an amplifier, a phonograph, a Blu-ray player, a memory storing digital media files). In some aspects, the local audio source105includes local music libraries on a smartphone, a computer, a networked-attached storage (NAS), and/or another suitable device configured to store media files. In certain embodiments, one or more of the playback devices110, NMDs120, and/or control devices130comprise the local audio source105. In other embodiments, however, the media playback system omits the local audio source105altogether. In some embodiments, the playback device110adoes not include an input/output111and receives all audio content via the network104.

The playback device110afurther comprises electronics112, a user interface113(e.g., one or more buttons, knobs, dials, touch-sensitive surfaces, displays, touchscreens), and one or more transducers114(referred to hereinafter as “the transducers114”). The electronics112is configured to receive audio from an audio source (e.g., the local audio source105) via the input/output111, one or more of the computing devices106a-cvia the network104(FIG. 1B)), amplify the received audio, and output the amplified audio for playback via one or more of the transducers114. In some embodiments, the playback device110aoptionally includes one or more microphones115(e.g., a single microphone, a plurality of microphones, a microphone array) (hereinafter referred to as “the microphones115”). In certain embodiments, for example, the playback device110ahaving one or more of the optional microphones115can operate as an NMD configured to receive voice input from a user and correspondingly perform one or more operations based on the received voice input.

In the illustrated embodiment ofFIG. 1C, the electronics112comprise one or more processors112a(referred to hereinafter as “the processors112a”), memory112b, software components112c, a network interface112d, one or more audio processing components112g(referred to hereinafter as “the audio components112g”), one or more audio amplifiers112h(referred to hereinafter as “the amplifiers112h”), and power112i(e.g., one or more power supplies, power cables, power receptacles, batteries, induction coils, Power-over Ethernet (POE) interfaces, and/or other suitable sources of electric power). In some embodiments, the electronics112optionally include one or more other components112j(e.g., one or more sensors, video displays, touchscreens, battery charging bases).

The processors112acan comprise clock-driven computing component(s) configured to process data, and the memory112bcan comprise a computer-readable medium (e.g., a tangible, non-transitory computer-readable medium, data storage loaded with one or more of the software components112c) configured to store instructions for performing various operations and/or functions. The processors112aare configured to execute the instructions stored on the memory112bto perform one or more of the operations. The operations can include, for example, causing the playback device110ato retrieve audio data from an audio source (e.g., one or more of the computing devices106a-c(FIG. 1B)), and/or another one of the playback devices110. In some embodiments, the operations further include causing the playback device110ato send audio data to another one of the playback devices110aand/or another device (e.g., one of the NMDs120). Certain embodiments include operations causing the playback device110ato pair with another of the one or more playback devices110to enable a multi-channel audio environment (e.g., a stereo pair, a bonded zone).

The processors112acan be further configured to perform operations causing the playback device110ato synchronize playback of audio content with another of the one or more playback devices110. As those of ordinary skill in the art will appreciate, during synchronous playback of audio content on a plurality of playback devices, a listener will preferably be unable to perceive time-delay differences between playback of the audio content by the playback device110aand the other one or more other playback devices110. Additional details regarding audio playback synchronization among playback devices can be found, for example, in U.S. Pat. No. 8,234,395, which was incorporated by reference above.

In some embodiments, the memory112bis further configured to store data associated with the playback device110a, such as one or more zones and/or zone groups of which the playback device110ais a member, audio sources accessible to the playback device110a, and/or a playback queue that the playback device110a(and/or another of the one or more playback devices) can be associated with. The stored data can comprise one or more state variables that are periodically updated and used to describe a state of the playback device110a. The memory112bcan also include data associated with a state of one or more of the other devices (e.g., the playback devices110, NMDs120, control devices130) of the media playback system100. In some aspects, for example, the state data is shared during predetermined intervals of time (e.g., every 5 seconds, every 10 seconds, every 60 seconds) among at least a portion of the devices of the media playback system100, so that one or more of the devices have the most recent data associated with the media playback system100.

The network interface112dis configured to facilitate a transmission of data between the playback device110aand one or more other devices on a data network such as, for example, the links103and/or the network104(FIG. 1B). The network interface112dis configured to transmit and receive data corresponding to media content (e.g., audio content, video content, text, photographs) and other signals (e.g., non-transitory signals) comprising digital packet data including an Internet Protocol (IP)-based source address and/or an IP-based destination address. The network interface112dcan parse the digital packet data such that the electronics112properly receives and processes the data destined for the playback device110a.

In the illustrated embodiment ofFIG. 1C, the network interface112dcomprises one or more wireless interfaces112e(referred to hereinafter as “the wireless interface112e”). The wireless interface112emay be, for example, a suitable interface comprising one or more antennas. A given antenna of the wireless interface112emay be a single-band antenna or a dual-band antenna having resonance on multiple frequencies, as discussed further below. The wireless interface112ecan be configured to wirelessly communicate with one or more other devices (e.g., one or more of the other playback devices110, NMDs120, and/or control devices130) that are communicatively coupled to the network104(FIG. 1B) in accordance with a suitable wireless communication protocol (e.g., WiFi, Bluetooth, LTE).

In some embodiments, the network interface112doptionally includes a wired interface112f(e.g., an interface or receptacle configured to receive a network cable such as an Ethernet, a USB-A, USB-C, and/or Thunderbolt cable) configured to communicate over a wired connection with other devices in accordance with a suitable wired communication protocol. In certain embodiments, the network interface112dincludes the wired interface112fand excludes the wireless interface112e. In some embodiments, the electronics112excludes the network interface112daltogether and transmits and receives media content and/or other data via another communication path (e.g., the input/output111).

The audio components112gare configured to process and/or filter data comprising media content received by the electronics112(e.g., via the input/output111and/or the network interface112d) to produce output audio signals. In some embodiments, the audio processing components112gcomprise, for example, one or more digital-to-analog converters (DAC), audio preprocessing components, audio enhancement components, a digital signal processors (DSPs), and/or other suitable audio processing components, modules, circuits, etc. In certain embodiments, one or more of the audio processing components112gcan comprise one or more subcomponents of the processors112a. In some embodiments, the electronics112omits the audio processing components112g. In some aspects, for example, the processors112aexecute instructions stored on the memory112bto perform audio processing operations to produce the output audio signals.

The amplifiers112hare configured to receive and amplify the audio output signals produced by the audio processing components112gand/or the processors112a. The amplifiers112hcan comprise electronic devices and/or components configured to amplify audio signals to levels sufficient for driving one or more of the transducers114. In some embodiments, for example, the amplifiers112hinclude one or more switching or class-D power amplifiers. In other embodiments, however, the amplifiers include one or more other types of power amplifiers (e.g., linear gain power amplifiers, class-A amplifiers, class-B amplifiers, class-AB amplifiers, class-C amplifiers, class-D amplifiers, class-E amplifiers, class-F amplifiers, class-G and/or class H amplifiers, and/or another suitable type of power amplifier). In certain embodiments, the amplifiers112hcomprise a suitable combination of two or more of the foregoing types of power amplifiers. Moreover, in some embodiments, individual ones of the amplifiers112hcorrespond to individual ones of the transducers114. In other embodiments, however, the electronics112includes a single one of the amplifiers112hconfigured to output amplified audio signals to a plurality of the transducers114. In some other embodiments, the electronics112omits the amplifiers112h.

The transducers114(e.g., one or more speakers and/or speaker drivers) receive the amplified audio signals from the amplifier112hand render or output the amplified audio signals as sound (e.g., audible sound waves having a frequency between about 20 Hertz (Hz) and 20 kilohertz (kHz)). In some embodiments, the transducers114can comprise a single transducer. In other embodiments, however, the transducers114comprise a plurality of audio transducers. In some embodiments, the transducers114comprise more than one type of transducer. For example, the transducers114can include one or more low frequency transducers (e.g., subwoofers, woofers), mid-range frequency transducers (e.g., mid-range transducers, mid-woofers), and one or more high frequency transducers (e.g., one or more tweeters). As used herein, “low frequency” can generally refer to audible frequencies below about 500 Hz, “mid-range frequency” can generally refer to audible frequencies between about 500 Hz and about 2 kHz, and “high frequency” can generally refer to audible frequencies above 2 kHz. In certain embodiments, however, one or more of the transducers114comprise transducers that do not adhere to the foregoing frequency ranges. For example, one of the transducers114may comprise a mid-woofer transducer configured to output sound at frequencies between about 200 Hz and about 5 kHz.

By way of illustration, SONOS, Inc. presently offers (or has offered) for sale certain playback devices including, for example, a “SONOS ONE,” “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “PLAYBASE,” “BEAM,” “AMP,” “CONNECT,” and “SUB.” Other suitable playback devices may additionally or alternatively be used to implement the playback devices of example embodiments disclosed herein. Additionally, one of ordinary skilled in the art will appreciate that a playback device is not limited to the examples described herein or to SONOS product offerings. In some embodiments, for example, one or more playback devices110comprises wired or wireless headphones (e.g., over-the-ear headphones, on-ear headphones, in-ear earphones). In other embodiments, one or more of the playback devices110comprise a docking station and/or an interface configured to interact with a docking station for personal mobile media playback devices. In certain embodiments, a playback device may be integral to another device or component such as a television, a lighting fixture, or some other device for indoor or outdoor use. In some embodiments, a playback device omits a user interface and/or one or more transducers. For example,FIG. 1Dis a block diagram of a playback device110pcomprising the input/output111and electronics112without the user interface113or transducers114.

FIG. 1Eis a block diagram of a bonded playback device110qcomprising the playback device110a(FIG. 1C) sonically bonded with the playback device110i(e.g., a subwoofer) (FIG. 1A). In the illustrated embodiment, the playback devices110aand110iare separate ones of the playback devices110housed in separate enclosures. In some embodiments, however, the bonded playback device110qcomprises a single enclosure housing both the playback devices110aand110i. The bonded playback device110qcan be configured to process and reproduce sound differently than an unbonded playback device (e.g., the playback device110aofFIG. 1C) and/or paired or bonded playback devices (e.g., the playback devices110land110mofFIG. 1B). In some embodiments, for example, the playback device110ais full-range playback device configured to render low frequency, mid-range frequency, and high frequency audio content, and the playback device110iis a subwoofer configured to render low frequency audio content. In some aspects, the playback device110a, when bonded with the first playback device, is configured to render only the mid-range and high frequency components of a particular audio content, while the playback device110irenders the low frequency component of the particular audio content. In some embodiments, the bonded playback device110qincludes additional playback devices and/or another bonded playback device. e

c. Suitable Network Microphone Devices (NMDs)

FIG. 1Fis a block diagram of the NMD120a(FIGS. 1A and 1B). The NMD120aincludes one or more voice processing components124(hereinafter “the voice components124”) and several components described with respect to the playback device110a(FIG. 1C) including the processors112a, the memory112b, and the microphones115. The NMD120aoptionally comprises other components also included in the playback device110a(FIG. 1C), such as the user interface113and/or the transducers114. In some embodiments, the NMD120ais configured as a media playback device (e.g., one or more of the playback devices110), and further includes, for example, one or more of the audio components112g(FIG. 1C), the amplifiers114, and/or other playback device components. In certain embodiments, the NMD120acomprises an Internet of Things (IoT) device such as, for example, a thermostat, alarm panel, fire and/or smoke detector, etc. In some embodiments, the NMD120acomprises the microphones115, the voice processing124, and only a portion of the components of the electronics112described above with respect toFIG. 1B. In some aspects, for example, the NMD120aincludes the processor112aand the memory112b(FIG. 1B), while omitting one or more other components of the electronics112. In some embodiments, the NMD120aincludes additional components (e.g., one or more sensors, cameras, thermometers, barometers, hygrometers).

In some embodiments, an NMD can be integrated into a playback device.FIG. 1Gis a block diagram of a playback device110rcomprising an NMD120d. The playback device110rcan comprise many or all of the components of the playback device110aand further include the microphones115and voice processing124(FIG. 1F). The playback device110roptionally includes an integrated control device130c. The control device130ccan comprise, for example, a user interface (e.g., the user interface113ofFIG. 1B) configured to receive user input (e.g., touch input, voice input) without a separate control device. In other embodiments, however, the playback device110rreceives commands from another control device (e.g., the control device130aofFIG. 1B).

Referring again toFIG. 1F, the microphones115are configured to acquire, capture, and/or receive sound from an environment (e.g., the environment101ofFIG. 1A) and/or a room in which the NMD120ais positioned. The received sound can include, for example, vocal utterances, audio played back by the NMD120aand/or another playback device, background voices, ambient sounds, etc. The microphones115convert the received sound into electrical signals to produce microphone data. The voice processing124receives and analyzes the microphone data to determine whether a voice input is present in the microphone data. The voice input can comprise, for example, an activation word followed by an utterance including a user request. As those of ordinary skill in the art will appreciate, an activation word is a word or other audio cue that signifying a user voice input. For instance, in querying the AMAZON® VAS, a user might speak the activation word “Alexa.” Other examples include “Ok, Google” for invoking the GOOGLE® VAS and “Hey, Siri” for invoking the APPLE® VAS.

After detecting the activation word, voice processing124monitors the microphone data for an accompanying user request in the voice input. The user request may include, for example, a command to control a third-party device, such as a thermostat (e.g., NEST® thermostat), an illumination device (e.g., a PHILIPS HUE® lighting device), or a media playback device (e.g., a Sonos® playback device). For example, a user might speak the activation word “Alexa” followed by the utterance “set the thermostat to 68 degrees” to set a temperature in a home (e.g., the environment101ofFIG. 1A). The user might speak the same activation word followed by the utterance “turn on the living room” to turn on illumination devices in a living room area of the home. The user may similarly speak an activation word followed by a request to play a particular song, an album, or a playlist of music on a playback device in the home.

d. Suitable Control Devices

FIG. 1His a partially schematic diagram of the control device130a(FIGS. 1A and 1B). As used herein, the term “control device” can be used interchangeably with “controller” or “control system.” Among other features, the control device130ais configured to receive user input related to the media playback system100and, in response, cause one or more devices in the media playback system100to perform an action(s) or operation(s) corresponding to the user input. In the illustrated embodiment, the control device130acomprises a smartphone (e.g., an iPhone™, an Android phone) on which media playback system controller application software is installed. In some embodiments, the control device130acomprises, for example, a tablet (e.g., an iPad™), a computer (e.g., a laptop computer, a desktop computer), and/or another suitable device (e.g., a television, an automobile audio head unit, an IoT device). In certain embodiments, the control device130acomprises a dedicated controller for the media playback system100. In other embodiments, as described above with respect toFIG. 1G, the control device130ais integrated into another device in the media playback system100(e.g., one more of the playback devices110, NMDs120, and/or other suitable devices configured to communicate over a network).

The control device130aincludes electronics132, a user interface133, one or more speakers134, and one or more microphones135. The electronics132comprise one or more processors132a(referred to hereinafter as “the processors132a”), a memory132b, software components132c, and a network interface132d. The processor132acan be configured to perform functions relevant to facilitating user access, control, and configuration of the media playback system100. The memory132bcan comprise data storage that can be loaded with one or more of the software components executable by the processor302to perform those functions. The software components132ccan comprise applications and/or other executable software configured to facilitate control of the media playback system100. The memory112bcan be configured to store, for example, the software components132c, media playback system controller application software, and/or other data associated with the media playback system100and the user.

The network interface132dis configured to facilitate network communications between the control device130aand one or more other devices in the media playback system100, and/or one or more remote devices. The network interface may include, for instance, a single- or dual-band antenna as discussed herein. In some embodiments, the network interface132dis configured to operate according to one or more suitable communication industry standards (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G, LTE). The network interface132dcan be configured, for example, to transmit data to and/or receive data from the playback devices110, the NMDs120, other ones of the control devices130, one of the computing devices106ofFIG. 1B, devices comprising one or more other media playback systems, etc. The transmitted and/or received data can include, for example, playback device control commands, state variables, playback zone and/or zone group configurations. For instance, based on user input received at the user interface133, the network interface132dcan transmit a playback device control command (e.g., volume control, audio playback control, audio content selection) from the control device304to one or more of the playback devices100. The network interface132dcan also transmit and/or receive configuration changes such as, for example, adding/removing one or more playback devices100to/from a zone, adding/removing one or more zones to/from a zone group, forming a bonded or consolidated player, separating one or more playback devices from a bonded or consolidated player, among others.

The user interface133is configured to receive user input and can facilitate control of the media playback system100. The user interface133includes media content art133a(e.g., album art, lyrics, videos), a playback status indicator133b(e.g., an elapsed and/or remaining time indicator), media content information region133c, a playback control region133d, and a zone indicator133e. The media content information region133ccan include a display of relevant information (e.g., title, artist, album, genre, release year) about media content currently playing and/or media content in a queue or playlist. The playback control region133dcan include selectable (e.g., via touch input and/or via a cursor or another suitable selector) icons to cause one or more playback devices in a selected playback zone or zone group to perform playback actions such as, for example, play or pause, fast forward, rewind, skip to next, skip to previous, enter/exit shuffle mode, enter/exit repeat mode, enter/exit cross fade mode, etc. The playback control region133dmay also include selectable icons to modify equalization settings, playback volume, and/or other suitable playback actions. In the illustrated embodiment, the user interface133comprises a display presented on a touch screen interface of a smartphone (e.g., an iPhone™, an Android phone). In some embodiments, however, user interfaces of varying formats, styles, and interactive sequences may alternatively be implemented on one or more network devices to provide comparable control access to a media playback system.

The one or more speakers134(e.g., one or more transducers) can be configured to output sound to the user of the control device130a. In some embodiments, the one or more speakers comprise individual transducers configured to correspondingly output low frequencies, mid-range frequencies, and/or high frequencies. In some aspects, for example, the control device130ais configured as a playback device (e.g., one of the playback devices110). Similarly, in some embodiments the control device130ais configured as an NMD (e.g., one of the NMDs120), receiving voice commands and other sounds via the one or more microphones135.

The one or more microphones135can comprise, for example, one or more condenser microphones, electret condenser microphones, dynamic microphones, and/or other suitable types of microphones or transducers. In some embodiments, two or more of the microphones135are arranged to capture location information of an audio source (e.g., voice, audible sound) and/or configured to facilitate filtering of background noise. Moreover, in certain embodiments, the control device130ais configured to operate as playback device and an NMD. In other embodiments, however, the control device130aomits the one or more speakers134and/or the one or more microphones135. For instance, the control device130amay comprise a device (e.g., a thermostat, an IoT device, a network device) comprising a portion of the electronics132and the user interface133(e.g., a touch screen) without any speakers or microphones.

As noted above, dual-band antennas are implemented as part of a communications interface in a wide variety of hardware devices. However, the relatively small form factor of many consumer electronics devices, such as the playback devices and control devices discussed above, can pose challenges in the design of a dual-band antenna.

For example,FIG. 2Ashows an example of a conventional dual-band antenna200that may be implemented in, for example, a mobile phone. The dual-band antenna200includes a primary radiator201that is mounted on a substrate203. The primary radiator201is shown as a bent monopole that is fed from a transmission line204and has a single-band resonance at a native frequency. In this example, the primary radiator201is responsible for what may be referred to as the low-band resonance (e.g., 2.4 GHz). A second radiator202, shorter than the primary radiator201, is then extended from the feed point to form a second, adjacent conductive path. The second radiator202has its own resonant frequency and is responsible for what is typically referred to as the high-band resonance (e.g., 5 GHz).

Although the design of the dual-band antenna200shown inFIG. 2Aallows it to be relatively compact, the design introduces constraints that can make fine tuning the dual-band antenna200difficult. For instance, because the two radiating elements share a common feed point from the transmission line204, and because they are both part of the same conductive structure, a modification to one radiator (e.g., a length modification) to adjust its resonant frequency, for instance, will also affect the other radiator.

This effect can be seen with reference toFIG. 2B, which shows a plot of two example frequency responses for the dual-band antenna200. The first frequency response250illustrates the behavior of the primary radiator201acting as a single-band antenna, before the second radiator202is added, and shows the low-band resonance at a native frequency between 2 and 3 GHz. Dual-band behavior is then achieved by extending the second radiator202. The dual-band behavior is represented by the second frequency response251shown inFIG. 2B, where the second radiator202is responsible for the high-band resonance that can be seen just below 5 GHz. However, as predicted above, the low-band resonance has been affected by the addition of the second radiator202. For example, as compared to the frequency response250the low-band resonance in frequency response251has been tuned to a lower frequency (i.e., shifted to the left). Further, the low-band resonance in the frequency response251includes a narrower frequency range, which may correspond to a loss in bandwidth for low-band communications. In this way, geometric changes, impedance mismatch optimizations, or other adjustments to one of the two radiators in the dual-band antenna200will affect the performance of the other radiator. For this reason, it can be challenging to obtain a desired dual-band antenna behavior.

Turning now toFIG. 3, an example of a new dual-band antenna design is shown that may mitigate some of the effects discussed above by providing the secondary radiator as a parasitic element that is unconnected to the primary radiator.FIG. 3shows a dual-band antenna300that is disposed on a substrate303. The substrate may be a printed circuit board (PCB), a flexible printed circuit (FPC), polymide, or similar material for mounting the radiating elements thereon. The dual-band antenna includes a primary radiator301disposed on the substrate303and connected to a transmission line304for driving the primary radiator301. The transmission line304may be, for example, a microstrip, a stripline, or a coaxial cable, among other possibilities.

In some implementations, as shown inFIG. 3, the primary radiator301may be arranged as a monopole radiator. Other configurations are also possible, including a dipole radiator for example. InFIG. 3, the primary radiator301is a bent monopole having a first end306and a second end307. The dual-band antenna300also includes an electrically conductive ground plane disposed on the substrate303, and the transmission line304is connected between the first end306of the primary radiator301and the ground plane305. Regardless of its configuration, the primary radiator301of the dual-band antenna300includes a first resonant frequency when driven via the transmission line304.

The dual-band antenna300also includes a secondary radiator302disposed on the substrate304and unconnected to the primary radiator301. Further, and as shown inFIG. 3, the secondary radiator302is also unconnected to the ground plane305. In this way, the secondary radiator302is not fed directly from the transmission line304or the primary radiator301, but rather acts as a parasitic element that achieves its resonance by capacitively coupling to the adjacent primary radiator301. Thus, when the primary radiator301is driven via the transmission line304, it induces a current in the secondary radiator302such that the secondary radiator302includes a second resonant frequency that is different from the first resonant frequency. The length of the secondary radiator302may be determined and/or adjusted based on the desired frequency of operation in the high-band. Importantly, the parasitic arrangement of the secondary radiator302in the dual-band antenna300may reduce the effect that both the addition of the secondary radiator302, as well as adjustments to the secondary radiator302, have on the primary radiator301, as will be discussed further below.

In some implementations, such as the example shown inFIG. 3, the secondary radiator302may be arranged as a monopole radiator. Further, the secondary radiator302may be disposed on the substrate304such that the secondary radiator302is substantially parallel to the primary radiator301. In such an arrangement, the polarization of the two radiating elements will also be linear, and parallel to each other.

FIG. 4shows a dual-band antenna400according to another example implementation. Similar to the example shown inFIG. 3, the dual-band antenna400includes a primary radiator401arranged as a bent monopole having a first end406and a second end407, as well as a ground plane405disposed on a substrate403. A transmission line404is connected between the ground plane405and the first end406of the primary radiator401. The secondary radiator402is disposed on the substrate403and is unconnected to both the primary radiator401and the ground plane405. However, the secondary radiator402inFIG. 4is arranged as a slotted radiator having two parallel arms408and409that are joined by a base section410and separated by a slot411. Further, the two arms408and409of the secondary radiator402may be substantially parallel to the primary radiator401.

In this arrangement, similar to the example shown inFIG. 3, the secondary radiator402acts as a parasitic element and capacitively couples to the primary radiator401to achieve its resonant behavior. However, the slotted secondary radiator402has, by definition, a polarization that is horizontal (as arranged inFIG. 4), and orthogonal to the vertical polarization of the primary radiator401. This orthogonal arrangement allows for the dual-band antenna400to be cross-polarized between the low-band and high-band ranges, which may also provide for improved signal coverage and polarization diversity in some implementations where there are barriers or other constraints that might otherwise inhibit RF communication in one direction, but not the other.

As mentioned above, the impact of the parasitic secondary radiator402on the behavior of the primary radiator401is improved over some conventional dual-band antennas.FIG. 5shows a plot of two example frequency responses for the dual-band antenna400. The first frequency response550shows the behavior of the primary radiator401acting as a single-band antenna, before the secondary radiator402is added. Dual-band behavior is then achieved by adding the secondary radiator402, and is represented by the second frequency response551, which includes the secondary resonance between 5 and 6 GHz. Although there is a minor shift in the lower frequency band, it is much smaller than that observed in the conventional dual-band antenna discussed above. Further, the example shown inFIG. 5does not exhibit the same bandwidth reduction in the low-band as observed previously. Accordingly, the secondary radiator402in the dual-band antenna400may be adjusted to modify the antenna's high band behavior, for instance, without significantly affecting the primary radiator401and the antenna's low-band behavior.

FIGS. 6 and 7further illustrate this point.FIG. 6shows another example of the dual-band antenna400. As can be seen inFIG. 6, the length of the arms408and409of the secondary radiator402have been extended from their initial position shown inFIG. 4. This also extends the length of the slot411and alters the high-band frequency response of the dual-band antenna400, as shown inFIG. 7.

FIG. 7shows a plot of three example frequency responses for the modified version of the dual-band antenna400that is shown inFIG. 6. The three responses represent the behavior of the dual-band antenna400as the length of the slot411is swept from its initial, shorter length, as shown inFIG. 4, to the longer length shown inFIG. 6. For example, the frequency response551shown inFIG. 7is the same frequency response551as shown inFIG. 5. As the length of the slot411of the secondary radiator402increases, the high-band is tuned lower (i.e., shifted left) and the impedance is decreased, as shown by the frequency response552. As the length of the slot411is further increased and reaches the length shown inFIG. 6, the high-band is further adjusted, and is represented by the frequency response553.

However, despite the variation in the high-band tuning range based on the changes to the secondary radiator402,FIG. 7illustrates that the primary element401largely maintains the same resonant behavior in the low-band range. This effect may allow the designer of a dual-band antenna more freedom in determining the design of a dual-band antenna, as it reduces the interdependence between the behavior of the two radiating elements. For instance, the primary radiator401can be designed for a desired low-band performance, and then secondary radiator402can be designed for a desired high-band performance without significantly altering the low-band behavior of the primary radiator401. This may avoid what might otherwise be an iterative and tedious design process.

Moreover, the advantages of the parasitic secondary radiators discussed above also have additional practical applications that may allow a dual-band antenna increased operational flexibility. For example, one or more elements, such as a variable inductor or a variable capacitor, may be added to the secondary radiator that can be used to alter its effective electrical length, resulting in an adjustment to the high-band behavior similar to that shown inFIG. 7.

For instance, referring now toFIG. 8, the dual-band antenna400discussed above is shown, including an additional lumped inductor812applied at the slot411. The inductor812may then be used to manipulate the effective length of the slot411. For example, the inductor812may include a multi-state switch having difference inductance values that can be used to set its effective position within the slot411, thereby manipulating the effective length of the slot411and the high-band radiation of the secondary radiator402. Further, the multiple inductor states can be specified to desired levels such that controlled adjustments to the high-band may be made, all while leaving the low-band behavior of the dual-band antenna400relatively unaffected. In addition to the initial design flexibility discussed above, this may also allow the dual-band antenna to be tuned based the environment where it is being operated, based on the constraints of the environment.

In a similar way, as shown inFIG. 9, a variable capacitor912may be applied at the slot411. Like the inductor812, the capacitor912may be configured to adjust the electrical length of the slot411to tune the high-band frequency of the secondary radiator402. Combinations of one or more inductors, capacitors, or both are also possible to achieve similar effects.

Useful applications for a dual-band antenna that is adjustable in this way are numerous. For example, a device including the dual-band antenna400shown inFIG. 8may be involved in different wireless communications situations that benefit from different high-band frequency responses. In some implementations, the device may benefit from a shallower frequency response that delivers the highest amount of power to the system, whereas another application may call for relatively low antenna gain. As another example, the secondary radiator402of the dual-band antenna400may be manipulated to bias the high-band resonance away from an operational frequency band that is restricted in some geographic areas, such as certain Unlicensed National Information Infrastructure (UNIT) channels at 5 GHz.

As another example, there may be instances where it is desirable to utilize the flexibility of the dual-band antenna400discussed herein to manipulate the performance in the high-band range to intentionally avoid coupling with signals in that range. For instance, an example playback device as discussed herein may be capable of communications via either a Bluetooth link (e.g., operating in a single band around 2.4 GHz) or via a WiFi network (e.g., a dual band network operating around 2.4 GHz and 5 GHz). When communicating via Bluetooth, it may be desirable to avoid potential noise by intentionally degrading the high-band response of the dual-band antenna so as not to couple with 5 GHz WiFi signals, and instead focus purely on the 2.4 GHz band. Various other possibilities exist.

Another advantage that arises from the flexibility of the independent, secondary radiator402discussed herein is its ability to adapt to future communication standards that may arise. For instance, most current WiFi standards generally operate within a high-band range between 5-6 GHz. However, new and upcoming standards (e.g., 802.11ax) may use frequency bands greater than 6 GHz. Thus, a playback device utilizing one of the example dual-band antennas400discussed herein may update its communication capabilities to take advantage of the most current standards. Moreover, these and other advantages are not limited to the playback devices mentioned herein, but could be equally applied to any network communication device.

FIG. 10shows a partial cut away view of a playback device1020including a dual-band antenna1000according to an example implementation. The dual-band antenna1000may be substantially similar to, for example, the dual-band antenna400including the lumped inductor812shown inFIG. 8. The playback device1020may be any of the playback devices shown inFIG. 1A-1Gand discussed above, or any other playback device. Further, the dual-band antennas having a parasitic secondary radiator, as discussed above, are not limited to use within a playback device. Rather, they may be used in any wireless communications device that would benefit from a dual-band antenna having the advantages discussed herein.

FIG. 10illustrates a flowchart1100of an example method for driving a dual-band antenna, such as the dual-band antenna300shown inFIG. 3or the dual-band antenna400shown inFIGS. 4 and 8-9. The following examples will refer to the dual-band antenna400.

At block1102, the method1100includes driving a primary radiator401via a transmission line404connected to the primary radiator401. The primary radiator401is disposed on a substrate403and has a first resonant frequency. The dual-band antenna400may also include an electrically conductive ground plane405disposed on the substrate403, and the transmission line may be connected between a first end406of the primary radiator401and the ground plane405. The primary radiator401may be arranged as a monopole radiator as shown in the examples discussed herein, although other configurations are also possible.

At block1104, the method1104includes inducing a current in a secondary radiator402via the driven primary radiator401, where the secondary radiator402is disposed on the substrate403and unconnected to the primary radiator401. The secondary radiator402may also be unconnected to the ground plane405. The secondary radiator402has a second resonant frequency different from the first resonant frequency. As discussed above, the secondary radiator402may be responsible for the high-band resonant behavior of the dual-band antenna400, while the primary radiator401is responsible for the low-band resonant behavior.

In some implementations, the secondary radiator402may be arranged as a monopole radiator and disposed on the substrate such that the secondary radiator402is substantially parallel to the primary radiator401. Additionally or alternatively, the secondary radiator402may be arranged as a slotted radiator having two parallel arms408and409joined by a base section410and separated by a slot411. Further, the two parallel arms408and409of the secondary radiator402, and thus the orientation of the slot411, may be substantially parallel to the primary radiator401.

Further, the primary radiator401may include a first polarization and the secondary radiator402may include a second polarization that is substantially orthogonal to the first polarization. For instance, in the dual-band antenna400shown in the FIGS., the primary radiator401has a linear, vertical polarization based on the orientation of the monopole radiator. The secondary radiator402has an orthogonal polarization that is linear and horizontal, based on the orientation of the slot411.

In some implementations, as shown inFIG. 8, the dual-band antenna400may include a variable inductor812coupled to the secondary radiator402. In such examples, the method1100may include adjusting, via the variable inductor812, an electrical length of the slot411to tune the second resonant frequency of the secondary radiator402. Various benefits may be achieved from such an adjustable dual-band antenna400, as mentioned above. Similarly, and as shown inFIG. 9, the dual-band antenna400may include a variable capacitor912coupled to the secondary radiator402. In such examples, the method1100may include adjusting, via the variable capacitor912, an electrical length of the slot411to tune the second resonant frequency of the secondary radiator402.