Patent Description:
Aspects of the present disclosure relate generally to wireless communications systems, and more particularly, to low-loss multi-band multiplexing (e.g., duplexing) schemes used for wireless communications systems (e.g., <NUM> New Radio).

Wireless communications systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available system resources (e.g., time, frequency, power, and/or spectrum). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA).

An example telecommunication standard is Long Term Evolution (LTE) or LTE-Advanced (LTE-A). However, although newer multiple access systems, such as an LTE or LTE-A system, deliver faster data throughput than older technologies, such increased downlink rates have triggered a greater demand for higher-bandwidth content, such as high-resolution graphics and video, for use on or with mobile devices. As such, demand for bandwidth, higher data rates, better transmission quality as well as better spectrum utilization, and lower latency on wireless communications systems continues to increase.

The 5th Generation (<NUM>) New Radio (NR) communications technology, used in a wide range of spectrum, is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, <NUM> NR communications technology includes, for example: enhanced mobile broadband (eMBB) addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable low-latency communications (URLLC) with strict requirements, especially in terms of latency and reliability; and massive machine type communications (mMTC) for a very large number of connected devices and typically transmitting a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, there exists a need for further improvements in <NUM> communications technology and beyond.

Accordingly, due to the requirements for increased data rates, higher capacity, low-power consumption, and system reliability and flexibility, new approaches may be desirable to support low-loss multi-band operations, in order to satisfy consumer demand and improve user experience in wireless communications, such as <NUM> NR communications.

Further reference is made to <CIT> disclosing an apparatus that includes a frequency multiplexer circuit coupled to an input node and configured to receive an input signal via the input node. The frequency multiplexer circuit comprises a first filter circuit, a second filter circuit, and a third filter circuit. The apparatus also includes a switching circuit that is configurable to couple at least two of a first output of the first filter circuit, a second output of the second filter circuit, or a third output of the third filter circuit to a single output port.

Further reference is made to <CIT> disclosing systems for reducing magnetic coupling in integrated circuits (ICs). Related components and methods are also disclosed. The ICs have a plurality of inductors. Each inductor generates a magnetic flux that has a discernible axis. To reduce magnetic coupling between the inductors, the flux axes are designed so as to be non-parallel. In particular, by making the flux axes of the inductors non-parallel to one another, magnetic coupling between the inductors is reduced relative to the situation where the flux axes are parallel. This arrangement may be particularly well suited for use in diplexers having a low pass and a high pass filter. Further reference is made to <CIT> disclosing a low loss multiple output switch with integrated distributed attenuation. In an exemplary embodiment, an apparatus includes a switchable shunt network having an input terminal and a plurality of network output terminals, the switchable shunt network comprising selectable signal paths that connect the input terminal to the network output terminals. The apparatus also includes selectable shunt impedances connected to the selectable signal paths to adjust parasitic loading on the selectable signal paths.

Further reference is made to <CIT> disclosing a transmit/receive circuit arrangement wherein a transceiver circuit including a transmit/receive switch is fabricated on an integrated circuit chip. A matching network is wholly disposed off-chip relative to the integrated circuit chip. In embodiments, at least a portion of the matching network is formed off-chip and a portion of the matching network is formed on-chip.

In accordance with the present invention a method, and an apparatus is set forth in the independent claims, respectively. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

According to an example, a multiplexer for multi-band wireless communications is provided. In an aspect, the multiplexer comprises at least one tuning component configured to transmit or receive at least one signal within a frequency band that is selected from a plurality of frequency bands. The multiplexer further comprises at least one combining component, communicatively coupled with the at least one tuning component, configured to transmit or receive the at least one signal within the selected frequency band. In an aspect, the at least one tuning component is integrated on a chip and the at least one combining component is not integrated on the chip.

In an aspect, a method related to multi-band operations in a wireless communications system is provided. The method may include selecting a frequency band from a plurality of frequency bands, and adjusting at least one tuning component to transmit or receive at least one signal within the selected frequency band. The method may also include transmitting or receiving the at least one signal within the selected frequency band using at least one combining component. In an aspect, the at least one tuning component is on a chip, and the at least one combining component is not on the chip.

In another aspect, a multiplexer for multi-band wireless communications is provided. The multiplexer may comprise means for selecting a frequency band from a plurality of frequency bands, and means for adjusting at least one tuning component to transmit or receive at least one signal within the selected frequency band. The multiplexer may also comprise means for transmitting or receiving the at least one signal within the selected frequency band using at least one combining component. In an aspect, the at least one tuning component is on a chip, and the at least one combining component is not on the chip.

In a further aspect, a computer-readable medium storing computer code executable by a processor for multi-band wireless communications is provided. The computer-readable medium may comprise code for selecting a frequency band from a plurality of frequency bands, and code for adjusting at least one tuning component to transmit or receive at least one signal within the selected frequency band. The computer-readable medium may also comprise code for transmitting or receiving the at least one signal within the selected frequency band using at least one combining component. In an aspect, the at least one tuning component is on a chip, and the at least one combining component is not on the chip.

In order to facilitate a fuller understanding of aspects described herein, reference is now made to the accompanying drawings, in which like elements are referenced with like numerals. These drawings should not be construed as limiting the present disclosure, but are intended to be illustrative only.

In wireless communications systems, for example, the 5th Generation (<NUM>) New Radio (NR) communications systems (e.g., at millimeter wave (mm-wave) frequencies) may require signal transmissions and receptions at a user equipment (UE) to share a single antenna or an antenna of an array of antennas, and support multi-band operations (e.g., multiplexing or duplexing). In conventional implementations, off-chip components such as duplexers or circulators are not practical at mm-wave frequencies due to high cost and performance issues. On the other hand, on-chip multiplexing or duplexing schemes may suffer from poor performance such as high loss (e.g., loss > <NUM> dB). Furthermore, some conventional solutions may suffer from high loss for single-band operations, or higher loss to enable multi-band operations. As such, to support different carrier frequency allocations (e.g., at different mm-wave frequencies) and save cost in wireless communications systems (e.g., <NUM> NR systems), new approaches using low-loss multiplexing (e.g., duplexing) schemes that support multi-band operations may be desirable to improve capability, reliability, and flexibility of wireless communications systems (e.g., <NUM> NR systems).

Several aspects of telecommunication systems will now be presented with reference to various apparatus (e.g., a multiplexer) and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements").

Accordingly, in one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium (e.g., a non-transitory computer-readable medium). By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

Each of the aspects described herein are performed or implemented in connection with <FIG>, which are described in more detail below.

Referring to <FIG>, in an aspect, a wireless communication system <NUM> (e.g., a <NUM> NR system) includes at least one UE <NUM> in communication coverage of at least one network entity <NUM> (e.g., a base station or an eNB, or a cell thereof, in a long term evolution (LTE) or a <NUM> NR network). The UE <NUM> may communicate with a network via the network entity <NUM>. In some aspects, multiple UEs including UE <NUM> may be in communication coverage with one or more network entities, including network entity <NUM>. In an aspect, the network entity <NUM> may be a base station such an eNode B/eNB in a <NUM> NR network, and/or in an LTE network. Although various aspects are described in relation to the Universal Mobile Telecommunications System (UMTS), LTE, or <NUM> NR networks, similar principles may be applied in other wireless wide area networks (WWAN). The wireless network may employ a scheme where multiple base stations may transmit on a channel. In an example, the UE <NUM> may transmit and/or receive wireless communications to and/or from the network entity <NUM>. For example, the UE <NUM> may be actively communicating with the network entity <NUM>.

In some aspects, the UE <NUM> may also be referred to by those skilled in the art (as well as interchangeably herein) as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a wearable computing device (e.g., a smart-watch, smart-glasses, a health or fitness tracker, etc.), an appliance, a sensor, a vehicle communication system, a medical device, a vending machine, a device for the Internet-of Things, or any other similar functioning device.

Additionally, the network entity <NUM> may be a macrocell, picocell, femtocell, relay, Node B, mobile Node B, eNB, gNB, small cell box, UE (e.g., communicating in peer-to-peer or ad-hoc mode with the UE <NUM>), or substantially any type of component that can communicate with UE <NUM> to provide wireless network access at the UE <NUM>.

According to the present aspects, the UE <NUM> may include one or more processors <NUM> (including a modem <NUM>), a memory <NUM>, and/or other components that may operate in combination with a radio frequency (RF) front end <NUM> (including a multi-band multiplexer <NUM>) for performing multi-band operations as described herein.

In an aspect, the term "component" or "elements" as used herein may be one of the parts that make up a system, may be hardware, firmware, and/or software, and may be divided into other components. The multi-band multiplexer <NUM> may be communicatively coupled with a transceiver <NUM>, which may include a receiver <NUM> for receiving and processing RF signals and a transmitter <NUM> for processing and transmitting RF signals. The processor <NUM> may be coupled to the transceiver <NUM> and memory <NUM> via at least one bus <NUM>.

The receiver <NUM> may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The receiver <NUM> may be, for example, a radio frequency (RF) receiver. In an aspect, the receiver <NUM> may receive signals transmitted by network entity <NUM>. The receiver <NUM> may obtain measurements of the signals. For example, the receiver <NUM> may determine Ec/Io, signal-to-noise ratio (SNR), etc..

The transmitter <NUM> may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). The transmitter <NUM> may be, for example, a RF transmitter.

In an aspect, the one or more processors <NUM> can include a modem <NUM> that uses one or more modem processors. The various functions related to multi-band operations (e.g., multiplexing) may be included in modem <NUM> and/or processors <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a transceiver processor associated with transceiver <NUM>. In particular, for example, the one or more processors <NUM> may implement components included in the RF front end <NUM>, including the multi-band multiplexer <NUM>.

Moreover, in an aspect, the UE <NUM> may include an RF front end <NUM> and a transceiver <NUM> for receiving and transmitting radio transmissions, for example, wireless communications <NUM>. For example, the transceiver <NUM> may transmit or receive a signal that includes a pilot signal (e.g., common pilot channel (CPICH)). The transceiver <NUM> may measure the received pilot signal to determine signal quality and for providing feedback to the network entity <NUM>. In some examples, the transceiver <NUM> may be communicatively coupled with a single antenna (e.g., antenna <NUM>), or multiple antennas (e.g., one or more antennas <NUM>) simultaneously. For example, the RF front end <NUM> may be communicatively coupled with multiple antennas <NUM>, where signals may be combined and sent to the transceiver <NUM>. In some cases, the RF front end <NUM> and the transceiver <NUM> may be on a same chip or implemented separately (e.g., not on a same chip).

The RF front end <NUM> may be connected to a single antenna <NUM> or at least one antenna <NUM> that is part of an array of antennas (or multiple antennas which is not shown), and may include a multi-band multiplexer <NUM>, one or more low-noise amplifiers (LNAs) <NUM>, one or more power amplifiers (PAs) <NUM>, one or more switches (not shown), and one or more filters (not shown) for transmitting and receiving RF signals. In an aspect, the components of RF front end <NUM> may be communicatively coupled with the transceiver <NUM> (e.g., a beamforming transceiver, or a transceiver requires multiple antennas for transmissions/receptions). The transceiver <NUM> may be communicatively coupled with one or more processors <NUM> and modem <NUM>.

In some aspects, one or more chips may be used according to one or more of the presently described aspects, and each chip may include a transceiver (e.g., the transceiver <NUM>), a transmitter (e.g., the transmitter <NUM>), and/or a receiver (e.g., the receiver <NUM>).

The multi-band multiplexer <NUM> may include hardware, firmware, and/or software code executable by a processor for performing multi-band operations. For example, the hardware may include, for example, a hardware accelerator, or specialized processor. In an aspect, the multi-band multiplexer <NUM> may be configured to perform multiplexing or duplexing of wireless signals transmitted to and/or received from at least the antenna <NUM>. In an aspect, the multi-band multiplexer <NUM> may be configured or tuned to operate at one or more specified frequencies such that the UE <NUM> may communicate with, for example, the network entity <NUM> or other network entities. In an aspect, for example, the modem <NUM> may configure the multi-band multiplexer <NUM> to operate at a specified frequency based on the UE configuration of the UE <NUM> and/or communication protocol(s) used by the modem <NUM>. In some examples, the multi-band multiplexer <NUM> may be communicatively coupled with at least one antenna, an RF module, an RF cable, or any component discussed herein.

In an aspect, the LNA <NUM> may amplify a received signal at a desired output level. In an aspect, the RF front end <NUM> may use the multi-band multiplexer <NUM>, and/or one or more switches to select a particular LNA <NUM> and/or its specified gain value based on a desired gain value for a particular application. In another aspect, the RF front end <NUM> may use the multi-band multiplexer <NUM>, and/or one or more switches to select a particular LNA <NUM> with a specified frequency band based on a desired frequency band of a network (e.g., a carrier network) or a frequency band of the network entity <NUM>.

Further, for example, one or more PA(s) <NUM> may be used by the RF front end <NUM> to amplify a signal for an RF output at a desired output power level and/or a desired frequency band. In an aspect, each PA <NUM> may have a specified minimum and maximum gain values. In an aspect, the RF front end <NUM> may use the multi-band multiplexer <NUM>, and/or one or more switches to select a particular PA <NUM> and/or a specified gain value for the RF front end <NUM> or the particular PA <NUM> based on a desired gain value for a particular application. In another aspect, the RF front end <NUM> may use the multi-band multiplexer <NUM>, and/or one or more switches to select a particular PA <NUM> with a specified frequency band based on a desired frequency band of a network (e.g., a carrier network) or a frequency band of the network entity <NUM>.

The multi-band multiplexer <NUM> may be used by the UE <NUM> to route a received signal from the antenna <NUM> to a particular LNA <NUM>. Similarly, in an aspect, for example, the multi-band multiplexer <NUM> may be used by the UE <NUM> to route an output from a respective PA <NUM> to produce an output signal to the antenna <NUM> for transmission. In an aspect, the multi-band multiplexer <NUM> may be connected to one or more LNAs <NUM> and/or one or more PAs <NUM>. In an aspect, the RF front end <NUM> can use the multi-band multiplexer <NUM> to select a transmit or receive path using a specified LNA <NUM>, and/or PA <NUM>, based on a configuration as specified by the transceiver <NUM>, one or more processors <NUM>, and/or modem <NUM>.

The transceiver <NUM> may be configured to transmit and receive wireless signals through the antenna <NUM> via the RF front end <NUM>. In an aspect, the transceiver <NUM> may be tuned to operate at one or more specified frequencies such that the UE <NUM> can communicate with, for example, a network entity <NUM>. In an aspect, for example, the modem <NUM> can configure the transceiver <NUM> to operate at a specified frequency and power level based on the UE configuration of the UE <NUM> and communication protocol used by the modem <NUM>.

In an aspect, the modem <NUM> can be a multiband-multimode modem, which can process digital data and communicate with the transceiver <NUM> such that the digital data is sent and received using the transceiver <NUM>. In an aspect, the modem <NUM> can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, the modem <NUM> can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, the modem <NUM> can control one or more components of the UE <NUM> (e.g., RF front end <NUM>, multi-band multiplexer <NUM>, transceiver <NUM>) to enable transmission and/or reception of signals based on a specified modem configuration. In another aspect, the modem configuration can be based on UE configuration information associated with the UE <NUM> as provided by the network, e.g., during cell selection and/or cell reselection.

The UE <NUM> may further include memory <NUM>, such as for storing data used herein and/or local versions of applications or multi-band multiplexer <NUM> being executed by the processor <NUM>. The memory <NUM> can include any type of computer-readable medium usable by a computer or processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, the memory <NUM> may be a computer-readable storage medium that stores one or more computer-executable codes defining or operating the multi-band multiplexer <NUM>, and/or data associated therewith, when the UE <NUM> is operating the processor <NUM> to execute the multi-band multiplexer <NUM> or other related components. In another aspect, for example, the memory <NUM> may be a non-transitory computer-readable storage medium.

The wireless communications network <NUM> may further include base stations (e.g., network entity <NUM>) operating according to Wi-Fi technology, e.g., Wi-Fi access points (AP), in communication with UEs (e.g., UE <NUM>) operating according to Wi-Fi technology, e.g., Wi-Fi stations (STAs) via communication links in an unlicensed frequency spectrum (e.g., <NUM>). When communicating in an unlicensed frequency spectrum, the STAs and AP may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure prior to communicating in order to determine whether the channel is available.

Additionally, the network entity <NUM> and/or the UE <NUM> may operate according to a <NUM> NR technology referred to as millimeter wave (mm-W or mm-wave) technology. For example, mm-wave technology includes transmissions in mm-wave frequencies and/or near mm-wave frequencies. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. EHF has a range of <NUM> to <NUM> (e.g., <NUM>) and a wavelength between <NUM> millimeter and <NUM> millimeters. Near mm-wave may extend down to a frequency of <NUM> with a wavelength of <NUM> millimeters. For example, the super high frequency (SHF) band extends between <NUM> and <NUM> (e.g., <NUM>), and may also be referred to as centimeter wave. Communications using the mm-wave and/or near mm-wave radio frequency band may have extremely high path loss and a short range. As such, the network entity <NUM> and/or the UE <NUM> operating according to the mm-wave technology may utilize beamforming in their transmissions to compensate for the extremely high path loss and short range.

In some aspects, wireless communications systems (e.g., a <NUM> NR system) may be time-division duplexing (TDD) based and operate at mm-wave radio frequencies. In an example, the receiver (e.g., receiver <NUM> in <FIG>) and/or transmitter (e.g., transmitter <NUM> in <FIG>) of a UE (e.g., UE <NUM> in <FIG>) may operate at a same frequency band, or at one or more predetermined frequency bands, and may feed a single antenna (e.g., antenna <NUM> in <FIG>). In this case, the UE (e.g., UE <NUM> in <FIG>) may need to combine the signal transmissions and receptions to feed the antenna.

In some conventional implementations in wireless communications systems (e.g., in a <NUM> NR system) off-chip duplexers, circulators, and/or some other off-chip components may not be practical at millimeter-wave radio frequencies, and may not be cost-efficient because each antenna element may require at least a set of off-chip components. In an example, if a UE has eight to sixteen or more antenna elements, the UE may require eight to sixteen or more sets of off-chip components. Furthermore, a practical wireless communications systems (e.g., a <NUM> NR system) may require supports for multi-band operations from a single antenna in order to support different carrier frequency allocations. However, conventional solutions (e.g., for mm-wave or Wi-Fi systems) may suffer from high loss for single-band operation, or higher loss to enable multi-band operations.

Referring to <FIG>, in a conventional implementation, an RF front end design <NUM> may implement a switch used for selecting an LNA or a PA. In an aspect, the RF front end design <NUM> may operate at more than one frequency band, however, the loss of this RF front end design may be very high, e.g., <NUM> dB to <NUM> dB at least. In another conventional implementation, an RF front end design <NUM> may implement shunt-based switches, however, the implementation of the RF front end design <NUM> may result in high loss (e.g., <NUM> dB or more) when using one or more on-chip combining components. In addition, the RF front end design <NUM> may only operate at narrow-band frequencies and may require a large on-chip area for circuits and/or components. In another example, an RF front end design <NUM> may include a switch on one side (e.g., at the receiving side with an LNA), and may significantly sacrifice the other side (e.g., no switch at the transmitting side with a PA). In other words, for system reliability, the RF front end design <NUM> may only have a switch on an LNA but no switch on a PA. In this design <NUM>, the PA may parasitically affect the LNA and vice-versa, and experience high loss (e.g., <NUM> dB loss or higher).

Referring to <FIG>, in an aspect of the present disclosure, a low-loss multi-band multiplexing (e.g., duplexing) scheme <NUM> is proposed to support multiple mm-wave frequencies (e.g., <NUM> and <NUM>). In an example, a single multiplexer <NUM> (e.g., the multi-band multiplexer <NUM> in <FIG>) using the multiplexing scheme 300supports multiple mm-wave frequency bands, and the multiplexer <NUM> is frequency tunable. In some examples, the multiplexer <NUM> may be communicatively coupled with one or more antennas <NUM>, and/or one or more RF components <NUM> (e.g., an inductor, a capacitor, or a resistor), and may be communicatively coupled with one or more amplifiers <NUM> and <NUM>. In particular, in an aspect, the multiplexer <NUM> (e.g., a duplexer, or the multi-band multiplexer <NUM> in <FIG>) includes one or more combining components <NUM> and one or more multi-band tuning components <NUM>, and may be separated by a chip boundary <NUM>. The one or more combining components <NUM> are off-chip components (or elements) and may be configured to transmit and receive multiplexed signals or waveforms and are communicatively coupled with the one or more multi-band tuning components <NUM> to perform signal transition(s) from off-chip to on-chip, or from on-chip to off-chip, enabling low-loss operations. The one or more multi-band tuning components <NUM> are on-chip components (or elements) (e.g., components on a chip, such as an integrated circuit (IC) chip or a silicon chip) and includes one or more shunt-based switches, enabling multi-band operations. In some cases, the terms "components" and "elements" discussed here may be interchanged.

In some examples, the off-chip components discussed herein (e.g., the combining components <NUM>) may be one or more components that are not fabricated or integrated on the chip (e.g., an IC chip or a silicon chip) used for the on-chip components (e.g., the multi-band tuning components <NUM>). For example, the off-chip components may be fabricated or integrated on a module substrate, a printed circuit board (PCB), or a chip different from the chip used for the on-chip components. In an aspect, impedance transformation circuits may be implemented off-chip and include the chip or signal transition(s), enabling low-loss switching or selection. Therefore, both low-loss and multi-band operations may be supported. In some examples, the proposed low-loss multi-band multiplexing (e.g., duplexing) scheme(s) may provide significant improvements in loss over conventional designs, may relax constraints on PA (e.g., wideband amplifier <NUM>) and/or LNA (e.g., wideband amplifier <NUM>) designs, and may reduce overall power consumption of a UE.

Referring to <FIG>, in an aspect of the present disclosure, a low-loss multi-band multiplexing (e.g., duplexing) scheme <NUM> to support multiple mm-wave frequencies (e.g., <NUM> and <NUM>) is illustrated in more detail. In some examples, the multiplexing scheme <NUM> may be a TDD-based scheme without frequency filtering, and may support wideband operations that match predetermined high frequency bands. In an example, a single multiplexer <NUM> (e.g., the multi-band multiplexer <NUM> in <FIG>) using the multiplexing scheme <NUM> supports multiple mm-wave frequency bands, and the single multiplexer is frequency tunable.

In particular, in an aspect, a UE (e.g., UE <NUM> in <FIG>) may include an RF front end (e.g., RF front end <NUM> in <FIG>) which may include the multiplexer <NUM> (e.g., a duplexer, or the multi-band multiplexer <NUM> in <FIG>), and the RF front end may be communicatively coupled with one or more antennas <NUM>. In an example, each antenna may be communicatively coupled with a respective set of combining components. In another example, multiple antennas may be communicatively coupled with a switch or a module, and may share a set of combining components.

In an aspect, the multiplexer <NUM> may include off-chip components (e.g., <NUM> and <NUM>) and on-chip components (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>), and the off-chip components and the on-chip components may be separated by a chip boundary <NUM>. In an example, the multiplexer <NUM> may be communicatively coupled with one or more off-chip RF components <NUM> (e.g., an inductor, or a resistor), and may be communicatively coupled with one or more wideband amplifiers <NUM> (e.g., an LNA) or <NUM> (e.g., a PA). In an implementation, the off-chip components may be communicatively coupled with or connected to the on-chip components through chip soldering at one or more connections <NUM>. In an example, the multiplexer <NUM> may be a low-loss duplexer having one or more single-pole double-throw (SPDT) switches, or a low-loss multiplexer having one or more single-pole N-throw (SPNT) switches, where N = <NUM>, <NUM>, <NUM>, etc. In some cases, the SPDT or SPNT switches may include on-chip switches (e.g., switches <NUM>, <NUM>, <NUM>, and <NUM>), and may be used for switching between transmission and reception, and/or between different frequency bands, or may be used for selecting or adjusting to a predetermined frequency band. For example, the multiplexer may be configured or reconfigured for multi-band operations. In an example, when N = <NUM>, the low-loss multiplexer may use multiple single-pole <NUM>-throw (SP4T) switches, and may be configured to perform four-way multiplexing (an example is shown in <FIG>). In an aspect, the SPDT or SPNT switches may be shunt-based switches, with same or different logic (e.g., low/high, or on/off) that may be digital. In some examples, the tuning components may include shunt-based switches (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) and band-select components (e.g., <NUM> and <NUM>), and may be integrated on-chip and incorporated into matching networks or circuits of the wideband amplifiers (e.g., <NUM> and/or <NUM>) to enable multi-band operations. In an aspect, a band-select component (e.g., <NUM> or <NUM>) is a fixed or tunable reactance, inductor, capacitor, and/or resistor. In an aspect, the wideband amplifiers may include one or more LNAs (e.g., <NUM>), and/or one or more PAs (e.g., <NUM>).

In an aspect, combining components (e.g., off-chip combining components <NUM> and <NUM>) includes impedance transformation circuits on at least a module substrate or a printed circuit board (PCB), and may be used for transmission/reception line combining or splitting (e.g., TDD-based combining or splitting). In some examples, these impedance transformation circuits may be implemented on the module substrate or PCB as transmission/reception lines or signal paths, and incorporate the chip transition to enable low-loss characteristic for low-loss switching. For example, implementing one or more off-chip impedance transformation circuits may realize low-loss characteristic for the multiplexing scheme <NUM> because module or PCB level routing may exhibit much lower loss than on-chip routing due to larger line widths and thicknesses, as well as higher quality dielectric material(s). In addition, routing on the module may avoid unnecessary discontinuities (e.g., turns or bends) which may contribute to additional loss. Therefore, the multiplexing scheme <NUM> is a hybrid approach using both on-chip and off-chip components to enable low-loss and low-cost operations.

Still referring to <FIG>, in an aspect, at a high level, the multiplexer or duplexer used in multiplexing scheme <NUM> may function similar to a shunt SPDT switch. For example, a short circuit on one side is transformed into an open circuit at the common junction through the effective length (e.g., electrical length) of the combining network/circuit. The off-chip combining networks or components are configured to transform the impedances of a non-operational signal path to present a desirable load (e.g. an open circuit) to an operational signal path. In some examples, an open circuit may be the ideal impedance loading of an operational path. In some cases, a circuit design may target some reactive load rather than a pure open circuit to help with impedance matching.

Additionally, each combining element may have an associated set of on-chip shunt-based switches (e.g., <NUM> and <NUM>, or <NUM> and <NUM>) and one or more band-select components (e.g., <NUM> and/or <NUM>). In an aspect, the band-select components may include one or more tunable reactances that may be configured to adjust the effective length of one or more individual legs of a combining circuit network or the multiplexer, enabling the shunt-based switches to operate effectively over many different frequency bands. Therefore, the hybrid approach using both on-chip and off-chip components enables multi-band operations.

Referring to <FIG>, in another aspect of the present disclosure, a low-loss multi-band multiplexing (e.g., four-way multiplexing) scheme <NUM> to simultaneously support multiple mm-wave frequencies (e.g., four frequency bands) is provided. Similar to multiplexing scheme <NUM>, a UE (e.g., UE <NUM> in <FIG>) using the multiplexing scheme <NUM> may include an RF front end (e.g., RF front end <NUM> in <FIG>) which may include a multiplexer <NUM> (e.g., a multi-band multiplexer <NUM> in <FIG>), and the RF front end may be communicatively coupled with at least one antenna <NUM>. In an aspect, the multiplexer <NUM> may be communicatively coupled with one or more off-chip RF components <NUM> (e.g., an inductor, a capacitor, or a resistor), and may be configured to perform multi-band operations using one or more single-pole <NUM>-throw (SP4T) switches. In some examples, switches <NUM>, <NUM>, <NUM>, and <NUM> may be configured as a first SP4T, and switches <NUM>, <NUM>, <NUM>, and <NUM> may be configured as a second SP4T. In an implementation, for example, the first SP4T may be configured by a controller or processor to set one of the four switches (e.g., the switch <NUM>) to be closed (or "ON"), and to set the other three switches (e.g., the switches <NUM>, <NUM>, and <NUM>) to be open (or "OFF"). In another example, the second SP4T may be configured by a controller or processor to set one of the four switches (e.g., the switch <NUM>) to be closed (or "ON"), and to set the other three switches (e.g., the switches <NUM>, <NUM>, and <NUM>) to be open (or "OFF"). In some cases, the first SP4T or second SP4T may be controlled by a controller or processor using logic or gate information (e.g., "<NUM>"/"<NUM>", low/high, or on/off).

In an aspect, two, four, or more off-chip combining components (e.g., <NUM>, <NUM>, <NUM>, or <NUM>) may be used to separate or combine multiple (e.g., two, four, or more) signal paths. In the multiplexing scheme <NUM>, for example, four combining components (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) may be used to separate, route, or combine four signal paths. In an implementation, the off-chip components may be communicatively coupled with or connected to the on-chip components through chip soldering at one or more connections <NUM> and/or <NUM>. In an aspect, the off-chip components and the on-chip components may be separated by a chip boundary <NUM>.

In an example, using the multiplexing scheme <NUM>, the multiplexer <NUM> may be communicatively coupled with multiple amplifiers that may be wideband amplifiers (e.g., LNAs <NUM>, <NUM>, and/or PAs <NUM>, <NUM>) or multiple single-band amplifiers (e.g., LNAs <NUM>, <NUM>, and/or PAs <NUM>, <NUM>). In an aspect, the on-chip tuning components may include multiple shunt-based switches (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>) and multiple band-select components (e.g., <NUM>, <NUM>, <NUM>, and/or <NUM>), and may be integrated on-chip and incorporated into matching networks or circuits of the amplifiers (e.g., LNAs <NUM>, <NUM>, and/or PAs <NUM>, <NUM>) to enable multi-band operations. In an aspect, a band-select component (e.g., <NUM>, <NUM>, <NUM>, and/or <NUM>) may be a fixed or tunable reactance, inductor, capacitor, and/or resistor.

Referring to <FIG>, in an aspect, a multiplexer (e.g., multi-band multiplexer <NUM> in <FIG>) may be configured to perform a multi-band operation using multiplexing scheme <NUM>. In particular, similar to multiplexing scheme <NUM>, a UE (e.g., UE <NUM> in <FIG>) may include an RF front end (e.g., RF front end <NUM> in <FIG>) which may include a multiplexer <NUM>, and the RF front end may be communicatively coupled with at least one antenna <NUM>. In an aspect, the multiplexer <NUM> includes off-chip components (e.g., <NUM> and <NUM>) and on-chip components (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). In an example, the multiplexer <NUM> may be communicatively coupled with one or more off-chip RF components <NUM> (e.g., an inductor, a capacitor, or a resistor), and may be communicatively coupled with wideband amplifiers <NUM> (e.g., an LNA) and <NUM> (e.g., a PA). In an implementation, the off-chip components may be communicatively coupled with or connected to the on-chip components through chip soldering at one or more connections <NUM>. In an aspect, the off-chip components and the on-chip components may be separated by a chip boundary <NUM>.

In an aspect, the combining components (e.g., off-chip combining components <NUM> and <NUM>) of the multiplexer <NUM> includes impedance transformation circuits on at least a module substrate or a PCB, and may be used for transmission/reception line combining or splitting (e.g., TDD-based combining or splitting). In some implementations, the combining components <NUM> and <NUM> can be used as part of the routing to the antenna (i.e. reduce length and loss of element <NUM>). In an example, the multiplexer <NUM> may be a low-loss duplexer having one or more on-chip SPDT switches, and may be used for switching between signal transmission and reception, and/or between different frequency bands. In some examples, the tuning components (e.g., switches <NUM>, <NUM>, <NUM>, and <NUM>) are formed or configured to perform as one or more on-chip SPDT switches (shunt-based switches). Additionally, the tuning components includes one or more band-select components (e.g., <NUM> or <NUM>), and are integrated on-chip and may be incorporated into matching networks or circuits of the wideband amplifiers (e.g., <NUM> and/or <NUM>) to enable multi-band operations. In an aspect, the one or more band-select components (e.g., <NUM> or <NUM>) includes at least one of a fixed or tunable reactance, an inductor, a capacitor, a resistor, or any combination of these components. In an aspect, the wideband amplifiers may include at least the LNA <NUM> and PA <NUM>.

In an example, the multiplexer <NUM> may be configured to use the multiplexing scheme <NUM> (e.g., via one or more SPDT switches) in a <NUM> mode (or around <NUM>). In an aspect, switches <NUM>, <NUM>, <NUM>, and <NUM> may logically form a SPDT switch to control signals. For example, logic for switches <NUM> and <NUM> may be complementary to switches <NUM> and <NUM> with respect to transmission or reception operations (e.g., "<NUM>"/"<NUM>", high/low, or on/off). In an aspect, logic for switches <NUM> and <NUM> may be complementary to switches <NUM> and <NUM> with respect to band selection(s) (e.g., "<NUM>"/"<NUM>", high/low, or on/off). In an example, by closing the switch <NUM> and opening switches <NUM>, <NUM>, and <NUM>, a short circuit on the LNA <NUM> side is transformed into a high impedance at the common junction of the off-chip components <NUM> and <NUM> (or point <NUM> in <FIG>), where the PA <NUM> is configured to be on, and the LNA <NUM> is configured to be off. As shown in the table in <FIG>, in an example of a <NUM> mode configuration, the impedance transformation circuits are configured to transform impedances of a non-operational signal path of the multiplexer <NUM> to present a load to an operational signal path of the multiplexer <NUM>. For example, the input impedance (Zin) toward LNA <NUM> at point <NUM> (or chip soldering connection <NUM>) may be low (e.g., a short circuit) for both a <NUM> path and a <NUM> path. At point <NUM> (the common junction of the off-chip components <NUM> and <NUM>), Zin is high for the <NUM> path (e.g., an open circuit), and for the <NUM> path, Zin may be transformed to another impedance based on the off-chip component <NUM>. For example, if the off-chip component <NUM> is a transmission line sized to transform a short circuit to an open circuit at <NUM>, then Zin would be capacitive at <NUM>.

Referring to <FIG>, in an aspect, the multiplexer <NUM> (e.g., multi-band multiplexer <NUM> in <FIG>) may be configured to perform a multi-band operation using multiplexing scheme <NUM>. For example, the multiplexer <NUM> may be configured to use the multiplexing scheme <NUM> (e.g., via one or more SPDT switches) in a <NUM> mode (or around <NUM>). In an aspect, switches <NUM> and <NUM> may logically form a SPDT switch to control signals. For example, logic for switches <NUM> and <NUM> may be complementary to switches <NUM> and <NUM> with respect to transmission or reception operations (e.g., "<NUM>"/"<NUM>", high/low, or on/off). In an aspect, logic for switches <NUM> and <NUM> may be complementary to switches <NUM> and <NUM> with respect to band selection(s) (e.g., "<NUM>"/"<NUM>", high/low, or on/off). In an example, by closing the switch <NUM> and opening switches <NUM>, <NUM>, and <NUM>, a short circuit with the on-chip component <NUM> (e.g., a tunable reactance) on the LNA <NUM> side is transformed into an open circuit at the common junction of the off-chip components <NUM> and <NUM> (or point <NUM>), and may be adjusted (e.g., by a controller or a processor) to an effective length (e.g., electrical length) of the individual leg, where the PA <NUM> is configured to be on, and the LNA <NUM> is configured to be off. As shown in the table in <FIG>, in an example of a <NUM> mode configuration, the impedance transformation circuits are configured to transform impedances of a non-operational signal path of the multiplexer <NUM> to present a load to an operational signal path of the multiplexer <NUM>. For example, the input impedance (Zin) toward LNA <NUM> at point <NUM> (or chip soldering connection <NUM>) may be low (e.g., a short circuit) for both a <NUM> path and a <NUM> path. At point <NUM> (the common junction of the off-chip components <NUM> and <NUM>), Zin is high for the <NUM> path (e.g., an open circuit), and for the <NUM> path, Zin may be transformed to another impedance based on the off-chip component <NUM>. In an example, Zin may depend on the off-chip component <NUM> and/or the on-chip component <NUM> (e.g., the individual leg of a tunable reactance).

Referring to <FIG>, in an aspect, a multiplexer <NUM> (e.g., multi-band multiplexer <NUM> in <FIG>) may be configured to perform a multi-band operation using multiplexing scheme <NUM>. In an example, multiplexing scheme <NUM> is an asymmetrical design to avoid shunt switches on the LNA side (e.g., an LNA <NUM>). In this asymmetrical implementation, a combining network/component may be simplified and reduced in area, and PA loss performance is maintained at a low level, with some additional loss from the LNA side. As a result, the PA loss performance is maintained at the cost of LNA loss. In this implementation, the total system loss may be reduced, and the RF front end is simplified.

For example, by using multiplexing scheme <NUM>, a UE (e.g., UE <NUM> in <FIG>) may include an RF front end (e.g., RF front end <NUM> in <FIG>) which may include the multiplexer <NUM>, and the RF front end may be communicatively coupled with at least one antenna <NUM>. In an aspect, the multiplexer <NUM> may include at least an off-chip component <NUM> and on-chip components <NUM>, <NUM>, <NUM>, and <NUM>, may be communicatively coupled with one or more off-chip RF components <NUM> (e.g., an inductor, a capacitor, or a resistor), and may be communicatively coupled with wideband amplifiers <NUM> (e.g., an LNA) and <NUM> (e.g., a PA). In an implementation, the off-chip components may be communicatively coupled with or connected to the on-chip components through chip soldering at one or more connections <NUM>. In an aspect, the off-chip components and the on-chip components may be separated by a chip boundary <NUM>.

In an aspect, the off-chip combining component(s) of the multiplexer <NUM> may include impedance transformation circuits on at least a module substrate or a PCB, and may be used for transmission/reception line combining or splitting (e.g., TDD-based combining or splitting). In an example, the multiplexer <NUM> may be a low-loss duplexer having one or more on-chip switches (e.g., <NUM>, <NUM>, or <NUM>), and may be used for switching between signal transmission and reception, and/or between different frequency bands. In some examples, the tuning components may include on-chip shunt-based switches <NUM> and <NUM> and at least a band-select component <NUM>, and may be integrated on-chip and incorporated into matching network(s) or circuit(s) of at least one of the wideband amplifiers <NUM> and <NUM> to enable multi-band operations. In an aspect, switches <NUM> and <NUM> may logically form a SPDT switch when controlling signals or logic for switches <NUM> and <NUM> are complementary (e.g., "<NUM>"/"<NUM>", high/low, or on/off). In an aspect, the band-select component <NUM> may be a fixed or tunable reactance, inductor, capacitor, and/or resistor. In an aspect, the wideband amplifiers may include at least LNA <NUM> and PA <NUM>.

In some aspects, by using a low-loss multi-band multiplexer, system performance may be improved and the transmission losses (e.g., within a UE) in a particular frequency band may be reduced. In an example, the loss at a PA port may occur when the PA is tuned/switched to <NUM> band, and the loss at an LNA port may occur when the LNA is tuned/switched to <NUM> band. In an aspect, the LNA loss may be higher than the PA loss. In an example, the switch(es) on the PA side may introduce more loss than the switch(es) used on the LNA side. In an aspect, on the PA side, the switch(es) may be designed for better reliability rather than less loss. In some examples, the loss of the proposed multiplexing schemes in <FIG> is much less than the conventional solutions discussed herein, for example, with more than <NUM> dB less loss at mm-wave frequencies and with SPDT or duplexers quoted. In addition, the proposed multiplexing schemes in <FIG> may support multi-band operations.

For purposes of simplicity of explanation, the methods discussed herein are shown and described as a series of acts, it is to be understood and appreciated that the method (and further methods related thereto) is/are not limited by the order of acts, as some acts may, in accordance with one or more aspects, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, it is to be appreciated that a method could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a method in accordance with one or more features described herein.

Referring to <FIG>, in an operational aspect, a UE such as UE <NUM> (<FIG>) may perform one or more aspects of a method <NUM> for multi-band operations in a wireless communications system (e.g., a <NUM> NR system). For example, one or more of the processors <NUM>, the memory <NUM>, the modem <NUM>, the RF front end <NUM>, and/or the multi-band multiplexer <NUM>, may be configured to perform one or more aspects of the method <NUM>. In an aspect, for example, one or more of the processors <NUM>, the memory <NUM>, and/or the modem <NUM> may configure the transceiver <NUM> (e.g., a beamforming transceiver, or a transceiver requires multiple antennas for transmissions/receptions), the RF front end <NUM>, and/or the multi-band multiplexer <NUM> to perform one or more aspects of the method <NUM>.

In an aspect, at block <NUM>, the method <NUM> includes selecting a frequency band from a plurality of frequency bands. In an aspect, for example, the multi-band multiplexer <NUM> may be configured by one or more of the processors <NUM>, the memory <NUM>, and/or the modem <NUM> to perform frequency band selection as described herein. For example, the multi-band multiplexer <NUM> may be configured to use at least one of the multiplexing schemes <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and select a frequency band from multiple mm-wave frequency bands that are supported by the multi-band multiplexer <NUM>.

In an aspect, at block <NUM>, the method <NUM> includes adjusting at least one tuning component to transmit or receive at least one signal within the selected frequency band. In an aspect, for example, one or more on-chip tuning components (e.g., on-chip components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc.) of the multi-band multiplexer <NUM> may be configured by one or more of the processors <NUM>, the memory <NUM>, and/or the modem <NUM> to tune or adjust (e.g., to adjust on-chip components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc.) in order to transmit or receive signals in a selected or predetermined frequency band (e.g., the frequency band selected or determined at block <NUM>). In an example, the one or more on-chip tuning components of the multi-band multiplexer <NUM> may comprise at least two shunt-based switches to form an SPDT switch or an SPNT switch, and one or more band-select components (e.g., a tunable reactance) to perform the frequency band adjustment.

In an aspect, at block <NUM>, the method <NUM> includes transmitting or receiving the at least one signal within the selected frequency band using at least one combining component. In an aspect, for example, one or more combining components (e.g., combining components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>) of the multi-band multiplexer <NUM> may be communicatively coupled with the at least one tuning component, and configured by one or more of the processors <NUM>, the memory <NUM>, and/or the modem <NUM> to transmit or receive multiplexed signals within the frequency band that is selected at block <NUM>, as described herein. In some examples, the at least one tuning component is integrated on a chip (e.g., an IC chip), and the at least one combining component is off-chip and is not integrated on the chip having the at least one tuning component. For example, the one or more combining components may be on a module substrate, a PCB, or a chip different from the chip used by the at least one tuning component.

Referring to <FIG>, in an aspect, a UE (e.g., UE <NUM>) may include a system <NUM>, wherein the system <NUM> may include RF components such as an antenna (e.g., antenna <NUM>, or antenna <NUM> in <FIG>), a RF front end (e.g., the RF front end <NUM>), a transmitter (e.g., a transmitter <NUM>) and a receiver (e.g., a receiver <NUM>). In addition, system <NUM> may include a multiplexer <NUM> (e. , the multi-band multiplexer <NUM>) configured to perform multi-band operations as described herein. In some implementation, system <NUM> may perform multi-band operations according to at least one of the multiplexing schemes in <FIG>.

In an example, the system <NUM> may include a signal conversion component <NUM> and a communication component <NUM>. The signal conversion component <NUM> may include one or more digital-to-analog converters (DACs) (e.g., 914a and 914b) and one or more analog-to-digital converters (ADCs) (e.g., 916a and 916b). The communication component <NUM> may include a transmitter <NUM> and a receiver <NUM>. In some implementations, in addition to the multiplexer <NUM>, the communication component <NUM> may also comprise one or more RF components, which may include low-pass filters (932a, 932b, 964a, 964b), amplifiers (934a, 934b, 962a, 962b), an up-convertor <NUM>, a down-convertor <NUM>, filters (<NUM>, <NUM>), a PA <NUM>, an LNA <NUM>, a transmission (TX) phase-locked loop (PLL) <NUM>, a reception (RX) PLL <NUM>, a TX local oscillator (LO) signal generator <NUM>, or a RX LO signal generator <NUM>, as shown in <FIG>.

Several aspects of a telecommunication system have been presented with reference to an LTE/LTE-A or a <NUM> communication system.

By way of example, various aspects may be extended to other communication systems such as satellite, radar systems, and cellular systems, High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+) and TD-CDMA. Various aspects may also be extended to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems.

Claim 1:
A multiplexer for multi-band wireless communications (<NUM>, <NUM>) configured for operating at mm-wave frequencies or near mm-wave frequencies, comprising:
at least one tuning component (<NUM>) including one or more shunt-based switches (<NUM>, <NUM>, <NUM>, <NUM>) and one or more band-select components (<NUM>, <NUM>) and configured to transmit or receive at least one signal within a frequency band that is selected from a plurality of frequency bands, wherein the band-select components (<NUM>, <NUM>) comprise at least one of a fixed reactance, a tunable reactance, an inductor, a capacitor or a resistor; and
at least one combining component (<NUM>, <NUM>, <NUM>) including impedance transformation circuits configured to transform the impedance of a non-operational signal path of the multiplexer to present a load to an operational signal path of the multiplexer based on the selected frequency-band, and communicatively coupled with the at least one tuning component (<NUM>), configured to transmit or receive the at least one signal within the selected frequency band,
wherein the at least one tuning component (<NUM>) is integrated on a chip and the at least one combining component (<NUM>, <NUM>, <NUM>) is not integrated on the chip.