Patent Description:
The present disclosure relates generally to transceivers, and more specifically to multiplex modules for improved signal routing in carrier aggregation receivers.

In a radio frequency (RF) transceiver, a communication signal is developed, upconverted, amplified and transmitted by a transmitter and is received, amplified, downconverted and recovered by a receiver. In the receiver, the communication signal is typically received and downconverted by receive circuitry to recover the information contained in the communication signal. A single transmitter or receiver can be configured to operate using multiple transmit frequencies and/or multiple receive frequencies. For a receiver to be able to simultaneously receive two or more receive signals, the concurrent operation of two or more receive paths is used. Such systems are sometimes referred to as "carrier-aggregation" (CA) systems. The term "carrier- aggregation" may refer to systems that include inter-band carrier aggregation (Inter-CA) and intra-band carrier aggregation (Intra-CA). Inter-CA refers to the processing of two or more separate (either contiguous or non-contiguous) carrier signals that occur in different communication bands. Intra-CA refers to the processing of two or more separate (either contiguous or non-contiguous) carrier signals that occur in the same communication band. A received carrier aggregated RF signal is typically down- converted using one or more distinct local oscillator (LO) frequencies. The downconverted signals are then processed to extract the information transmitted using the multiple carriers.

Communication devices have RF transceivers that are becoming more and more complex as they are designed to handle an ever-increasing number of different frequencies in multiple communication bands. It is common for a communication device to be able to communicate over a variety of different frequencies over many different communication bands. In many cases, the receiver includes multiple receive paths that may have long signal routing paths and duplicate amplification and filtering. Such implementations may have high costs and space requirements while resulting in inconsistent gain, inconsistent impedance matching, and inconsistent current in the different receive paths.

It is therefore desirable to have a cost effective and space efficient way to obtain consistent receiver performance when processing different carrier signals in a carrier aggregation transceiver. Attention is drawn to <CIT> describing that in a radio receiver, an N: <NUM> multiplexer multiplexes N signals received through N receiver antennas into one output, and a downconverter downconverts the combined signals into baseband signals, and two <NUM> :N analog demultiplexers demultiplex the N combined and downconverted received signals into in-phase signal elements of N received signals and quadrature-phase signal elements of N received signals. Attention is further drawn to <CIT> describing multiple low noise amplifiers (LNAs) with combined outputs are disclosed. In an exemplary design, an apparatus includes a front-end module and an integrated circuit (IC). The front-end module includes a plurality of LNAs having outputs that are combined. The IC includes receive circuits coupled to the plurality of LNAs via a single interconnection. In an exemplary design, each of the plurality of LNAs may be enabled or disabled via a respective control signal for that LNA. The front-end module may also include receive filters coupled to the plurality of LNAs and a switchplexer coupled to the receive filters. The front-end module may further include at least one power amplifier, and the IC may further include transmit circuits coupled to the at least one power amplifier. Attention is also drawn to <CIT> relating to an integrated antenna device for a vehicle. The antenna device includes: an antenna implemented as a circuit on a PCB; a head unit; and a transmission line, which includes one cable to be connected electrically to the antenna and the head unit. Also a BPF and a BSF is arranged on each line on a circuit in a special method to improve the miniaturization, lighting, and isolation properties of the device. In accordance with the present invention a apparatus, and a method, as set forth in the independent claims, respectively, are provided.

The detailed description set forth below is intended as a description of exemplary designs of the present disclosure and is not intended to represent the only designs in which the present disclosure can be practiced. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration. " Any design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other designs. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary designs of the present disclosure. It will be apparent to those skilled in the art that the exemplary designs described herein may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary designs presented herein.

<FIG> shows an exemplary embodiment of multiplex modules <NUM> that efficiently route received carrier signals to a demodulator in a wireless device <NUM> communicating within a wireless system <NUM>. Wireless system <NUM> may be a Long Term Evolution (LTE) system, a Code Division Multiple Access (CDMA) system, a Global System for Mobile Communications (GSM) system, a wireless local area network (WLAN) system, or some other wireless system. A CDMA system may implement Wideband CDMA (WCDMA), CDMA 1X, Evolution-Data Optimized (EVDO), Time Division Synchronous CDMA (TD-SCDMA), or some other version of CDMA. For simplicity, <FIG> shows wireless system <NUM> including two base stations <NUM> and <NUM> and one system controller <NUM>. In general, wireless system <NUM> may include any number of base stations and any set of network entities.

Wireless device <NUM> may also be referred to as a user equipment (UE), a mobile station, a terminal, an access terminal, a subscriber unit, or a station. Wireless device <NUM> may be a cellular phone, a smartphone, a tablet, a wireless modem, a personal digital assistant (PDA), a handheld device, a laptop computer, a smartbook, a netbook, a cordless phone, a wireless local loop (WLL) station, a Bluetooth device, or other communicating device. Wireless device <NUM> may communicate with devices in the wireless system <NUM>. Wireless device <NUM> may also receive signals from broadcast stations (e.g., a broadcast station <NUM>), or signals from satellites (e.g., a satellite <NUM>) in one or more global navigation satellite systems (GNSS). Wireless device <NUM> may support one or more radio technologies for wireless communication such as LTE, WCDMA, CDMA IX, EVDO, TD-SCDMA, GSM, <NUM>. In various exemplary embodiments, the multiplex modules <NUM> efficiently route received carriers in multiple communication bands to a demodulator to obtain consistent receiver performance when processing different carrier signals in multiple communication bands.

<FIG> shows diagrams <NUM> that illustrate exemplary signal carrier configurations in a carrier aggregation communication system. For example, the signal configurations show carriers that may be transmitted or received in various band groups of the communication system <NUM> shown in <FIG>. For example, the diagrams <NUM> show low-band, mid-band and high-band groups and each band group may have one or more carrier signals. In diagram <NUM>, the low-band group is further divided into two low band groups.

Diagram <NUM> shows an illustration of a contiguous intra-band carrier configuration. For example, there are multiple contiguous carriers in one band (e.g., four contiguous carriers in the low-band). Wireless device <NUM> may send and/or receive transmissions on the four contiguous carriers within the same band.

Diagram <NUM>, shows an illustration of a non-contiguous intra-band carrier configuration. For example, there are multiple non-contiguous carriers in one band (e.g., four non-contiguous carriers in the low-band). The carriers may be separated by <NUM>, <NUM>, or some other amount. Wireless device <NUM> may send and/or receive transmissions on the four non-contiguous carriers within the same band.

Diagram <NUM> shows an illustration of an inter-band carrier configuration using the same band group. For example, there are multiple carriers in two bands (e.g., two contiguous carriers in low band <NUM> and two contiguous carriers in low-band <NUM>). Wireless device <NUM> may send and/or receive transmissions on the four carriers in different bands in the same band group.

Diagram <NUM> shows an illustration of an inter-band carrier configuration using different band groups. For example, there are multiple carriers in two bands of different band groups (e.g., two carriers in the low-band group and two carriers in the mid-band group. Wireless device <NUM> may send and/or receive transmissions on the four carriers in the different band groups. It should also be noted that other carrier configurations using different band groups are also supported by the exemplary embodiments.

<FIG> shows a block diagram of a receiver front end <NUM> that comprises an exemplary embodiment of a multiplex module <NUM>. For example, the multiplex module <NUM> is suitable for use as the multiplex modules <NUM> shown in <FIG>. The front end <NUM> includes an antenna switch <NUM> that is connect to receive RF signals from a primary (Pr) antenna and a diversity (Dv) antenna. In this embodiment, it will be assumed that three RF signals (Rxl, Rx2, Rx3) are output from the antenna switch <NUM>. For example, the RF signals are received by one or both of the primary and the diversity antennas and input to the switch <NUM>. The switch <NUM> operates to switch selected RF signals to the three outputs. In an exemplary embodiment, each of the RF signals comprises one or more RF carrier signals. For example, the carrier signals may be any of the carrier signals illustrated in <FIG>, which may be received from either or both of the primary and diversity antennas.

The front end <NUM> comprises a receiver printed circuit board <NUM> onto which are mounted the multiplex module <NUM> and a demodulator <NUM>. The printed circuit board <NUM> comprises signal traces that route signals between the components mounted to the printed circuit board.

A low noise amplifier having a signal combiner (LNA mux) <NUM> receives the RF signals (Rxl, Rx2, and Rx3) and combines these signals into a combined RF signal <NUM> that is output from the LNA mux <NUM>. The combined RF signal <NUM> is routed using a single signal trace of the PCB <NUM> to an LNA having a signal de-multiplexer (LNA demux) <NUM>. Since the RF signals have been multiplexed together, they are routed over the same signal trace to the LNA demux <NUM>.

The LNA demux <NUM> receives the combined RF signal that is output from the LNA mux <NUM> and routed over the signal trace of the PCB <NUM>. The LNA demux <NUM> distributes the combined RF signal to multiple down-converters of the demodulator <NUM> for RF demodulation. Each down-converter uses an associated local oscillator to downconvert a carrier signal of interest. Thus, in various exemplary embodiments, the multiplex module <NUM> operates to receive and route multiplexed RF signals to a demodulator of a carrier aggregation receiver. It should be noted that the LNA mux <NUM> and the LNA demux <NUM> comprises separate components that are located at different locations on the PCB <NUM> and that the received RF signals are routed between the LNA mux <NUM> and the LNA demux <NUM> using a single signal trace.

<FIG> shows exemplary detailed embodiments of the LNA mux <NUM> and the LNA demux <NUM> of the multiplex module <NUM> shown in <FIG>. In an exemplary embodiment, an LNA mux <NUM> comprises optional filters <NUM>, <NUM> and <NUM>, matching circuits <NUM>, <NUM> and <NUM>, and adjustable LNAs <NUM>, <NUM> and <NUM>. The LNA mux <NUM> also comprises a combining circuit <NUM>.

In an exemplary embodiment, the first RF signal Rx1 is input to the LNA mux <NUM> at input terminal <NUM>. The Rx1 signal flows from terminal <NUM> to the filter <NUM> where it is appropriately filtered to remove any unwanted signal. The filtered signal output from the filter <NUM> is input to the matching circuit <NUM>, which provides impedance matching to prevent signal loss. The output of the matching circuit <NUM> is input to the adjustable amplifier <NUM>, which amplifies the signal by a selected gain factor. The amplified signal is then input to the combining circuit <NUM>.

In an exemplary embodiment, the second RF signal Rx2 is processed by the optional filter <NUM>, matching circuit <NUM>, and adjustable LNA <NUM> as describe above with respect to the first RF signal Rx1. The filtered and amplified Rx2 signal output from the amplifier <NUM> in then input to the signal combiner <NUM>. Similarly, the third RF signal Rx3 is processed by the filter <NUM>, matching circuit <NUM>, and adjustable LNA <NUM> as describe above with respect to the first RF signal Rx1. The filtered and amplified Rx3 signal output from the amplifier <NUM> in then input to the signal combiner <NUM>.

The combining circuit <NUM> combines the signals at its inputs to generate a combined signal <NUM> that is output from the terminal <NUM>. Thus, the combined signal <NUM> comprises the first RF signal (Rxl), the second RF signal (Rx2), and the third RF signal (Rx3). In an exemplary embodiment, the three RF signals comprise three carrier signals in selected band groups as illustrated in <FIG>. The combined signal <NUM> is input to an input terminal <NUM> of the LNA demux <NUM>.

In an exemplary embodiment, the LNA demux <NUM> comprises an adjustable LNA <NUM>. The LNA <NUM> amplifies the combined signal and distributes an amplified version of the combined signal to mixer circuits <NUM>, <NUM> and <NUM> of the demodulator <NUM>. The mixer circuits <NUM>, <NUM> and <NUM> downconvert the output of the adjustable LNA <NUM> to generate baseband information signals using corresponding local oscillator (LO) signals. The LO signals are not shown for simplicity of illustration, however, each mixer circuit utilizes its own LO signal so that each mixer circuit can downconvert any desired carrier signal that may be included in the combined RF signal <NUM>.

In an exemplary embodiment, the routing of the combined signal <NUM> on the PCB <NUM> between the LNA mux <NUM> the LNA demux <NUM> is simplified because one physical connection (or signal path) from terminal <NUM> to terminal <NUM> is used to transfer, in this example, three RF signals.

<FIG> shows an exemplary detailed embodiment of the adjustable LNA <NUM> of the LNA demux <NUM> shown in <FIG>. In an exemplary embodiment, the adjustable LNA <NUM> operates to distribute the combined RF signal <NUM> (Rx <NUM>+<NUM>+<NUM>) so that each RF signal can be demodulated by the appropriate mixer (downconverter).

The adjustable LNA <NUM> comprises a gain transistor <NUM> and cascode transistors <NUM>, <NUM> and <NUM>. The drain terminal of the transistor <NUM> is coupled to the source terminals of the transistors <NUM>, <NUM> and <NUM>. The gate terminal of the transistor <NUM> is coupled to signal ground in a common gate configuration. The combined RF signal <NUM> on terminal <NUM> is applied to the source terminal of the transistor <NUM>.

In an exemplary embodiment, the combined RF signal flows from the drain terminal of the transistor <NUM>, over connection <NUM> to a transformer <NUM>. In an exemplary embodiment, the transformer <NUM> provides single-ended to differential conversion and provides the combined RF signal as a differential signal over connections <NUM> to the mixer circuit <NUM>. The mixer <NUM> receives a local oscillator (LO) signal LO1 and uses this signal to demodulate a first selected carrier signal from the combined RF signal. The demodulated first carrier signal results in a first baseband signal (BB <NUM>) being output from the mixer <NUM>.

In an exemplary embodiment, the combined RF signal flows from the drain terminal of the transistor <NUM>, over connection <NUM> to a transformer <NUM>. In an exemplary embodiment, the transformer <NUM> provides single-ended to differential conversion and provides the combined RF signal as a differential signal over connections <NUM> to the mixer circuit <NUM>. The mixer <NUM> receives a local oscillator signal LO2 and uses this signal to demodulate a second selected carrier signal from the combined RF signal. The demodulated second carrier signal results in a second baseband signal (BB2) being output from the mixer <NUM>.

In an exemplary embodiment, the combined carrier signal flows from the drain terminal of the transistor <NUM>, over connection <NUM> to a transformer <NUM>. In an exemplary embodiment, the transformer <NUM> provides single-ended to differential conversion and provides the combined RF signal as a differential signal over connections <NUM> to the mixer circuit <NUM>. The mixer <NUM> receives a local oscillator signal LO3 and uses this signal to demodulate a third selected carrier signal from the combined RF signal. The demodulated third carrier signal results in a third baseband signal (BB3) being output from the mixer <NUM>.

Thus, in various exemplary embodiments, the LNA <NUM> operates to receive a combined RF signal and routes this signal to the appropriate demodulators to allow individual carriers in the combined RF signal to be demodulated to generate the corresponding baseband signals.

<FIG> shows a detailed exemplary embodiment of the signal combiner <NUM> of the LNA mux <NUM> shown in <FIG>. In exemplary embodiment, the signal combiner <NUM> combines the three RF signals Rx1, Rx2 and Rx3 into the combined RF signal <NUM> that appears at terminal <NUM>. It will be assumed that the optional filters <NUM>, <NUM> and <NUM>, matching circuits <NUM>, <NUM> and <NUM>, and adjustable LNAs <NUM>, <NUM> and <NUM> are not used such that the RF signals presented at the terminals <NUM>, <NUM> and <NUM> are input directly to the signal combiner <NUM>.

The signal combiner <NUM> comprises gain transistors <NUM>, <NUM>, <NUM> and respective cascode transistors <NUM>, <NUM> and <NUM>. In an exemplary embodiment, the signal combiner <NUM> also comprises degeneration inductors <NUM>, <NUM> and <NUM>, and load inductors <NUM>, <NUM> and <NUM>.

The source of the transistor <NUM> is coupled to the inductor <NUM> so that the source degeneration provided to the transistor <NUM> comprises the inductors <NUM>, <NUM> and <NUM>. The source of the transistor <NUM> is coupled to the node between the inductors <NUM> and <NUM> so that the source degeneration provided to the transistor <NUM> comprises the inductors <NUM> and <NUM>. The source of the transistor <NUM> is coupled to the node between the inductors <NUM> and <NUM> so that the source degeneration provided to the transistor <NUM> comprises the inductor <NUM>.

The drain of the transistor <NUM> is coupled to the source of the transistor <NUM>. The drain of the transistor <NUM> is coupled to the source of the transistor <NUM>, and the drain of the transistor <NUM> is coupled to the source of the transistor <NUM>.

The first RF signal (Rx1) from connection <NUM> is coupled to the gate terminal of the transistor <NUM>, the second RF signal (Rx2) from connection <NUM> is coupled to the gate terminal of the transistor <NUM>, and the third RF signal (Rx3) from connection <NUM> is coupled to the gate terminal of the transistor <NUM>.

The drain terminal of the transistor <NUM> is coupled to the load inductor <NUM>, so that the load at the drain of the transistor <NUM> comprises the inductors <NUM>, <NUM> and <NUM>. The drain of the transistor <NUM> is coupled to the node between the load inductor <NUM> and the load inductor <NUM>, so that the load at the drain of the transistor <NUM> comprises the inductors <NUM> and <NUM>. The drain of the transistor <NUM> is coupled to the node between the load inductor <NUM> and the load inductor <NUM>, so that the load at the drain of the transistor <NUM> comprises the inductor <NUM>. The load inductors <NUM>, <NUM> and <NUM> are inductively coupled to an inductor <NUM>, which provides the combined output signal <NUM> (Rx <NUM>+<NUM>+<NUM>) at the terminal <NUM>.

<FIG> shows a detailed exemplary embodiment of a multiplex routing module (MRM) <NUM>. For example, the MRM <NUM> is suitable for use as the multiplex modules <NUM> shown in <FIG> to efficiently route RF signals from an antenna to a demodulator for demodulation.

The MRM <NUM> comprises input switch <NUM>, output switch <NUM>, feed-through signal path <NUM>, filter <NUM>, matching circuit <NUM>, and variable gain amplifier <NUM>. An RF signal received at an input terminal <NUM> of the input switch <NUM> is connected flow to the feed-through path <NUM> or to the filter <NUM>. If the input switch <NUM> connects the input terminal <NUM> to the terminal <NUM> that is connected to the feed-through path, the input RF signal flows through the feed-through path <NUM> to a first terminal <NUM> of the output switch <NUM>. If the input switch <NUM> connects the input terminal <NUM> to the terminal <NUM> that is connected to the filter <NUM>, the input RF signal flows to the filter <NUM> where it is filtered and a filtered output is then input to the matching circuit <NUM>. The matching circuit <NUM> provides matching characteristics to reduce loss or distortion of the filtered signal. The output of the matching circuit <NUM> is input to the variable gain amplifier <NUM> where amplification is provided to the filtered signal to generate an amplified filtered signal that flows to a second terminal <NUM> of the output switch <NUM>.

The output switch <NUM> has an output terminal <NUM> that is connected to either the first <NUM> or second <NUM> terminals to allow the RF signal to be output from the multiplex routing module <NUM> In an alternative embodiment, the terminal <NUM> outputs a signal <NUM> that flows on the bypass path <NUM>. The terminal <NUM> outputs a signal <NUM> that flows through the non-bypass path. In various exemplary embodiments, the multiplex routing module <NUM> efficiently routes RF signals in one or more bands to a demodulator in a receiver front end.

<FIG> shows a block diagram of a receiver front end <NUM> that comprises exemplary embodiments of the multiplex routing module <NUM> shown in <FIG>. For example, the multiplex routing module <NUM> is suitable for use as the multiplex routing modules (MRM) <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> shown in <FIG>. In this exemplary embodiment, it will be assumed that three RF signals (Rxl, Rx2, and Rx3) are received by the multiplex modules <NUM>, <NUM> and <NUM>. In an exemplary embodiment, the RF signals may be received from the primary and/or diversity antennas through the antenna switch <NUM> shown in <FIG>.

The front end <NUM> comprises a printed circuit board <NUM> onto which are mounted the multiplex routing modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and a demodulator <NUM>. The printed circuit board comprises signal traces that route signals between the components mounted to the printed circuit board.

The MRM <NUM> receives the Rx1 signal at its input terminal <NUM> and selects a signal path through which the Rx1 signal will flow. A first signal path <NUM> comprises a filter, matching network, and amplifier (FMA) and a second signal path comprises a bypass signal path <NUM>. In this example, the input switch and the output switch of the MRM <NUM> are set to select the bypass path <NUM>, which outputs the Rx1 signal along path <NUM> that is input to the input switch of the MRM <NUM>. The MRM <NUM> also routes the signal it receives through one of a FMA path <NUM> or a bypass path <NUM>. In this example, the input switch of the MRM <NUM> is set to select the FMA path <NUM>, which outputs a filtered and amplified signal that is input to the demodulator <NUM>. In this example, each of the paths <NUM> and <NUM> have a separate input into the demodulator <NUM>, thereby facilitating separate processing of each path by the demodulator. In an exemplary embodiment, the signal path selected to route the Rx1 signal is configured to provide filtering and gain adjustment by MRM <NUM>, which is close to the demodulator. This configuration can be used when the desired signal (Rx1) is received with good signal to noise ratio (SNR) (e.g., signal power of -60dBm).

The MRM <NUM> receives the Rx2 signal at its input terminal <NUM> and selects a signal path through which the Rx2 signal will flow. A first signal path <NUM> comprises a filter, matching network, and amplifier (FMA) and a second signal path comprises a bypass path <NUM>. In this example, the input and output switches of the MRM <NUM> are set to select the FMA path <NUM>, which outputs a filtered and amplified signal along path <NUM> that is input to the MRM <NUM>. The MRM <NUM> routes the signal it receives through one of an FMA path <NUM> or a bypass path <NUM>. In this example, the input switch of the MRM <NUM> is set to select the bypass path <NUM>, which outputs the filtered and amplified Rx2 signal, which is then input to the demodulator <NUM>. In this example, each of the paths <NUM> and <NUM> have a separate input into the demodulator <NUM>, thereby facilitating separate processing of each path by the demodulator. In an exemplary embodiment, the signal path selected to route the Rx2 signal is configured to provide filtering and gain adjustment by MRM <NUM>, which is close to the antenna switch. This configuration can be used when there the desired signal (Rx2) is received with average SNR (e.g., signal power of -80dBm).

The MRM <NUM> receives the Rx3 signal at its input terminal <NUM> and selects a signal path through which the Rx3 signal will flow. A first signal path <NUM> comprises a filter, matching network, and amplifier (FMA) and a second signal path comprises a bypass path <NUM>. In this example, the input and output switches of the MRM <NUM> are set to select the FMA path <NUM>, which outputs a filtered and amplified signal along signal path <NUM> that is input to the input switch of the MRM <NUM>. The MRM <NUM> routes the signal it receives through one of a FMA path <NUM> or a bypass path <NUM>. In this example, the input and output switches of the MRM <NUM> are set to select the FMA path <NUM>, which provides additional filtering and amplification to the Rx3 signal. The output of the MRM <NUM> is input to the demodulator <NUM>. In this example, both of the paths <NUM> and <NUM> have the same input into the demodulator <NUM>, thereby facilitating the same processing of each path by the demodulator. In an exemplary embodiment, the MRMs <NUM> and <NUM> are configured to provide filtering and gain adjustment by both of the MRM <NUM> and the MRM <NUM>. This configuration can be used when there the desired signal (Rx3) is received with poor SNR (e.g., signal power of -100dBm).

Thus, in various exemplary embodiments, the multiplex routing modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> operate to receive and route RF signals to a demodulator. It should be noted that the configuration of the front end <NUM> is exemplary and that other configurations and/or routing paths using the same number or a different number of MRMs are possible within the scope of the exemplary embodiments.

<FIG> shows a block diagram of a receiver front end <NUM> that comprises exemplary embodiments of the multiplex module shown in <FIG> and the multiplex routing module shown in <FIG>. In an exemplary embodiment, the front end <NUM> comprises MRMs <NUM>, <NUM>, and <NUM> that receive RF signals Rx1, Rx2, and Rx3 from, for example, the antenna switch <NUM>. Each of the MRMs <NUM>, <NUM>, and <NUM> routes their respective RF signals through FMA paths or bypass paths as selected by their input and output switches to generate outputs signals that are input to an LNA mux <NUM>. In an exemplary embodiment, the LNA mux <NUM> comprises a combining circuit <NUM>, which in an exemplary embodiment is configured as the combining circuit shown in <FIG>. The LNA mux <NUM> sums together the outputs of the MRM <NUM>, <NUM>, and <NUM> and outputs a combined RF signal <NUM> that is output from the output terminal <NUM> and routed to an input terminal <NUM> of an LNA demux <NUM>. The components of the front end <NUM> are mounted on printed circuit board <NUM>, such that a single signal trace carries the combined RF signal <NUM> to the LNA demux <NUM>. In an exemplary embodiment, the LNA demux <NUM> is configured as the LNA demux shown in <FIG>. The LNA demux <NUM> distributes the received combined RF signal <NUM> and provides amplified outputs to mixers <NUM>, <NUM>, and <NUM> of demodulator <NUM>. The outputs of the mixers are the baseband signals BB1, BB2, and BB3.

Thus, the MRMs <NUM>, <NUM>, and <NUM> route received RF signals along a selected path (FMA or bypass) to the LNA mux <NUM> which combines the three signals into the combined output <NUM>. This combined output can be routed across the printed circuit board <NUM> and each of the RF signals will flow over an identical signal path. The LNA demux <NUM> distributes the combined signal to a demodulator where the RF signals are demodulated using the appropriate LO signals to generate the desired baseband signals. Accordingly, the various multiplex modules operate to efficiently route signals in a carrier aggregation receiver.

<FIG> shows an exemplary embodiment of a multiplex module apparatus <NUM>. In an exemplary embodiment, the apparatus <NUM> is suitable for use as the multiplex module <NUM> shown in <FIG>.

The apparatus <NUM> includes a first means (<NUM>) for receiving a plurality of RF signals, which in an exemplary embodiment comprises the input terminals <NUM>, <NUM>, and <NUM>. The apparatus <NUM> also includes a second means (<NUM>) for combining the RF signals into a combined RF signal that is output from an output terminal, which in an exemplary embodiment comprises the LNA multiplexer <NUM>. The apparatus <NUM> also comprises a third means (<NUM>) for receiving the combined RF signal at an input port that is connected to the output terminal, which in an exemplary embodiment comprises the input port <NUM>. The apparatus <NUM> also comprises a fourth means (<NUM>) for distributing the combined RF signal to a plurality of output ports, which in an exemplary embodiment comprises the LNA demultiplexer <NUM>.

The exemplary embodiments described herein may be implemented on an IC, an analog IC, an RFIC, a mixed-signal IC, an ASIC, a printed circuit board (PCB), an electronic device, etc. The exemplary embodiments may also be fabricated with various IC process technologies such as complementary metal oxide semiconductor (CMOS), N-channel MOS (NMOS), P-channel MOS (PMOS), bipolar junction transistor (BJT), bipolar-CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), heterojunction bipolar transistors (HBTs), high electron mobility transistors (HEMTs), silicon-on-insulator (SOI), etc..

An apparatus implementing an exemplary embodiment described herein may be a stand-alone device or may be part of a larger device. A device may be (i) a stand-alone IC, (ii) a set of one or more ICs that may include memory ICs for storing data and/or instructions, (iii) an RFIC such as an RF receiver (RFR) or an RF transmitter/receiver (RTR), (iv) an ASIC such as a mobile station modem (MSM), (v) a module that may be embedded within other devices, (vi) a receiver, cellular phone, wireless device, handset, or mobile unit, (vii) etc..

Claim 1:
An apparatus comprising:
a low noise amplifier, LNA, multiplexer (<NUM>) configured to receive a plurality of radio frequency, RF, signals (Rx1, Rx2, Rx3) at a plurality of input terminals and to combine the plurality of RF signals into a combined RF signal that is output at an output terminal, the LNA multiplexer including a plurality of input signal paths, each input signal path coupled to a respective input terminal of the plurality of input terminals and configured to receive a respective RF signal of the plurality of RF signals; and
an LNA demultiplexer (<NUM>) configured to receive the combined RF signal at an input port that is connected to the output terminal and to distribute the combined RF signal to a plurality of output ports, each output port of the plurality of output ports configured to output the combined RF signal to a respective downconverter of a plurality of downconverters, the LNA demultiplexer comprising:
a gain transistor configured to receive the combined RF signal at a source terminal;
a plurality of cascode transistors having source terminals connected to the gain transistor; and
plurality of transformers having a plurality of first inductors connected to a plurality of drain terminals of the cascode transistors, each transformer having an output inductor connected to a selected demodulator.