Patent Description:
5th generation (<NUM>) mobile communication is a next generation wireless system and network architecture, and may provide a faster data rate, a lower-latency connection, and a higher bandwidth on a millimeter-wave (mm Wave) band, to support many high-data-rate applications, for example, a <NUM> mobile phone, a wireless infrastructure, the wireless gigabit alliance (Wireless Gigabit Alliance, WiGig), an advanced driver assistance system (Advanced Driver Assistance Systems, ADAS), a small cell, and broadband satellite communication. With the advent of the <NUM> era, application of a phased array technology supporting multiple-input multiple-output (MIMO) in a <NUM> system has been developed unprecedentedly, and a multi-channel transceiver having a beamforming function is widely studied and applied.

Currently, 3GPP (The 3rd Generation Partnership Project, the 3rd generation partnership project) divides a <NUM> communication band into two parts: sub-<NUM> and a <NUM> high frequency. Bands n257, n258, n260, and n261 are <NUM> high frequency millimeter-wave bands, n257, n258, and <NUM> are concentrated around <NUM>, and n260 is concentrated around <NUM>. Generally, when a <NUM> high frequency band is put into commercial use, different countries or operators support different bands. For example, in a country A, an operator a supports the band n257 and an operator b supports the band n258, and an operator c in a country B supports the band n260. For a <NUM> communications device (for example, a smart terminal or a tablet computer), if a phased array system needs to be used, to support bands operated by different operators, a high frequency circuit in the phased array system needs to be compatible with both of two millimeter-wave bands of <NUM> and <NUM>, to meet requirements of a communications device for low power consumption, a small area, and low costs.

Generally, on the high frequency circuit, power matching needs to be performed on ports by using matching networks (including an output matching network and an input matching network), to meet a power transmission condition. A transformer is an important passive device of the matching network. To implement compatibility with the two millimeter-wave bands of <NUM> and <NUM>, a ratio of a quantity of coil turns of a primary coil to a quantity of coil turns of a secondary coil of the transformer and resonant capacitors connected in parallel to the primary coil and the secondary coil of the transformer may be adjusted to obtain an appropriate impedance transformation ratio, to implement power matching.

A conventional manner of implementing a high frequency matching network compatible with a plurality of bands includes:
In a first manner, as shown in <FIG>, impedance matching (namely, an input matching network and an output matching network) of an input port and an output port of an element of a high frequency circuit is respectively implemented by using a transformer with a fixed parameter and a resonant capacitor with a fixed parameter. Broadband power matching may be implemented in the bands of <NUM> to <NUM> by adjusting a coupling coefficient of the transformer. A primary element of the high frequency circuit is a cascode (cascode) amplifier. In other words, a broadband matching network is implemented by using a transformer.

However, the structure has the following two defects:.

In a second manner, as shown in <FIG> and <FIG>, an example in which an element of a high frequency circuit element is a cascode amplifier is still used. On the high frequency circuit, band switching is implemented by changing a parameter of a matching network, to implement compatibility with a plurality of bands. <FIG> shows that band switching is implemented by changing capacitance values of resonant capacitors respectively connected in parallel to a primary coil and a secondary coil of a transformer, and <FIG> shows that band switching is implemented by changing inductance values of a primary coil and a secondary coil of a transformer.

The circuit structure has the following disadvantage: A switch is needed to switch an inductance value or a capacitance value of a matching network. However, on a millimeter-wave band, a CMOS (complementary metal-oxide-semiconductor, Complementary Metal-Oxide-Semiconductor Transistor) process cannot provide a switch with good performance. Especially in a process of switching the inductance value or the capacitance value of the matching network, a millimeter-wave switch introduces a relatively high loss, and as a result, a quality factor of a passive device of the matching network decreases. The decrease in the quality factor causes a decrease in an amplifier gain and deterioration in noise performance.

<CIT> discloses a dual-band amplifier for wireless communications for operation at either the <NUM> or the <NUM> band.

United States patent application <CIT> discloses an ultra-wide-band transformer comprising a primary coil and a secondary coil that mutually couples with the primary coil.

In view of accelerated commercialization of <NUM>, a design solution that can be compatible with a plurality of bands and that has low power consumption, a small area, and low costs is urgently required to meet a requirement of <NUM> millimeter-wave communication.

Embodiments of this application disclose a multi-band radio frequency front-end device that has a low insertion loss and a small chip area, to meet a requirement of <NUM> millimeter-wave communication.

The present invention is defined by the independent claim.

The following describes the embodiments of this application in detail with reference to the accompanying drawings in the embodiments of this application.

In the specification, claims, and accompanying drawings of this application, the terms such as "first" and "second" are intended to distinguish between different objects but do not indicate a particular order. In addition, the terms "including", "having", and any other variant thereof are intended to cover a non-exclusive inclusion. For example, a process, a method, a system, a product, or a device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes an unlisted step or unit, or optionally further includes another inherent step or unit of the process, the method, the product, or the device.

It should be further understood that in this application, "at least one" means one or more, "a plurality of" means two or more, and "at least two" means two, three, or more. The term "and/or" is used to describe an association relationship between associated objects and represents that three relationships may exist. For example, "A and/or B" may represent the following three cases: Only A exists, only B exists, and both A and B exist, where each of A and B may be in a singular form or a plural form. The character "/" usually indicates an "or" relationship between associated objects. "At least one of the following" or a similar expression means any combination of these items, including a single item or any combination of a plurality of items. For example, at least one of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

<FIG> is a schematic circuit structural diagram of a multi-band radio frequency front-end device <NUM> according to an embodiment of this application. In <FIG>, the radio frequency front-end device <NUM> includes:.

A person skilled in the art should learn that in a mobile communications system, a radio frequency front-end circuit, as an important composition part of a transceiver (transceiver), is mainly configured to completely extract, without distortion, a wanted radio frequency signal in a spatial signal received by an antenna and transmit the signal to a downstream down-conversion circuit, or perform power amplification on a signal converted by an up-conversion circuit and then send an amplified signal by using an antenna. Herein, either of the first radio frequency front-end circuit <NUM> and the second radio frequency front-end circuit <NUM> may mainly include power amplifier devices such as a power amplifier (PA), a low noise amplifier (LNA), and a variable gain amplifier (VGA), and may further include devices such as a filter, a phase shifter, and a frequency mixer. For details, refer to the prior art, and details are not described herein again.

In this embodiment, parameters of the first output matching network <NUM> and the first input matching network <NUM> are set based on the first band, the second output matching network <NUM> and the second input matching network <NUM> are set based on the second band, and both the first band and the second band are millimeter-wave bands. Using a matching network with a fixed parameter can avoid problems of the prior art shown in <FIG> and <FIG> such as a decrease in a quality factor, a decrease in a gain, and deterioration in noise caused because band switching is performed by using a millimeter-wave switch.

Specifically, the first output matching network <NUM> and the first input matching network <NUM> may be set based on a frequency range of the first band.

<FIG> is a schematic diagram of a layout design of the radio frequency front-end device <NUM> shown in <FIG>. It should be noted that because both the first radio frequency front-end circuit <NUM> and the second radio frequency front-end circuit <NUM> use a conventional layout design, and complexity degrees of layout designs are different for different radio frequency front-end circuits, <FIG> shows respective layouts of the first output matching network <NUM>, the second output matching network <NUM>, the first input matching network <NUM>, and the second input matching network <NUM>, and the first radio frequency front-end circuit <NUM> and the second radio frequency front-end circuit <NUM> are represented by using symbols of circuit elements.

In a possible implementation, referring to <FIG>, the first output matching network <NUM> and the second output matching network <NUM> each are a transformer, the first output matching network <NUM> includes a first primary coil 33a and a first secondary coil 33b, and similarly, the second output matching network <NUM> includes a second primary coil 34a and a second secondary coil 34b.

Further, as shown in <FIG>, the first input matching network <NUM> and the second input matching network <NUM> each are an inductor.

It should be noted that in this embodiment, the first input matching network <NUM> and the second input matching network <NUM> may be inductors. Similarly, the first input matching network <NUM> and the second input matching network <NUM> may be alternatively transformers. Therefore, in this embodiment, an output matching network and an input matching network each may be any element that can implement impedance matching, and includes but is not limited to: a transformer, an inductor, a balun, or a transformer with a tuning capacitor. Layout designs of the output matching networks and the input matching networks may be mutually referenced.

In this embodiment, routing of the first output matching network <NUM> and routing of the second output matching network <NUM> on a layout are annular and nested, and routing of the first input matching network <NUM> and routing of the second input matching network <NUM> on a layout are also annular and nested. It should be understood that the ring shape described in this specification may be a regular ring, or a shape such as a hexagon or an octagon. Because two matching networks correspond to different operating bands, and inductances needed for implementing impedance matching are different, lengths (or referred to as sizes) of routing of the matching networks on a layout are different. When the routing is bent to form a loop, longer routing may surround shorter routing, so that a part without routing on a layout area enclosed by the longer routing can be provided for the shorter routing, thereby improving utilization of the layout area, and helping reduce a chip area. For sizes of the routing of the two input/output matching networks, details are provided below.

Specifically, when the first output matching network <NUM> and the second output matching network <NUM> perform impedance matching by using transformers, referring to <FIG>, on the layout, the first primary coil 33a is embedded in the second primary coil 34a, and the first secondary coil 33b is also embedded in the second secondary coil 34b.

For example, as shown in <FIG> and <FIG>, in this embodiment, the first band is marked as a <NUM> band, and the second band is marked as a <NUM> band. A person skilled in the art should learn that a <NUM> millimeter-wave band includes n257 (<NUM> to <NUM>), n258 (<NUM> to <NUM>), n260 (<NUM> to <NUM>), and n261 (<NUM> to <NUM>). Frequency ranges of n257 and n261 are concentrated around a <NUM> frequency, and n257 and n261 each are generally referred to as a <NUM> band. A frequency of n260 is concentrated around <NUM>, and n260 is generally referred to as a <NUM> band. A frequency of n258 is concentrated around <NUM>, and n258 generally is referred to as a <NUM> band. Because the <NUM> band is close to the <NUM> band, the second band with a center frequency of <NUM> is used, and a frequency range of the second band is (<NUM> to <NUM>), that is, all of n257, n258, and n261 can be covered. In addition, the first band with a center frequency of <NUM> is used, to cover n260. It should be noted that the two center frequencies <NUM> and <NUM> mentioned herein are merely an example. During specific implementation, the center frequencies of the first band and the second band may be other values, for example, <NUM> and <NUM>, provided that the first band can cover n260, and the second band can cover n257, n258, and n261. This is not specifically limited in this application. In addition, although only the foregoing several NR bands are currently formulated in the <NUM> millimeter-wave band, it should be understood that the technical solutions provided in this application are also applicable to another band in the millimeter-wave band and another high frequency band.

In this embodiment, it should be noted that when the radio frequency front-end device <NUM> works, if a signal on the band n260 is currently processed, from the perspective of a <NUM> input port, an input/output matching network corresponding to the <NUM> band is in a high impedance state. Therefore, no interference is caused to the <NUM> band, and vice versa.

Further, the first radio frequency front-end circuit <NUM> and the second radio frequency front-end circuit <NUM> each have an independently controlled active bias circuit. When the first radio frequency front-end circuit <NUM> processes a signal on n260, the active bias circuit corresponding to the second radio frequency front-end circuit <NUM> may be disabled. Similarly, when the second radio frequency front-end circuit <NUM> processes a signal on n257, n258, or n261, the active bias circuit corresponding to the first radio frequency front-end circuit <NUM> may be disabled.

In this embodiment, because the first radio frequency front-end circuit <NUM> works on the first band with the center frequency of <NUM>, when impedance matching is implemented separately on the input end and the output end of the first radio frequency front-end circuit <NUM>, a needed inductance value is less than an inductance needed for impedance matching of the second radio frequency front-end circuit <NUM>. Therefore, a size of the first primary coil 33a in the first output matching network <NUM> is smaller than a size of the second primary coil 34a in the second output matching network <NUM>. Therefore, in a layout design, the first primary coil 33a is embedded in the second primary coil 34a, and the second primary coil 34a surrounds the first primary coil 33a. Similarly, the first secondary coil 33b is also embedded in the second secondary coil 34b. For the first input matching network <NUM> and the second input matching network <NUM>, during implementation of impedance matching, a size of an inductor used in the first input matching network <NUM> is less than a size of an inductor used in the second input matching network <NUM>. Therefore, the inductor of the first input matching network <NUM> is embedded in the inductor of the second input matching network <NUM>.

Further, for high frequency millimeter-wave bands such as <NUM> and <NUM>, during implementation of impedance matching, an inductance value needed by each of the output matching network and the input matching network is relatively small, and a one-turn coil may be used as a primary coil or a secondary coil. Therefore, the inductor, the primary coil, and the secondary coil each can be implemented through single-layer routing. Referring to <FIG>, the first primary coil 33a and the second primary coil 34a are disposed on a same layer (layer <NUM>). To avoid crossing of routing of a secondary coil and routing of a primary coil, the first secondary coil 33b and the second secondary coil 34b need to be disposed on another layer (layer <NUM>). A person skilled in the art should learn that if a quantity of coil turns of the primary coil or the secondary coil is n, where n is an integer greater than <NUM>, during layout designing, the primary coils and the secondary coils need to be disposed at at least two layers. At any layer, a smaller coil needs to be embedded in a larger coil.

In this embodiment, the first radio frequency front-end circuit <NUM> shown in <FIG> is an amplification circuit including a transistor. Further, as shown in <FIG>, the first radio frequency front-end circuit <NUM> may be alternatively a phase shifter including a plurality of transistors. In addition, the first radio frequency circuit <NUM> may be alternatively a cascode circuit shown in <FIG>. In other words, in this embodiment, for a specific circuit structure of the first radio frequency front-end circuit <NUM>, refer to circuit structures of radio frequency front-end devices such as a power amplifier (PA), a low noise amplifier (LNA), a filter, a phase shifter, a duplexer, and a variable gain amplifier (VGA) provided in the prior art. This is not specifically limited herein. Because the second radio frequency front-end circuit <NUM> and the first radio frequency front-end circuit <NUM> are circuits of a same type, for example, are LNAs or PAs, a circuit structure of the second radio frequency front-end circuit <NUM> is similar to the circuit structure of the first radio frequency front-end circuit <NUM>, and details are not described again.

<FIG> and <FIG> are schematic diagrams of simulation results of the multi-band radio frequency front-end device <NUM> provided in this application. As shown in <FIG>, when the multi-band radio frequency front-end device <NUM> works on the first band, that is, when the first radio frequency front-end circuit <NUM> in the multi-band radio frequency front-end device <NUM> works, a transmission coefficient S21 of the multi-band radio frequency front-end device <NUM> is the largest at a <NUM> frequency, and at the same time, reflection coefficients S11 and S22 are the smallest. A person skilled in the art should learn that for a radio frequency front-end device, a larger transmission coefficient S21 indicates smaller reflection coefficients S11 and S22, and this means that higher transmission efficiency of the radio frequency front-end device indicates a lower insertion loss. Further, as shown in <FIG>, when the multi-band radio frequency front-end device <NUM> works on the second band, that is, when the second radio frequency front-end circuit <NUM> in the multi-band radio frequency front-end device <NUM> works, a transmission coefficient S21 of the multi-band radio frequency front-end device <NUM> is the largest at a <NUM> frequency, and at the same time, reflection coefficients S11 and S22 are the smallest, and an insertion loss is also relatively low. It can be learned that according to the technical solutions provided in this application, compared with the prior art shown in <FIG>, and <FIG>, the radio frequency front-end device can implement a low insertion loss when supporting a plurality of bands. In addition, because the multi-band radio frequency front-end device is disposed in a nested manner during layout designing, and this is equivalent to that a function of the multi-band radio frequency device is implemented with a chip area of a conventional single-band radio frequency device, the chip area can be reduced, to meet requirements of the communications device for low power consumption, a small area, and low costs.

Further, as shown in <FIG>, during packaging of the multi-band radio frequency front-end device <NUM>, the multi-band radio frequency front-end device <NUM> may be packaged in a same packaging structure (a shadow part in the figure). Compared with a single-band radio frequency front-end device, the multi-band radio frequency front-end device <NUM> can support more bands without increasing a chip area. Therefore, application of the <NUM> millimeter-wave band can be better supported.

Further, during packaging, one differential output end of each of the first output matching network <NUM> and the second output matching network <NUM> may be coupled to a first output pin (pin A), and the other differential output end of each of the first output matching network <NUM> and the second output matching network <NUM> is coupled to a second output pin (pin B), to obtain a differential output multi-band radio frequency front-end device <NUM>.

It should be noted that if either of the first output pin (pin A) and the second output pin (pin B) is grounded, the multi-band radio frequency front-end device <NUM> may also be used as a single-ended output device.

Generally, another upstream radio frequency front-end device is packaged in the same packaging structure together with the multi-band radio frequency front-end device <NUM>. Therefore, the first input matching network <NUM> and the second input matching network <NUM> receive, through on-chip routing, a radio frequency signal input by the upstream radio frequency front-end device. Therefore, the first input matching network <NUM> and the second input matching network <NUM> are not connected to pins. However, if a packaging structure includes only the multi-band radio frequency front-end device <NUM>, for pin designs corresponding to the first input matching network <NUM> and the second input matching network <NUM>, refer to pin designs of the first output matching network <NUM> and the second output matching network <NUM>.

An embodiment of this application further provides a multi-band transceiver applied to <NUM> millimeter-wave communication. The transceiver includes a plurality of channels, and each channel includes the multi-band radio frequency front-end device <NUM> described in the foregoing embodiment.

Specifically, as shown in <FIG>, the transceiver may specifically include:.

Correspondingly, the first matching network supports the band n260, and the second matching network supports the band n257, the band n258, and the band n261.

It should be noted that the transceiver shown in <FIG> is also applicable to a zero-intermediate frequency architecture. In addition, because the PPS 63a and the PPS 63a' need to be used only in a phased array system, the PPS 63a and the PPS 63a' may be omitted for a receiver of another type, or an RFVGA and a frequency mixer are connected by using a bypass (bypass) circuit.

In this embodiment, any pair of radio frequency front-end circuits in the first receive channel and the second receive channel, for example, (the LNA 61a and the LNA 61a'), (the RFVGA 62a and the RFVGA 62a'), (the PPS 63a and the PPS 63a'), or (the frequency mixer 64a and the frequency mixer 64a'), are the two radio frequency front-end circuits in the multi-band radio frequency front-end device described in the foregoing embodiment. For example, the LNA 61a, the LNA 61a', and their respective matching networks as a whole are considered as the multi-band radio frequency front-end device described in the foregoing embodiment. Correspondingly, routing of the first matching network and routing of the second matching network (namely, their respective input/output matching networks) on a layout are nested. For a specific layout design, refer to the descriptions of the foregoing embodiment and <FIG>.

When the transceiver shown in <FIG> uses the multi-band radio frequency front-end device <NUM> described in the foregoing embodiment, the transceiver may be compatible with <NUM> NR bands such as <NUM>, <NUM>, and <NUM>, and has advantages of the multi-band radio frequency front-end device <NUM> such as a low insertion loss and a small chip area, to better meet a requirement of a communications device such as a <NUM> smartphone.

Further, in this embodiment, the LNA 61a in the first receive channel needs to be coupled to an antenna <NUM> by using a first input matching network, and the LNA 61a' in the second receive channel needs to be coupled to the antenna <NUM> by using a second input matching network. Routing of the first input matching network and routing of the second input matching network on a layout are nested. During packaging of their respective input networks, reference may be made to a design in <FIG>, that is, one differential input end of the first input matching network of the LNA 61a and one differential input end of the first input matching network of the LNA 61a' are coupled to one input pin (pin A), the other differential input end of the first input matching network of the LNA 61a and the other differential input end of the first input matching network of the LNA 61a' are coupled to the other input pin (pin B), and then the LNA 61a and the LNA 61a' are coupled to the antenna <NUM> by using the two pins, to receive a radio frequency signal input by using the antenna <NUM>. It should be learned that using this layout design is equivalent to that a single-ended-to-differential function is implemented by using the respective input matching networks of the LNAs (61a, 61a').

Similarly, the input pin, namely, the pin A or the pin B, may be grounded, to enable the LNAs (61a, 61a') to be single-ended input devices.

Further, as shown in <FIG>, when impedance matching is separately performed on the LNAs (61a, 61a') and the RFVGAs (62a, 62a'), because the LNAs (61a, 61a') and the RFVGAs (62a, 62a') may be in a same packaging structure (shown in a shadow part in the figure), the output matching networks of the LNAs (61a, 61a') are respectively connected to the input matching networks of the RFVGAs (62a, 62a') through on-chip routing.

Similarly, for connection between radio frequency front-end devices, for example, between the RFVGAs (62a, 62a') and the PPSs (63a, 63a'), and between the PPSs (63a, 63a'), and the frequency mixers (64a, 64a'), refer to the layout design that is of the LNAs (61a, 61a') and the RFVGAs (62a, 62a') during impedance matching.

Further, as shown in <FIG>, the transceiver further includes:.

The first transmit channel includes a first matching network, and the second transmit channel includes a second matching network.

The first matching network and the second matching network correspond to a radio frequency front-end circuit of a same type. For example, an output matching network of the PA 61b is the first matching network, and correspondingly, an output matching network of the PA 61b' is the second matching network.

Further, routing of the first matching network and routing of the second matching network on a layout are nested. For a specific layout design, refer to the descriptions of the foregoing embodiment and <FIG>.

It should be learned that in the receive channel, an input signal of the antenna <NUM> is received by using the LNAs (61a, 61a'), and in the transmit channel, a radio frequency signal is sent to the antenna <NUM> by using the PAs (61b, 61b'), and radiated out by using the antenna <NUM>. For a connection relationship between each of the respective output matching networks of the PAs (61b, 61b') and the antenna <NUM>, refer to the connection relationship between each of the input matching networks of the LNAs (61a, 61a') and the antenna <NUM>. Correspondingly, during packaging, for a manner of packaging of the respective output matching networks of the PAs (61b, 61b') and pins, refer to the layout design in <FIG>. Details are not described again.

Claim 1:
A multi-band radio frequency front-end device adapted for millimeter wave communication, comprising:
a first radio frequency front-end circuit (<NUM>), wherein the first radio frequency front-end circuit (<NUM>) works on a first band;
a second radio frequency front-end circuit (<NUM>), wherein the second radio frequency front-end circuit (<NUM>) works on a second band, and a frequency of the first band is higher than a frequency of the second band;
a first matching network, coupled to the first radio frequency front-end circuit (<NUM>); and
a second matching network, coupled to the second radio frequency front-end circuit (<NUM>), wherein
the first matching network comprises a first output matching network (<NUM>), coupled to an output end of the first radio frequency front-end circuit (<NUM>);
the second matching network comprises a second output matching network (<NUM>), coupled to an output end of the second radio frequency front-end circuit (<NUM>); and
a parameter of the first output matching network (<NUM>) is set based on the first band, and a parameter of the second output matching network (<NUM>) is set based on the second band,
characterized in that
the first output matching network (<NUM>) and the second output matching network (<NUM>) each comprise a transformer and
the first output matching network (<NUM>) comprises a first primary coil (33a) and a first secondary coil (33b), the second output matching network (<NUM>) comprises a second primary coil (34a) and a second secondary coil (34b), the first primary coil (33a) is embedded in the second primary coil (34a), and the first secondary coil (33b) is embedded in the second secondary coil (34b).