WO2016112711A1

WO2016112711A1 - Radio frequency circuit in multi-mode terminal, and multi-mode terminal

Info

Publication number: WO2016112711A1
Application number: PCT/CN2015/090448
Authority: WO
Inventors: 秦宇; 沈俊
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-01-13
Filing date: 2015-09-23
Publication date: 2016-07-21
Also published as: CN105846847A

Abstract

A radio frequency circuit in a multi-mode terminal, and multi-mode terminal, the radio frequency circuit in the multi-mode terminal comprising a radio frequency transceiving circuit module, and a plurality of radio frequency front-end circuit modules each connected to the radio frequency transceiving circuit module; each radio frequency front-end circuit module is connected to a first-stage single/multiple-path convertor via a corresponding impedance conversion circuit module; the first-stage single/multiple-path convertor is connected to an antenna via an antenna matching circuit module, wherein impedance characteristic differences between different radio frequency paths in the same frequency range before the antenna matching circuit module are restricted to a preset range through the corresponding impedance conversion circuit modules. The technical solution of the present invention respectively processes different radio frequency paths in the same frequency range, respectively connects the different radio frequency paths to corresponding impedance conversion circuit modules, and restricts the impedance characteristic differences between the different radio frequency paths before the antenna matching circuit module to the preset range, thus enabling an excellent match between an antenna and the different radio frequency paths, and addressing the quadrant problem of antenna matching in a multi-mode terminal.

Description

Radio frequency circuit and multimode terminal of multimode terminal

Technical field

This paper relates to the field of communication terminal circuit design, especially to a multi-mode terminal RF circuit and multi-mode terminal.

Background technique

At present, multiple communication systems coexist in mobile networks, such as GSM, CDMA, WCDMA, and LTE. In order to achieve terminal compatibility, various multi-mode mobile phones have emerged, but because different communication systems exhibit different impedance characteristics at the common end, there are There are obvious differences, even in different quadrants, such as: 850MHz in GSM and 850MHz in WCDMA. Although they are RF signals in the 850MHz band, the impedance characteristics of the two RF paths are due to different RF paths. There is a big difference. On the Smith chart, the impedance curves of the two RF ports in the 850MHz band are different, and the distance is far, even in different quadrants. In this case, the antenna debugging will not be suitable. If the 850MHz requirement under the GSM standard is met, the 850MHz requirement of the WCDMA system cannot be met, that is, the antenna performance of a communication system is inevitably poor.

Summary of the invention

The technical problem to be solved by the present invention is to provide a radio frequency circuit and a multi-mode terminal of a multi-mode terminal, and to solve the problem of poor antenna performance caused by the quadrant problem of antenna matching in the case of the same-frequency multi-radio channel.

In order to solve the above technical problems, the following technical solutions are adopted:

A radio frequency circuit for a multimode terminal, comprising:

RF transceiver circuit module;

a plurality of radio frequency front end circuit modules respectively connected to the radio frequency transceiver circuit module, each of the radio frequency front end circuit modules respectively corresponding to a radio frequency path, each of the radio frequency paths corresponding to only one frequency band of one communication system or corresponding to two The same frequency band of the above communication system;

Each of the RF front end circuit modules is respectively connected to a corresponding impedance conversion circuit module First stage single multiplexer;

The first stage single multiplexer is connected to the antenna through an antenna matching circuit module.

The difference between the impedance characteristics of the different RF paths in the same frequency band before the antenna matching circuit module is limited to a preset range after passing through the corresponding impedance conversion circuit module.

Optionally, the circuit further includes:

a baseband and control circuit module coupled to the radio frequency transceiver circuit module, wherein the baseband and control circuit module is further coupled to the first stage single multiplexer.

Optionally, the RF front end circuit module has a one-to-one correspondence with the impedance conversion circuit module.

Optionally, the circuit further includes:

a second-stage single multiplexer connected in one-to-one correspondence with the impedance conversion circuit module;

Each of the RF front end circuit modules is respectively connected to the corresponding second stage single multiplexer, and is connected to the corresponding impedance conversion circuit module by the second stage single multiplexer;

Each of the second stage single multiplexers is coupled to the baseband and control circuit module.

Optionally, the second-stage single multiplexer corresponding to the radio frequency path corresponding to the same frequency band is different.

Optionally, the circuit further includes a second stage single multiplexer, wherein

A plurality of RF front-end circuit modules having the same communication system are connected to the same second-stage single-multiplex converter, and a second-stage single-multiplex converter corresponds to one impedance conversion circuit module, and multiple RF front-end circuits having the same communication system The module is connected to the same second-stage single multiplexer, and is connected to the corresponding impedance conversion circuit module through the second-stage single multiplexer;

Optionally, the circuit further includes:

Each of the RF front end circuit modules is respectively connected to the corresponding second stage single multiplexer, and is connected to the corresponding impedance conversion circuit module by the second stage single multiplexer.

Optionally, wherein the second-stage single multiplexer corresponding to the radio frequency path corresponding to the same frequency band is different.

Multiple RF front-end circuit modules with the same communication system are connected to the same second-stage single multiplex a converter, a second-stage single multiplexer corresponding to an impedance conversion circuit module, and a plurality of RF front-end circuit modules having the same communication system are connected to the same second-stage single multiplexer, and pass the second-stage single The multiplexer is connected to the corresponding impedance conversion circuit module.

Optionally, the communication system includes at least two of a GSM system, a CDMA system, a WCDMA system, or an LTE system.

Optionally, the frequency band comprises at least two of 700 MHz, 850 MHz, 1900 MHz or 2100 MHz.

Optionally, after the corresponding impedance conversion circuit module passes, the difference between the impedance characteristics of the different RF paths in the same frequency band before the antenna matching circuit module is limited to a preset range, which means:

The impedance characteristics of the different RF paths in the same frequency band before the antenna matching circuit module are adjusted to the preset range of the same quadrant of the Smith chart.

A multimode terminal comprising any of the above radio frequency circuits.

Optionally, the multimode terminal comprises: a multimode mobile phone and a multimode tablet computer.

The beneficial effects of the embodiments of the present invention are: a radio frequency circuit and a multi-mode terminal of a multi-mode terminal, respectively, by separately processing different radio frequency paths in the same frequency band, respectively accessing corresponding impedance conversion circuit modules, and different RF paths in the antenna The difference between the impedance characteristics of the matching circuit module is limited to a preset range, so that the antenna can be well matched to different RF paths, and the quadrant problem of multi-mode terminal antenna matching is solved.

BRIEF abstract

1 is a schematic diagram of a circuit module according to Embodiment 1 of the present invention;

Fig. 2 is a block diagram showing the circuit module of the second embodiment of the present invention.

The meaning of each mark in the figure is as follows:

101, baseband and control circuit module

201, RF transceiver circuit module

301, RF front-end circuit module

302, RF front end circuit module

303, RF front-end circuit module

304, RF front-end circuit module

305, RF front-end circuit module

401, second-stage single multiplexer

402, second stage single multiplexer

501, impedance conversion circuit module

502, impedance conversion circuit module

503, impedance conversion circuit module

504, impedance conversion circuit module

505, impedance conversion circuit module

601, first stage single multiplexer

701, antenna matching circuit module

801, antenna

Preferred embodiment of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While the invention has been shown and described with reference to the embodiments Rather, these embodiments are provided so that this invention may be more fully understood and the scope of the invention can be fully conveyed by those skilled in the art.

Embodiment 1

With the popularity and maturity of mobile networks, the communication system used in mobile networks has evolved from the early single-band analog system to the current multi-band digital multi-mode system, thus supporting multiple communication modes. Multimode terminals came into being. However, since the impedance characteristics of the RF path of the same frequency band in different systems before the antenna matching circuit module are greatly different, even falling in different quadrants, the quadrant problem of multi-mode terminal antenna matching is generated. In order to solve the problem, an embodiment of the present invention provides a radio frequency circuit of a multimode terminal, including: a baseband and a control circuit module; a radio frequency transceiver circuit module connected to the baseband and the control circuit module; and a radio frequency transceiver circuit module a plurality of RF front-end circuit modules; an impedance conversion circuit module connected to the RF front-end circuit module in one-to-one correspondence with the baseband and the control circuit module; and a first-stage single-multiplex converter connected to the plurality of impedance conversion circuit modules; An antenna matching circuit module connected to the first stage single multiplexer; and an antenna connected to the antenna matching circuit module.

The baseband and control circuit module is configured to generate a baseband signal and control a gating state of the first-stage single multiplexer. The RF transceiver circuit module is configured to modulate the baseband signal transmitted by the baseband and the control circuit module into a radio frequency signal, and distribute the radio frequency signal to the corresponding radio frequency path according to the communication system and the difference of the radio frequency working frequency band. The RF front-end circuit module includes a power amplifier for amplifying and transmitting the RF signal transmitted by the RF transceiver circuit module to the impedance conversion circuit. The impedance conversion circuit is configured to convert the impedance characteristics of the corresponding RF front-end circuit module, so that the difference in impedance characteristics of the different RF paths before the antenna matching circuit module is limited to a preset range, that is, the RF channels of the same frequency band The impedance curves of the impedance characteristics in the Smith chart fall within the same quadrant and the characteristic curves are similar or identical. The first stage single multiplexer combines the RF signals from different RF paths and transmits them to the antenna matching circuit module. The antenna matching circuit module matches the RF circuit with the port of the antenna, and transmits the transmitted signal to the antenna for transmission.

The antenna receives the radio frequency signal in the air, and transmits the radio frequency signal to the first-stage single multiplexer through the antenna matching circuit module. The first stage single multiplexer is used to distribute the RF signal to the corresponding impedance conversion circuit module according to the difference between the communication system and the RF operating frequency band. The corresponding impedance conversion circuit module realizes impedance conversion of the RF path below the antenna to the corresponding RF front-end circuit module, and transmits the received RF signal to the RF front-end circuit module. The RF front-end circuit module performs low-noise amplification on the corresponding RF information, and sends the processed RF signal to the RF transceiver circuit module. The RF transceiver circuit module converts the received RF signal into a baseband signal identifiable by the baseband and control circuit modules. The baseband and control circuit module performs a series of processing on the baseband signal to obtain target information.

It should be noted that the modules in the radio frequency circuit in the embodiment of the present invention, such as the baseband and control circuit module, the radio frequency transceiver circuit module, the radio frequency front end circuit, the antenna matching circuit module, etc., may all adopt similar modules in the related art.

The radio frequency circuit of the present invention separates the different RF paths in the same frequency band and respectively accesses the corresponding impedance conversion circuit modules, and limits the difference between the impedance characteristics of the different RF paths before the antenna matching circuit module to a preset range. In order to achieve good matching of antennas to different RF paths, the quadrant problem of antenna matching in the case of multi-mode terminals with multiple frequency RF channels is solved.

Optionally, the communication systems commonly used in mobile networks include: GSM standard, CDMA standard, WCDMA standard, and LTE standard. The commonly used frequency bands include: 700 MHz, 850 MHz, 1900 MHz, or 2100 MHz, etc. It is worth noting that the above enumerated communications The frequency bands supported by the system and the corresponding communication system are not limited to the above, depending on the actual situation.

In the first embodiment, the radio frequency circuit of the present invention will be described with the circuit structure shown in FIG. 1.

The baseband and control circuit module 101 is connected to the radio frequency transceiver circuit module 201 and the first-stage single multiplexer 601, which can realize the baseband signal transmission between the baseband and the radio frequency transceiver circuit module 201, and can realize the single-stage single-multiple transmission Gating control of the road converter 601.

One end of the RF transceiver circuit module 201 is connected to the baseband and the control circuit module 101, and the other end is connected to a plurality of RF front-end circuit modules, such as the RF front-end circuit module 301 respectively applicable to the frequency band of the communication system, which is suitable for the communication system. The RF front-end circuit module 302 of the frequency band 2 is applicable to the RF front-end circuit module 303 of the frequency band 1 under the communication system 2 and the communication system 3, and is applicable to the RF front-end circuit module 304 of the frequency band 2 under the communication system 2 and the communication system 3. The radio frequency front end circuit module 305 of the frequency band three under the communication system 2 or the communication system 3 is connected. This does not mean that there are only five RF front-end circuit modules, which can be other numbers. Because some communication systems can share one RF channel, such as communication system 2 and communication system 3, some cannot share a single RF channel, such as communication system 1 and communication system 2. Each RF front-end circuit module corresponds to a radio frequency path, and each radio frequency path corresponds to only one frequency band of one communication system or the same frequency band corresponding to two or more communication systems, and the specific corresponding manner is based on whether the radio frequency path can be shared. definite.

The RF front-end circuit module 301, the RF front-end circuit module 302, the RF front-end circuit module 303, the RF front-end circuit module 304, and the RF front-end circuit module 305 are respectively corresponding to the impedance conversion circuit 501, impedance conversion circuit 502, impedance conversion circuit 503, impedance conversion circuit 504 and impedance conversion circuit 505 are connected.

One end of the first-stage single multiplexer 601 is connected to an impedance conversion circuit 501, an impedance conversion circuit 502, an impedance conversion circuit 503, an impedance conversion circuit 504, and an impedance conversion circuit 505. The other port of the first stage single multiplexer 601 is connected to the baseband and control circuit module 101 and thus controlled by the control circuit module 101.

One end of the antenna matching circuit module 701 is connected to the first-stage single multiplexer 601, and the other end is connected to the antenna 801.

When transmitting the signal, the baseband and control circuit module 101 transmits the baseband signal to be transmitted to the radio frequency transceiver circuit module 201; the radio frequency transceiver circuit module 201 converts the baseband signal into a radio frequency signal, and according to the communication system and the working frequency band of the modulated radio frequency signal Transmitted to the corresponding RF front-end circuit module, for example, the modulated RF signal is the communication system 1 and the frequency band 1, the RF signal is transmitted to the RF front-end circuit module 501; the RF front-end circuit module performs power amplification on the received RF signal, and The signal is transmitted to the corresponding impedance conversion circuit module; the impedance conversion circuit module transmits the radio frequency signal to the first-stage single multiplexer 601, and is sent to the antenna 801 via the antenna matching circuit module 701.

When receiving the radio frequency signal, the antenna 801 transmits the received radio frequency signal to the first stage single multiplexer 601 through the antenna matching circuit module 701. The first-stage single multiplexer 601 is subjected to a radio frequency path corresponding to the control strobe of the baseband and the control circuit module 101, and sends the radio frequency signal to the corresponding impedance conversion circuit module and the RF front-end circuit module, for example, it will be suitable for communication. The RF signal of the one-band one of the system is sent to the impedance conversion circuit module 501 and the RF front-end circuit module 301. The radio frequency signal is subjected to low noise amplification processing by the RF front end circuit module, and then transmitted to the radio frequency transceiver circuit module 201, and demodulated by the radio frequency transceiver circuit module 201, and the radio frequency signal is converted into a baseband signal and transmitted to the baseband and the control circuit. Module 101, for receiving a target radio frequency signal.

Embodiment 2

In order to further improve the integration of RF circuits. In the second embodiment, the radio frequency circuit of the present invention will be described with the circuit structure shown in FIG. 2.

The baseband and control circuit module 101 is connected to the radio frequency transceiver circuit module 201 and the first stage single multiplexer 601, and can realize baseband signal transmission between the baseband and the radio frequency transceiver circuit module 201. Gating control of the first stage single multiplexer 601 can also be implemented.

One end of the RF transceiver circuit module 201 is connected to the baseband and the control circuit module 102, and the other end is connected to a plurality of RF front-end circuit modules, such as the RF front-end circuit module 301 respectively applicable to the frequency band of the communication system, which is suitable for the communication system. The RF front-end circuit module 302 of the frequency band 2 is applicable to the RF front-end circuit module 303 of the frequency band 1 under the communication system 2 and the communication system 3, and is applicable to the RF front-end circuit module 304 of the frequency band 2 under the communication system 2 and the communication system 3. The radio frequency front end circuit module 305 of the frequency band three under the communication system 2 or the communication system 3 is connected. Because some communication systems can share one RF channel, such as communication system 2 and communication system 3, some cannot share a single RF channel, such as communication system 1 and communication system 2. Each RF front-end circuit module corresponds to a radio frequency path, and each radio frequency path corresponds to only one frequency band of one communication system or the same frequency band corresponding to two or more communication systems, and the specific corresponding manner is based on whether the radio frequency path can be shared. definite.

According to the principle that the same frequency band in different communication systems can be shared, the same frequency band that cannot be shared is separately processed, that is, the RF front end circuit module 301 and the RF front end circuit module 302 are connected to the second stage single multiplexer 401; The RF front end circuit module 303, the RF front end circuit module 304, and the RF front end circuit module 305 are connected to another second stage single multiplexer 402.

The second stage single multiplexer 401 is connected to the corresponding impedance conversion circuit module 501, and the second stage single multiplexer 402 is connected to the corresponding impedance conversion circuit 502.

The first stage single multiplexer 601 is connected to the impedance conversion circuit 501 and the impedance conversion circuit 502, respectively. The other port of the first stage single multiplexer 601 is connected to the baseband and control circuit module 101 and is thus controlled.

When transmitting the signal, the baseband and control circuit module 101 transmits the baseband signal to be transmitted to the radio frequency transceiver circuit module 201; the radio frequency transceiver circuit module 201 converts the baseband signal into a radio frequency signal, and according to the communication system and the working frequency band of the modulated radio frequency signal Transmitted to the corresponding RF front-end circuit module, for example, the modulated RF signal is the communication system 1 and the frequency band 1, the RF signal is transmitted to the RF front-end circuit module 501; the RF front-end circuit module performs power amplification on the received RF signal, and Transmission to a corresponding second-stage single multiplexer, impedance conversion circuit module; impedance conversion circuit module The radio frequency signal is transmitted to the first stage single multiplexer 601 and sent to the antenna 801 via the antenna matching circuit module 701.

When receiving the radio frequency signal, the antenna 801 transmits the received radio frequency signal to the first stage single multiplexer 601 through the antenna matching circuit module 701. The first-stage single multiplexer 601 is subjected to an RF path corresponding to the control gate of the baseband and the control circuit module 101, and sends the RF signal to the corresponding impedance conversion circuit module, the second-stage single multiplexer, and the RF front-end. The circuit module, for example, sends a radio frequency signal suitable for the communication system one frequency band one to the impedance conversion circuit module 501, the second-stage single multiplexer 401, and the radio frequency front-end circuit module 301. The radio frequency signal is subjected to low noise amplification processing by the RF front end circuit module, and then transmitted to the radio frequency transceiver circuit module 201, and demodulated by the radio frequency transceiver circuit module 201, and the radio frequency signal is converted into a baseband signal and transmitted to the baseband and the control circuit. Module 101, for receiving a target radio frequency signal.

According to another embodiment of the present invention, there is also provided a multimode terminal comprising the radio frequency circuit as described above, the multimode terminal comprising: a multimode mobile phone and a multimode tablet computer supporting a plurality of communication systems.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. Within the scope of protection of the invention.

Industrial applicability

The technical solution of the present invention separates the different RF paths in the same frequency band and respectively access the corresponding impedance conversion circuit modules, and limits the difference between the impedance characteristics of the different RF paths before the antenna matching circuit module to a preset range. In order to achieve good matching of different RF paths, the antenna can solve the quadrant problem of multi-mode terminal antenna matching. Therefore, the present invention has strong industrial applicability.

Claims

A radio frequency circuit for a multimode terminal, comprising:

RF transceiver circuit module;

a plurality of radio frequency front end circuit modules respectively connected to the radio frequency transceiver circuit module, each of the radio frequency front end circuit modules respectively corresponding to a radio frequency path, each of the radio frequency paths corresponding to only one frequency band of one communication system or corresponding to two The same frequency band of the above communication system;

Each of the RF front end circuit modules is respectively connected to the first stage single multiplexer through a corresponding impedance conversion circuit module;

The first stage single multiplexer is connected to the antenna through an antenna matching circuit module.

The difference between the impedance characteristics of the different RF paths in the same frequency band before the antenna matching circuit module is limited to a preset range after passing through the corresponding impedance conversion circuit module.
The radio frequency circuit of claim 1 further comprising:

a baseband and control circuit module coupled to the radio frequency transceiver circuit module, wherein the baseband and control circuit module is further coupled to the first stage single multiplexer.
The radio frequency circuit according to claim 2, wherein the radio frequency front end circuit module and the impedance conversion circuit module are in one-to-one correspondence.
The radio frequency circuit according to any one of claims 2-3, further comprising:

a second-stage single multiplexer connected in one-to-one correspondence with the impedance conversion circuit module;

Each of the RF front end circuit modules is respectively connected to the corresponding second stage single multiplexer, and is connected to the corresponding impedance conversion circuit module by the second stage single multiplexer;

Each of the second stage single multiplexers is coupled to the baseband and control circuit module.
The radio frequency circuit according to claim 4, wherein the second-stage single multiplexers corresponding to the radio frequency paths corresponding to the same frequency band are different.
The radio frequency circuit according to any one of claims 2 to 3, further comprising a second-stage single multiplexer, wherein

A plurality of RF front-end circuit modules having the same communication system are connected to the same second-stage single-multiplex converter, and a second-stage single-multiplex converter corresponds to one impedance conversion circuit module, and multiple RF front-end circuits having the same communication system The module is connected to the same second-stage single multiplexer and passes the The second stage single multiplexer is connected to the corresponding impedance conversion circuit module;

Each of the second stage single multiplexers is coupled to the baseband and control circuit module.
The radio frequency circuit of claim 1 further comprising:

a second-stage single multiplexer connected in one-to-one correspondence with the impedance conversion circuit module;

Each of the RF front end circuit modules is respectively connected to the corresponding second stage single multiplexer, and is connected to the corresponding impedance conversion circuit module by the second stage single multiplexer.
The radio frequency circuit according to claim 7,

The second-stage single multiplexer corresponding to the radio frequency path corresponding to the same frequency band is different.
The radio frequency circuit according to claim 1, further comprising a second-stage single multiplexer, wherein

A plurality of RF front-end circuit modules having the same communication system are connected to the same second-stage single-multiplex converter, and a second-stage single-multiplex converter corresponds to one impedance conversion circuit module, and multiple RF front-end circuits having the same communication system The module is connected to the same second stage single multiplexer and is connected to the corresponding impedance conversion circuit module through the second stage single multiplexer.
The radio frequency circuit according to claim 1, wherein said communication system comprises at least two of a GSM system, a CDMA system, a WCDMA system, or an LTE system.
The radio frequency circuit of claim 1, wherein the frequency band comprises at least two of 700 MHz, 850 MHz, 1900 MHz, or 2100 MHz.
The radio frequency circuit according to claim 1, wherein a difference between impedance characteristics of the different radio frequency paths in the same frequency band before the antenna matching circuit module is limited to a predetermined range after passing through the corresponding impedance conversion circuit module Internal means:

The impedance characteristics of the different RF paths in the same frequency band before the antenna matching circuit module are adjusted to the preset range of the same quadrant of the Smith chart.
A multimode terminal comprising the radio frequency circuit according to any one of claims 1 to 12.
The multimode terminal of claim 13, wherein the multimode terminal comprises: a multimode handset and a multimode tablet.