CN111295799B

CN111295799B - Antenna for mobile terminal and mobile terminal with same

Info

Publication number: CN111295799B
Application number: CN201780096514.3A
Authority: CN
Inventors: 吕伟; 阮勇; 胡澈; 章富洪
Original assignee: Shenzhen Transsion Manufacture Ltd
Current assignee: Shenzhen Transsion Manufacture Ltd
Priority date: 2017-11-01
Filing date: 2017-11-01
Publication date: 2021-12-28
Anticipated expiration: 2037-11-01
Also published as: CN111295799A; WO2019084837A1

Abstract

The invention provides an antenna for a mobile terminal and the mobile terminal with the antenna, wherein the antenna comprises a radiator, a feed end and a feed circuit for connecting the radiator and the feed end, and the antenna also comprises: the change-over switch comprises a fixed end, a grounding end and at least two free ends, wherein the fixed end is connected with the radiating body; the first end of each matching unit is connected with a free end, and the second ends of all the matching units are connected with the feed circuit after being connected in parallel; and the grounding matching unit is connected between the radiator and the grounding end in series. The technical scheme of the invention reduces the loss of the received signal and improves the performance of the antenna; common components in the feed circuit are placed at the front end of the change-over switch, so that the component cost is saved; the performance of a single frequency band can be optimized, and the performance of the antenna can be improved.

Description

Antenna for mobile terminal and mobile terminal with same

Technical Field

The present invention relates to the field of antennas, and in particular, to an antenna for a mobile terminal and a mobile terminal having the same.

Background

Nowadays, with the development of communication technology, 2G, 3G, 4G, WIFI, GPS networks coexist, and in order to be compatible with different networks, the antenna of the mobile device needs to be capable of operating on multiple frequency bands. In the field of mobile terminal devices, the design environment of an antenna is very complex, space is limited, and it is necessary to consider sharing a spatial structure with other functional components. One of the limitations is that any antenna simply designed cannot cover all the required frequency bands, and in order to meet the requirement of operating in multiple frequency bands, multiple antenna units must be designed and the antenna must be tested in full frequency band. The antenna comprises a feed circuit, wherein the feed circuit comprises components such as a resistor, a capacitor and an inductor, and parameters of the feed circuit with optimal performance need to be found in the test process, namely, the parameters of a group of the resistor, the capacitor and the inductor are found to be matched with the working frequency band of the antenna. The method adopted by the prior art is to use a switch to select different feed circuits to work in a matching way, and select corresponding signal channels according to different frequency bands of received wireless signals so as to realize the optimal antenna performance. However, the following problems still exist in the performance improvement of the antenna by using the switch:

1. the received signal passes through the feed circuit after passing through the selector switch, so that the signal loss is large;

2. and a plurality of groups of feed circuits need to be designed, so that more space is occupied, and the cost is increased.

Therefore, it is desirable to design an antenna suitable for a mobile terminal, which can reduce the loss of received signals and reduce the cost of components.

Disclosure of Invention

In order to overcome the technical defects, an object of the present invention is to provide an antenna for a mobile terminal and a mobile terminal having the same, in which a ground matching unit is disposed between a ground terminal and a radiator of a switch, so as to achieve a technical effect of reducing signal loss.

In a first aspect of the present application, an antenna for a mobile terminal is disclosed, including a radiator, a feeding terminal and a feeding circuit connected to the radiator and the feeding terminal, the antenna further includes: the change-over switch comprises a fixed end, a grounding end and at least two free ends, wherein the fixed end is connected with the radiating body; the first end of each matching unit is connected with a free end, and the second ends of all the matching units are connected with the feed circuit after being connected in parallel; and the grounding matching unit is connected between the radiator and the grounding end in series.

Preferably, the change-over switch is a single-pole double-throw switch comprising a first free end and a second free end; the matching unit is one and is connected between the first free end and the feed circuit in series; the second free end is connected with the feeding circuit.

Preferably, the matching unit is a 0 ohm resistor.

Preferably, the ground matching unit is a first inductor, and an inductance value of the first inductor is 4 to 6 nanohenries.

Preferably, the feeding circuit includes: the first end of the first capacitor is connected with the feed end; a first end of the second inductor is connected with a second end of the first capacitor, and a second end of the second inductor is grounded; a first end of the third inductor is connected with a second end of the first capacitor; a first end of the second capacitor is connected with a second end of the third inductor, and a second end of the second capacitor is grounded; the matching unit is connected with the first end of the second capacitor.

Preferably, the capacitance value of the first capacitor is 6 picofarads to 8 picofarads; the inductance value of the second inductor is 10-20 nanohenries; the inductance value of the third inductor is 1 nanohenry to 3 nanohenry; the capacitance value of the second capacitor is 1 picofarad to 3 picofarads.

Preferably, the antenna is a slot antenna, the radiator is arranged at one side of a slot, and the switch, the feed circuit, the matching unit and the feed end are arranged at the other side of the slot; the gap width is 1 mm to 3 mm.

Preferably, when the fixed end is connected with the first free end, the antenna operates at 790MHz to 2170 MHz; and/or when the fixed end is connected with the second free end, the antenna works at 2300MHz to 2700 MHz.

Preferably, the switch selects a preset free end to be connected with the fixed end according to the frequency band of the wireless signal received by the radiator.

In a second aspect of the present application, a mobile terminal is disclosed, which comprises the above antenna.

After the technical scheme is adopted, compared with the prior art, the method has the following beneficial effects:

1. the loss of received signals is reduced, and the antenna performance is improved;

2. common components in the feed circuit are placed at the front end of the change-over switch, so that the component cost is saved;

3. the performance of a single frequency band can be optimized, and the performance of the antenna can be improved.

Drawings

Fig. 1 is a schematic diagram of an antenna for a mobile terminal according to a preferred embodiment of the present invention;

fig. 2 is a schematic structural view of an antenna for a mobile terminal according to another preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of a feed circuit according to a preferred embodiment of the present invention;

fig. 4 is a diagram illustrating experimental results of an antenna for a mobile terminal according to a preferred embodiment of the present invention;

fig. 5 is a schematic structural diagram of an antenna for a mobile terminal in the prior art;

fig. 6 is a diagram illustrating experimental effects of an antenna for a mobile terminal in the prior art.

Reference numerals:

the antenna comprises a 1-radiator, a 2-feed end, a 3-change-over switch, a 31-fixed end, a 32-free end, a 33-grounding end, a 34-first free end, a 35-second free end, a 4-feed circuit, a 5-matching unit, a 6-grounding matching unit, a 7-first capacitor, an 8-second inductor, a 9-third inductor and a 10-second capacitor.

Detailed Description

The advantages of the invention are further illustrated in the following description of specific embodiments in conjunction with the accompanying drawings.

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, unless otherwise specified and limited, it is to be noted that the terms "mounted," "connected," and "connected" are to be interpreted broadly, and may be, for example, a mechanical connection or an electrical connection, a communication between two elements, a direct connection, or an indirect connection via an intermediate medium, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.

In the following description, suffixes such as "module", "component", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no specific meaning in themselves. Thus, "module" and "component" may be used in a mixture.

Referring to fig. 1, a schematic structural diagram of an antenna for a mobile terminal according to a preferred embodiment of the present invention is shown, where the antenna includes:

a radiator 1

The radiator 1 is used for transmitting or receiving radio signals and supports the antenna to work on a plurality of frequency bands. The radiator 1 is an antenna in the narrow sense, and is a converter that converts a signal propagating on a wired medium into an electromagnetic wave propagating in an unbounded medium (usually free space), or vice versa; is a component used in a radio device to transmit or receive electromagnetic waves. Engineering systems such as radio communication, broadcasting, television, radar, navigation, electronic countermeasure, remote sensing, radio astronomy and the like all use electromagnetic waves to transmit information and work by depending on antennas. The antennas are usually reversible, i.e. the same pair of antennas can be used as both transmitting and receiving antennas; the same antenna is the same as the basic characteristic parameter for transmission or reception; i.e. the reciprocity theorem of the antenna. In this embodiment, the antenna has a richer meaning than a narrow antenna, and further includes a feed circuit and a feed terminal 2 that cooperate with the radiator 1. The antenna works in a frequency band of a mobile communication network, comprises various network modes such as 2G, 3G, 4G and the like, and supports the mobile terminal to carry out information interaction with the outside. According to different working frequency bands and application occasions, the radiator 1 is designed to have different structures, for example, the radiator 1 in the mobile terminal needs to be correspondingly designed according to the structural characteristics of the mobile terminal, for example, electromagnetic oscillation is realized by utilizing a metal shell of the mobile terminal and a gap on the shell, and the miniaturization of the radiator 1 is realized. For another example, the radiator 1 may also be used in an antenna for laboratory tests, and the antenna is designed according to a laboratory environment, so that various frequency bands required by experiments can be covered, and the size is less limited.

-a feeding terminal 2

The feed end 2 is a signal input end or an output end of the antenna, and when the antenna transmits signals, the feed end 2 receives electric signals transmitted by a signal source and forms radio signals through the feed circuit 4 and the radiator 1 to transmit the radio signals; when the antenna receives signals, the wireless signals received by the radiator 1 are converted into electric signals through the feed circuit 4, and then the electric signals are transmitted to other components for processing through the feed end 2. The feed end 2 is usually connected to a radio frequency chip or a baseband chip, and processes a received radio frequency signal to convert the radio frequency signal into a digital signal.

-a supply circuit 4

The feed circuit 4 is composed of components such as a resistor, a capacitor, and an inductor, and can oscillate with the radiator 1 and transmit the oscillation in the form of electromagnetic waves through the radiator 1, or convert a wireless signal received by the radiator 1 into an electrical signal. The function of the feed circuit 4 in the antenna is crucial, and without the feed circuit 4, the antenna cannot generate oscillation, and thus cannot transmit or receive electromagnetic wave signals. The structure and electrical parameters of the feed circuit 4 are different, which affects the working frequency band and the performance of the antenna, so that the performance of the antenna can be optimized and adjusted by changing the parameters of the components of the feed circuit. The feed circuit often adopts an L-type circuit, a pi-type circuit, a combination of the L-type circuit and the pi-type circuit, a combination of two L-type circuits or a combination of two pi-type circuits.

A change-over switch 3

The change-over switch 3 includes a fixed end 31 connected to the radiator 1, a ground end 33, and at least two free ends 32, and the change-over switch 3 switches the fixed end 31 to be connected to any one of the free ends 32. The change-over switch 3 can control the fixed end 31 to be connected with one of the free ends 32 respectively, so as to realize the communication of circuits on two sides, and the free end 32 which is not connected is in a suspended state. The change-over switch 3 may be an on-off device having a switching function, such as a single-pole double-throw switch or a single-pole triple-throw switch. The switch 3 also has a ground terminal 33 connectable to ground the switch 3 to provide a ground reference. The fixed end 31 is directly connected to the radiator 1.

-a matching unit 5

The number of the matching units 5 is at least 1, the first end of each matching unit 5 is connected with a free end 32, and the second ends of all the matching units 5 are connected with the feed circuit 4 after being connected in parallel. Each matching unit 5 can select different types of components or the same type of components with different parameters. The selector switch 3 selects different free ends 32 to be connected to the fixed end 31, i.e. different matching units 5 to be connected to the fixed end. The matching unit 5 can select components suitable for matching different frequency bands, and the components and the feed circuit 4 form a signal path together, so that the selector switch 3 can select the signal path suitable for different frequency bands, and the optimal antenna performance under different frequency bands is realized.

-a ground matching unit 5

The ground matching unit 5 is connected in series between the radiator 1 and the ground terminal 33. The ground matching unit 5 is an important technical feature different from the prior art, in which the ground terminal 33 is directly connected to the radiator 1 (see fig. 5) to provide ground impedance for the switch 3 and the antenna. In the present invention, the ground matching unit 5 is connected in series between the radiator 1 and the ground terminal 33, and the signal generated by the radiator 1 is matched with the ground matching unit 5 before entering the switch 3, so that the signal loss is reduced.

Referring to fig. 2, which is a schematic structural diagram of an antenna for a mobile terminal according to another preferred embodiment of the present invention, the switch 3 is a single-pole double-throw switch, and includes a first free end 34 and a second free end 35. In this embodiment, the number of the free ends 32 of the switch 3 is 2, and the switch 3 is a single-pole double-throw switch, and the common model is RF1119ATR7 or ADRF 5024. The matching unit 5 is connected in series between the first free end 34 and the feeding circuit 4; the second free end 35 is connected to the supply circuit 4. In this embodiment, there are only 1 matching unit 5, which connects the first free end 34 and the feeding circuit 4, and the second free end 35 has no corresponding matching unit 5. In this embodiment, the selector switch 3 selects the first free end 34 or the second free end 35 to form different signal paths, so as to implement two frequency band matching modes.

As a further improvement of the above antenna, the matching unit 5 is a 0 ohm resistor. The 0 ohm resistor has a resistance value of approximately 0 ohm, but still plays a role of signal matching in the antenna field, and has a difference in performance compared with the mode that the wires are directly connected. In addition, the problem of replacing components is often considered in the design of the circuit board, each matching unit 5 is provided with a corresponding welding point, and the use of a 0-ohm resistor is also an optional connection mode, so that a new circuit board does not need to be manufactured again, and the cost is saved.

As a further improvement of the above antenna, the ground matching unit 6 is a first inductor, and an inductance value of the first inductor is 4 nanohenries to 6 nanohenries. The present modified embodiment further prefers that the ground matching unit 6 is a first inductor, and the inductance value thereof is preferably 5.1 nanohenries. The nano-henries are nH.

As a further improvement of the antenna, when the fixed end 31 is connected with the first free end 34, the antenna operates at 790MHz to 2170 MHz; when the fixed end 31 is connected to the second free end 34, the antenna operates at 2300MHz to 2700 MHz. The improved embodiment further defines the optimal working frequency range of the antenna when the switch 3 is switched to different free ends on the basis of fig. 2.

In this embodiment, the matching element that plays the same role in the matching unit 5 or the feed circuit 4 in the prior art is disposed between the radiator 1 and the switch 3, so that the received signal is matched before passing through the switch 3, thereby reducing signal loss.

Referring to fig. 3, which is a schematic diagram of a structure of a feeding circuit 4 according to a preferred embodiment of the present invention, the feeding circuit 4 includes:

a first capacitance 7

The first end of the first capacitor 7 is connected with the feed end 2, and the capacitance value of the first capacitor 7 is 6-8 picofarads, namely pF.

Second inductance 8

A first end of the second inductor 8 is connected to a second end of the first capacitor 7, and a second end of the second inductor 8 is grounded. The inductance value of the second inductor 8 is 10 nanohenries to 20 nanohenries.

Third inductance 9

A first terminal of the third inductor 9 is connected to a second terminal of the first capacitor 7. The inductance value of the third inductor 9 is 1 nanohenry to 3 nanohenry.

A second capacitance 10

A first end of the second capacitor 10 is connected to a second end of the third inductor 9, and a second end of the second capacitor 10 is grounded. The capacitance of the second capacitor 10 is 1 picofarad to 3 picofarads.

The matching unit 5 is connected to a first terminal of the second capacitor 10. That is to say all the second terminals of the matching units 5 are connected in parallel at one point and then connected to the first terminal of the second capacitor 10, which is also the connection point of the matching units 5 to the feed circuit 4. The connection point of the feeding circuit 4 and the feeding end 2 is at the first end of the first capacitor 7.

As a further improvement of the antenna, the antenna is a U-shaped antenna. The U-shaped antenna strap is a design of a back of a body commonly adopted by the mobile terminal, and is named because the antenna strap is in a bent shape similar to a letter U. The mobile terminal applying the U-shaped antenna is generally designed as a metal shell, the U-shaped antenna is arranged at the top or the bottom of the mobile terminal, a double-antenna design can also be adopted, and the U-shaped antenna is arranged at the top and the bottom of the mobile terminal.

As a further improvement of the antenna, the antenna is any one of a slot type, a monopole type, or an inverted F type. The present preferred embodiment makes the preference for the type of antenna. The slot type antenna is a common antenna used for a mobile terminal, a slot needs to be formed on the mobile terminal, the slot is insulated, metal areas are arranged on two sides of the slot, a feed circuit is bridged on the slot, a radiating body 1 is arranged on one side of the slot, and a feed end 2 is arranged on the other side of the slot. The monopole antenna is characterized in that a radiator 1 of the antenna extends in a monopole mode, a physical structure extending left and right is omitted, and the working frequency band of the monopole antenna is concentrated. The radiator 1 of the inverted-F antenna is integrally in a lying F shape, two transverse extending ends of the F are respectively connected with the feed circuit, the inverted-F antenna can adapt to various frequency range, and if the inverted-F antenna is matched with the change-over switch 3, the switching of various frequency ranges can be realized.

As a further improvement of the antenna, the antenna is a slot antenna, the radiator 1 is arranged on one side of a slot, and the selector switch 3, the feed circuit 4, the matching unit 5 and the feed end 2 are arranged on the other side of the slot; the width of the gap is 1 mm to 3 mm, preferably 2 mm. Slot-type antennas are increasingly used in such mobile terminals, particularly in mobile terminals having a metal housing, the slot being an insulator that divides the metal housing into two separate parts that operate as an inductive part and a radiator of the antenna. The radiator 1 is connected with a circuit on the other side of the gap through 1 or more positions. The position of each component in the antenna also affects the performance of the antenna, and in this embodiment, the distance between the switch 3 and the feeding end 2 is 26 mm.

As a further improvement of the antenna, the change-over switch 3 is a single-pole multi-throw switch of a micro electro mechanical technology. The Micro Electro Mechanical process is a popular manufacturing technology in recent years, and the manufactured devices or components are also called Micro Electro Mechanical Systems (MEMS) for short, and Micro-Electro-Mechanical systems for full name. The micro electro mechanical system is also called a micro electro mechanical system, a micro machine and the like, and refers to a high-tech device with the size of several millimeters or even smaller, and the internal structure of the micro electro mechanical system is generally in the micrometer or even nanometer level, so that the micro electro mechanical system is an independent intelligent system. The micro electro mechanical system is developed on the basis of microelectronic technology (semiconductor manufacturing technology), and integrates high-tech electronic mechanical devices manufactured by technologies such as photoetching, corrosion, thin film, LIGA, silicon micromachining, non-silicon micromachining, precision machining and the like. Due to the shortage of available space resources in the mobile terminal, components produced by micro-electromechanical technology have the advantage of small size, and the diverter switch 3 is also called a MEMS switch. The concept of MEMS switches was proposed in the late 80 s and early 90 s of the 20 th century, with great appeal to radio frequency engineers, with their potential including reduction in overall chip area, power consumption and device cost. Common MEMS switches are single-pole four-throw (SP4T) MEMS switches with the type ADGM1304 and also have the characteristic of electrostatic protection, and compared with radio frequency relays, the volume of the MEMS switches is reduced by 95%, the reliability is improved by 10 times, the speed is improved by 30 times, and the power consumption is reduced by 10 times. The change-over switch 3 is a single-pole multi-throw switch, wherein a single pole is connected with the fixed end 31, different free ends 32 can be selected for throwing connection, finally, a one-to-many selection mode is realized, and the change-over switches 3 with the corresponding number of the free ends 32 can be selected according to the number of the feed circuits.

As a further improvement of the antenna, the control logic is embedded in the switch 3, and a preset free end 32 is selected to be connected with the fixed end 31 according to the frequency band of the wireless signal received by the radiator 1. The switch 3 is a programmable logic control device and has the capability of identifying the frequency band of the signal received by the fixed end 31. When the change-over switch 3 is used, control logic can be written into the change-over switch 3 in advance, and according to different received signal frequency bands, the free ends 32 corresponding to different matching units 5 are selected to be connected with the fixed ends 31, so that the selection of the feed circuits corresponding to different frequency bands is realized, and the optimal matching of the antenna performance on the frequency band is realized.

As a further improvement of the antenna, the feed circuit 4 and the changeover switch 3, and the feed circuit 4 and the feed terminal 2 are connected by impedance cables having a resistance value of 50 ohms, respectively. The improvement further limits the connection mode among all components in the antenna, the impedance of a signal line plays a crucial role in signal transmission and interference resistance, and in the embodiment, a 50-ohm impedance cable is selected to connect the feed circuit 4 and the change-over switch 3 and connect the feed circuit 4 and the feed end 2, so that signal crosstalk on a transmission line can be reduced, and the distortion degree of signals is reduced.

Fig. 4 is a diagram of an experimental effect of the antenna for the mobile terminal according to a preferred embodiment of the present invention, which is obtained on the basis of the antenna shown in fig. 2. When the working frequency band of the antenna is 790MHz to 2170MHz, the switch 3 selects the first free end 34 to connect; when the working frequency band of the antenna is 2300MHz to 2700MHz, the switch 3 selects the second free end 35 to connect. The abscissa of the experimental effect graph is a frequency band, and the unit is MHz, namely megahertz; the ordinate of the experimental effect plot is the signal gain in dB, i.e. decibels.

Referring to fig. 5, which is a schematic structural diagram of an antenna for a mobile terminal in the prior art, the ground matching unit 6 is not disposed in the antenna in the prior art, and the radiator 1 is directly connected to the ground terminal 33. The first free end 34 is connected to the feeding circuit 4 through the matching unit 5, and the matching unit 5 is an inductor of 5.1 nanohenries. The second free end 35 is directly connected to the supply circuit 4. The biggest difference between the prior art and the invention shown in fig. 2 is that the 5.1 nanohenry inductance of the prior art located in the matching unit 5 is moved between the radiator 1 and the ground terminal 33, and the position of the matching unit 5 is replaced by a 0 ohm resistor.

Referring to fig. 6, an experimental effect diagram of an antenna for a mobile terminal in the prior art is shown, which is obtained through experiments based on fig. 5. When the working frequency band of the antenna is 790MHz to 2170MHz, the switch 3 selects the first free end 34 to connect; when the working frequency band of the antenna is 2300MHz to 2700MHz, the switch 3 selects the second free end 35 to connect.

Comparing the experimental results in fig. 4 and fig. 6, it can be seen that in fig. 4, the efficiency of the antenna in the present invention is higher than that in the prior art, especially in the range of 2110MHz to 2170MHz, i.e. in the range of 2100MHz in WCDMA, the antenna in the present invention has lower loss and higher efficiency.

In a second aspect of the present application, a mobile terminal is disclosed, which comprises the above antenna. The mobile terminal comprises a radio frequency chip which is responsible for radio frequency transceiving, frequency synthesis and power amplification. The radio frequency chip is simply a part for receiving and sending signals, and is a part for mainly communicating with the base station when the mobile terminal makes a call and receives a short message. The radio frequency chip is provided with a radio frequency signal interface and is connected with the feed end 2. With the development of integrated circuit technology, many manufacturers integrate the rf chip into a communication baseband chip, and integrate the transceiving and processing of signals together.

The mobile terminal may be implemented in various forms. For example, the terminal described in the present invention may include a mobile terminal such as a mobile phone, a smart phone, a notebook computer, a PDA (personal digital assistant), a PAD (tablet computer), a PMP (portable multimedia player), a navigation device, and the like, and a fixed terminal such as a digital TV, a desktop computer, and the like. In the following, it is assumed that the terminal is a mobile terminal. However, it will be understood by those skilled in the art that the configuration according to the embodiment of the present invention can be applied to a fixed type terminal in addition to elements particularly used for moving purposes.

It should be noted that the embodiments of the present invention have been described in terms of preferred embodiments, and not by way of limitation, and that those skilled in the art can make modifications and variations of the embodiments described above without departing from the spirit of the invention.

Claims

1. An antenna for a mobile terminal, comprising a radiator, a feeding terminal and a feeding circuit connected to the feeding terminal, wherein the antenna further comprises:

the change-over switch comprises a fixed end, a grounding end and at least two free ends, wherein the fixed end is connected with the radiating body;

the first end of each matching unit is connected with a free end, the second ends of all the matching units are connected with one end of the feed circuit after being connected in parallel, the other end of the feed circuit is connected with the feed end, the feed circuit and the radiator generate oscillation and transmit the oscillation in an electromagnetic wave mode through the radiator, and wireless signals received by the radiator are converted into electric signals;

and the grounding matching unit is connected between the radiator and the grounding end of the change-over switch, wherein the signal generated by the radiator is matched with the grounding matching unit before entering the change-over switch so as to reduce the signal loss.

2. The antenna of claim 1,

the change-over switch is a single-pole double-throw switch and comprises a first free end and a second free end; the matching unit is connected between the first free end and the feed circuit;

the second free end is connected with the feeding circuit.

3. The antenna of claim 2,

the matching unit is a resistor.

4. The antenna according to any of claims 1 to 3,

the ground matching unit is a first inductor.

5. The antenna according to any of claims 1 to 3,

the feeding circuit includes:

the first end of the first capacitor is connected with the feed end;

a first end of the second inductor is connected with a second end of the first capacitor, and a second end of the second inductor is grounded;

a first end of the third inductor is connected with a second end of the first capacitor;

a first end of the second capacitor is connected with a second end of the third inductor, and a second end of the second capacitor is grounded;

the matching unit is connected with the first end of the second capacitor.

6. The antenna of claim 5,

the capacitance value of the first capacitor is 6 picofarads to 8 picofarads;

the inductance value of the second inductor is 10-20 nanohenries;

the inductance value of the third inductor is 1 nanohenry to 3 nanohenry;

the capacitance value of the second capacitor is 1 picofarad to 3 picofarads.

7. The antenna according to any of claims 1 to 3,

the antenna is a slot type antenna, the radiator is arranged on one side of a slot, and the change-over switch, the feed circuit, the matching unit and the feed end are arranged on the other side of the slot.

8. The antenna of claim 2 or 3,

when the fixed end is connected with the first free end, the antenna works at 790MHz to 2170 MHz; and/or the presence of a gas in the gas,

when the fixed end is connected with the second free end, the antenna works in 2300MHz to 2700 MHz.

9. The antenna according to any of claims 1 to 3,

and the change-over switch selects a preset free end to be connected with the fixed end according to the frequency band of the wireless signal received by the radiating body.

10. A mobile terminal, characterized in that it comprises an antenna according to any of claims 1 to 9.