KR20130039269A - Mobile terminal and method for control thereof - Google Patents

Abstract

According to an embodiment of the present invention, a mobile terminal includes a duplexer configured to classify frequencies transmitted to or received from an antenna, and a match for matching impedances for respective frequencies received from the duplexer or transmitted to the duplexer. A memory having a signal sensing unit configured to detect a standing wave ratio (VSWR) for the frequencies, a control unit for controlling the matching unit, and a table in which coordinates of a Smith chart according to standing wave ratios of the frequencies are recorded. By including the unit, it is possible to improve the transmission and reception sensitivity of the terminal while maintaining the optimum impedance matching actively to the environment changes around the antenna.

Description

MOBILE TERMINAL AND METHOD FOR CONTROL THEREOF

One embodiment of the present invention relates to an antenna circuit capable of matching impedance.

As the functions are diversified, the terminal is implemented in the form of a multimedia device having a complex function of, for example, taking pictures or moving pictures, playing music or moving picture files, receiving games and receiving broadcasts have.

The terminal can move And can be divided into a mobile / portable terminal and a stationary terminal depending on whether the mobile terminal is a mobile terminal or a mobile terminal. A mobile terminal is a portable device that is portable and has one or more functions of making voice and video calls, inputting and outputting information, and storing data.

In particular, in mobile terminals, antennas play a very important role in providing reliable communication. Once an antenna is selected for a mobile terminal, antenna performance is generally optimized by matching its impedance to the desired impedance, which is often determined by the electronic circuitry connected to the antenna. However, antenna impedance may be affected by adjacent objects, which are electromagnetically dissipative or reflective.

For example, an electrical length or an electrical ground plane may be easily affected by a grip operation holding a terminal in a hand or attaching an accessory to a terminal. The influenced electrical characteristics deteriorate the antenna performance of the mobile terminal by changing the impedance of the antenna.

As a result, there is a problem that the optimum antenna performance is not provided, and a solution to solve this problem may be considered.

A mobile terminal according to an embodiment of the present invention is to provide a mobile terminal having an impedance matching device for more actively performing impedance matching between an antenna and a circuit according to a change in an external environment of the terminal.

A mobile terminal according to an embodiment of the present invention for achieving the above object, a duplexer is formed to classify the frequencies transmitted to or received from the antenna, and each of the frequencies received from the duplexer or transmitted to the duplexer Matching unit for matching the impedance with respect to the signal sensing unit formed to detect the standing wave ratio (VSWR) for the frequencies, the control unit for controlling the matching unit and the coordinates of the Smith chart according to the standing wave ratio of the frequencies And a memory unit having a recorded table, wherein the controller is configured to match impedance based on a result of comparing the detected standing wave ratio of the frequency with coordinates of the table.

In example embodiments, the matching unit may move the coordinates on the Smith chart of the frequency and the first matching circuit to move the coordinates on the Smith chart of the frequency in the first direction according to the change of the capacitance value according to the change of the capacitance value. It may include a second matching circuit for moving in the second direction.

According to an example related to the present disclosure, the matching circuits may include at least one inductor and a variable capacitor.

According to an example related to the present invention, the matching unit may further include a low noise amplifier (LNA) for amplifying and outputting a reception frequency output by matching impedances.

According to an example related to the present disclosure, the apparatus may further include a power amplifier (PA) for amplifying a transmission frequency output to the matching unit.

In order to achieve the above object, embodiments of the present invention detect a standing wave ratio of a frequency, comparing a table coordinate of the pre-stored frequency with respect to the detected standing wave ratio and a Smith chart, and comparing the result of the comparison. Disclosed is a control method of a mobile terminal including changing capacitance values of a first matching circuit and a second matching circuit for impedance matching.

The mobile terminal according to at least one embodiment of the present invention configured as described above can improve the transmission and reception sensitivity of the terminal while actively maintaining the optimum impedance matching with respect to the environment around the antenna.

In addition, it is possible to solve the mismatch problem at a low cost by reducing the development cost and necessity of the broadband antenna considered to avoid the existing mismatch.

In addition, it is possible to prevent the performance degradation of the mobile terminal due to the VSWR change of the antenna and the mismatch of the antenna.

In addition, it improves the noise figure of the low noise amplifier (LNA) and the ACPR margin of the power amplifier (PA) at the same time, and can operate efficiently in multiband.

1 is a front perspective view of a mobile terminal according to an embodiment of the present invention;
2 is a rear perspective view of a mobile terminal according to an embodiment of the present invention;
3 is an exploded perspective view of the mobile terminal of FIG.
4 is a conceptual diagram illustrating an impedance matching apparatus of an antenna according to an embodiment of the present invention.
5 is an exemplary view of a matching unit of FIG. 4.
6 to 9 are diagrams for explaining the impedance matching method of the antenna according to an embodiment of the present invention.
10 is a flowchart of an impedance matching method of an antenna according to an embodiment of the present invention.

Hereinafter, a mobile terminal and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

1 is a front perspective view of an embodiment of a mobile terminal 100 according to the present invention.

The case (casing, housing, cover, etc.) forming the exterior of the main body of the terminal is formed by the front case 111 and the rear case 121. Various electronic components are embedded in the space formed by the front case 111 and the rear case 121. At least one intermediate case may be additionally disposed between the front case 111 and the rear case 121. [ The cases may be formed by injecting a synthetic resin or may be formed of a metal material, for example, a metal material such as stainless steel (STS) or titanium (Ti).

The front case 111 may include a display unit 113, a first sound output unit 114, a first image input unit 115, a first manipulation unit 116, a sound input unit 117, and the like.

The display unit 113 includes a display module 141 (see FIG. 3) such as a liquid crystal display (LCD) module, an organic light emitting diodes (OLED) module, and the like, which visually express information. The display unit 113 may be formed as a touch screen to enable information input by a user's touch.

The first sound output unit 114 may be implemented in the form of a receiver or a speaker.

The first image input unit 115 may be implemented in the form of a camera module for capturing an image or a video of a user.

The first operation unit 116 receives a command for controlling the operation of the mobile terminal 100 according to an embodiment of the present invention. The first manipulation unit 116 may be a key area formed to receive a user's touch input on the window unit.

The sound input unit 117 may be implemented in the form of, for example, a microphone to receive a user's voice, other sounds, and the like.

The second operation unit 123, the interface 124, the power supply unit 125, and the like may be disposed on the rear case 121 mounted on the rear side of the mobile terminal 100.

The second manipulation unit 123 may be installed on the side of the rear case 121. In addition to the first manipulation unit 116, the second manipulation unit 123 may be collectively referred to as a manipulating portion, and may be adopted in any manner as long as the user is tactile in a tactile manner. . For example, the operation unit may be implemented as a dome switch or a touch screen or a touch pad capable of receiving commands or information by a push or touch operation of a user, or may be a wheel, a jog type, a joystick, Or the like.

In terms of functionality, the first operation unit 116 may be used to input a menu such as start, end, etc., and the second operation unit 123 may have a special function such as activation of the first image input unit 115 in addition to the scroll function. It can act as a hot-key that performs. If the first and second manipulation units 116 and 123 are minimized as illustrated, a telephone number or a text may be input by a touch screen provided in the display unit 113.

The interface 124 may be a passage through which the mobile terminal 100 may exchange data with an external device. For example, the interface 124 may be wired or wirelessly, and a connection terminal for connecting with an earphone, a port for short-range communication (for example, an infrared port (IrDA port), a Bluetooth port, a wireless LAN port ( wireless Lan port), or at least one of power supply terminals for supplying power to the mobile terminal 100. The interface 124 may be a card socket for receiving an external card, such as a subscriber identification module (SIM) or a user identity module (UIM), a memory card for storing information.

The power supply 125 is mounted to a rear case 121 for supplying power to the mobile terminal 100. The power supply unit 125 may be detachably coupled for charging, for example, as a rechargeable battery.

2 is a rear perspective view of the mobile terminal 100 of FIG. 1.

Referring to FIG. 2, the rear case 121 may further include a second image input unit 127, a second sound output unit 130, and a broadcast signal receiving antenna 131.

The second image input unit 127 may be a camera having a photographing direction substantially opposite to that of the first image input unit 115 (see FIG. 1) and having different pixels from the first image input unit. For example, the first image input unit 115 has a low pixel so that the user's face is photographed and transmitted to the counterpart in case of a video call, and the second image input unit 127 immediately photographs a general subject. It is preferable to have a high pixel because it is not transmitted in many cases.

The flash 128 and the mirror unit 129 are further disposed adjacent to the second image input unit 127. The flash 128 emits light toward the subject when the subject is photographed by the second image input unit 127. The mirror unit 129 allows the user to see his / her face or the like when the user wants to photograph (self-photograph) the user by using the second image input unit 127.

The second sound output unit 130 may implement a stereo function together with the first sound output unit 114 (refer to FIG. 1), and may be used for a call in a speakerphone mode.

The broadcast signal receiving antenna 131 may be disposed at one side of the rear case 121 separately from the antenna for a call or the like. The antenna 131 may be installed in the rear case 121 to be pulled out.

In the above description, the first operation unit 116 and the like have been described as being mounted to the front case 111, and the second operation unit 123 and the like are mounted to the rear case 121, but the present invention is not necessarily limited thereto. For example, the second operation unit 123 may be disposed in the front case 111 adjacent to the first operation unit 116. In addition, even if the second image input unit 127 is not provided separately, the first image input unit 115 may be rotatably formed so that the image capturing direction of the second image input unit 127 may be taken.

3 is an exploded perspective view of the mobile terminal 100 of FIG. 1.

Referring to this drawing, the window 140 is coupled to cover one surface of the front case 111. The window unit 140 covers one surface of the display module 141 so that visual information output from the display module 141 is recognized from the outside. The display module 141 and the window unit 140 form the display unit 113 (see FIG. 1).

The window unit 140 is formed to recognize a user's touch and enables input of information (command, signal, etc.).

The window unit 140 may have an area corresponding to the display module 141 and may be formed of a material through which light can pass. The window unit 140 may be formed with an opaque region in which light is not transmitted or the light transmittance is very low. For example, the surface may be treated to prevent light from passing along the edge of the window 140.

An operation pad may be formed in the front case 111 in correspondence with the first manipulation unit 116. The operation pad is a target to be touched or pressed by the user. It may be formed as a manipulation area on a portion of the manipulation pad window 140.

In the front case 111, a sound hole 114b, a window hole 112b, and an image window may be formed.

The sound hole 114b is formed to correspond to the sound output unit 114 so that the sound of the mobile terminal, for example, a ringtone, music, and the like is emitted to the outside. The window hole 112b is formed to correspond to the display unit 113. Corresponding to the first image input unit 115 (see FIG. 1 above), a light transmission image window may be formed.

The rear case 21 may include a circuit board 170, a display module 141, a speaker module 114a, a camera module 115a, and a switch.

The circuit board 170 may be configured as an example of a controller for operating various functions of the mobile terminal 100. The circuit board 170 may detect an electrical change, for example, a change in capacitance or a charge amount, generated inside the window 140 generated when the user touches the window 140.

Inside the window 140 is formed so that the electrode is embedded. The electrode may be formed in a conductive pattern. The electrode may be charged with charge, and if the conductor moves at a close distance, the amount of charged charge may change accordingly. When a conductor, for example a user's finger, touches a window, the amount of charge charged in the electrode changes, which is like changing the capacitance between the finger and the electrode.

The electrode of the window unit 140 is electrically connected to a control unit for detecting a change in the charge amount, for example, the circuit board 170. For this electrical connection, the flexible circuit board 150 may be connected to the circuit board 170 (see FIG. 3 above) through the hole 152. According to the detection of the change in the amount of charge, the circuit board 170 may change the state of at least one of the functions related to the mobile terminal 100.

The flexible circuit board 150 extends from one end of the window unit 140. One end of the flexible circuit board 150 may be connected to the electrode by forming a connection portion 151 and the other end may be connected to the circuit board 170 by the connector 185. The connection part 151 may be formed of a metal material to maintain a certain stiffness and elasticity.

4 is a conceptual diagram illustrating an impedance matching apparatus of an antenna according to an embodiment of the present invention, and FIG. 5 is an exemplary diagram of a matching unit of FIG. 4.

As shown, the impedance matching device according to an embodiment of the present invention, may be connected to the antenna or the transceiver 240, respectively, or each configuration may be connected in combination with each other. The transceiver 240 may be divided into a transmitter and a receiver to operate.

The impedance matching device may include a duplexer 230, a matching unit 220, and a controller 250.

The duplexer 230 separates the high frequency reception signal received through the antenna and inputs the received high frequency signal to the receiver, and transmits the high frequency transmission signal output by the transmitter to the antenna for transmission.

The receiver receives a high frequency received signal separated by the duplexer 230 and converts the received signal into an electrical baseband signal.

The transmitter converts the input baseband transmission signal into a high frequency signal and outputs the duplexer 230 to transmit the signal.

Upon reception of the wireless signal, the mobile terminal detects the signal via an antenna to generate a detected voice and / or data signal. The transceiver 240 connected to the antenna converts the detected signal into electrical base band signals and recovers incoming information transmitted by the wireless signal such as voice and / or data. Demodulate the electrical baseband signal. After receiving the inflow information from the transceiver 240, the controller 250 formats the inflow information for output to the display and / or audio.

As such, in the transmission of the wireless signal, the controller 250 formats the leakage information, and transmits the leakage information to the transceiver 240 to modulate the carrier and convert the carrier into a modulated signal. The transceiver 240 transmits the modulated signal to an antenna for transmission to a remote transceiver (not shown).

For example, the controller 250 outputs a telephone call voice signal to a telephone call unit (not shown) from the baseband signal input from the transmission / reception unit 240 at all times, and outputs the telephone call voice of the user. By converting the signal into a baseband signal and outputting the signal to the transceiver unit 240, the user of the mobile terminal controls the telephone call.

In such a mobile terminal, the impedances of the antenna and the duplexer 230 and the duplexer 230 and the transceiver 240 must be exactly matched so that a signal received through the antenna is not lost and the transceiver is transmitted through the duplexer 230. By transmitting to 240, the transceiver 240 may receive the received signal with high reception sensitivity. In addition, the impedances of the antenna and the duplexer 230, the duplexer 230 and the transceiver 240 must also be exactly matched to transmit the transmission signal output from the transceiver 240 to the antenna without being lost and to transmit at maximum transmission power. Can be.

To this end, when the mobile terminal is manufactured, the impedances of the antenna and the duplexer 230, the impedances of the duplexer 230 and the transceiver 240, and the impedances of the duplexer 230 and the transceiver 240 are accurately matched with each other. I'm making it.

In general, however, the antenna is embedded in the mobile terminal to reduce the size of the mobile terminal. The slide-type mobile terminal slides up or slides down the slider, and the folder-type mobile terminal is used while opening and closing the folder. In addition, when a user uses a mobile terminal, the user usually uses the hand.

Therefore, even when the impedance of the antenna and the duplexer 230 and the impedance of the duplexer 230 and the transceiver 240 in the manufacturing process of the mobile terminal exactly match, the impedance mismatch occurs according to the use environment of the mobile terminal as described above. do.

The mismatch of the generated impedance causes the maximum transmission power of the transmission signal transmitted by the mobile terminal to be low, and also causes the reception sensitivity of the reception signal to deteriorate.

The impedance mismatch can be solved by providing a matching unit 220. The matching unit 220 matches an impedance for each frequency received from the duplexer 230 or transmitted to the duplexer 230.

The matching unit 220 may be formed with a plurality of circuits. Each circuit may include at least one inductor and a variable capacitor. The matching unit 220 includes the first matching circuit 221 for moving the coordinates on the Smith chart of the frequency in the first direction according to the change of the value of the capacitance and the coordinates on the Smith chart of the frequency to the change of the value of the capacitance. Accordingly, the second matching circuit 222 may move in the second direction. The relationship between the Smith chart and the matching circuit will be described later.

The signal detector 210 may be formed to detect the standing wave ratio VSWR of the frequencies so that the matching unit 220 may obtain impedance information about the frequencies. The signal detector 210 detects a signal received from an antenna and outputs the signal to the controller 250. The signal detecting unit 210 is a standing wave ratio (VSWR: voltage standing wave ratio) detecting unit, and a standing wave ratio (VSWR: Voltage Standing Wave) in which a magnitude signal and a phase signal input through the antenna are added together. Ratio) signal is detected and output to the controller 250.

The controller 250 may detect the standing wave ratio VSWR with respect to the frequencies from the signal detector 210 and may transmit a predetermined command signal to the matcher 220 for impedance matching.

In addition, a low noise amplifier (LNA) 231 may be formed to amplify and output a reception frequency output by matching impedances from the matching unit 220, and a transmission frequency output to the matching unit 220. A power amplifier (PA) 232 for amplifying the power amplifier may be formed.

The memory unit 260 may include a program memory and data memories. The program memory stores programs for controlling general operations of the mobile terminal, and the data memory temporarily stores data generated while the programs are executed.

In the memory unit 260, coordinates of a Smith chart according to standing wave ratios of frequencies according to an embodiment of the present invention may be recorded and stored.

6 to 9 are diagrams for describing an impedance matching method of an antenna according to an embodiment of the present invention.

6 is a diagram related to the coordinates on the Smith chart for the detected frequency of the current mobile terminal.

Smith impedance chart is a circular chart used for obtaining input impedance when power frequency, line length or load impedance is changed.

When a specific frequency is detected by the signal detector 210, the forward power (FP) value and the reflected power (RP) value of the detected frequency may be quantified through a constant conversion. The FP and RP values are related to the maximum and minimum voltages due to frequency, respectively.

As shown in FIG. 6, when the FP value and the RP value of the sensed frequency are 1203 and 897, respectively, the standing wave ratio is 6: 1 and the phase is 120 degrees. The standing wave ratios and phases for the FP value and the RP value can be obtained using a table calculated in advance or an equation related to the standing wave ratios.

7 and 8 illustrate the impedance matching conditions that are changed when the user holds the terminal by hand on the Smith chart, respectively. In FIG. 7, the first point C1 is a coordinate when the user loosens the terminal, the second point C2 is a coordinate when the user slightly holds the terminal, and the standing wave ratio of the circle is 2: 1. The in circle shows a collection of coordinates in which the antenna performs well.

The first point C1 is located on a circle having a standing wave ratio of 4: 1, and the second point C2 is located on a circle having a standing wave ratio of 5: 1. At this point, the antenna does not perform well.

Therefore, since the impedance matching condition of the antenna is changed according to the user's usage aspect, each point (first point and second point) where the impedance matching condition is changed within a circle where the standing wave ratio that can exhibit good terminal performance becomes 2: 1. You need to move them. In FIG. 8, C1 moves to D1 and C2 moves to D2 due to the operation of the impedance matching unit.

BAND
VSWR 2: 1 VSWR 3: 1 VSWR 4: 1 VSWR 5: 1 FP RP FP RP FR RP FP RP GSM 850 1007 980 900 800 800 650 700 400 EGSM 1269 1150 1030 850 950 680 780 460 DCS 900 840 750 650 600 400 480 300 PCS 860 795 770 590 650 430 500 320

Table 1 is a lookup table arranging standing wave ratios, FP values, and RP values for each frequency. This lookup table may be stored in the memory unit 260 to compare the FP value and RP value of the current sensed frequency with the FP value and RP value exhibiting good antenna performance during impedance matching. This makes it possible to adjust the impedance more quickly.

9 shows that the coordinate of the sensed frequency moves on the Smith chart as the capacitance value of the matching circuit changes.

For example, the coordinates corresponding to the frequency may move in the first direction W1 according to the change of the capacitance C value of the first matching circuit. When the value of the capacitance C of the first matching circuit is increased, the coordinates may move upward. On the contrary, when the value of capacitance C is lowered, the coordinates may move leftward downward. Also, the coordinates corresponding to the frequency may move in the second direction W2 according to the change of the capacitance C value of the second matching circuit. At this time, when the value of the capacitance C of the second matching circuit is increased, the coordinate may move leftward downward, and when the value of the capacitance C is decreased, the coordinate may move upward right.

The first direction W1 and the second direction W2 may cross each other, so that impedance matching may be more easily performed.

As such, when the transmission or reception frequency detected by the signal detection unit 210 corresponds to one point on the Smith chart, the capacitance values of the first and second matching circuits are changed to move to a desired point. Impedance matching can be performed quickly.

To this end, the table stored in the memory unit 260 may be formed to have a change value of the capacitance of the first and second matching circuits necessary to move from the coordinates corresponding to each point on the Smith chart to the desired coordinates. .

10 is a flowchart of an impedance matching method of an antenna according to an embodiment of the present invention.

The signal detector 210 detects the standing wave ratio of the frequency (S110). In more detail, after sensing the power of the frequency output from the transceiver 240, it can be converted to detect the standing wave ratio of the frequency.

The controller 250 compares the sensed standing wave ratio with the table coordinates of the frequencies pre-stored in relation to the Smith chart (S120). Comparing the coordinates recorded on the table with the coordinates of the sensed frequencies, we can see how far we have to move on the Smith chart to achieve good frequency performance. In other words, it is more convenient to predict how much the capacitance values of the first matching circuit 221 and the second matching circuit 222 should achieve the desired frequency performance.

Thereafter, the capacitance values of the first matching circuit 221 and the second matching circuit 222 are changed for impedance matching based on the comparison result (S 130). For example, if the table is provided with a change value of the capacitance of the first and second matching circuits 221 and 222 required to move from the coordinates corresponding to each point on the Smith chart to the desired coordinates, Change the capacitance value of the circuit.

After changing each capacitance value of the matching unit 220, it is determined whether a match is made due to the changed impedance (S 140), and if it is not matched, the at least one or more steps S120 and S130 are repeated.

The above-described mobile terminal and its control method may not be limitedly applied to the configuration and method of the above-described embodiments, but the embodiments may be selectively or partially all of the embodiments so that various modifications may be made. It may be configured in combination.

Claims (8)

A duplexer configured to classify frequencies transmitted to or received from the antenna;
A matching unit matching an impedance for each of the frequencies received from the duplexer or transmitted to the duplexer;
A signal detector configured to detect a standing wave ratio (VSWR) with respect to the frequencies;
A control unit controlling the matching unit; And
A memory unit having a table in which coordinates of a Smith chart according to standing waves of the frequencies are recorded;
The control unit,
And matching impedance based on a result of comparing the detected standing wave ratio of the frequency with the coordinates of the table. The method of claim 1,
The matching unit,
A first matching circuit for moving the coordinates on the Smith chart of the frequency in a first direction according to a change in the value of the capacitance; And
And a second matching circuit for moving the coordinates on the Smith chart of the frequency in the second direction according to the change in the value of the capacitance. The method of claim 2,
The matching circuit comprises at least one inductor and a variable capacitor. The method of claim 1,
And a low noise amplifier (LNA) for amplifying and outputting a reception frequency output by matching impedances from the matching unit. The method of claim 1,
And a power amplifier (PA) for amplifying a transmission frequency output to the matching unit. Detecting a standing wave ratio of frequency;
Comparing the detected standing wave ratios with table coordinates of the frequencies previously stored in relation to the Smith chart; And
And changing capacitance values of the first matching circuit and the second matching circuit for impedance matching based on the comparison result. The method according to claim 6,
The first matching circuit and the second matching circuit control method of the mobile terminal, characterized in that the movement direction of the frequency cross each other on the Smith chart in accordance with the change of the capacitance value. The method according to claim 6,
And the matching circuits comprise at least one inductor and a variable capacitor.

Images