Mobile terminal

A mobile terminal including a terminal body having a ground; a first conductive member and a second conductive member mounted in the terminal body, and spaced from each other and configured to transmit and receive a radio signal; a feed connection portion connected to the first conductive member and configured to feed-connect the first conductive member to the ground; and a first ground connection portion connected to the second conductive member and configured to ground-connect the second conductive member to the ground. Further, the first conductive member and the second conductive member are connected to each other so as to form a loop.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2011-0061340, filed on Jun. 23, 2011, the contents of which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mobile terminal, and more particularly, to a mobile terminal having an antenna portion for transmitting and receiving a radio signal.

2. Background of the Invention

In general, a terminal may be classified into a mobile (portable) terminal and a stationary terminal according to a moveable state. The mobile terminal may be also classified into a handheld terminal and a vehicle mount terminal.

The terminal support many complicated functions such as capturing images or video, reproducing music or video files, playing games, receiving broadcast signals, and the like. Thus, the mobile terminal now functions as a multimedia player or a device.

Various attempts have been made to implement complicated functions in such a multimedia device using hardware or software. For instance, the mobile terminal includes a User Interface (UI) environment allowing a user to easily and conveniently search for or select a desired function. The mobile terminal has also become a necessity for many users and thus the efficient design and appearance of the mobile terminal is desired by the user.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to address the above-noted and other problems with the related art.

Another object is to provide a mobile terminal having an antenna device with an enhanced function that can transmit and receive a multi radio signal of a high frequency and a low frequency.

To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, the present invention provides a mobile terminal including a terminal body having a ground; a first conductive member and a second conductive member mounted in the terminal body, and spaced from each other and configured to transmit and receive a radio signal; a feed connection portion connected to the first conductive member and configured to feed-connect the first conductive member to the ground; and a first ground connection portion connected to the second conductive member and configured to ground-connect the second conductive member to the ground. Further, the first conductive member and the second conductive member are connected to each other so as to form a loop.

In another aspect, the present invention provides a mobile terminal including a terminal body having a ground; first and second conductive members mounted in the terminal body, spaced from each other in a predetermined interval and disposed in parallel so as to form at least one slot, and connected to each other so as to form a loop; a feed connection portion connected to the first conductive member and configured to feed-connect the ground to the first conductive member; and one or more ground connection portions configured to ground-connect the ground to the second conductive member so that paths formed from the feed-connection portion via the respective first and second conductive members have different resonant lengths for transmitting and receiving radio signals at different frequency bands.

DETAILED DESCRIPTION OF THE INVENTION

The mobile terminal according to an embodiment of the present invention includes a portable phone, a smart phone, a laptop computer, a digital broadcasting terminal, Personal Digital Assistants (PDA), Portable Multimedia Player (PMP), a navigation system, etc., and a fixed terminal such as a digital TV, a desktop computer, etc.

FIG. 1is a block diagram of a mobile terminal100according to one embodiment of the present invention. The mobile terminal100may be a bar-type mobile terminal including one body. However, the present invention is not limited to this. That is, the present invention is also applicable to various structures such as a slide type where at least two bodies are coupled to each other so as to perform a relative motion, a folder type, a swing type, a swivel type, etc.

As shown inFIG. 1, a case (casing, housing, cover, etc.) forming an outer appearance of a body includes a front case101and a rear case102. A space formed by the front case101and the rear case102accommodates various components therein. At least one intermediate case may further be disposed between the front case101and the rear case102. Such cases may be formed by injection-molded synthetic resin, or may be formed using a metallic material such as stainless steel (STS) or titanium (Ti).

In addition, the front case101includes a display unit151, an audio output unit152, a camera121, user input units131and132, a microphone122, an interface unit170, etc. As shown, in this embodiment, the display unit151occupies most a main surface of the front case101. Further, the audio output unit152and the camera121are arranged at a region adjacent to one end of the display unit151, and the user input unit131and the microphone122are arranged at a region adjacent to another end of the display unit151. The user input unit132, the interface unit170, etc. may be arranged on side surfaces of the front case101and the rear case102.

In addition, the display unit151displays information processed in the mobile terminal100. For example, when the mobile terminal100is in a phone call mode, the display unit151may display a User Interface (UI) or a Graphic User Interface (GUI) associated with a call or other communication (such as text messaging, multimedia file downloading, etc.). When the mobile terminal100is in a video call mode or image capturing mode, the display unit151may display a captured image and/or received image, a UI or GUI that shows videos or images and functions related thereto, and the like.

The display unit151may include at least one of a Liquid Crystal Display (LCD), a Thin Film Transistor-LCD (TFT-LCD), an Organic Light Emitting Diode (OLED) display, a flexible display, a three-dimensional (3D) display, or the like. Some of these displays may be configured to be transparent so that outside may be seen therethrough, which may be referred to as a transparent display. A representative example of the transparent display may include a Transparent Organic Light Emitting Diode (TOLED), and the like. The rear surface portion of the display unit151may also be implemented to be optically transparent. Under this configuration, a user can view an object positioned at a rear side of a body through a region occupied by the display unit151of the body.

Further, the display unit151may be implemented in two or more in number according to a configured aspect of the mobile terminal100. For instance, a plurality of displays may be arranged on one surface integrally or separately, or may be arranged on different surfaces.

Also, if the display unit151and a touch sensitive sensor (referred to as a touch sensor) have a layered structure therebetween, the structure can be referred to as a touch screen. The display unit151may also be used as an input device rather than an output device, and the touch sensor may be implemented as a touch film, a touch sheet, a touch pad, and the like.

Further, the interface unit170is generally implemented to interface the mobile terminal100with external devices. The interface unit170may allow a data reception from an external device, a power delivery to each component in the mobile terminal100, or a data transmission from the mobile terminal100to an external device. The interface unit170may include, for example, wired/wireless headset ports, external charger ports, wired/wireless data ports, memory card ports, ports for coupling devices having an identification module, audio Input/Output (I/O) ports, video I/O ports, earphone ports, and the like.

The touch sensor may be configured to convert changes of a pressure applied to a specific part of the display unit151, or a capacitance occurring from a specific part of the display unit151, into electric input signals. Also, the touch sensor may be configured to sense not only a touched position and a touched area, but also a touch pressure.

When touch inputs are sensed by the touch sensors, corresponding signals are transmitted to a touch controller. The touch controller processes the received signals, and then transmits corresponding data to the controller180. Accordingly, the controller180can sense which region of the display unit151has been touched.

In addition, the user input unit is manipulated to receive a command for controlling the operation of the mobile terminal100, and inFIG. 1includes a plurality of manipulation units131and132. The manipulation units131and132may be referred to as manipulating portions, and may include any type of ones that can be manipulated in a user's tactile manner. Also, commands input through the first or second user input units131and132may be variously set. For instance, the first manipulation unit131is configured to input commands such as START, END, SCROLL or the like, and the second manipulation unit132is configured to input commands for controlling a level of sound output from the audio output unit152, or commands for converting the current mode of the display unit151to a touch recognition mode.

Next,FIG. 2is a rear perspective view of the mobile terminal100ofFIG. 1. Referring toFIG. 2, a camera121′ is additionally provided on the rear case102. The camera121′ faces a direction which is opposite to a direction faced by the camera121, and may have different pixels from those of the camera121.

In addition, the camera121may operate with relatively lower pixels (lower resolution). Thus, the camera121may be useful when a user can capture his face and send it to another party during a video call or the like. On the other hand, the camera121′ may operate with a relatively higher pixels (higher resolution) such that it can be useful for a user to obtain higher quality pictures for later use. The cameras121and121′ may be installed at a terminal body so as to rotate or pop-up.

A flash123and a mirror124are additionally disposed adjacent to the camera121′. The flash123operates in conjunction with the camera121′ when taking a picture using the camera121′, and the mirror124can cooperate with the camera121′ to allow a user to photograph himself or herself in a self-portrait mode.

An audio output unit130may be additionally arranged on a rear surface of the terminal body and cooperate with the audio output unit152disposed on a front surface of the terminal body so as to implement a stereo function. Also, the audio output unit130may be configured to operate as a speakerphone.

A broadcast signal receiving antenna as well as an antenna for calling may also be disposed on a side surface of the terminal body. The broadcast signal receiving antenna which constitutes a part of a broadcasting receiving module may be configured to retract into the terminal body.

In addition, a power supply unit150for supplying power to the mobile terminal100is mounted to the terminal body. The power supply unit may be mounted in the terminal body, or may be configured to be detachable from the outside of the terminal body. The power supply unit150may be mounted to the mobile terminal100by a battery cover190(seeFIG. 3).

A touch pad for detecting touch may be additionally mounted to the rear case102. The touch pad may be also configured to be transmissive like the display unit151. When the display unit151is configured to output visual information from two surfaces, the visual information may be recognized even through the touch pad. The visual information output from the two surfaces of the display unit151may be controlled by the touch pad. A display may be additionally mounted to the touch pad, and a touch screen may be arranged at the rear case102.

The touch pad interworks with the display unit151of the front case101. The touch pad may be arranged at a rear side of the display unit151in parallel, and may have a size equal to or smaller than that of the display unit151.

FIG. 3is a disassembled perspective view of the mobile terminal ofFIG. 1, andFIG. 4is a rear perspective view of the mobile terminal ofFIG. 2, which shows the rear case102removed from the mobile terminal. As shown inFIG. 3, the mobile terminal100according to one embodiment of the present invention includes an antenna device180which operates in a folded dipole manner. A display module153is mounted to one surface of the first case101, and a printed circuit board160is disposed to cover the display module153.

Each type of electronic device may be mounted on one surface of the PCB160, and a shield member for protecting the electronic devices may be mounted to the one surface. The shield member may be electrically connected to the PCB160for extension of a ground of the PCB160.

The PCB160may also be implemented as an example of a controller for operating each function of the mobile terminal100. The PCB160may be formed in plurality, and may serve as a controller through combination thereof. In addition, the PCB160is electrically connected to the antenna device180, and is configured to process a radio signal (or radio electromagnetic wave) transmitted or received by the antenna device180. For processing of a radio signal, a plurality of transceiver circuits161and162, for example, may be formed at the PCB160.

The transceiver circuits161and162may include one or more integrated circuits, and relevant electric devices. For instance, the transceiver circuits may include a transmission integrated circuit, a reception integrated circuit, a switching circuit, an amplifier, etc. The plurality of transceiver circuits161and162may simultaneously operate by simultaneously feeding conductive members included in radiators. For instance, while one performs transmission, another can perform reception. Alternatively, both transceiver circuits can perform transmission or reception.

As an example of the power supply unit, a battery191is disposed inside the mobile terminal. The battery191is accommodated in a mounting member formed of a metallic material and having a mounting space. The mounting member may be electrically connected to the PCB160, and may be configured to extend a ground of the PCB160. Furthermore, the mounting member, the shield member, and a ground layer of the PCB160may be electrically connected to each other, thereby forming a ground of the mobile terminal.

The antenna device180may be implemented as part thereof and be thermally melted or compressed to a case of the terminal body, a battery cover, or a carrier. Alternatively, part of the antenna device180may be printed on the case of the terminal body, the battery cover or the carrier. Still alternatively, part of the antenna device180may be attached onto the case of the terminal body, the battery cover or the carrier in the form of a film. Here, the compression indicates that a conductive metallic plate to serve as a radiator is mounted to a plastic carrier of a predetermined shape in a pressed manner.

Next,FIG. 4shows conductors are printed on a carrier. Further, the antenna device180according to one embodiment of the present invention may be formed in plurality near an upper end or a lower end of the terminal body. Alternatively, the antenna device180may be formed near a side end of the terminal body.

The antenna device180is an antenna configured to transmit and receive radio signals corresponding to at least one of a personal communication system (PCS), an advanced wireless service (AWS), a digital communications network (DCN) and a long term evolution (LTE). Alternatively, the antenna device180may be one of a broadcast signal receiving antenna which operates in an FM radio frequency band or a Bluetooth band or a WIFI band, a Bluetooth antenna, a satellite signal receiving antenna, and a wireless Internet data receiving antenna. The antenna device180according to one embodiment of the present invention may be a smart MIMO (multi input multi out) antenna system, which may be considered as ‘hybrid antenna’ since the antenna systems operate in different bands and have different forms.

Next,FIGS. 5A and 5Bare conceptual views showing embodiments of an antenna device according to the present invention. As shown, the antenna device180includes a plurality of conductive members, more specifically, a first conductive member181and a second conductive member182which are disposed in parallel. A feed connection portion183or a ground connection portion184is connected to one of the two conductive members, and the ground connection portion184or the feed connection portion183is connected to another of the two conductive members. The members are connected to each other at one point, thereby forming a loop.

Under the configuration that the feed connection portion183and the ground connection portion184are coupled to the conductive members facing each other, the antenna device180serves as a loop antenna having different resonant lengths according to rotation directions. Here, the resonant length indicates a physical length of an antenna for transmitting and receiving a radio signal at a specific frequency band.

Referring toFIG. 5A, the antenna device180according to one embodiment of the present invention is formed to have a resonant length (L1) in a clockwise direction from the feed connection portion183to the first ground connection portion184via the first conductive member181and the second conductive member182, and is formed to have a resonant length (L2) in a counterclockwise direction from the feed connection portion183to the first ground connection portion184via the first conductive member181and the second conductive member182. In addition, a slot antenna having a third resonant length may be defined by a gap between the first conductive member181and the second conductive member182, and may have a length (L3) from one connection point between the first conductive member181and the second conductive member182to the first ground connection portion184.

A first resonant length, a second resonant length and a third resonant length correspond to a half wavelength (λ/2) of a central frequency. Accordingly, the radiation resistance is enhanced, and a ‘Q’ value of an antenna is lowered. As a result, the antenna device180according to one embodiment of the present invention has a higher radiation efficiency and a wider band than a PIFA antenna or an antenna having a monopole structure.

Generally, a radio function of an antenna device is influenced by an electric device. In addition, in the related art, an antenna device is installed in a free space inside a mobile terminal at a position spaced from a display panel by a predetermined distance. However, the antenna device180according to one embodiment of the present invention is disposed to cover part of the display module153, as shown inFIG. 4, due to an enhanced antenna characteristic.

Under this configuration, no free space for mounting the antenna device180is required between the antenna device180and the display module153, or between the antenna and the terminal case. This advantage miniaturizes the entire size of the mobile terminal. The antenna device180according to one embodiment of the present invention may also be disposed to cover part of the display module153and be disposed near one end of the terminal case.

Referring toFIG. 5B, the antenna device180according to another embodiment of the present invention may be designed to transmit and receive radio signals at different frequency bands by changing the positions of the feed connection portion183and the ground connection portion184. Referring toFIGS. 4 and 5A, the first conductive member181and the second conductive member182are spaced from each other, and are disposed in parallel. In addition, the first conductive member181and the second conductive member182are bent from extended points, and extend from the bent positions in parallel toward one direction.

As shown inFIG. 4, the first conductive member181and the second conductive member182extend in parallel from a first plane (P1), and are bent from one or more points. In addition, the first conductive member181and the second conductive member182extend from the bent positions in parallel toward one direction. Here, the first conductive member181and the second conductive member182which extend from the bent positions may be disposed on a second position (P2) crossing the first plane (P1). The first plane (P1) may be one surface of upper and lower surfaces of the terminal body, and the second plane (P2) may be one surface of side surfaces of the terminal body.

The first conductive member181or the second conductive member182may have a meander structure in which the first conductive member181or the second conductive member182is implemented in the form of a curved conductor so as to have a predetermined length corresponding to a specific frequency.

One of the first conductive member181and the second conductive member182may also be ground-connected to a PCB160having a ground by the ground connection portion184. The ground connection portion184is ground-connected to one of the first conductive member181and the second conductive member182to electrically short the one, thereby performing impedance matching with respect to a resonance frequency.

The ground connection portion184is configured to ground the first conductive member181or the second conductive member182, by electrically connecting an electric ground to one end of the first conductive member181or the second conductive member182. Here, the electric ground may be a ground of the PCB160.

The ground connection portion184may be provided with two or more paths having different lengths, and may be provided with switches corresponding to the respective paths. Here, each path connects an electric ground to one of radiators (e.g., first member) in a different length, through a corresponding switch provided thereat. The path indicates an electric passage which connects an electric ground to a radiator, and may include a ground plate, a ground clip and a ground line. The path may have a different length by having a ground line of a different length.

The PCB160is feed-connected to one of the first conductive member181and the second conductive member182by the feed connection portion183. The feed connection portion183is configured to feed one of the first conductive member181and the second conductive member182, in an electric connection manner (or electro-magnetic (EM) feeding manner). The feed connection portion183electrically connects a feeding device to one of the first conductive member181and the second conductive member182.

For this connection, the feed connection portion183may include a ground plate, a ground clip and a ground line. The ground plate, the ground clip and the ground line are connected to each other, and transmits a current (or voltage) fed through a feeding device to a conductor of a radiator. Here, the ground line may include a microstrip printed on the PCB.

The first conductive member181or the second conductive member182is partially or entirely formed as a conductor, and operates as a radiator. The first conductive member181or the second conductive member182may be formed in various manners according to a resonance characteristic or a frequency characteristic. Further, a current is fed to the conductor through the feed connection portion183, and the fed current is shorted through the ground connection portion184. Thus, the antenna device180includes independent tuning and has an optimized design in an easy manner.

Next,FIG. 6Ais a conceptual view of an antenna device180according to a comparative example of the present invention,FIGS. 6B and 6Care graphs showing shifts of central frequencies due to tuning,FIG. 7Ais a conceptual view of the antenna device180according to one embodiment of the present invention, andFIGS. 7B to 7Dare graphs showing shifts of central frequencies due to tuning.

In particular,FIG. 6Ais a view showing that a resonant length is adjusted by changing a connection point between the first conductive member181and the second conductive member182. Referring toFIGS. 6A and 6B, once the resonant length is adjusted (T1), a central frequency is shifted (M1) at all frequency bands. Referring toFIGS. 6A and 6C, once the resonant length is adjusted (T2), a central frequency is shifted (M2) at all frequency bands.

For instance, for a multi-band antenna configured to transmit and receive radio signals in all frequency bands of GSM (global system for mobile communication)850, PCS and WCDMA (wideband CDMA) (2.4 GHz), the multi-band antenna may not function at a specific band. In this instance, once a resonant length of the multi-band antenna is adjusted for tuning, an antenna function may be lowered at a specific band.

Also, for a folded dipole antenna, a central frequency is shifted in all frequency bands due to control of a resonant length at a specific part. This causes a difficulty in a frequency design. In order to solve this problem, in the present invention, the feed connection portion183and the ground connection portion184are coupled to the conductive members181and182facing each other. In this instance, resonant lengths of other central frequencies rather than a corresponding central frequency do not change at the time of turning. This facilitates an antenna design.

Referring toFIGS. 7A to 7D, when the respective resonant lengths are adjusted (T3, T4and T5), central frequencies at other frequency bands are not shifted, but only a central frequency at a corresponding frequency band is shifted (M3, M4and M5).

Next,FIGS. 8A to 8Eare conceptual views of antenna devices180,280and380according to modified examples of the present invention. Referring toFIG. 8A, a feed connection portion183is connected to a first conductive member181, and a ground connection portion184is connected to a second conductive member182. The first conductive member181and the second conductive member182are spaced from each other, and are disposed in parallel. Also, the first conductive member181and the second conductive member182are bent from extended points, and extend from the bent positions in parallel toward one direction.

A tuning bar185configured to connect the first conductive member181and the second conductive member182to each other is also formed at one point on a path implemented in a clockwise direction from the feed connection portion183to the ground connection portion184via the first conductive member181. The tuning bar185changes a maximum impedance value of a loop by changing the impedance of the first conductive member181and the impedance of the second conductive member182and the impedances implemented near connection points between the first and second conductive members.

Referring toFIG. 8B, a feed connection portion283is connected to a first conductive member281, and a first ground connection portion284ais connected to a second conductive member282.FIG. 8Bis differentiated fromFIG. 8Ain that the second conductive member282is formed to encompass the first conductive member281, and a second ground connection portion284bis added to the second conductive member282.

Under this configuration, a second resonant length is formed. Here, the second resonant length means a path formed in a counterclockwise direction from the feed connection portion283to the first ground connection portion284avia the first conductive member281. In addition, the second ground connection portion284bmay be formed at a point on a path implemented in a clockwise direction from the feed connection portion283to the first ground connection portion284avia the first conductive member281, thereby controlling the first resonant length.

A slot antenna having a third resonant length may also be defined by a gap between the first conductive member281and the second conductive member283, and has a length from one connection point between the first and second conducive members to the first ground connection portion284a. In this instance, the third resonant length may be variable due to the second ground connection portion284b.

Referring toFIG. 8C, a feed connection portion183is connected to a first conductive member181, and a ground connection portion184is connected to a second conductive member182. Also, sub-conductive members186aand186bextend from a path formed in a clockwise direction from the feed connection portion183to the ground connection portion184via the first conductive member181and the second conductive member182. Due to the length of the sub-conductive members186aand186b, the entire length of the path is extended and the first resonant length can be adjusted. Here, an area of an antenna radiator is increased by an adjusted length, resulting in enhancing a bandwidth. The sub-conductive members186aand186bmay be implemented to have a meander structure or a planner patch form.

Referring toFIG. 8D, a feed connection portion283is connected to a first conductive member281, and a ground connection portion284is connected to a second conductive member282. A sub-conductive member286or a tuning bar285may be formed on a path implemented in a counterclockwise direction from the feed connection portion283to the ground connection portion284via the first conductive member281and the second conductive member282. The sub-conductive member286or the tuning bar285changes an antenna characteristic by controlling a second resonant length.

Referring toFIG. 8E, a first conductive member383and a second conductive member382are formed on different planes spaced from each other, and are connected to each other at one point. A feed connection portion383is connected to the first conductive member383, and a ground connection portion384is connected to the second conductive member382. In the same manner as in the aforementioned embodiments, connection points between the conductive members are variable to enable tuning at a desired frequency band. Furthermore, in the antenna device ofFIG. 8E, the first conductive member383and the second conductive member382are spaced from each other in a Z-direction in space, not in X and Y directions on the same plane. In this instance, an area occupied by the conductive members383and382on one plane is deceased. As a result, the entire size of the antenna can be miniaturized.

The first conductive member383and the second conductive member382may also be formed in a carrier to have a double structure, or may be respectively formed on an upper and lower surfaces of the carrier. Alternatively, the first conductive member383and the second conductive member382may be formed at different cases, and may be connected to each other.

Thus, the present invention may have the following advantages. First, the feed connection portion and the ground connection portion are respectively coupled to conductive members facing each other. This implements a loop antenna having different resonant lengths according to rotation directions. As a result, the antenna device can be tuned in an independent manner, and have an optimum design.

Secondly, a first resonant length, a second resonant length and a third resonant length correspond to a half wavelength (λ/2) of a central frequency. Accordingly, the radiation resistance is enhanced, and a ‘Q’ value of an antenna is lowered. As a result, no free space for mounting the antenna device is required between the antenna device and a display panel, or between an antenna and a terminal case. This miniaturizes the entire size of the mobile terminal.