Antenna structure and wireless communication device using same

An antenna structure includes a housing and a feeding source. The housing forms a radiating portion, a first coupling portion, and a second coupling portion. The first coupling portion and the second coupling portion are grounded. The feeding source is electrically connected to the radiating portion for feeding current to the radiating portion and divides the radiating portion into a first radiating section and a second radiating section. When the feeding source supplies current, the current flows through the first radiating section and is coupled to the first coupling portion to activate a first operation mode and a second operation mode. When the feeding source supplies current, the current flows through the second radiating section and is coupled to the second coupling portion to activate a third operation mode and a fourth operation mode.

FIELD

The subject matter herein generally relates to an antenna structure and a wireless communication device using the antenna structure.

BACKGROUND

Antennas are important components in wireless communication devices for receiving and transmitting wireless signals at different frequencies, such as signals in Long Term Evolution Advanced (LTE-A) frequency bands. However, the antenna structure is complicated and occupies a large space in the wireless communication device, which is inconvenient for miniaturization of the wireless communication device.

DETAILED DESCRIPTION

The present disclosure is described in relation to an antenna structure and a wireless communication device using same.

FIG. 1illustrates an exemplary embodiment of a wireless communication device200using an exemplary antenna structure100. The wireless communication device200can be a mobile phone or a personal digital assistant, for example. The antenna structure100can receive and transmit wireless signals.

As illustrated inFIG. 2andFIG. 3, the antenna structure100includes a housing11, a feeding source13, and a matching circuit15(shown inFIG. 2).

The housing11houses the wireless communication device200. In this exemplary embodiment, the housing11includes a backboard111and a side frame113. In this exemplary embodiment, the backboard111is made of non-metallic material, for example, plastic or glass. The side frame113is made of metallic material. The backboard111and the side frame113cooperatively form the housing of the wireless communication device200.

The side frame113is substantially annular. The side frame113defines an opening (not labeled). The wireless communication device200includes a display201. The display201is received in the opening. The display201has a display surface. The display surface is exposed at the opening and is positioned parallel to the backboard111.

In this exemplary embodiment, the side frame113is positioned around a periphery of the backboard111. The side frame113and the backboard111cooperatively form a receiving space114with the opening. The receiving space114can receive a printed circuit board, a processing unit, or other electronic components or modules.

In this exemplary embodiment, the side frame113includes an end portion115, a first side portion116, and a second side portion117. In this exemplary embodiment, the end portion115is a bottom portion of the wireless communication device200. The first side portion116is spaced apart from and parallel to the second side portion117. The end portion115has first and second ends. The first side portion116is connected to the first end of the end portion115and the second side portion117is connected to the second end of the end portion115. In this exemplary embodiment, the end portion115, the first side portion116, and the second side portion117are all perpendicularly connected to the backboard111.

The side frame113further defines a through hole119, a gap121, and a groove122. The through hole119is defined at a middle position of the end portion115and passes through the end portion115.

The wireless communication device200further includes a substrate21and at least one electronic elements. In this exemplary embodiment, the substrate21is a printed circuit board (PCB) and is made of dielectric material, for example, epoxy resin glass fiber (FR4) or the like. In this exemplary embodiment, the wireless communication device200includes five electronic elements, that is, a first electronic element23, a second electronic element25, a third electronic element26, a fourth electronic element27, and a fifth electronic element28.

The first electronic element23is a Universal Serial Bus (USB) module. The first electronic element23is received in the receiving space114. The first electronic element23is positioned adjacent to and is electrically connected to the substrate21. The first electronic element23corresponds to the through hole119. Then, the first electronic element23is partially exposed from the through hole119. A USB device can be inserted in the through hole119and be electrically connected to the first electronic element23.

The second electronic element25is a microphone. The second electronic element25is received in the receiving space114between the groove122and the first electronic element23. The third electronic element26is a battery. The third electronic element26is received in the receiving space114. The third electronic element26is spaced apart from the first electronic element23and the second electronic element25. The fourth electronic element27is a loudspeaker. The fourth electronic element27is received in the receiving space114between the substrate21and the first side portion116. The fifth electronic element28is a vibrator. The fifth electronic element28is received in the receiving space114between the substrate21and the second side portion117.

In this exemplary embodiment, the gap121is defined at the side frame113between the through hole119and the first side portion116. The groove122is defined at the side frame113between the through hole119and the second side portion117. The gap121and the groove122are defined at two sides of the through hole119. In this exemplary embodiment, the gap121and the groove122are both pass through and extend to cut across the side frame113. The side frame113is divided into three portions by the gap121and the groove122. The three portions are a radiating portion A1, a first coupling portion A2, and a second coupling portion A3.

In this exemplary embodiment, a first portion of the side frame113between the gap121and the groove122forms the radiating portion A1. A second portion of the side frame113extending from a side of the gap121adjacent to the first side portion116forms the first coupling portion A2. A third portion of the side frame113extending from a side of the groove122away from the gap121and adjacent to the second side portion117forms the radiating portion A3. In this exemplary embodiment, the first coupling portion A2and the second coupling portion A3are both grounded.

In this exemplary embodiment, the gap121and the groove122are both filled with insulating material, for example, plastic, rubber, glass, wood, ceramic, or the like, thereby isolating the radiating portion A1, the first coupling portion A2, and the second coupling portion A3.

FIG. 3illustrates the feeding source13is positioned in the receiving space114between the first electronic element23and the second electronic element25. One end of the feeding source13is electrically connected to the first radiating portion A1through the matching circuit15. The feeding source13divides the radiating portion A1into two portions, that is, a first radiating section A11and a second radiating section A12. A first portion of the side frame113between the feeding source13and the gap121forms the first radiating section A11. A second portion of the side frame113between the feeding source13and the groove122forms the second radiating portion A12.

In this exemplary embodiment, a location of the feeding source13does not correspond to a middle portion of the radiating portion A1. The first radiating section A11is longer than the second radiating section A12.

When the feeding source13supplies current, a first portion of the current flows through the first radiating section A11and is coupled to the first coupling portion A2through the gap121. Then, the feeding source13, the first radiating section A11, and the first coupling portion A2cooperatively form a coupling-feed antenna to activate the first operation mode and a second operation mode to generate radiation signals in a first radiation frequency band and a second radiation frequency band.

When the feeding source13supplies current, a second portion of the current flows through the second radiating section A12and is coupled to the second coupling portion A3through the groove122. Then, the feeding source13, the second radiating section A12, and the second coupling portion A3cooperatively form a coupling-feed antenna to activate the third operation mode and a fourth operation mode to generate radiation signals in a third radiation frequency band and a fourth radiation frequency band.

In this exemplary embodiment, a frequency of the second radiation frequency band is higher than a frequency of the first radiation frequency band. A frequency of the third radiation frequency band is higher than a frequency of the second radiation frequency band. A frequency of the fourth radiation frequency band is higher than a frequency of the third radiation frequency band.

In this exemplary embodiment, the first operation mode is a Long Term Evolution Advanced (LTE-A) low frequency operation mode. The first radiation frequency band is about 700-960 MHz. The second operation mode is a LTE-A first middle frequency operation mode. The second radiation frequency band is about 1450-1990 MHz. The third operation mode is a LTE-A second middle frequency operation mode. The third radiation frequency band is about 1920-2170 MHz. The fourth operation mode is a LTE-A high frequency operation mode. The fourth radiation frequency band is about 2300-2690 MHz.

As illustrated inFIG. 4, in this exemplary embodiment, the matching circuit15is used for impedance matching for the radiation frequency bands of the antenna structure100. The matching circuit15includes a first impedance element151and a second impedance element153. One end of the first impedance element151is electrically connected to feeding source13. Another end of the first impedance element153is electrically connected to the radiating portion A1. One end of the second impedance element153is electrically connected between the first impedance element151and the radiating portion A1. Another end of the second impedance element153is grounded.

In this exemplary embodiment, the first impedance element151is a capacitor. The second impedance element153is an inductor. A capacitance value of the first impedance element151is about 3 pF. An inductance value of the second impedance element13is about 6.2 nH.

In other exemplary embodiments, the first impedance element151and the second impedance element153are not limited to be a capacitor and an inductor, and can be other impedance elements or a combination.

As illustrated inFIG. 1,FIG. 3, andFIG. 5, in this exemplary embodiment, the antenna structure100further includes a matching element16and a switching circuit17. The matching element16and the switching circuit17are both received in the receiving space114between the feeding source13and the first electronic element23.

In this exemplary embodiment, the matching element16a capacitor and a capacitance value of the matching element16is about 33 pF. One end of the impedance element16is electrically connected to a location of the first radiating section A11adjacent to the groove122. Another end of the impedance element16is electrically connected to the switching circuit17. One end of the switching circuit17is electrically connected to the matching element16. Then the switching circuit17is electrically connected to the first radiating section A11through the matching element16. Another end of the switching circuit17is grounded.

The switching circuit17includes a switch171and a plurality of switching elements173. The switch171is electrically connected to the matching element16. Each of the switching elements173can be an inductor, a capacitor, or a combination of the inductor and the capacitor. The switching elements173are connected in parallel to each other. One end of each switching element173is electrically connected to the switch171. The other end of each switching element173is grounded.

Through control of the switch171, the first radiating section A11can be switched to connect with different switching elements173. Since each switching element173has a different impedance, the operating frequency band of the first operation mode can be adjusted.

FIG. 6toFIG. 9illustrate scattering parameter graphs of the antenna structure100when the switch171switches to different switching elements173.FIG. 6toFIG. 9respectively corresponds to four different frequency bands, and respectively correspond to four of multiple low frequency operation modes that the switching circuit17can be switched. For example, inFIG. 6, the antenna structure100can work at a frequency band of 700 MHz. InFIG. 7, the antenna structure100can work at a frequency band of 750 MHz. InFIG. 8, the antenna structure100can work at a frequency band of 800/850 MHz. InFIG. 9, the antenna structure100can work at a frequency band of 900/1400/1800/1900/2100/2300/2500 MHz.

In addition, when the switching circuit17is switched to one of the switching elements173and the antenna structure100works at a frequency band of 900 MHz, the antenna structure100also has good effects in the middle and the high frequency bands.

FIG. 10illustrates a gain efficiency graph of the antenna structure100when the switch171switches to different switching elements173. Curves S101to S104respectively corresponds to four different frequency bands, and respectively correspond to four of multiple low frequency operation modes that the switching circuit17can be switched. Similarly, when the switching circuit17is switched to one of the switching elements173and the antenna structure100works at a frequency band of 900 MHz, the antenna structure100also has good effects in the middle and the high frequency bands.

As illustrated inFIG. 6toFIG. 10, the antenna structure100may work at a corresponding LTE-A low frequency band, for example, a frequency band of 699-960 MHz. The antenna structure100may also work at a LTE-A middle frequency band (a frequency band of 1450-1990 MHz and a frequency band of 1920-2170 MHz) and a LTE-A high frequency band (a frequency band of LTE-A 2300-2690 MHz). That is, the antenna structure100may completely cover the LTE-A low, middle, and high frequency bands. When the antenna structure100works at these frequency bands, the antenna structure100has a good radiating efficiency, which satisfies antenna design requirements.

As described above, the antenna structure100defines the gap121and the groove122, then the side frame113is divided into a first radiating section A11, a second radiating section A12, a first coupling portion A2, and a second coupling portion A3. The antenna structure100further includes the feeding source13. The current from the feeding source13flows through the first radiating section A11and is further coupled to the first coupling portion A2. The current from the feeding source13further flows through the second radiating section A12and is coupled to the second coupling portion A3. Then the first radiating section A11and the first coupling portion A2cooperatively activate the first operation mode and the second operation mode to generate radiation signals in the low frequency band and the first middle frequency band. The second radiating section A12and the second coupling portion A3cooperatively activate the third operation mode and the fourth operation mode to generate radiation signals in the second middle frequency band and the high frequency band. The wireless communication device200can use the first radiating section A11, the second radiating section A12, the first coupling portion A2, and the second coupling portion A3to receive or send wireless signals at multiple frequency bands simultaneously through carrier aggregation (CA) technology.

In addition, the antenna structure100includes the housing11. The gap121and the groove122are both defined on the side frame113instead of the backboard111. Then the antenna structure100can only use the side frame113to activate corresponding low, middle, and high frequency bands. Then the backboard111can be entirely made of non-metallic material, which is complete and beautiful, and can effectively adapt to a trend of a miniaturization of antenna clearance areas, and can also effectively ensure a stability of wireless signal reception.