Tunable antenna and wireless communication device employing same

The subject matter herein generally relates to antenna structures, and particular to a tunable antenna and wireless communication device employing same.

With improvements in the integration of wireless communication systems, broadband antennas have become increasingly important. For a wireless communication device to utilize various frequency bandwidths, antennas having wider bandwidths have become a significant technology.

Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.

FIG. 1 is an isometric view of one embodiment of a wireless communication device employing a tunable antenna.

FIG. 2 is a circuit diagram of the tunable antenna shown in FIG. 1 .

FIG. 3 is a diagram showing high-frequency band return loss (RL) measurements of the tunable antenna of FIG. 1 .

FIG. 4 is a diagram showing high-frequency band transmission efficiency measurements of the tunable antenna of FIG. 1 .

FIG. 5 is a diagram showing low-frequency band RL measurements of the tunable antenna of FIG. 1 .

FIG. 6 is a diagram showing low-frequency band transmission efficiency measurements of the tunable antenna of FIG. 1 .

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure.

Several definitions that apply throughout this disclosure will now be presented.

The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “comprising” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like.

FIG. 1 illustrates an isometric view of one embodiment of a wireless communication device 200 employing a tunable antenna 100 and a substrate 20 . The substrate 20 has a signal source 21 . The tunable antenna 100 includes a metal cover 10 and at least one matching circuit 30 . The metal cover 10 serves as a cover of the wireless communication device 100 , and includes a radiation body 11 , a main body 15 , and a dielectric member 13 coupled between the radiation body 11 and the main body 15 . The radiation body 11 is electronically coupled to the signal source 21 and dielectric relative to the main body 15 . The at least one matching circuit 30 is electronically coupled to the radiation body 11 and arranged on the substrate 20 . The at least one matching circuit 30 is configured to switch between multiple working mode to enable the radiation body 11 to receive and send wireless signals at different frequency bands.

In one embodiment, the at least one matching circuit includes a first matching circuit 31 and a second matching circuit 32 (shown in FIG. 1 ). The radiation body 11 includes a first signal point 111 , a second signal point 112 , and a feeding point located between the first signal point 111 and the second signal point 112 , the first signal point 111 and the second signal point 112 are arranged at two opposite ends of the radiation body 11 respectively. The first signal point 111 , the second signal point 112 and the feeding point are electronically coupled to the first matching circuit 31 , the second matching circuit 32 and the signal source 21 , respectively.

The tunable antenna 100 further includes a connecting assembly 40 . The connecting assembly 40 includes a first connecting member, a second connecting member 42 , and a third connecting member 43 , all of which are located on the substrate 20 corresponding to the first signal point 111 , the second signal point 112 and the feeding point, respectively. The first connecting member is configured to electronically couple the first signal point 111 with the first matching circuit 31 ; the second connecting member 42 is configured to electronically couple the second signal point 112 with the second matching circuit 32 ; and the third connecting member 43 is configured to electronically couple the feeding point with the signal source 21 . In one embodiment, the first connecting member, the second connecting member 42 , and the third connecting member 43 are metal sheets.

The substrate 20 includes a ground layer 23 formed thereon. The main body 15 is electronically coupled to the ground layer 23 , such that noise signals generated by the main body 15 can be eliminated, and the radiation body 11 can be prevented from being interfered by the noise signals.

FIG. 2 illustrates a circuit diagram of the tunable antenna 100 as shown in FIG. 1 . The first matching circuit 31 includes a first switch 311 , a plurality of first loads and a first open-circuit load 312 . Each of the plurality of first loads is grounded. The first switch 311 is configured to selectively couple the first signal point 111 with either the first open-circuit load 312 or one of the plurality of first loads. In one embodiment, the plurality of first loads includes a capacitor L 1 , an inductor L 1 , and an inductor L 2 , each of which has a first end can be coupled to the first switch 311 , and a second end that is grounded. When the first switch 311 couples the first signal point 111 with the first open-circuit load 312 , the first signal point 111 is brought into an open-circuit state.

The second matching circuit 32 includes a second switch 321 , a plurality of second loads, a second open-circuit load 322 , and a short-circuit load 323 . Each of the plurality of second loads is ground. The second switch 321 is configured to selectively coupled the second signal point 112 with the third end of one of the second loads, the second open-circuit load 322 or the short-circuit load 323 . In one embodiment, the plurality of second loads includes two capacitors C 2 -C 3 , and two inductors L 3 -L 4 , each of which has a third end can be coupled to the second switch 321 , and a fourth end that is grounded. When the second switch 321 couples the second signal point 112 with the second open-circuit load 322 , the second signal point 112 is brought into an open-circuit state. When the second switch 321 couples the second signal point 112 with the short-circuit load 323 , the second signal point 112 is brought into a short-circuit state.

In one embodiment, a capacitance of the capacitor C 1 is 9.1 pF; a capacitance of the capacitor C 2 is 0.8 pF; a capacitance of the capacitor C 3 is 0.5 pF; an inductance of the inductor L 1 is 1.8 nH; an inductance of the inductor L 2 is 1 nH; an inductance of the inductor L 3 is 91 nH; and an inductance of the inductor L 4 is 22 nH.

When the second switch 321 couples the second signal point 112 to the short-circuit load 323 to bring the second signal point 112 into a short-circuit state, the first switch 311 can selectively couple the first signal point 111 with one of the inductor L 1 , the inductor L 2 , or the capacitor C 1 , to enable the radiation body 11 to receive and send a first high-frequency band signal, a second high-frequency band signal or a third high-frequency band signal, respectively. When the second switch 321 couples the second signal point 112 to the second open-circuit load 322 to bring the second signal point 112 into an open-circuit state, and the first switch 311 couples the first signal point 111 with the capacitor C 1 , the radiation body 11 can receive and send a fourth high-frequency band wireless signal.

When the first switch 311 couples the first signal point 111 to the first open-circuit load 312 to bring the first signal point 111 into an open-circuit state, the second switch 321 is configured to selectively couple the second signal point 112 with one of the capacitor C 2 , the capacitor C 3 , the inductor L 3 , and the inductor L 4 , thereby enabling the radiation body 11 to receive and send a first low-frequency band signal, a second low-frequency band signal, a third low-frequency band signal, and a fourth low-frequency band signal.

FIG. 3 illustrates a diagram showing high-frequency band return loss (RL) measurements of the tunable antenna 100 of FIG. 1 . Curve S 1 represents a RL of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the inductor L 1 , it can be derived from the curve S 1 that the tunable antenna 100 can receive/send signal at the first high-frequency band of GSM1800/LET Band 3. Curve S 2 represents a RL of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the inductor L 2 , it can be derived from the curve S 2 that the tunable antenna 100 can receive/send signal at the second high-frequency band of GSM1900/LET Band 2. Curve S 3 represents a RL of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the capacitor C 1 , it can be derived from the curve S 3 that the tunable antenna 100 can receive/send signal at the third high-frequency band of WCDMA/LET Band 1. Curve S 4 represents a RL of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the second open-circuit load 322 , and the first switch 311 couples the first signal point 111 with the capacitor C 1 , it can be derived from the curve S 4 that the tunable antenna 100 can receive/send signal at the fourth high-frequency band of LET Band 7.

FIG. 4 illustrates a diagram showing high-frequency band transmission efficiency measurements of the tunable antenna 100 of FIG. 1 . Curve M 1 represents a transmission efficiency of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the inductor L 1 . Curve M 2 represents a transmission efficiency of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the inductor L 2 . Curve M 3 represents a transmission efficiency of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the short-circuit load 323 , and the first switch 311 couples the first signal point 111 with the capacitor C 1 . Curve M 4 represents a transmission efficiency of the tunable antenna 100 when the second switch 321 couples the second signal point 112 to the second open-circuit load 322 , and the first switch 311 couples the first signal point 111 with the capacitor C 1 . It can be derived from FIG. 4 that the antenna structure 100 can achieve exceptional transmission efficiency when the first matching circuit 31 switches to different working modes.

FIG. 5 illustrates a diagram showing low-frequency band return loss (RL) measurements of the tunable antenna 100 of FIG. 1 . Curve S 5 represents a RL of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the capacitor C 2 , it can be derived from the curve S 5 that the tunable antenna 100 can receive/send signal at the first high-frequency band of LET Band 17. Curve S 6 represents a RL of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the capacitor C 3 , it can be derived from the curve S 6 that the tunable antenna 100 can receive/send signal at the first high-frequency band of LET Band 13. Curve S 7 represents a RL of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the inductor L 3 , it can be derived from the curve S 7 that the tunable antenna 100 can receive/send signal at the first high-frequency band of GSM850/LTE Band 5. Curve S 8 represents a RL of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the inductor L 4 , it can be derived from the curve S 8 that the tunable antenna 100 can receive/send signal at the first high-frequency band of GSM900/LTE Band 8.

FIG. 6 illustrates a diagram showing low-frequency band transmission efficiency measurements of the tunable antenna 100 of FIG. 1 . Curve M 5 represents a transmission efficiency of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the capacitor C 2 . Curve M 6 represents a transmission efficiency of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the capacitor C 3 . Curve M 7 represents a transmission efficiency of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the inductor L 3 . Curve M 8 represents a transmission efficiency of the tunable antenna 100 when the first switch 311 couples the first signal point 111 to the open-circuit load 312 , and the second switch 321 couples the second signal point 112 with the inductor L 4 . It can be derived from FIG. 6 that the antenna structure 100 can achieve exceptional transmission efficiency when the second matching circuit 32 switches to different working modes.

The embodiments shown and described above are only examples. Many details are often found in the art. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.