Multiband mobile communication device and antenna thereof
A multiband mobile communication device has a ground plane and an antenna. The antenna is disposed on a dielectric substrate. The antenna includes a monopole, a shorted radiating portion, a first radiating branch, and a second radiating branch. The monopole includes a feeding end, and the feeding end is the feeding point of the antenna. The shorted radiating portion has a shorting end electrically connected to the ground plane, and its other end is left open. The shorted radiating portion is extended along the monopole and has a coupling gap to the monopole. The first radiating branch has an end electrically connected to the shorted radiating portion, and its other end is left open. The first radiating branch is extended toward the shorting end of the shorted radiating portion and located on the opposite side of the monopole. The second radiating branch has an end electrically connected to the shorted radiating portion, and its other end is left open. The second radiating branch is extended along the first radiating branch, with the first radiating branch located between the second radiating branch and the shorted radiating portion.
1. A multiband mobile communication device having a ground plane and an antenna, wherein the antenna is disposed on a dielectric substrate, the antenna comprising:
a monopole including a feeding end which is a feeding point of the antenna, with the monopole generating a first resonant mode of the antenna;
a shorted radiating portion having one end as a shorting end electrically connected to the ground plane and another end left open, with the shorted radiating portion extending along the monopole and having a coupling gap to the monopole, with the shorted radiating portion generating a second resonant mode of the antenna by coupling excitation of the monopole;
a first radiating branch having one end electrically connected to the shorted radiating portion and another end left open, with the first radiating branch extending toward the shorting end of the shorted radiating portion, with the shorted radiating portion located between the first radiating branch and the monopole, with the first radiating branch generating a third resonant mode, wherein the third resonant mode and the first resonant mode form a first operating band of the antenna; and
a second radiating branch having one end electrically connected to the shorted radiating portion and another end left open, with the second radiating branch extending along the first radiating branch, with the first radiating branch located between the second radiating branch and the shorted radiating portion, with the second radiating branch generating a fourth resonant mode, wherein the fourth resonant mode and the second resonant mode form a second operating band of the antenna.
2. The multiband mobile communication device as claimed in claim 1 , wherein the coupling gap is less than 2 mm.
3. The multiband mobile communication device as claimed in claim 1 , wherein the monopole is approximately of an inverted-L shape, T shape, or inverted-U shape.
4. The multiband mobile communication device as claimed in claim 1 , wherein the ground plane is a system ground plane of a mobile phone.
5. The multiband mobile communication device as claimed in claim 1 , wherein the first operating band covers 1710˜2690 MHz.
6. The multiband mobile communication device as claimed in claim 1 , wherein the second operating band covers 698˜960 MHz.
7. The multiband mobile communication device as claimed in claim 1 , wherein the antenna comprises a third radiating branch having one end electrically connected to the shorted radiating portion and another end left open, with the third radiating branch extending toward the shorting end of the shorted radiating portion, with the third radiating branch located between the first radiating branch and the shorted radiating portion, with the third radiating branch generating a resonant mode for enhancing an operating bandwidth of the antenna.
8. An antenna used in a mobile communication device having a ground plane, the antenna comprising:
a monopole including a feeding end which is a feeding point of the antenna, with the monopole generating a first resonant mode of the antenna;
a shorted radiating portion having one end as a shorting end electrically connected to the ground plane and another end left open, with the shorted radiating portion extending along the monopole and having a coupling gap to the monopole, with the shorted radiating portion generating a second resonant mode of the antenna by coupling excitation of the monopole;
a first radiating branch having one end electrically connected to the shorted radiating portion and another end left open, with the first radiating branch extending toward the shorting end of the shorted radiating portion, with the shorted radiating portion located between the first radiating branch and the monopole, with the first radiating branch generating a third resonant mode, wherein the third resonant mode and the first resonant mode form a first operating band of the antenna; and
a second radiating branch having one end electrically connected to the shorted radiating portion and another end left open, with the second radiating branch extending along the first radiating branch, with the first radiating branch located between the second radiating branch and the shorted radiating branch, with the second radiating branch generating a fourth resonant mode, wherein the fourth resonant mode and the second resonant mode form a second operating band of the antenna.
9. The antenna as claimed in claim 8 , wherein the antenna is disposed on a dielectric substrate.