Shorted monopole antenna
The present invention discloses a shorted monopole antenna comprising a radiating portion comprises a first metal portion and a second metal portion and is located on the dielectric substrate, without overlapping with the ground plane. The first metal portion comprises a coupling section formed by bending the front portion of the first metal portion into two adjacent sections with a coupling gap. A first end of the feeding portion is electrically connected to the first metal portion. A second end of the feeding portion is the antenna's feeding point. The shorting portion is disposed on the dielectric substrate, without overlapping with the ground plane. A first end of the capacitive element is electrically connected to the antenna's feeding point. A second end of the capacitive element is electrically connected to a source.
1. A shorted monopole antenna comprising:
a dielectric substrate;
a ground plane disposed on a portion of the dielectric substrate;
a radiating portion disposed on the dielectric substrate, wherein the radiating portion does not overlap with the ground plane, and the radiating portion comprises:
a first metal portion bent to form two adjacent coupling metal portions with a coupling gap, wherein the coupling gap is less than 2 mm, and a length of the first metal portion is larger than one-eighth wavelength of a central frequency of the antenna's lower band; and
a second metal portion, the second metal portion having a first end electrically connected to the first metal portion, and a second end being open-ended;
a feeding portion disposed on the dielectric substrate, without overlapping with the ground plane, the feeding portion having a first end electrically connected to the first metal portion, and a second end being an antenna feeding point;
a shorting portion disposed on the dielectric substrate, wherein the shorting portion does not overlap with the ground plane, the shorting portion has a first end electrically connected to the first metal portion, and a second end electrically connected to the ground plane; and
a capacitive element disposed on the dielectric substrate, the capacitive element overlapping with the ground plane and having a first end electrically connected to the antenna feeding point, and a second end electrically connected to a source.
2. The shorted monopole antenna as claimed in claim 1 , wherein the dielectric substrate is a system board of a portable communication device.
3. The shorted monopole antenna as claimed in claim 1 , wherein the radiating portion, the feeding portion, and the shorting portion are formed on the dielectric substrate by printing or etching.
4. The shorted monopole antenna as claimed in claim 1 , wherein the capacitive element is a chip capacitor.
5. The shorted monopole antenna as claimed in claim 1 , wherein the first metal portion and second metal portion have a uniform width or a nonuniform width.
6. The shorted monopole antenna as claimed in claim 1 , wherein the second metal portion further comprises at least one branch.
7. The shorted monopole antenna as claimed in claim 1 , wherein the feeding portion has a uniform width or a nonuniform width.
8. The shorted monopole antenna as claimed in claim 1 , wherein the ground plane is on a plane of the dielectric substrate; the radiating portion, the feeding portion, the shorting portion and the capacitive element are on another plane of the dielectric substrate.
9. The shorted monopole antenna as claimed in claim 1 , wherein the ground plane, the radiating portion, the feeding portion, the shorting portion, and the capacitive element are on a plane of the dielectric substrate.