1. A dual-band inverted-F antenna, comprising:
a first radiating unit having a first long side and a first short side;
a second radiating unit having a second long side and a second short side, wherein the second long side is disposed opposite to the first short side of the first radiating unit; and
a third radiating unit having a first radiating part, a second radiating part, and a third radiating part, wherein the second radiating part and the third radiating part are extended respectively from one side of the first radiating part, and a gap exists between the third radiating unit and the first radiating unit.
2. The dual-band inverted-F antenna of claim 1, wherein the first radiating unit and the second radiating unit operate in a first band.
3. The dual-band inverted-F antenna of claim 2, wherein the first band is compliant with the IEEE 802.11bg standard between 2.4 GHz and 2.5 GHz.
4. The dual-band inverted-F antenna of claim 2, wherein a length of the first long side and a length of the second long side are roughly equal to one quarter of the wavelengths in the first band.
5. The dual-band inverted-F antenna of claim 1, wherein the third radiating unit operates in a second band.
6. The dual-band inverted-F antenna of claim 5, wherein the second band is compliant with the IEEE 802.11a standard between 4.5 GHz and 5.85 GHz.
7. The dual-band inverted-F antenna of claim 1, wherein the first radiating part, the second radiating part, and the third radiating part of the third radiating unit are quadrangles.
8. The dual-band inverted-F antenna of claim 5, wherein, in the third radiating unit, the first radiating part, the second radiating part, and the third radiating part are trapezoids, the lower bases of the second radiating part and the third radiating part are part of the upper base of the first radiating part, and the second and third radiating parts are extended from the upper base of the first radiating part.
9. The dual-band inverted-F antenna of claim 8, wherein the sum of lengths of the upper bases of the second radiating part and the third radiating part is greater than or equal to one third of a length of the lower base of the first radiating part.
10. The dual-band inverted-F antenna of claim 8, wherein a length of the upper base of the second radiating part is greater than a length of the upper base of the third radiating part.
11. The dual-band inverted-F antenna of claim 8, wherein a length of the lower base of the first radiating part is about one quarter of the wavelengths in the second band.
12. The dual-band inverted-F antenna of claim 1 further comprising an impedance matching unit, wherein one side of the impedance matching unit is disposed opposite to the third radiating unit, and another side of the impedance matching unit is disposed opposite to the first radiating unit.
13. The dual-band inverted-F antenna of claim 12, wherein the impedance matching unit is a polygonal.
14. The dual-band inverted-F antenna of claim 1 further comprising a substrate, wherein the first radiating unit, the second radiating unit, and the third radiating unit are disposed on the substrate.
15. The dual-band inverted-F antenna of claim 14, wherein the substrate is a print circuit board (PCB).
16. The dual-band inverted-F antenna of claim 1, wherein the gap has an L shape.
17. The dual-band inverted-F antenna of claim 1, wherein the first radiating unit and the second radiating unit have respectively a feed-in point and a ground point.
18. The dual-band inverted-F antenna of claim 17 further comprising a conducting unit, wherein the conducting unit has a conductor in electrical contact with the feed-in point and a ground conductor in electrical contact with the ground point.
19. The dual-band inverted-F antenna of claim 18, wherein the conducting unit is a coaxial cable.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system for manufacturing a multiple density substrate for differential impact energy absorption with a mold having a mold cavity of a predetermined shape, a first set of unbonded beads having a first density, and a second set of unbonded beads having a second density, the system comprising:
a casing for receiving the first set of unbonded beads, the casing being configured to be positioned in the mold cavity to leave a void in the mold cavity;
a mechanism for injecting a sufficient amount of the second set of unbonded beads into the void; and
a mechanism for bonding the first and second sets of beads together with steam to define a molded set of bonded beads having the predetermined shape.
2. The system of claim 1 wherein the casing has a higher melting temperature than the first and second sets of unbonded beads.
3. The system of claim 1 wherein the casing has a melting temperature that is sufficiently low such that the casing is meltable when the first and second sets of beads are bonded together.
4. The system of claim 1 wherein the casing is a premolded casing having a predetermined shape.
5. The system of claim 1 wherein the casing is a bag.
6. The system of claim 1 wherein the casing is a mesh bag.
7. The system of claim 6 wherein the mesh bag has a higher melting temperature than the first and second sets of unbonded beads.
8. The system of claim 1 wherein the casing comprises a low melt polymer bag.
9. The system of claim 1 wherein the mechanism for injecting the second set of unbonded beads includes a nozzle in communication with the cavity.
10. A system for manufacturing a multiple density substrate using a first set of unbonded beads having a first density, and a second set of unbonded beads having a second density different than the first density, the system comprising:
a mold having a cavity and an injection hole in communication with the cavity; and
a casing for receiving the first set of unbonded beads, the casing being configured to be positioned in the mold cavity with the first set of unbonded beads received therein so as to leave a void in the mold cavity;
wherein the injection hole of the mold is configured to receive the second set of unbonded beads and to introduce the second set of unbonded beads into the void.
11. The system of claim 10 wherein the casing has a higher melting temperature than the first and second sets of unbonded beads.
12. The system of claim 10 wherein the casing has a melting temperature that is sufficiently low such that the casing is meltable when the beads are bonded together.
13. The system of claim 10 wherein the casing is a premolded casing having a predetermined shape.
14. The system of claim 10 wherein the casing is a bag.
15. The system of claim 10 wherein the casing is a mesh bag.
16. The system of claim 15 wherein the mesh bag has a higher melting temperature than the first and second sets of unbonded beads.
17. The system of claim 10 wherein the casing comprises a low melt polymer bag.
18. The system of claim 10 further comprising a nozzle configured to extend into the injection hole for injecting the second set of unbonded beads through the injection hole.
19. The system of claim 10 wherein the mold has a steam hole in communication with the cavity, the steam hole being configured to receive steam and to introduce the steam into the cavity to bond the beads together.