Wireless gauge apparatus and manufacturing method thereof
Disclosed is a wireless gauge apparatus and manufacturing method thereof. The wireless gauge apparatus comprises a printed circuit board comprising a wireless transceiver and at least one sensor, a power source electrically coupled with the printed circuit board, an antenna electrically coupled with the wireless transceiver and a casing encasing the printed circuit board, the power source and the antenna. The casing is made of polyurethane having a density of 0.8-1.2 g/cm 3 . The antenna is surrounded by a protective layer having a thickness of 4-8 mm, a density of at most 50 kg/m 3 and a dielectric constant of 1-2.7.
1. A wireless gauge apparatus comprising:
a printed circuit board comprising a wireless transceiver and at least one sensor, the printed circuit board having a first side and a second side;
a power source electrically coupled with the printed circuit board;
an antenna electrically coupled with the wireless transceiver and mounted on the first side of the printed circuit board; and
a casing encasing the printed circuit board, the power source and the antenna, which casing is made of polyurethane having a density of 0.8-1.2 g/cm 3 ,
a protective layer disposed within the casing that is molded around and encases the antenna, the protective layer extending only around the antenna on the first side of the printed circuit board and on a corresponding portion of the second side of the second surface of the printed circuit board, the protective layer conforming to a shape of the antenna on the first side of the printed circuit board, the protective layer having a thickness of 4-8 mm, a density of at most 50 kg/m 3 and a dielectric constant of 1-2.7.
2. A wireless gauge apparatus according to claim 1 , wherein the protective layer is made of a closed cell plastic material.
3. A wireless gauge apparatus according to claim 2 , wherein the closed cell plastic material is selected from the group consisting of polyethylene, polypropylene, polyurethane and polystyrene.
4. A wireless gauge apparatus according to claim 1 , wherein the protective layer is made of a plastic material consisting of two sheets with gas entrapped in between the sheets.
5. A wireless gauge apparatus according to claim 1 , wherein the protective layer is a rigid protective casing filled with gas.
6. A wireless gauge apparatus according to claim 1 , wherein the density of the protective layer is 10-50 kg/m 3 .
7. A wireless gauge apparatus according to claim 1 , wherein the dielectric constant of the protective layer is between 1 and 2.4.
8. A wireless gauge apparatus according to claim 1 , wherein the antenna is a trace antenna, the trace antenna being disposed on the surface of printed circuit board and the wherein the protective layer extends only over the first surface of the printed circuit board corresponding to an area on which the trace antenna is disposed of the printed circuit board.
9. A wireless gauge apparatus according to claim 1 , wherein the casing comprises colour pigments.
10. A wireless gauge apparatus according to claim 1 , wherein a size of the casing is such that the distance from the printed circuit board, the power source and the antenna to an outer surface of the casing is at least 10 mm.
11. A wireless gauge apparatus according to claim 10 , wherein the at least one sensor is uncovered by the casing.
12. The wireless gauge apparatus of claim 1 , wherein the antenna is mounted flush with the first side of the printed circuit board.
13. The wireless gauge apparatus of claim 8 , wherein the trace antenna is mounted flush on the first side of the printed circuit board.