An electromagnetically coupled microstrip antenna with a rotatable patch

The performance of a newly developed microstrip antenna is investigated by FDTD analysis and experiments. The proposed new antenna consists of a patch, a shaft, a bearing, a weight and a microstrip line. The patch can rotate freely around the shaft. When the portable telephone unit is inclined, the patch rotates and remains vertical because of the weight. Therefore, the polarization direction of the new microstrip antenna is always kept vertical and there is no effective gain degradation due to the inclination. This new antenna also decreases the effective gain degradation due to the proximity of the operator´s body. This is because its radiation pattern is very directional with low levels towards the operator. Furthermore, this new antenna is very easy to handle and resists breakdown. This is because it is built into the portable telephone unit.