Integrated diversity antenna for laptop and PDA terminal in a MIMO system

The paper introduces an integrated diversity antenna for MIMO application specifically in a laptop and in a PDA terminal. The design is based on a double-folded dipole antenna filled with a slab of dielectric material. With the insertion of the dielectric slab, the size is reduced significantly while still maintaining good bandwidth and gain. One of the important features of the design is that the antennas can be spatially placed close to each other (less than /spl lambda//2), while implementing polarisation diversity. This is important especially in a PDA terminal where the size of the device is relatively small compared to a laptop. The antennas are designed on a laptop and PDA with frequency of operation at 5.2 GHz for the IEEE802.11a wireless systems. For the laptop design, two different orientations of the dielectric loaded doubled-folded dipole were considered. The isolation is better than 20 dB and measured bandwidth at -10 dB is up to 400 MHz for a laptop design and up to 200 MHz for a PDA design. Experimental verifications are reported for S-parameters and radiation patterns, while the envelope cross-correlation is calculated to be much less than 0.1 and the ratio of the mean effective gain (MEG) between the antennas is close to unity for the laptops and PDA.