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Description
The goal was to design a compact antenna or a wireless USB dongle type application of 4G LTE devices. This thesis presents a design of compact multiband Planar Inverted F Antenna to operate at LTE band 3 from 1.71GHz to 1.88GHz and band 7 from 2.5GHz to 2.7GHz ( w.r.t S__<-6dB). The antenna has total antenna efficiency of more than 50% and higher gain. The antenna was studied with parametric study approach to gain the required specifications. Meandered lines and dielectric loading techniques were used to reduce the size of the antenna. Then a prototype was fabricated to verify the simulated results. Fairly omni-directional patterns are obtained which are desired for all communication devices. It is a requirement for the LTE devices to have more than one antenna element to achieve higher data rates. Hence efforts were made to implement more than one element of same size groundplane. Also the literature review carried out showed that there is no MIMO (Multiple Input Multiple Output) antenna element which can operate for this two band for a USB sized devices making this thesis work more valuable. Thus, a two element design was studied for the MIMO configuration. The most challenging task was to have lower mutual coupling and the Envelope correlation (EC) value <0.5. A detailed studied was made on the position of the second antenna and best position was selected from the different cases. The proposed design operates at both bands maintaining a value of EC below 0.5 over the band of operation. Also the effect is studied when the proposed antenna is installed on a laptop. The results were also verified by prototype fabrication at AML (Antenna and Microwave Lab) and the results were in good comparisons with simulated results with some minor change due to hand fabrication. The same element was used as internal embedded antenna for laptop instead of external USB devices. 4 X4 elements MIMO configuration was studied and results in term of reflection coefficient, efficiency, and gain and radiation patterns are presented. Finally, geometries of the three antennas are presented, where first antenna operates for Digital TV application from 496MHz to 862MHz and other two antennas are MIMO implemented frequency reconfigurable antennas operating at LTE bands 3 and 7 with excellent EC value.
