Comparison of placements of MIMO antennas to GPS antenna for LTE user equipment

This research studies performances of different placements of Multiple-Input Multiple-Output (MIMO) antennas with GPS antenna. To simplify the research, the basic Inverted F Antenna (IFA) is used for the main, diversity, and GPS antennas. We adjoins the GPS antenna, considering the placement of main antenna and diversity antenna with its polarization diversity. Finally, we analyze the performance of four different antenna configurations depending on the placements of the GPS antenna. The performance comparison is executed through S-parameters and efficiency values, using network analyzer and anechoic chamber test method. We also compare simulations with SEMCAD X tool. The result depicts that a case, which the feeding point of the main antenna and the GPS antenna is located farthest, shows the best performance. In this case, S11 values of main antenna shows the average value of -9.67 dB at 824~896 MHz, S33 value of GPS antenna shows average value of -9.06 dB at 1450~1700 MHz, and S13 value representing isolation of main and GPS antenna shows the average value of -28.31 dB at 700~1700 MHz. Efficiencies of main and GPS antenna are measured at 83.35%, 69.87%.