High gain ultra wide band MIMO antenna

摘要

A High Gain compact ultra-wide band (UWB) microstrip MIMO antenna with fork shaped geometry is proposed. A C-slot is designed near to the feed line to provide a perfect match between return loss and isolation at the resonant frequency. Finally we achieved the Return loss(S11) of -42dB and mutual coupling is about -26dB respectively. A trade off is maintained between the bandwidth and the Gain of the Antenna to get rid of the problem of Non Line Of Sight communication in the UWB frequency range. The proposed antenna having partial ground plane having chair like structure is fabricated on a low cost FR4 substrate having dimensions 50 (Lsub) X 39 (Wsub) X 1.6 (h) mm3 and is fed by a 50Ω microstrip line. The results show that the proposed antenna achieves impedance bandwidth (VSWR<;2) from 7 GHz to 8.5 GHz and from 6.25 GHz to 6.8 GHz providing gain of 8.2 dB with a gain variation of less than 2 dB over the frequency band. Also the mutual coupling are below -25 dB and -15 dB respectively. This proves a better tradeoff between Gain and Bandwidth with regards to the MIMO antennas. For most of MIMO antennas gain is very less varying from 2 dB to 5 dB. Moreover the fabricated prototype MIMO antenna results of S11, S21 and Gain are found very similar to the Simulation results.