Multiband Reconfigurable MIMO Antenna for Wireless Applications

Abstract

This paper presents a compact multi-band frequency reconfigurable MIMO antenna for wireless applications. The antenna is designed and optimized to cover such wireless applications like satellite, Radar, and broadband applications. The frequency reconfigurability is obtained by using only one RF switch (PIN diode) for changing the operating frequency at ON/OFF states of the PIN diode. The dimensions of the 4-Elements MIMO antenna are 45×45×1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant $\varepsilon \mathrm{r}=4.3$ , loss tangent $\mathrm{tan} (\delta)=0.002$ and $50 \Omega$ microstrip feed line. The proposed antenna has two patch side arms connected by a single PIN diode. The antenna introduces three resonant frequencies under ( $\mathrm{S}11 \leq-10 \mathrm{dB}$ ) which are: 12 GHz, 13.95 GHz, and 14.91 GHz in the ON-state and OFF-state of the PIN diode with a fractional bandwidth of 1.85%, 6.66%, and 4.15% respectively. The obtained simulated gain is ranging from 8 to 10.45 dB and the maximum simulated gain is 10.45 dB at 17 GHz. The lowest return loss is obtained to be (−50) dB at 13.95 GHz. Detailed simulation results are explored and studied in this research. The return loss, Envelope Correlation Coefficient ECC, and Isolation are obtained to be less than −20 dB, less than 0.02, and less than - 17 dB respectively. The CST software is used to design and optimize the proposed MIMO antenna.