A Frequency Reconfigurable MIMO Antenna with Bandstop Filter Decoupling Network for Cognitive Communication

Abstract

A compact reconfigurable MIMO antenna was developed for cognitive radio applications in this research work. A bandstop filter-based decoupling network was employed in this MIMO antenna to keep mutual coupling at a minimum. A single PIN diode was connected in the filter configuration for the purpose of reconfiguration. Controlling the ON/OFF conditions of the PIN diode, it became possible to achieve a MIMO operating frequency of 4.75 GHz in mode 1 and 1.77 GHz in mode 2, respectively. At 4.75 GHz, isolation was 42.68 dB, while at 1.77 GHz, isolation was 26.52 dB. The proposed reconfigurable MIMO antenna achieved a peak gain and radiation efficiency of 6.63 dBi and 92.04 percent in mode 1 and 4.41 dBi and 89.64 percent in mode 2. MIMO characteristics such as an envelope correlation coefficient (ECC) less than 0.253, diversity gain (DG) greater than 9.675 dB, a mean effective gain (MEG) measurement ratio of less than 0.00388 dB, and channel capacity loss (CCL) of less than 0.06528 bits/s/Hz were measured for both operational frequency bands. To make it simple to integrate into small wireless devices, the overall size of the antenna is limited to 48 mm×24 mm 0.28 λ0×0.12 λ0.

Frequency Reconfigurable Quad-Element MIMO Antenna with Improved Isolation for 5G Systems

“…[18,19], MIMO antennas were reported for Bluetooth/WLAN applications. A frequency agile MIMO antenna for cognitive systems was investigated in [20], where a stop band filter was used to reduce mutual coupling. In refs.…”

A Frequency Reconfigurable Folded Antenna for Cognitive Radio Communication

“…Some of the employed techniques to achieve multiband behaviour are a fractal structure [ 9 , 10 ], a complementary split ring resonator metamaterial [ 11 ], a window grille cross-structure [ 12 ], a meandered offset-feed [ 13 ], a split ring resonator and inverted F slots [ 14 ], a bowtie slot patch [ 15 ], and DGS and DMS [ 16 , 17 ]. An additional capability that can be possibly integrated with the multiband behaviour of the antenna is the reconfigurability which has a vital role in the accomplishment of cognitive radio applications, and it can be carried out using PIN diodes [ 18 , 19 , 20 , 21 ], varactor diodes [ 22 ], lumped capacitors [ 23 , 24 ], and RF MEMS [ 25 ]. In [ 18 ], a semi-circular patch was loaded onto a triangular radiator with two inverted L-stubs to achieve reconfigurability between two frequency bands using a pair PIN diode.…”

“…In order to achieve a triple-band reconfigurable antenna, a pair of PIN diodes are inserted on the two slots of a rectangular-shaped patch [ 19 ] for WLAN/WiMAX/ITU applications. In [ 20 ], a reconfigurable MIMO antenna was designed using FR4 substrate to switch between two band-stop filters at 1.77 and 4.75 GHz using a PIN diode with high isolation. Two PIN diodes were utilized in [ 21 ] to achieve reconfigurable notched band characteristics for a UWB antenna.…”

Low-Profile Antenna System for Cognitive Radio in IoST CubeSat Applications

“…Extensive work has been undertaken to provide antennas for cognitive radio applications [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], but most of them do not fit with CubeSat regarding operating frequency, size, and compatibility. Although several designs have been employed for the CubeSat [ 34 ], such as slot antennas [ 8 , 35 ], the spiral antenna [ 36 ], helix [ 37 ], aperture antennas [ 38 , 39 ], superstrate antenna [ 40 ], solar cell-integrated antennas [ 40 , 41 , 42 , 43 ], dipole antenna [ 44 ], and folded dipole antenna [ 45 ], they do not support the UHF band with compact size and simple structure.…”