An Eight-Port Frequency Reconfigurable MIMO Slot Antenna with Multi-Band Tuning Characteristics

A novel compact eight-element frequency reconfigurable multiple-input multiple-output (MIMO) slot antenna design suitable for cognitive radio applications is presented. The proposed antenna design contains eight-elements on a single substrate board and is capable of multiband operation. Multi-band is achieved by inserting a meandered slot in the middle of each antenna element. It exhibits a wide frequency reconfigurable band from 1.6 to 2.48 GHz and two bands at 3.6 GHz and 5.2 GHz, covering well known wireless applications like global system for mobile communications (GSM), universal mobile telecommunications system (UMTS), long term evolution (LTE), worldwide interoperability for microwave access (WiMAX), Bluetooth and wireless fidelity (WiFi). Frequency reconfigurability is achieved by employing varactor diode in the center of each antenna element by altering the capacitive reactance of the slot. Moreover, rectangular defected ground slots are incorporated between vertically positioned antenna elements for isolation enhancement. The proposed antenna has a planar structure with compact size of 120 x 60 x 0.8 mm(3). The proposed design is validated by presenting simulated results of S-parameters, gain, efficiency, envelope correlation coefficient, displaying good performance.