Dual Monopole Frequency Reconfigurable Antenna for MIMO 5G sub-6 GHz Mobile Terminal

Abstract

In this paper, a Dual Monopole Frequency Reconfigurable Antenna (DMFRA) for two port Multiple Input Multiple Output (MIMO) Fifth Generation (5G) sub-6 GHz mobile terminal is presented. A combination of dual monopole strips is implemented at a port, respectively to achieve tunable and fixed resonant frequencies. Varactor diode is utilized in this design to perform the frequency reconfiguration. Dual tunable resonant frequencies at the lower band (1690 MHz to 2200 MHz) and higher band (4400 MHz to 5400 MHz) are created by the monopole branch which accommodates the varactor diode. On the other hand, a fixed frequency band at 2400 MHz with -10 dB bandwidth of 450 MHz is achieved by another monopole branch without variable diode. Maximum realized gain achieved at both lower and higher reconfigurable frequency bands and fixed frequency band are 2.73 dB, 3.8 dB and 2.57 dB, respectively. Besides that, high isolation between 2 DMFRAs decreases the mutual coupling to result in less than 0.1 of the Envelope Correlation Coefficient (ECC). In addition to its frequency reconfiguration capability and low ECC, the proposed MIMO antenna is considered suitable for potential 5G mobile terminal applications.