An equivalent circuit and analysis of reconfigurable antenna for penta-band wireless applications

Abstract This paper presents a cavity model analysis of a novel penta-band MIMO antenna that is compact in size (measuring 76×33 mm 2 ) and utilizes three PIN diodes for reconfigurability. This antenna resonates at 2.1, 3, 3.5, 4, and 4.2 GHz in different states (state-000, state-011, state-111, state-100, and state-000, respectively) and offers a fractional bandwidth of 4.95% (simulated), 5.5% (measured) and 4.92% (theoretical) in state-000, 3.09% (measured), 2.8% (simulated) and 2.3% (theoretical) at lower frequency (2.1 GHz), and 2.12% (simulated), 2% (measured) and 2.4% (theoretical) at higher frequency (4.2 GHz) in state-100, 12.5% (simulated), 12% (measured) and 11.6% (theoretical) in state-011 and 4.6% (simulated), 4.7% (measured) and 4.4% (theoretical) in state-111. Furthermore, the antenna exhibits impressive performance with a peak gain and isolation of 3.6 and 32.2 dB at 4 GHz and 3.5 GHz, respectively. The proposed design also maintains low specific absorption rate (SAR) and envelope correlation coefficient (ECC) values, with SAR and ECC values less than 1 W/kg and 0.01, respectively. Moreover, a lumped element RLC equivalent circuit for the intended antenna is proposed using cavity model circuit theory. The proposed circuit produces theoretical reflection coefficients of the proposed antenna and has been validated by comparison with simulated and measured results.