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"S" shape Defected Ground Structure four-band frequency reconfigurable antenna with PIN diode integration

In this work, a frequency reconfigurable inset-fed rectangular microstrip patch antenna is presented. The antenna consists of a patch on the top side and a defected ground structure having the letter ‘S’ type shape into the ground plane. Two PIN diodes equivalent circuits are applied inside this shape for switching operation in frequency bands. The designed antenna can switch its frequency bands between 4.9 GHz, 5.5 GHz, 2.6 GHz, and 3.5 GHz. The total size of the antenna is 26*22*1.6 mm. The material used for the substrate is FR4 with a dielectric constant of 4.3. Good radiation properties of the antenna are observed for all the configurations of the antenna. Frequency reconfigurability of the antenna is achieved by switching the operation of the PIN diode. The antenna can reconfigure between four frequencies with a good return loss and has a good performance in impedance matching at different resonating frequencies.