Annular-ring slotted microstrip patch antenna for ISM band applications

Anannular ring slotted microstrip patch antenna is presented in this paper for ISM band applications. These applications include ZigBee, WiMAX and Bluetooth. Prototypes of the proposed antenna designed for ZigBee operations in the 2.4 GHz band has been constructed and tested. The proposed antenna is constructed on an FR-4 epoxy substrate with thickness of 1.6 mm and ε_r =4.4. The proposed antenna operates from 2.26 GHz to 2.58GHz with good omnidirectional radiation patterns, its narrowband impedance bandwidth is an added advantage for interference problem from other applications in ISM band. Proposed antenna has compact size of 24×33 mm². Proposed antenna has advantages in simple design, compact in size and easy in fabrication. The measured result is in good agreement with simulated results.