A printed inverted-F antenna in 2. 4 GHz is designed for wireless sensor networks（ WSNs）. The size of antenna is only 25. 7 mm × 7. 5 mm. By using the 3 D electromagnetic simulation tool HFSS13. 0 modeling

the influence of parameters such as PCB thickness

and antenna size on the antenna is obtained

and thus different parameters is optimized to achieve the best design effect. When thickness of the PCB board H = 0. 8 mm

resonance length L

2

= 16. 4 mm

the resonant frequency of the antenna is 2. 45 GHz

echo loss S

11

=-25. 3 d B. Normalized input impedance is（ 0. 946 4 + 0. 092 0 i） Ω. Experimental

result indicates that under 2. 4 GHz

relative bandwidth of 12. 5 % is obtained

and the standing wave ratio is approximate 1. 7（ VSWR

<

2）. The antenna is used in practical engineering on the basis of CC2530 chip. PCB layout of the antenna is designed by using the tool of Altium Designer. The wireless network node with inverted-F antenna is actually manufactured and communication distance between two nodes is measured.