Compact ultra-wideband chip antenna using square spiral slot

In this paper, compact ultra wide band (UWB) chip antenna using square spiral slot and CPW (coplanar waveguide) feed are proposed. A square spiral slot structure is introduced for resonance of medium band operation. The two corner open slots of the CPW feeder line are modified for impedance matching and lower/higher band operation. The proposed antenna has a compact size (8mm × 15mm) and it is etched on the FR-4 (relative dielectric constant = 4.4, thickness =0.8 mm) dielectric substrate. The measured impedance bandwidth (VSWR¿ 2 ) and gain of the proposed antenna is 6.2 GHz (4.27 GHz ~ 10.47 GHz) and 5.4 dBi, respectively. Measured result show good impedance matching and radiation pattern over the interesting frequency bands. It can be applied to antenna of UWB wireless communication system.