Compact dual-band loop antenna using c-shaped resonator for USB dongle application

A dual-band loop antenna designed at the wireless LAN bands (2.4 GHz and 5 GHz) is proposed for USB dongle application. The fundamental resonance of a novel rectangular loop antenna is designed for the 2.4-GHz band, and its size is miniaturized by the C-shaped resonator connected. Furthermore, the 5-GHz band is designed by using the self resonance of the C-shaped resonator, and the impedance bandwidth is extended by the mutual coupling between the rectangular loop and the C-shaped resonator. The measured 10-dB impedance bandwidths are 8.7% (2.3 to 2.51 GHz) and 21.7% (4.92 to 6.12 GHz), and they satisfies the required bandwidths of the IEEE 802.11 a/b/g/n wireless LAN standards. The proposed antenna occupies a very small area of 9 × 8.5 mm², which is suitable for integration into a USB dongle of size 9 × 30 mm².