Folded Strip/Slot Antenna With Extended Bandwidth for WLAN Application

A compact and novel printed antenna for 2.4-GHz WLAN/Zigbee/Bluetooth applications is proposed in this letter. To extend the bandwidth, a strip mode and a slot mode are combined together, which generate a dual-mode response inside the radiating band. To miniaturize the overall size, the structure is folded in order to fully utilize the available antenna space. The antenna is fabricated on a 1-mm FR4 board and excited by an SMA connector using a short microstrip line. It achieves a -10-dB bandwidth of 5.09% with a compact size of 0.073 λ
₀
× 0.052 λ
₀
× 0.008 λ
₀
(9.2 × 6.5 × 1 mm
³
) and an in-band radiation efficiency above 73%. It is small and low-profile, which can be fabricated at a low cost using the standard printed circuit board (PCB) process. It shows good radiation performance and therefore is suitable for applications in Internet of Things and smart home devices.