Open Ended Folded-Slot Antenna with a Wide n-Shaped Slot for Ultra-Wideband Applications

Abstract

A microstrip feedline based open ended folded-slot antenna is proposed for ultra-wideband (UWB) applications. The prototype of the proposed antenna is fabricated on the FR4 dielectric substrate. The proposed antenna has a wide n-shaped slot that is useful for designing circuit components on the same printed circuit board (PCB) as that of the radio frequency (RF) modules. The proposed antenna use two kinds of slots as radiators, and each slots have different characteristics because of the different type of ends of the slot. The wideband characteristic can be obtained by resonances of each slot which are occurred at different frequencies. The measured impedance bandwidth (S11≤ -10 dB) is 2.9–11.56 GHz, and the antenna peak gain is 2–4 dBi over the UWB range. The antenna has a stable omni-directional radiation pattern and only a small groupdelay variation across the UWB passband. In addition, we present a modified design with band-notched characteristics of a 5 GHz wireless local area network (WLAN) frequency band.