A compact E-shaped antenna with C-shaped slots and
a back-patch for multiband applications

Kim Ho Yeap – Wei Long Yeo – Koon Chun Lai – Takefumi Hiraguri
– Kazuhiro Hirasawa – Zi Xin Oh

   We present the design of a tri-band E-shaped printed antenna with C-shaped slots. A Rectangular patch etched with an n-shaped slot is added at the back of the substrate to enhance the bandwidth and the return losses of the resonant bands - particularly, that of the second band. Our antenna is designed to operate at 1.51/2. 46/6.11 GHz. As can be observed from the experimental results, it has 10 dB bandwidths of 157 MHz (1.416 to 1.573 GHz) 358 MHz (2.221 to 2.579 GHz) and 367 MHz (5.918 to 6.285 GHz) The first two bands cover the LTE, Bluetooth, IEEE 802.15.4 ZigBee and IEEE 802.11 WLAN applications. The third resonant band covers the unlicensed 6 GHz band which is widely implemented in wireless power transmission, as well as, RFID and satellite communications. In order to ease wireless congestion, the 6 GHz band is also currently being considered by the FCC to be opened up for the use of WiFi applications. Our antenna is fabricated on a single-sided FR4-epoxy, and it constitutes a compact size of 34 × 36 mm × 1.6 mm or 0.17 λ × 0.18 λ × 0.0081 λ, (based on the 1.51 GHz lowest resonant frequency) The antenna exhibits omnidirectional radiation patterns at the three resonant bands.

Keywords: planar antenna, multiband, return loss, radiation patterns, surface current density, E-shaped antenna, C-shaped slots, back-patch

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