Compact hexa-band bio-inspired antenna using asymmetric microstrip feeding technique for wireless applications

A compact Hexa-band Bio-inspired antenna is presented in this paper. The structure of the proposed antenna is realized from a semi-Vine-leaf shape, Defected Ground Structure (DGS) and arc-slots techniques. The total dimension of the antenna is 0.35λd x 0.14λd; where λd is the guided wavelength at low frequency (2.37GHz). The design begins with a semi-Vitis vinifera leaf-shaped radiating patch monopole structure, fed with an asymmetric microstrip feedline to achieve compactness. Five (5) arc slits are then introduced on the radiating patch of the initiator with an intention to create band notches and thereby results in multiband and further miniaturization. The proposed antenna is analyzed, simulated and fabricated. The measurement results of the proposed antenna show that the antenna operates at 2.37GHz, 3.06GHz, 3.52GHz, 4.28GHz, 4.88GHz, and 6.0GHz with a -10dB fractional bandwidth of 11.97%, 4.61%, 12.43%, 6.77%, 2.46%, and 11.55% respectively. The peak gain of the proposed antenna is 3.21 dBi. The radiation patterns of the proposed antenna are Bi-directional at XZ-plane and XY-plane, but Omnidirectional at YZ-plane. Owing to the compactness of the antenna, suitable radiation pattern, acceptable gain and high radiation efficiency, the proposed antenna is suitable for several applications such as Industrial, Scientific and Medical (ISM) Band, Radar, WiMAX, 5G mid-band, Bluetooth, WLAN, WiMAX, LTE, and Wi-Fi. The contributions of this work are: (i) the use of asymmetric microstrip feedline for miniaturization purpose contrary to the commonly used asymmetric coplanar strip; (ii) simple formulation for the predictions of notch bands introduced by the slit on the radiating patch; and (iii) presentation of ultra-compact hexa-band antenna compared to the existing multiband antenna.