A Multiband Antenna Based on Mushroom Composite Right/Left-handed Transmission Line Structure

In this paper, a novel multiband planar antenna based on 2-D mushroom-like composite right/left-handed transmission line (CRLH-TL) structure is proposed. The metal patch of the mushroom cell is connected to the ground plane through via and planar inductor. It shows that the proposed structure gives an efficient approach to achieve multiband response and miniaturization. The operation frequency of the multiband antenna is dependent on the mushroom structure size and the equivalent parameters of the CRLH-TL, including capacitance and inductance. The proposed antenna is built with a total volume of 21 mm x 26mm x 1 mm, and four resonant bands have been got. The radiation patterns are similar with the omnidirectional characteristics and the gains are 1.27dBi, 2.23 dBi, 2.86 dBi, and 5.2 dBi at 2.62 GHz, 3.91 GHz, 6.52 GHz, and 8.05 GHz, respectively. The results show that the presented structure has reasonable radiation characteristics of efficiency, bandwidth, and size that it will be suitable for multiband wireless application.