Small square meander-line antennas with reduced ground plane size for multimedia WSN nodes

We developed four wideband printed antennas at 2.5 GHz, focusing on printed meander-line monopoles (MLMs), which were optimized according to the size and bandwidth constraints of multimedia sensor networks. Printed elements form a unified radiator with the RF ground plane of the device. We show that this overall radiator can become very efficient and small when designed asymmetrically. Electrical performance was characterized in terms of electrical size, fractional bandwidth, and broadband total radiation efficiency. The results show that MLMs can outperform more involved antenna configurations, and they can easily reach bandwidths on the order of 30%. The meander-line antenna having a GND plane size of 27 mm times 18 mm (0.22lambda₀ times 0.15lambda₀) provided peak overall performance in the 2-3 GHz frequency range.