Miniature dual-band meander-line monopole chip antenna with independent band control

A dual-band monopole chip antenna with an overall size of 5 × 3 × 2.1 mm³ is investigated for 2.4/5.2/5.8 GHz WLAN applications. The chip antenna has three substrates with four copper layers in total. It deploys a modified nonuniform folded meander line and capacitive loading patches to reduce the antenna size. A fundamental monopole mode and a higher order mode are excited to obtain the 2.4 GHz (2.40-2.48 GHz) and 5 GHz (5.150-5.350 GHz and 5.725-5.875 GHz) WLAN bands, respectively. The lower and upper bands can be independently controlled by the widths of the meander lines on the first and third layers, respectively. A prototype was fabricated and measured to verify the idea. A reasonable agreement between the measured and simulated results is observed. The measured 10 dB impedance bandwidths of the lower and upper bands are 5.3% (2.38-2.51 GHz) and 19.3% (5.14-6.24 GHz), respectively, fully covering the 2.4/5.2/5.8 GHz WLAN bands. The measured efficiency of the chip antenna is higher than 60% for the two bands.