Bandwidth Improvement of a Printed Log-Periodic Antenna

ABSTRACTA new printed log-periodic microstrip antenna (LPMA) with extended bandwidth based on a composite right/left-handed transmission line (CRLH-TL) is proposed. The microstrip patches composed of mushroom structures are placed in a log-periodic way, so that the characteristic of bandwidth enhancement can be achieved. The proposed antenna is verified by both full-wave simulations and experiments. The measured results show that the impedance bandwidth of the antenna with only five elements is from 4.2 to 8.5 GHz for VSWR < 3, and good radiation performance is achieved.