Broadband double-tuned element with low profile for base station antennas

A broadband element with low profile (0.1λ at 1710 MHz) for base station antennas is presented. A special loop-feed technique, which achieves a double-tuned response like a bandpass filter, is used to broaden the operation band of the antenna. The proposed antenna yields 29% bandwidth of 1710–2200 MHz with return loss less than 17 dB (VSWR<1.32). Simulated and measured results are given, showing the element is suitable in base station antennas for cellular networks.