This paper proposes a passive filtering antenna for ultra-wideband (UWB) applications. The edge chamfering technique is adopted to construct the UWB antenna. The designed UWB antenna has a fractional bandwidth of 135%. A low-pass filter (LPF) is embedded on the feed line of the UWB antenna to convert it into a narrowband antenna that works at 2.45 GHz with 29.5% fractional bandwidth by removing the high-frequency components. The LPF is a transmission line with a stepped impedance configuration loaded with an H-shaped unit cell. The proposed filtering antenna is fabricated and tested. The measured results indicate the gain is >4.2 dBi and the radiation efficiency is >75%.

A novel compact ultra-wideband (UWB) eight-way ring-cavity power divider is presented in this paper. To broaden the bandwidth of the power divider/combiner, the stepped-impedance technology is used to realize the impedance match. The network of this eight-way ring-cavity power divider has been analyzed. The measured results reasonably agree with the simulated ones. The measured return loss is greater than 10 dB from 5.2 to 18.6 GHz. The average insertion loss, amplitude imbalance, and phase imbalance are around 9.4 dB (including the 9-dB power-dividing insertion loss), ±0.7 dB, ±6°, respectively, across the entire operating frequency range.