Design of balanced band-notched UWB filtering high-gain slot antenna

摘要

A balanced band-notched ultra-wideband (UWB) filtering slot antenna with high gain is proposed in this article. The high gain is achieved by deploying two identical open-ended T-shaped slot radiators in a back-to-back fashion. These two slot radiators are fed by differential-mode (DM) signals output from a balanced band-notched UWB bandpass filter (BPF) constructed using a stepped-impedance one-wavelength (1) slotline resonator. The DM notched band for blocking the 5-GHz WLAN band signals is generated by symmetrically placing a pair of microstrip resonators and a pair of slotline resonators, both being half-wavelength long, on the two sides of the 1 slotline resonator. Measured and simulated DM return loss responses agree quite well. The common-mode (CM) response is excellent with a measured CM return loss of below 0.54 dB in 1-12 GHz. As compared with its single-ported standalone slot antenna counterpart, the proposed balanced filtering slot antenna exhibits 2-dB-higher measured peak realized gains at, if not all, most frequencies in the notch-band-excluded passband.