Design and implementation of planar ultra-wideband antennas with multiple notched bands based on stepped impedance resonators

A new family of microstrip-fed ultra-wideband (UWB) antennas with multiple (triple/quadruple) notched bands is proposed. The notched bands are generated by a band notched filter composed of double stepped impedance resonators (SIRs). Through tuning the characteristic impedance and the electrical length of each section of the SIRs, multiple notched bands as well as the desired high attenuation can be created in desired frequencies. Frequency domain measurements have been conducted to examine the band notched characteristics of the proposed antennas. Based on the analysis of antenna transfer function (S21), group delay and gain of the proposed antenna, it is shown that the proposed antenna is suitable for UWB applications or for multi-band applications.