Novel Broadband Filtering Slotline Antennas Excited by Multimode Resonators

A novel type of slotline antenna excited by multimode resonators are proposed in this letter. To widen the impedance bandwidth, two types of resonant modes are excited, including slotline mode and stub-loaded resonator mode. An equivalent multipoles filtering network is given for providing a physical insight into the in-band property. Two prototype antennas are finally designed and fabricated to experimentally validate the principle and design approach. Experimental results exhibit that proposed antennas feature not only broad impedance bandwidth but also good filtering response such as flat gain frequency response, sharp bandedge characteristic, as well as high stopband suppression.