A novel microstrip resonator with broadband filtering and narrowband radiating functions.

This letter proposes a novel microstrip resonator that can perform filtering and radiating functions simultaneously.The proposed structure consists of outer ring, inner ring, circular patch, and three ports. The operating frequencies ( f and f) for a filter and an antenna are different. At the lower band, in which the center frequency is f, the proposed structure represents the characteristics of a wideband bandpass filter that has three transmission poles in a passband. Also, the proposed structure is operated as a radiating element at f. The measured isolation between the filter and the antenna is less than −25 dB over the entire impedance bandwidth for the filter and the antenna. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:940-943, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25884 [ABSTRACT FROM AUTHOR]