MINIATURIZED STEPPED IMPEDANCE RESONATORS WITH DOUBLE COAXIAL STRUCTURE AND THEIR APPLICATION BANDPASS-FILTERS

This paper describes newly developed miniaturized stepped impedance re sonators with a double coaxial structure (DC-SIR's) and their applicat ion to bandpass filters. The new DC-SIR's using dielectric material ar e devised for more compact and lower frequency bandpass filters. Funda mental characteristics such as resonance properties and unloaded-Q mak e it clear that DC-SIR's have attractive features that miniaturization can be achieved without Q-factor degradation. Trial 400 MHz bandpass filters incorporating DC-SIR's are also made. Experimental results of bandpass filters proved that DC-SIR's are applicable to lower frequenc y band radio equipment and able to contribute to the expansion of appl icable frequency ranges of dielectric coaxial resonators.