An improved SIR filter designed using LTCC technology

An improved quarter wavelength (
^lambda
/
₄
) SIR (stepped impendence resonator) in LTCC (low temperature co-fired ceramic) is proposed. The improved SIR in LTCC can have much smaller resonant length at desired frequency and have much higher 1th spurious resonant frequency comparing to the traditional ones. Filters that are constructed by the improved SIRs can have small size and high spurious pass band. A three order bandpass filter with the improved SIR is designed in LTCC. The filter is simulated in HFSS. Simulation results show that the filter has a very good filter performance while it only covers a very small area and has a wide stop band.