Mixed LTCC Ultra Compact S-Band Filter with Wide Multispurious Stopband

In this paper, two main objectives were validated. The first one was to develop and validate an original new hybrid Low Temperature Co-fired Ceramic process mixing both low- permittivity (low-K) and high-permittivity (high-K) materials in the same substrate. This approach proceeds to be very efficient in decreasing circuits dimensions. The second objective was to design a novel compact S-band filter based on this new technology, with high electrical performances and wide multispurious stopband. A two-pole bandpass filter functioning at a central frequency f₀ = 2.52 GHz with 13 % relative bandwidth and very low insertion losses was optimized and manufactured successfully, validating the technology and the theoretical approach. The conceived structure is very compact and presents an excellent frequency isolation.