First Demonstration of Ultra-Miniaturized, High-Performance Filters on Alumina Ribbon Ceramic Substrates for 5G Applications

This paper reports the first demonstration of ultra-thin, ultra-miniaturized filters with footprint smaller than $0. 65\lambda_{0}\times 0.16\lambda_{0}\times 0.009\lambda_{0}$ fabricated on Alumina Ribbon Ceramic substrate operating at the frequency of 28-GHz band for 5G and mm-wave applications. A newly developed substrate material technology by Corning, Alumina Ribbon Ceramic can be utilized for realizing ultra-miniaturized, high-performance passive components due to its high dielectric constant and very low loss tangent. To show the effectiveness of Alumina Ribbon Ceramic for such applications, three bandpass filter (BPF) topologies, namely edge-coupled, interdigital and hairpin, and semi-lumped elliptical low-pass filter (LPF) topologies were modeled, designed, and fabricated on an $80-\mu \mathrm{m}$-thick Alumina Ribbon Ceramic metallized on both sides using a Semi-Additive Patterning (SAP) process. The performance of filters was characterized in the frequency range of 14–40 GHz using a vector network analyzer (VNA). In addition to exhibiting excellent agreement between the simulated and measured results of Alumina Ribbon Ceramic-based filters, their superiority is demonstrated through comparisons with those reported in the literature on other substrates in terms of performance and size. It is also highlighted that an insertion loss less than 1.3 dB is achieved for all filters.