New material technologies must be explored to realize high-performance packages for meeting the stringent requirements defined in the fifth generation (5G) and sub-THz frequency bands. To this end, electrical properties of the new materials such as dielectric constant (relative permittivity) and loss tangent need to be characterized along with the loss of interconnects on these substrates to investigate their suitability for mm-wave applications. In this paper, a newly developed material technology at Corning, namely, Alumina Ribbon Ceramic is introduced, and 40-μm-thick Alumina Ribbon Ceramic is characterized in the frequency range of 30-170 GHz using microstrip ring resonator (MRR) method. In addition, various planar transmission lines such as microstrip and coplanar waveguide (CPW) lines are designed and fabricated on a 40-μm-thick Alumina Ribbon Ceramic using a Semi-Additive Patterning (SAP) process to evaluate the performance of interconnects in decibels per millimeter (dB/mm) up to 170 GHz. Based on the measurements, the dielectric constant of Alumina Ribbon Ceramic is found to be steady around 9.87 and the extracted loss tangent varies from 0.0003 to 0.0013 in 30-170 GHz. Moreover, the average measured insertion loss of microstrip lines is between 0.089 dB/mm to 0.29 dB/mm from 30 GHz to 170 GHz. For the CPW lines, the average measured insertion loss varies from 0.053 dB/mm to 0.242 dB/mm in 30-170 GHz. According to the comparisons made with state-of-the-art substrate technologies, the CPW lines on Alumina Ribbon Ceramic exhibit the best performance in terms of loss (dB/mm) up to 170 GHz. These results demonstrate the excellent electrical properties of Alumina Ribbon Ceramic substrates for applications in 5G and sub-THz frequency bands.