W-band and D-band Transmission Lines on Glass Based Substrates for Sub-THz Modules

Abstract

Glass is a promising packaging and substrate material for high frequency applications. In this paper we provide the first results on the performance of transmission lines on polymer films laminated on glass substrates up to 170GHz. To benchmark the performance our stack up consists of 100um thick glass panel (AGC ENA1) with 15um thick build-up polymer (ABF GL102) laminated on both sides. Semi-additive processes (SAP) are employed to metallize the polymers. Coplanar Waveguide (Lines) have been designed and measured in a wide frequency range from 40GHz to 170GHz. We also present the insertion loss of microstrip lines in W-band (75GHz to 110GHz). In addition, for the first time, we present the characterization of electrical parameters (dielectric constant and loss tangent) of glass and polymer build up film-based stack up for W band (75GHz to 110GHz). For the extraction of dielectric constant and loss tangent of the proposed stack up, microstrip ring resonator (MRR) method is used. The dielectric constant of the presented stack up remains stable around 4.6 for the entire band while loss tangent varies from 0.004 to 0.008 from 75GHz to 100GHz. The average insertion loss for CPW lines at 40GHz,110GHz and 170GHz were measured to be 0.085dB/mm, 0.21dB/mm and 0.275dB/mm respectively. The measured insertion loss at 110GHz for microstrip line is 0.23dB/mm. The results show good and stable electrical performance of the glass-based stack up up to 170GHz and show its potential for utilization in designing high performance passives and packages for the development of future wireless generations.