A New Equivalent Circuit Scheme for Grounded Back-to-Back GCPW-MS-GCPW Transitions Fabricated on a Thin Low-k Substrate

We hereby present a new equivalent circuit model including both lumped and distributed elements for GCPW-MS transitions (GCPW for Grounded Coplanar Waveguide and MS for Microstrip). In order to validate the modelling results, such transitions have been fabricated on a 20 mu m-thick BCB (Benzocyclobutene resin) substrate using grounding pads including via-holes of different diameters. The study focused on the impact of the via-hole diameter on the performance of the transition and more specifically on its bandwidth. The transitions were made using a simple technological process based on photosensitive polymer. ADS simulation data of the new equivalent circuit model were in very good agreement with measured S-parameters. Both theoretical and experimental results have shown that the bandwidth of such a transition can reach up to 100 GHz using via-holes of 900 mu m diameter.

Automated summary

A new equivalent circuit model for GCPW-MS transitions was proposed, focusing on the impact of via-hole diameter on transition performance and bandwidth. Theoretical and experimental results showed that transitions with 900μm diameter via-holes can achieve a bandwidth of up to 100 GHz.