Phase compensation of cascaded conductor-backed CPW periodic cells

• Main Authors: Ma, Kaixue, Yeo, Kiat Seng, Ma, Jianguo
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/102702; http://hdl.handle.net/10220/16474
• Institution: Nanyang Technological University

Several unit cells of conductor-backed coplanar waveguides with and without loading using thin-film ceramic technology are investigated. The frequency-dependent lumped equivalent circuit values of the cells are extracted from the full-wave electromagnetic analysis. Slow-wave periodic transmission lines and end-coupling bandpass filters (BPFs) are designed, fabricated, and measured. Size reductions of 23% and 27% for the loaded filters and several times increase of inverter values for the coupling inverters are achieved compared to that for the unloaded ones. A systematic design method by using cell cascading with compensation is proposed for the designs of the lines and filters. It is also demonstrated that “finite ground,” used in conductor-backed coplanar waveguides in the literature, is no longer suitable for the end-coupling BPFs due to the leakages. The leakages of finite ground deteriorate the stopband rejection of filters as much as up to 32 dB compared with that of “via ground”.