A G-Band (140-220 GHz) planar stubbed branch-line balun in BCB technology

Paper in proceedings, 2014

A G-Band planar stubbed branch-line balun is designed and fabricated in 3μm thick BCB technology. This topology of the balun does not need thru-substrate via hole or thin-film resistor which makes it extremely suitable for realization on single-layer high-resistivity substrates commonly used at millimeter-wave or post-processed BCB layers on top of standard semi-insulating wafers. The design is simulated and validated by measurements. Measurement results on two fabricated back-toback baluns show better than 10 dB input and output return loss and 3.2 dB insertion loss from 140 to 220 GHz.