A compact 60-GHz band branch-line coupler using cpacitively loaded lower-ground coplanar-waveguide (LG-CPW) lines has been successfully demonstrated in a glass-substrate integrated passive device technology. The fabricated coupler has a size reduction of more than 83% compared to that of a conventional CPW branch-line coupler. The capacitive loading is achieved by utilizing the signal layer and the LG of the LG-CPW structure to form microstrip open-circuited stubs. The measured results show a phase error of less than 0.5° between the coupler's output ports and an amplitude imbalance of less than 1.2 dB over the frequency band 57-64 GHz. The measurements also show that both the return loss and isolation are better than 25 dB at 60 GHz and better than 15 dB over the 57-64-GHz band. The proposed coupler is well suited for low-cost high-performance system-on-package V-band radio front ends for high data rate applications.

Additional Metadata
Keywords 60-GHz band, branch-line coupler, coplanar-waveguide (CPW) transmission lines, integrated passive device (IPD) technology, system-on-package (SoP)
Persistent URL dx.doi.org/10.1109/TCPMT.2012.2186450
Journal IEEE Transactions on Components, Packaging and Manufacturing Technology
Haroun, I. (Ibrahim), Plett, C, Hsu, Y.-C. (Yuan-Chia), & Chang, D.-C. (Da-Chiang). (2012). Compact 60-GHz IPD-based branch-line coupler for system-on-package V-band radios. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2(7), 1070–1074. doi:10.1109/TCPMT.2012.2186450