Abstract
A 60 GHz tandem coupler using offset broadside coupled lines is proposed in a WLP (Wafer Level Packaging) technology. The fabricated coupler has a core chip area of 750 μm × 385 μm (0.288 mm2). The measured results show an insertion loss of 0.44 dB, an amplitude imbalance of 0.03 dB and a phase difference of 87.6° at 60 GHz. Also the measurement shows an insertion loss of less than 0.67 dB, an amplitude imbalance of less than 0.31 dB, a phase error of less than 3.7°, an isolation of more than 29.7 dB and a return loss of more than 27.9 dB at the input ant coupled ports and more than 14.3 dB at the direct and isolated ports over the frequency band of 57–66 GHz, covering 60 GHz band both in Japan and US. To the best of our knowledge the proposed coupler achieves the lowest ever reported insertion loss and amplitude imbalance for a 3-dB coupler on a silicon substrate. With its superior performance and lower cost compared to the CMOS counterparts, the proposed coupler is a suitable candidate for low-cost high-performance millimeter-wave systems.
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Acknowledgments
This work was partly supported by the Global COE Program “Photonics Integration-Core Electronics”. MIC.SCOPE, KAKENHI, and VDEC in collaboration with Agilent Technologies Japan. Ltd., Cadence Design Systems. Inc., and Mentor Graphics. Inc.
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Kiumarsi, H., Ito, H., Ishihara, N. et al. A 3‐dB Quadrature WLP Coupler for 60 GHz Applications. MRS Online Proceedings Library 1427, 8–13 (2012). https://doi.org/10.1557/opl.2012.1119
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DOI: https://doi.org/10.1557/opl.2012.1119