Embedded RF Balun for 3D System-in-Package Solutions

Compact concept for RF integration is highly desired, when future wireless communication circuits are designed. With three-dimensional SiP technologies it is possible to realize much smaller package size and weight, and higher integration rate than with planar technologies. However, miniaturization of passive devices is necessary to achieve small low-cost RF systems. In this paper, a multilayer RF balun for the state-of-art 3D SiP is designed. The balun is embedded on a single interposer layer of a three-layer 3D RF SiP. Two metal layers inside the interposer are used to realize the transmission line type balun. The balun is isolated from the other functional blocks with ground planes and via fences. This improves the electromagnetic compatibility of the balun and the package. A full-wave 3D electromagnetic solver is used to analyze the frequency behavior of the balun due to the complex structure of high-density environment. The final measures of the balun are 5.2 mm x 2.6 mm x 0.3 mm. In addition, a test structure is manufactured and measured. The correlation between simulation and experimental results is analyzed. Good input impedance match and excellent amplitude balance between output ports is achieved and phase imbalance is smaller than two degrees. Bandwidth from 1.8 GHz to 2.9 GHz is reported.

[1]  Branka Jokanovic,et al.  Review of printed Marchand and double Y baluns: characteristics and application , 1994 .

[2]  M. Mantysalo,et al.  System design issues for 3D system-in-package (SiP) , 2004, 2004 Proceedings. 54th Electronic Components and Technology Conference (IEEE Cat. No.04CH37546).

[3]  Joy Laskar,et al.  Gigabit wireless: system-on-a-package technology , 2004, Proceedings of the IEEE.

[4]  E. Ristolainen,et al.  Stacked modular package , 2004, IEEE Transactions on Advanced Packaging.

[5]  J. Miettinen,et al.  Stacked 3-D MCP with plastic ball vertical interconnections , 2003, 53rd Electronic Components and Technology Conference, 2003. Proceedings..

[6]  R. Mongia.  RF and microwave coupled-line circuits , 1999 .

[7]  M. Tentzeris,et al.  RF-microwave multi-band design solutions for multilayer organic system on package integrated passives , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[8]  Yicheng Lu,et al.  Spiral transmission-line baluns for RF multichip module packages , 1999 .

[9]  T. Weiland.  Time Domain Electromagnetic Field Computation with Finite Difference Methods , 1996 .

[10]  Said F. Al-Sarawi,et al.  A Review of 3-D Packaging Technology , 1998 .