Broadband, Thin-Film, Liquid Crystal Polymer Air-Cavity Quad Flat No-Lead (QFN) Package

We have developed a proprietary package that is fully compatible with variously sized chips. In this paper, we present design and development of a Quad Flat No-Lead (QFN) package. We will show how we have built and characterized low-loss packages using standard Printed Circuit Board (PCB) laminate materials. In particular, this package has been developed using Liquid Crystal Polymer (LCP). These packages are unique in that they fully account for and incorporate solder joint and ball bond wire parasitic effects into design. The package has a large cavity section that allow for a variety of chips and decoupling capacitors to be quickly and easily packaged. Insertion loss through a single package transition is measured to be less than 0.4 dB across DC to 40 GHz. Return losses are measured to be better than 15 dB up through 40 GHz. Further, a bare die low noise amplifier (LNA) is packaged using this technology and measured after being surface mounted onto PCB. The packaged LNA is measured to show 19 dB gain over 32 GHz to 44 GHz. Return loss for both bare die and packaged version show no difference, and both measure 15 dB. The LCP package LNA exhibits 4.5 dB noise figure over 37 GHz to 40 GHz.