Liquid Crystal Polymer for RF and Millimeter-Wave Multi-Layer Hermetic Packages and Modules

Abstract

In this chapter, we present the design and development of thin-film liquid crystal polymer (LCP) surface mount packages for X, K, and Ka-band applications. The packages are constructed using multi-layer LCP films and are surface mounted on a printed circuit board (PCB). Packages include a typical low pass feedthrough design, as well as a new bandpass feedthrough design. Our experimental results demonstrate that the low pass package feedthrough transition including a PCB launch and bond wires achieve a return loss of better than 20 dB and an insertion loss of less than 0.4 dB around Ka-band. We achieve more than 45 dB measured port-to-port isolation of the package across Ka-band. The leak rate of LCP cavities has been found to be 3.6×10–8 atm-cc/s. Experiments show exceptional reliability results for several reliability tests including temperature cycling and prolonged exposure to humidity of packaged amplifiers. Finally, we demonstrate that our bandpass package feedthrough transition including bond wires achieve a 13 dB or higher return loss and less than 0.5 dB insertion loss across K-band. The package transition offers 0.2 dB insertion loss and > 15 dB return loss across X-band, and operates well across 8–27 GHz.