High Frequency Characteristics of Liquid Crystal Polymer for a Millimeter-Wave Package

Abstract

The high frequency characteristics of liquid crystal polymer (LCP) have been investigated using a microstrip line (MSL) on a silicon (Si) substrate to verify the possibility of the application of the material in millimeter-wave packaging. A LCP film was fabricated using a direct-bonding technique on Si substrate. Measured characteristics of insertion loss are compared between a LCP film and a SiO₂ film. The loss of the LCP-MSL is approximately 1/2 of that of the SiO₂-MSL. Moreover, a GaAs low noise amplifier (LNA) microwave monolithic integrated circuit (MMIC) was fabricated using a flipchip bonding technique on a LCP substrate to demonstrate an application for a millimeter-wave package. The measured output gain of the LNA package is over 11dB. The millimeter-wave LCP package is a promising technology in realizing low cost millimeter-wave radio equipment.