A Flip-chip Low Band Harmonic Filter Based on GaAs Integrated Passives

摘要

Radio transmit modules continue to shrink in die size and cost, requiring novel approaches for integration of the numerous passive elements of the radio front-end. Flip-chip assembly of the passives enables further size reduction. A single inductor low band harmonic filter was designed and fabricated with a 200 μm pitch lead based bump technology and flip-chipped to a 4-layer HDI substrate. Test results showed insertion loss in the AMPS/GSM band (824-915MHz) of about 0.6 dB. The measurement results corroborated simulations which indicated the need for additional trace inductance on the HDI board to control the higher order harmonic rejections of the single inductor harmonic filter, since the inductance of the microvias to GND is rather small.