HBT MMICs for L band mobile radiocommunications

L band HBT MMICs, such as VCOs, mixers, frequency dividers and power transistors, which are required in the handset of the DCS1800 mobile telecommunication system, have been fabricated on the same wafer using a simple HBT process. These different modules have been tested separately using an on-wafer RF probe. All circuits operate as predicted in the DCS1800 frequency range. Furthermore, the VCO has a large bandwidth of 400 MHz, the mixer provides positive conversion gain up to 18.5 GHz, and the power transistor exhibits an output power of 1.8 W with a power added efficiency of 60% at 1.8 GHz. These performances demonstrate that all the mobile terminal RF parts can be integrated into a single chip, when using HBT technology.<
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