Monolithic 2-μm/0.5-μm GaAs HBT-HEMT (BiHEMT) process for low phase noise voltage controlled oscillators (VCOs)

This paper describes a 2.4-GHz single-ended and a 6-GHz differential voltage-controlled oscillators (VCOs) using a monolithic stacked 2-μm InGaP/GaAs heterojunction bipolar transistor (HBT) and 0.5-μm AlGaAs/GaAs pseudomorphic high-electron mobility transistor (PHEMT) (BiHEMT) process. The BiHEMT process features high integration, low noise, and high frequency performance, and also it provides great design flexibility to achieve good circuit performance. To demonstrate the property of this BiHEMT technology, two VCOs based on common-base/emitter configurations are presented. The 2.4-GHz VCO has a tuning range of 430 MHz with a bandwidth of 17.9% and a phase noise of -122 dBc/Hz at 1-MHz offset. The 6-GHz VCO has a tuning range of 470 MHz and a phase noise of -107.7 dBc/Hz at 1-MHz offset. The chip sizes of the two VCOs are both 1×1 mm².