40 GHz fully integrated and differential monolithic VCO with wide tuning range in AlInAs/InGaAs HBT

A fully integrated and differential AlInAs/InGaAs HBT voltage controlled oscillator (VCO) with wide tuning range was demonstrated for 40 GHz wireless and optical communication applications. To our knowledge, this 40 GHz IC is the highest frequency fundamental mode fully integrated and differential VCO with wide tuning range ever reported. This VCO delivers a typical differential output power of +5 dBm at a center frequency of 39 GHz with a tuning range of up to 3.5 GHz. Co-planar waveguide (CPW) circuit designs has been employed for the development of the InP HBT MMIC VCOs to reduce chip cost and make them flip chip compatible. The measured phase noise shows -95 dBc/Hz at 1 MHz offset and -75 dBc/Hz at 100 KHz offset. The VCO was realized in a high yield optical lithography triple mesa HBT process. Circuit performance was relatively insensitive to process variation indicating a highly robust circuit design and process.