High Speed Receiver Circuitry for Operation in the Sub-THz Wave Band
The ever present demand for high speed electronics has driven the engineering of advanced processes with increased cut-off frequencies and improved frequency response of devices. In response, IBM has offered SiGe BiCMOS technology packages that assist in allowing a designer to meet the broadband desires of many security, communications, and radar applications. Making use of this IBM SiGe 8HP process, receiver circuitry for such applications is presented. Several test chips containing different variations of a receiver design have been both fabricated and probe tested. These receiver designs contain low noise amplifiers, voltage controlled oscillators, mixers, and frequency doublers that each make use of circuit techniques to extend frequency response. As the very front end of the receiver is the low noise amplifier employing both resistive and frequency-dependant feedback to compensate at high frequencies for the negative effects of capacitance on frequency response. The voltage controlled oscillator is a four stage ring oscillator design in which feed forward interpolation is used to extend the output’s tunable frequency range. Evaluation of the chips through probe testing has shown functional receivers with input frequency bandwidths of .07 THz and tunable voltage controlled oscillators with a 0.012 THz tuning range. This work also includes the design of a high sample rate analog-to-digital converter that can be used at the back end of the receiver system. The building blocks for this converter are also presented. This material is based upon work supported by the National Science Foundation under Grant No. 0333314.