Advanced design and integration of microwave circuits and SoC

Today's micro- and nano- foundries allow design of high speed, high complexity circuits. Beside the use of complex technologies, for which high performance goes with high cost, BiCMOS and CMOS technology can be used for such high performance circuits, at a more reasonable price but at the expend of more careful design and techniques.

"Advanced design and integration of microwave circuits and SoC" members work at many different levels:

• Component level: we often develop our own models for components we want to use beyond their initial purpose.
• Material level: the "above-IC" technique consists of adding further technology steps at the end of a given process, to realize specific devices which offer improved performance over what we could expect from the initial process. For example, we are working on the developpement of new material to realize improved power RF LDMOS transistors with a minimized overcost.
• Design level : we are designing many original RF, microwave and millimeter-wave analog and digital functions, with the goal of maximising the performances of a given technology, correcting some well-known defaults of well-known functions or proposing alternatives, and initiate original topologies to take advantage of some design techniques becoming more and more interesting in the high frequency domain.

Examples of designed integrated circuits:

A 6-GHz direct digital synthesis: At the time of publication, this BiCMOS DDS was at the state-of-the-art, being the first to conciliate microwave frequency with low power consumption.

System level: we are working on integrated test-benches. Indeed, the growing complexity of systems does not allow easy characterization of some internal part: high cost, long time, inefficient access of low level components... Integrating test bench together with the functions or components to be tested overcomes these problems. The next microphotograph shows, for example, a whole integrated phase noise measurement test bench. This work demonstrates that instrumentation functions can be integrated on a BiCMOS chip, with all the high requirements required for a phase noise measurement behavior, and has been patented.

The following animation shows a 3-D "flight" over the voltage controlled oscillator show on the upper right corner of the previous microphotograph, in its standalone version. You will see the interconnections levels inside the technological steps.