MMIC. Oscillators, mixers, frequency converters

In amplifier or phase-shifter circuits, which have been presented elsewhere, the presence of nonlinearities is a drawback that may need to be taken into account. Instead, this article presents circuits where the presence of non-linearity is essential for the realization of functions. Examples of such functions are oscillation, mixing, frequency multiplication or division. But these circuits can also present more global non-linearities, in particular bifurcations, which in turn become drawbacks to be dealt with.

In the microwave and millimeter range, applications include systems such as radio local loops, high-speed point-to-point links with millimeter carriers, and car radars. These systems impose their own types of modulation, such as phase, frequency or amplitude modulation (QAM). In these applications, for reasons of cost and performance, sub-assemblies are increasingly produced in monolithic form. But the monolithic design of functions has repercussions on the circuits themselves, since we need to eliminate as far as possible those parts that require hybrid techniques. In the case of oscillators, for example, phase-locked loops have replaced dielectric resonators in some cases, especially since the advent of piezoelectric resonators, which can be realized using MEMS technology. However, the use of these loops requires the use of frequency divider or multiplier circuits. Similarly, in monolithic mixer designs, narrow-band filter circuits, which are generally only available in hybrid designs, are replaced by local oscillator suppression or image frequency suppression circuits, which are much easier to implement in monolithic designs.

All these aspects are covered in the circuits presented in this article. First, there are all the oscillator circuits, then the modulation or demodulation circuits, then the multipliers and finally the frequency dividers. Regenerative frequency divider circuits have led to the development of methods for handling global nonlinearities, i.e. those involving bifurcations. Although not entirely decanted, these methods will be discussed insofar as they are intended for use in other circumstances, for example, in pulse circuits where rise and fall times can involve significant instabilities.

Monolithic design techniques are gradually being applied to sub-assemblies, and are generating specific design rules. The last paragraph gives an overview of this field and presents a few achievements.

The study of microwave monolithic integrated circuits consists of several articles:

• [E 1 425] MMIC-Evolution and Technology deals with MMIC evolution and technology;