Developments in RF circuit design

This paper describes work of the authors which is relevant to the RF design field. The emphasis is mainly but not entirely on MMIC solutions, in order to meet the need for low weight and low size at reasonable cost (assuming high production volume). The enormous signal dynamic range in radio receiver systems provides very demanding challenges for distortion and noise of RF components, both amplifiers, mixers and filters. Third order nonlinear distortion is of particular concern because it causes in-band spurious frequency components, leading to corruption of wanted frequency channels by unwanted channels. In this paper, we also consider the key requirements of low power supply voltage and low DC power consumption. Section 2 of this paper is concerned with device modelling and CAD which are central to the tasks of RF circuit design to minimise power supply voltage and power consumption, while meeting performance specifications, including intermodulation distortion. Section 3 describes a new circuit synthesis technique for RF components (amplifiers and mixers) to provide very low intermodulation distortion. In section 4, we summarise work on integrated active RF filters based on the use of active simulated inductances. Finally, in Section 5, we consider an alternative approach based on passive resonators with loss compensation by means of active devices, providing a solution with lower noise