LNA and Square Law Detector at 60 GHz for Passive Radiometers

Abstract

Millimeter-wave passive radiometers have earlier been designed in III-V integrated circuit (IC) technologies, due to their higher carrier mobility when compared to silicon, resulting in higher transit frequencies (fT) thereby enabling to operate at higher frequencies. However, increased fT in SiGe BiCMOS technology has generated interest for passive radiometer realization in these technologies. This thesis focusses on the design of low noise amplifier (LNA) and square law detector meant for realizing a 60 GHz RF-front end for passive radiometer application using 0.25 ?m BiCMOS technology. The design details of the LNA including the influence of layout parasitic are described. In particular, a detailed discussion on the LNA layout at 60 GHz and the need for electromagnetic (EM) verification simulation is presented. To this end, a design procedure of LNA is presented which takes into account the layout parasitics at the early stages of the design. Two LNA designs are discussed. The first LNA is designed to drive the detector input impedance and the second one is designed with a tapped capacitive transformer for output matching. The LNA driving the detector impedance achieves a post layout simulation gain of 21.3 dB of gain, 4.8 dB of noise figure at 63 GHz while the LNA designed for output matching achieves 19.6 dB and a noise figure of 4.8 dB at 63 GHz. The design of square law detectors using standard bipolar configurations is also presented in this thesis and are benchmarked for performance in terms of the detector specifications.