UWB FMCW Radar Frontend Design
The first IMES Lecture of the year was opened by Gian-Luca Brazerol and Flavio Peter, who presented their master’s thesis “UWB FMCW Radar Frontend Design.” The work was carried out as part of the MSE Electrical Engineering program at OST, in cooperation with IMES and the Centre Suisse d’Electronique et Microtechnique (CSEM) in Neuchâtel.
The project focused on developing an energy-efficient transmit and receive path for a low-power Ultra-Wideband (UWB) Frequency-Modulated Continuous-Wave (FMCW) radar system designed for a frequency range of 7 to 9 GHz. The system aims to enable reliable, coarse-resolution presence detection at the lowest possible energy consumption. To achieve this, Gian-Luca Brazerol and Flavio Peter developed three key modules: a Class-D Power Amplifier (PA) for the transmit path, a Low-Noise Transconductance Amplifier (LNTA), and a mixer for the receive path.
All three modules were fully implemented at schematic and layout level and thoroughly verified through simulation. The results showed that layout-related parasitic effects had a noticeable impact - especially on the PA’s output power and the receive path’s noise figure at higher frequencies. Particularly noteworthy is the use of integrated inductors in both the PA and mixer - an uncommon solution in chip design due to the high integration and simulation effort associated with inductances.
The results achieved by Gian-Luca Brazerol and Flavio Peter are impressive: each module individually reaches performance levels comparable to published work, and the overall system promises a potential operating range of up to 20 meters.
Low-Power IC Design for Satellite Navigation Systems
Following this, Patrick Mächler from u‑blox AG continued the theme and dedicated his presentation to low-power chip design in the field of satellite navigation systems. The Swiss company, headquartered in Thalwil, operates globally today and develops chips and modules for satellite navigation, Bluetooth, Wi-Fi, and related technologies - serving both private customers and industrial or autonomous applications.
To begin, Patrick Mächler explained the wide range of challenges modern satellite navigation systems must overcome to achieve the desired positioning accuracy via multilateration. This is especially relevant for precision applications requiring centimeter-level accuracy, where effects such as multipath propagation, noise, and ionospheric disturbances must be understood and specifically compensated. Developing such a navigation chip is demanding, as it must operate in highly diverse system configurations. Parameters such as the GNSS used, the update rate, required accuracy, and the resulting energy consumption can vary significantly and must be handled flexibly.
Nevertheless, several promising and proven solution approaches were presented. These include a low-power backup mode in which relevant parameters of the most recently active satellite connection are cached to accelerate restart and save energy. Another approach is reducing the process node size, enabling lower operating voltages. Although smaller geometries come with increased leakage currents, these can be dynamically reduced using Active Body Biasing (ABB). Complementing this is Dynamic Voltage Scaling, where the supply voltage of individual submodules is adapted as needed.
The results are remarkable: compared to the previous generation of satellite navigation systems, energy consumption was reduced by up to 30%.