International audience

International audience

In this paper, the design of a 77.3 GHz Standing-Wave oscillator (SWO) is presented. The proposed SWO relies on the distribution of varactors along an asymmetrical slow-wave coplanar stripline, which enables the improvement of the quality factor of the tunable resonator, resulting in superior performance in terms of phase noise and DC-to-RF efficiency. The design methodology, based on the use of analytical models and abaci, is presented in detail and applied to a design in a 55-nm CMOS technology. With a core consumption of 15.1 mW, the proposed SWO operates from 76.09 GHz to 78.60 GHz and presents a phase noise of -115.1 dBc/Hz at 10 MHz offset, leading to a Figure of Merit (FOM) of -181 dBc/Hz. The DC-to-RF efficiency obtained is 3.1%.

This paper presents an innovative Through-Load element aimed at characterization applications at mm-wave frequencies. The proposed structure can behave as a Through connection or as a 50-Ω load depending on a DC control voltage. Among other potential applications, this system can be used to implement a transfer switch or an attenuator. A demonstrator was fabricated and measured in the STM 55-nm BiCMOS technology. Over a wide bandwidth, from 55 GHz up to 170 GHz, experimental measurements demonstrate a maximum 1.6-dB of insertion loss when behaving as a Through connection and a minimum 14-dB of insertion loss when behaving as a 50-Ω load. In both cases, the return loss is better than 10 dB. The insertion loss at 90 GHz is 0.6 dB for the Through connection and 20 dB for the 50-Ω load connection.

Beam-forming techniques using phased arrays are one of the most promising solutions for the practical implementation of future high-data-rate point-to-point communication protocols. The functionality of phased arrays is based on the use of phase shifters that should provide an accurate and controllable phase difference between the different paths of the array. However, the integration of phase shifters in current nanometric technologies is prone to imperfections that may affect the intended phase shift and degrade the performance of the antenna array. This requires extensive testing and calibration and represents a bottleneck in the production line of these system. In this work, we propose a simple Oscillation-Based Test technique that may be suitable for Built-In Self-Test applications of phase shifters. The technique is demonstrated on a Reflection-Type Phase Shifter implemented in a 55 nm BiCMOS technology. Electromagnetic and electrical simulation results show the feasibility of the proposed technique.