Stability assessment of non-Foster circuits based on time-domain method

作者：Elfrgani Aseim M^*; Moussounda Renaud; Rojas Roberto G

来源：IET Microwaves Antennas & Propagation, 2015, 9(15): 1769-1777.

DOI：10.1049/iet-map.2014.0671

• time-domain analysis
• microwave circuits
• microwave antennas
• circuit stability
• Lyapunov methods
• time series
• negative impedance convertors
• invertors
• non-Foster circuit
• time-domain method
• microwave applications
• antenna applications
• potential instability
• maximal Lyapunov exponent
• time series signals
• circuit stability analysis
• negative impedance converters
• inverters
• MLE

Non-Foster circuits are attractive for microwave and antenna applications since they are not restricted by the gain-bandwidth product. A persistent problem with these circuits is the potential instability (mainly unwanted oscillations) due to the presence of positive feedback. The stability properties of these circuits are discussed with a time-domain technique that computes the largest (maximal) Lyapunov exponent (MLE) for time-series signals within the circuit's structure as well as at its output to determine with confidence the circuit's stability. In case of instability, the circuit is stabilised with different controllers. A circuit or system is considered stable when the MLEs obtained from signals at multiple nodes are negative. Moreover, the effect of small DC bias variations on stability is also studied. The proposed stability analysis approach has been successfully applied to two known topologies: namely, negative impedance converters and inverters.

• 出版日期2015-12-10