# Two-Terminal Electronic Circuits with Controllable Linear NDR Region and Their Applications
## 9 Conclusions  
In this article, we have demonstrated new two-terminal NDR circuits based on a combination of a field-effect transistor and multiple-output cascode, Wilson, and improved Wilson BJT current mirrors. The proposed circuits allow controlling the slope of the current-voltage characteristics in the NDR region by changing the number of mirrored currents, thus setting the peak-to-valley current ratio to any desired value. We have conducted modeling total current in the NDR region when the FET is a JFET and MESFET, HEMT, or PHEMT; the obtained current equations calculate the negative resistance at the operating point. We considered possible applications of the proposed two-terminal NDR circuits as oscillators and VCOs. We found that the NDR circuit with multiple-output improved Wilson current mirror has the smallest absolute value of negative resistance, which means that the NDR oscillator based on this circuit has the best conditions for self-excitation. We analyzed the effect of loading on the performance characteristics of the oscillators and VCOs. We found that a 50-ohm load reduces, in comparison to infinite load, the performance of the oscillators and VCOs by a maximum of 4.9% and 0.7 %, respectively. By simulation, we show that the microwave oscillator based on multiple-output improved Wilson current mirror has the lowest phase noise (\(-154.6\) dBc/Hz at offset 100 kHz) and the best figure of merit (\(-221.6\) dBc/Hz) compared to other considered oscillators. We also \begin{table}
\begin{tabular}{c c} \hline \hline
**Circuit Elements** & **Part Numbers and Nominal Values** \\ \hline Transistor \(T_{0}\) & BF245B \\ \hline Transistors \(\overline{T_{1}},T_{M}\) & BFT92W \\ \hline Inductor \(L\) & ELJQF8N2 (8.2 nH) \\ \hline Capacitor \(C_{a}\) & C0603C0G1E100D (10 pF) \\ \hline Capacitor \(C_{b}\) & C0603Y5V1C103Z (10 nF) \\ \hline Capacitors \(C_{1}\), \(C_{2}\) & C0603C0G1E0R5C (0.5 pF) \\ \hline Resistor \(R_{c}\) & ERJ1 GEJ102 (1 k\(\Omega\)) \\ \hline Resistor \(R_{d}\) & ERJ1 GEJ392 (3.9 k\(\Omega\)) \\ \hline \hline \end{tabular}
\end{table} 
Table 16: Circuit elements used in the oscillator with MIWCM assembled on a printed circuit board. Figure 31: The output spectrum of the oscillator with multiple-output improved Wilson current mirror (\(m=0\)). show that the VCO with multiple-output improved Wilson current mirror has the best FOM in the tuning range (\(-205.1\), \(-203.9\) dBc/Hz). Comparison of the developed oscillators and those previously published showed that the oscillators based on the proposed two-terminal NDR circuits are superior to the well-known GaN and GaAs HEMT oscillators by 10-20 dB with respect to the commonly used figure of merit. It is also interesting to note that the proposed oscillator circuits are higher in effectiveness than even CMOS oscillators, despite the much lower power consumption of the latter. This advantage is due to the low level of phase noise in the designed oscillators. Our future work will focus on developing and studying two-terminal NDR circuits, in which the multiple-output current mirrors consist of MOS transistors. Conceptualization, V.U. ; methodology, V.U. and A.R. ; software, D.M. ; validation, V.U., A.R. and D.M. ; formal analysis, V.U. ; investigation, V.U., A.R. and D.M. ; data curation, V.U. and D.M. ; writing--original draft preparation, V.U. and A.R. ; writing--review and editing, V.U. ; visualization, V.U. and D.M. ; supervision, V.U. ; project administration, A.R. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The authors express thanks to engineer [PERSON] for technical support. The authors declare no conflict of interest. The following abbreviations exist in the manuscript: