# A Temperature-Robust Envelope Detector Receiving OOK-Modulated Signals for Low-Power Applications
## 5 Conclusions  
EDs are often used in communication applications, such as in Wake-Up Receivers, which are widely employed in IoT Wireless Sensor Networks. The target of this paper is to develop a passive ED with a temperature compensation mechanism in order to reduce the overall receiving chain sensitivity loss due to temperature changes. This is accomplished by keeping the input resistance of the ED constant with temperature with the aim of making it a constant load for the preceding matching network.  
The central idea of the paper has been proven through a design in an STMicroelectronics 90 nm CMOS technology, receiving 1 kbps OOK-modulated packets with a 433 MHz carrier frequency and a 0.6 V supply. The use of the PTAT block yields a 5 dB reduction in sensitivity temperature variation across the \(-40\)\({}^{\circ}\)C to 120 \({}^{\circ}\)C range. Moreover, two different implementations were compared, one targeting minimal mismatch and the other one targeting minimal area. The minimal area version appears to be better in terms of estimated overall chain sensitivity at all temperatures, despite a higher sensitivity spread.  
**Author Contributions:** \"State-of-the-Art Passive EDs with Temperature Compensation\", all authors; \"ED and PTAT Block Description\"-\"ED model and receiving chain sensitivity optimization\", A.M.E., M.D. and L.P.; \"ED and PTAT Block Description\"-\"Temperature compensation through the PTAT block\", all authors; \"ED and PTAT Block Description\"-\"ED differential approach\", A.M.E., M.D., L.P., E.F.S. and A.G.; \"ED and PTAT Block Description\"-\"Maximum input power\", A.M.E., M.D., L.P.,  
Figure 8: Simulated \(P_{sens}\) of versions 1 and 2, both with the use of the PTAT block.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Version 1** & **Version 2** \\ \hline Target bitrate [kbit/s] & 1 & 1 \\ Power consumption at 20 \({}^{\circ}\)C [nW] & 6 & 14 \\ Diode dimensions [nm] & (\(450\times 2\))/450 & 120/100 \\ Coupling capacitances [fF] & 36 & 13 \\ \(C_{in}\) [pF] & 3 & 1.9 \\ \(R_{in}\) at 20 \({}^{\circ}\)C [k\(\Omega\)] & 10.7 & 10 \\ \(\Delta R_{in}\) for \(-40\div 120\)\({}^{\circ}\)C [k\(\Omega\)] & 24 & 13.7 \\ \(P_{sens}\) at 20 \({}^{\circ}\)C [dBm] & \(-66.1\) & \(-68.9\) \\ \(\Delta P_{sens}\) for \(-40\div 120\)\({}^{\circ}\)C [dB] & 4.6 & 4.6 \\ \(\sigma P_{sens}\) at 120 \({}^{\circ}\)C [dB] & 0.4 & 1.1 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison table between the two implemented versions.  
E.F.S. and A.G.; \"Implementation Criteria\", all authors; \"Conclusion\", all authors. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
Authors [PERSON], [PERSON], [PERSON] and [PERSON] were employed by the company STMicroelectronics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} ED & Envelope Detector \\ OOK & On-Off Keying \\ WuRX & Wake-Up Radio Receivers \\ IoT & Internet of Things \\ PTAT & Proportional-to-Absolute Temperature \\ MOSFET & Metal-Oxide-Semiconductor Field-Effect Transistor \\ SNR & Signal-to-Noise Ratio \\ NF & Noise Figure \\ \end{tabular}