Impedance Adaptation Technique to Improve Pipeline Communication Distance

In recent years, a growing necessity of monitoring facilities like gas or water pipelines has raised to ensure high security and proper maintenance of the infrastructures. In particular, in piping systems, there is the need to monitor the cathodic protection voltage, whose presence allows to protect the pipeline from corrosive effects and avoid damage to the system. The state of protection of the pipes also needs to be communicated outside of the measurement point. Unfortunately, most pipelines are located in places where creating a wireless communication network is very expensive. An innovative and unconventional way to achieve this goal is to use the pipelines as a communication channel, avoiding installing dedicated data communication systems. Starting from the authors' background, in this paper, an opamp-based circuit is presented and adopted for the information transfer over gas pipelines. A characterization of the presented circuit is made to find the relationship between the reflection coefficient and the impedance connected to a specific port of the circulator. Measured the pipeline input impedance and knowing the theory about the transmission lines, the output impedance of the circulator is adjusted to obtain the impedance matching with the line to have a complete transmission of the signal on the gas pipeline. In the last section of the paper, the effective improvement of the communication channel obtained by inserting the circulator in the communication link is shown. The final aim is to transmit a certain number of bytes with a private communication protocol, in order to avoid informatic attacks and to improve the cyber-security level.