Gas detectors are a mandatory safety and environment protection feature to be installed in industrial plants today. On the other hand, there is an increase of Wireless Sensor Network (WSN) implementation for process parameter measurement (e.g. pressure, temperature monitoring) in the industrial plant.
In this research project, a novel concept of integration of gas sensing into industrial wireless sensor node is introduced. It is proposed that the antenna of the wireless sensor node can be made dual-function, where the antenna does not utilize the microwave signal only to transmit and receive data, but also to detect the presence of gas. This enhanced wireless sensor node can then be utilized to expand the gas detection coverage from existing separate gas sensing system, which is important from the plant safety perspective. This research could also bring significant advantage to the industrial wireless sensor’s manufacturer, plant operator, as well as the industry in general.
The principle of gas detection through microwave is to include sensitive material in the antenna structure. Upon the exposure of gas, the dielectric permittivity of the sensitive material will change, which will result in the change of microwave’s scattering parameters (S-parameters) accordingly. The change of S-parameters (e.g. resonant frequency shift, magnitude variation) can then be correlated to the concentration of the gas being exposed.
However, the change of S-parameters should not compromise the specification of the antenna (e.g. bandwidth, gain, directivity, radition pattern, phase shift). Therefore, this work is non-trivial and includes:
- Optimisation of the current design of the antenna (hybrid monopole-dielectric resonator antenna)
- Fabrication of antenna prototype and performance measurement both as antenna and gas detector
- Modelling of the impact of gas detection’s integration in WSN
- Integration of RF interrogator’s signal processing component into the wireless transceiver
