Assessment of a low-profile planar antenna for a wireless sensor network monitoring the local water distribution network

Abstract

This study presents an assessment on the suitability of a low‐profile planar antenna for a wireless sensor network (WSN) application monitoring the water supply at fire hydrants (FHs). The antenna must have a low profile so that it can be mounted on the FH lid; it must have an omnidirectional radiation pattern so that it can communicate with base stations at low elevations; and it must operate in the 2.4 GHz industrial, scientific and medical (ISM) band. Measurements show that for the majority of the 2.4 GHz ISM band, the antenna has a return loss of at least −10 dB and efficiency greater than 60%. For the FH WSN assessment, the antenna was deployed as a transmitter mounted on the FH lid above the underground FH chamber and a vertically polarised monopole antenna mounted on a mast at various specified heights above ground level was used to measure the received power as a function of distance. The path loss results were compared with those from a previous deployment, where the FH antenna was located in the FH chamber, and it is found that using the low‐profile antenna reduced the path loss by at least 10 dB over the measured transmitter and receiver separation.