Radio frequency identification in internet of underground things using a soil dielectric attenuator and microstrip antenna as tag sensor

This work proposes an underground things (UT) based on radio frequency identification for internet of UT (IoUT) systems. The UT is formed by a microstrip antenna encapsulated in a soil dielectric attenuator (SDA). The dimensions of the antenna and SDA are designed through simulations and a prototype is manufactured for experimentation in two types of soil. Reflection coefficient (S11) and received signal strength indicator (RSSI) measurements were performed to verify the viability of the prototype. The measured results of S11 showed satisfactory agreement with the simulations and the antenna encapsulated in the SDA has small variations in the resonance frequency in the presence of moisture. The RSSI results indicated the potential of UT as a soil moisture sensor.