Novel Design of a Highly Sensitive RF Strain Transducer for Passive and Remote Sensing in Two Dimensions

Abstract

Abstract-A novel design of a highly sensitive wireless passive RF strain transducer is presented based on a patch antenna loaded with an open loop that is capable of sensing strain independently in two directions. An original idea of utilizing a cantilever at the gap of the open loop significantly improves the sensitivity of resonant frequency shifts. The frequency shifts in two distinct resonant modes are detected based on two dominant orthogonal modes of the patch resonators. In measurements, the prototypes achieved a sensitivity of 2.35% frequency shift per 1% strain, more than twice that of existing strain transducers of the same class. In simulations, the new design achieved a theoretical sensitivity up to four times as high as existing designs of RF passive wireless strain transducers. The ground plane allows for the sensitivity of the sensor to be independent from the applied surface. An implementation example of the passive remote sensing system based on the proposed strain transducer is also discussed as a proof-of-concept case. Based on calculations, the interrogation method in the example shows a radar cross section fluctuation of 3.8 dB corresponding to the strain induced at the sensor.

Stretchable Complementary Split Ring Resonator (CSRR)-Based Radio Frequency (RF) Sensor for Strain Direction and Level Detection

“…In Table 2, the proposed sensor is compared with other RF strain sensors in [29,30,31,32,33]. Because the proposed sensor is built on liquid metal and Ecoflex substrate, wider frequency tuning range and higher strain level are achieved compared with other sensors.…”

“…In addition, rapid prototyping with 3D printing provides the flexibility required to make this crucial trial and error process possible for physical products. Compared with RF sensors with low lossy substrates in [32,33], the Q-factor of the proposed sensor is relatively low due to dielectric loss of stretchable materials.…”

Extremely Sensitive Microwave Sensor for Evaluation of Dielectric Characteristics of Low-Permittivity Materials

“…Initially, these novel properties were achieved using a split-ring resonator (SRR) [16] and complementary split-ring resonator (CSRR) [17]. Later, these artificial structures were used to design microwave sensors for testing liquids [18][19][20][21][22], measurement of thickness [23][24][25][26], relative humidity [27], displacement [28][29][30][31][32], rotation [33][34][35][36], strain [37][38][39], permittivity and permeability [40][41][42]. The main advantages of SRR-and CSRR-based sensors are the small size with high sensitivity, lower cost with robustness, and high precision.…”

Wireless hydrogen pressure dosimeter for nuclear high dose monitoring

“…Wireless, chipless (without integrated circuit) and passive (battery-less) sensors could be a very convenient solution for the remote sensing of physical parameters in harsh environments. Applying the electromagnetic transduction principle many microwave and millimeter-wave sensors have been manufactured at LAAS-CNRS, such as pressure, temperature and strain sensors, as well as a radar-based solution for the wireless and long-range sensors interrogation (see, e.g., [1][2][3][4][5]). Very recently the authors have proposed a new concept of wireless, chipless and passive dosimeter which overcomes the limitations of state-of-the-art dosimeter [6][7].…”