Alignment and Position Sensors Based on Split Ring Resonators

Abstract

In this paper compact alignment and position sensors based on coplanar waveguide (CPW) transmission lines loaded with split ring resonators (SRRs) are proposed. The structure consists of a folded CPW loaded with two SRRs tuned at different frequencies to detect both the lack of alignment and the two-dimensional linear displacement magnitude. Two additional resonators (also tuned at different frequencies) are used to detect the displacement direction. The working principle for this type of sensor is explained in detail, and a prototype device to illustrate the potential of the approach has been designed and fabricated.

Two‐dimensional displacement and alignment sensor based on reflection coefficients of open microstrip lines loaded with split ring resonators

“…One advantage of this method is that both SRRs can be designed to operate at the same resonance frequency. This is in contrast to the previously proposed two-dimensional displacement sensors based on transmission characteristics of a through TL, where SRRs needed to have distinct resonance frequencies [9,10]. For electromagnetic simulations, two 0.81 mm thick Rogers RO4003 substrates (ǫr = 3.38 and tan δ = 0.0022) with 35 µm thick copper metalization are used.…”

“…Various types of displacement and rotation sensors based on variation of resonance frequency, quality factor and notch depth in the transmission spectrum of SRR-loaded transmission lines (TLs) have been proposed in the literature [1,5,6,7,8]. The concept was also extended for the design of two-dimensional displacement sensors [9,10].This letter proposes a two-dimensional displacement and alignment sensor based on the variation in the depth of resonant notch in the reflection coefficients of two SRR-loaded microstrip lines. Since both SRRs and microstrip lines are inherently compact structures, the proposed sensor benefits form a small size.…”

“…This is an important feature because it enables the sensor to work at a fixed frequency. This sensing mode allows to operate based on two reflection coefficients rather than using the transmission coefficient of the structure, where at least two fixed frequencies are required for the operation of two-dimensional displacement sensors [9,10]. …”

“…Various types of displacement and rotation sensors based on variation of resonance frequency, quality factor and notch depth in the transmission spectrum of SRR-loaded transmission lines (TLs) have been proposed in the literature [1,5,6,7,8]. The concept was also extended for the design of two-dimensional displacement sensors [9,10].…”

High data density and capacity in chipless radiofrequency identification (chipless-RFID) tags based on double-chains of S-shaped split ring resonators (S-SRRs)

“…Transmission lines loaded with split ring resonators (SRRs) and with other electrically small resonators [1][2][3][4][5] have been used in numerous microwave applications, including filters [6,7], enhanced bandwidth components [8], multiband components [9][10][11][12], microwave sensors [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and chipless radiofrequency identification (chipless-RFID) tags [31,32], among others. Concerning chipless RFID tags, the interest in this work, transmission lines loaded with multiple resonant elements, each tuned to a different frequency, have been proposed as multi-resonant frequency domain based tags [31][32][33][34][35][36][37][38][39][40][41][42][43][44].…”