Angular Displacement and Velocity Sensors Based on Coplanar Waveguides (CPWs) Loaded with S-Shaped Split Ring Resonators (S-SRR)

Abstract

In this paper, angular displacement and angular velocity sensors based on coplanar waveguide (CPW) transmission lines and S-shaped split ring resonators (S-SRRs) are presented. The sensor consists of two parts, namely a CPW and an S-SRR, both lying on parallel planes. By this means, line-to-resonator magnetic coupling arises, the coupling level being dependent on the line-to-resonator relative angular orientation. The line-to-resonator coupling level is the key parameter responsible for modulating the amplitude of the frequency response seen between the CPW ports in the vicinity of the S-SRR fundamental resonance frequency. Specifically, an amplitude notch that can be visualized in the transmission coefficient is changed by the coupling strength, and it is characterized as the sensing variable. Thus, the relative angular orientation between the two parts is measured, when the S-SRR is attached to a rotating object. It follows that the rotation angle and speed can be inferred either by measuring the frequency response of the S-SRR-loaded line, or the response amplitude at a fixed frequency in the vicinity of resonance. It is in addition shown that the angular velocity can be accurately determined from the time-domain response of a carrier time-harmonic signal tuned at the S-SRR resonance frequency. The main advantage of the proposed device is its small size directly related to the small electrical size of the S-SRR, which allows for the design of compact angular displacement and velocity sensors at low frequencies. Despite the small size of the fabricated proof-of-concept prototype (electrically small structures do not usually reject signals efficiently), it exhibits good linearity (on a logarithmic scale), sensitivity and dynamic range.

Spectral signature barcodes based on S-shaped Split Ring Resonators (S-SRRs)

“…Note that this model is formally identical to the one describing a SRR-loaded CPW transmission line [1,3]. As discussed in [26], the mutual coupling depends on the relative orientation between the line and the resonator, it being maximum for the 90°orientation, i.e., the one indicated in Figure 3a. In the circuit of Figure 3b, losses have been excluded.…”

“…The typical topology (including relevant dimensions) and circuit model of a CPW loaded with a square S-SRR, etched on the back substrate side, are depicted in Figure 3 [26]. The line is modeled by the inductance L and the capacitance C, the S-SRR is described by the capacitance C s and by the inductance of each loop, L s .…”

“…S-SRRs have been successfully applied to the design of microwave filters [25] and sensors [26] as well. Coupled to CPW transmission lines, S-SRRs generate notches (transmission zeros) in the transmission coefficient at their resonance frequency.…”

Design and Fabrication of a Novel Wideband DNG Metamaterial with the Absorber Application in Microwave X-Band

“…Figure 1(b) shows the parameters that represent the electric topology of a modified S-SRR unit cell with the ( , 1 , 2 , 3 ) inductors and ( , 1 , , ) capacitors. Explicit expressions for and can be found in [12][13][14]. A unit cell of the proposed structure together with the ports applied in the simulations is shown in Figure 2.…”

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].…”