A Wireless Metamaterial-Inspired Passive Rotation Sensor With Submilliradian Resolution

Abstract

A novel passive wireless rotation sensing system with high levels of sensitivity and resolution is proposed and demonstrated for measuring elastic-region bending in materials such as steel. This system is composed of a transceiver antenna and a double-plate sensor in the form of an inter-digital configuration, which does not incorporate any active component. The sensor exhibits a large rotation resolution of 20 µ-rad, an excellent sensitivity of 28 MHz/°in average, and a large linear dynamic range of approximately 40°. In operation, as a result of the relative rotation between the plates of the sensor, the operating resonance frequency of the system is shifted. This is read out and tracked in the S 11 response of the transceiver antenna from which the rotation angle is determined. The prototype is designed for microwave regime and it is suitable for measuring very small angles (10 −4 ∼ 10 −5 rad). Critical figuresof-merit of the sensor including sensitivity, dynamic range, and resolution are assessed via systematic measurements, and the validity of resolution experiment is verified by employing digital image correlation method for 2-D measurements.

An ultrahigh‐sensitivity microwave angular displacement sensor with a wide dynamic range

“…In Horestani et al 10 and Seo et al, 11 the angular displacement sensors with wide range of 360° were developed by using SRR and rotational cross‐shaped resonator (CSR), but their sensitivities were relatively low. A high sensitivity angular displacement SRR‐based sensor was proposed in Maleki Gargari, 12 but its dynamic range was only 40°.…”

3D-Printed All-Dielectric Electromagnetic Encoders with Synchronous Reading for Measuring Displacements and Velocities

“…In recent years, many different microwave sensors for measuring angular or linear displacements and velocities have been reported. In [4][5][6][7][8][9][10], the microwave sensors are based on a transmission line loaded with a resonant element, which is etched in a different substrate and positioned in close proximity to the transmission line. Typically, the rotation angle or linear displacement of the resonant element with regard to the transmission line is determined from a change in the frequency response of the whole structure (bandwidth, quality factor, resonance frequency, etc.).…”

Directional‐coupler‐basedmicrowave sensors for differentialangular‐displacementmeasurement

“…Considerable attention is thus being dedicated to the engineering of angular-displacement sensors due to their potential interest in control systems, such as in the reaction wheels of space vehicles for altitude control and torque measurement, as well as in other relevant applications as seismic scenarios since they are sensitive to structure or ground rotations. [12][13][14][15][16][17][18][19][20][21][22][23] Whereas some realizations of this type of sensors operating at the lowfrequency region have been devised, 12 most of them exploit microwave-measurement techniques based on resonating circuits in their angular-displacement detection mechanism. Attending to the specific measurable that is considered for the sensing process, these microwave-resonator-based angular-displacement sensors can be classified into three different families.…”

“…14,15 The second category of microwave-resonator-based angular-displacement sensors, which are mostly based on metamaterial-inspired resonators, operate in basis to the variation of a notch frequency or TZ in their transmission response as a function of the angular-displacement to be measured. Some exponents to be highlighted, [16][17][18] which exploit different solutions as follows: (a) the overlapping area of U-shaped resonators for the stator and the rotor depending on the rotational angle, (b) microstrip-coupled complementary SRRs (CSRRs), and even (c) comb-like or nested SRR pairs that are interrogated by a single-slot microstrip antenna to obtain sub-milliradian resolution along with high sensitivity. However, they exhibit some limitations, such as a dynamic range that cannot exceed 90 17 and good linearity only for a very-reduced 5 angularvariation interval.…”

“…However, they exhibit some limitations, such as a dynamic range that cannot exceed 90 17 and good linearity only for a very-reduced 5 angularvariation interval. 18 The dynamic range limitation of the SRR sensors can be addressed by using multiple resonators in a microwave rotatory encoder configuration to improve the sensing capability. Angular displacement and velocities sensors using microwave rotatory encoders have been proposed to provide instantaneous velocities output.…”