Variation Of Reflection Coefficient Research Articles

Characterization and analysis of attenuation anisotropy in viscoelastic vertical transverse isotropic media

AbstractDue to the intrinsic attenuation of the earth, the study of wave propagation characteristics, considering seismic attenuation plays an important role in high‐precision reservoir prediction. Therefore, we investigate the propagation and reflection characteristics of seismic waves in viscoelastic vertical transverse isotropic media in the complex frequency domain. Specifically, we analyse the response characteristics of velocity, propagation vector and attenuation vector with respect to viscosity media with different attenuation intensities. Furthermore, based on the quasi‐Zoeppritz equation, the variation of reflection coefficient amplitude with offset at different attenuation angles and different attenuation intensities is studied. We also compare the trends in the amplitude variation of reflection coefficients with offset in elastic isotropic, elastic anisotropic and viscoelastic anisotropic media. Due to the complexity of the exact reflection coefficient expression, we first propose the approximate expression of the attenuation–anisotropy parameters and then derive the approximate expression of the reflection coefficient. The numerical simulation results show that the approximate expression of the reflection coefficient is still accurate, even in media with strong anisotropy. Finally, the accuracy evaluations of the reflection coefficient formulas using four typical theory models demonstrate that the approximate reflection coefficient formulas are highly accurate in both weak and strong anisotropic media.

H-plane SIW horn antenna with enhanced front-to-back ratio for 5G applications

Millimeter-wave (mmWave) antennas are indispensable components in the fifth-generation (5G) wireless communication systems. With the inherent advantages of integration capability, substrate integrated waveguide (SIW) antenna is an excellent choice for applications in the mmWave frequency bands. However, reflection losses occur at dielectric-filled thin apertures of SIW antennas. These reflections can be overcome by impedance matching between the aperture and the free space. In this study, we introduce an mmWave SIW horn antenna having impedance matching transitions (IMTs) across the horn's aperture width. The designed antenna, operating in the 24-28 GHz band, is simulated with a full-wave analysis tool. The simulation results of the modified SIW horn have been confirmed by the experimental results and shown to be satisfactory. The IMTs result in an enhancement of the front-to-back ratio (FTBR). The modified SIW horn antenna with a novel printed transition achieves sidelobe levels (SLLs) of better than ?9 dB at 27 GHz, with an enhanced FTBR above 15 dB. In the 24?28 GHz band, the antenna has a reflection coefficient variation of better than ?10 dB.

Delamination thickness measurement based on Stoneley wave in bilayered composite structure

Introduction: For composite structures, delamination usually occurs at the interface. Ultrasonic guided waves have been widely used to detect the delamination. However, most researches focus on the measurement of the delamination length along the interface, and the measurement of the delamination thickness is less studied. Method: In this paper, based on the characteristic that the Stoneley wave only propagates along the interface, the reflection coefficient of interaction between Stoneley wave and delamination is used to measure the delamination thickness. The effects of delamination thickness and frequency on the reflection coefficient are investigated via dividing integral region and reciprocity theorem. Some experimental validations are carried out on two aluminum-steel bilayered composite plates with different delamination thickness. Results: It is found the reflection coefficient increases linearly at first, then its rate of increase slows down gradually, and finally becomes stable, in theory. And the experimental results can verify the theoretical relationship between the reflection coefficients and the delamination thickness. Conclusion: The variation of reflection coefficient provides a reference for the measurement of delamination thickness in Stoneley-wave-based non-destructive testing.

Зависимость отражательных свойств агропочв в сверхширокой полосе частот от типа, степени шероховатости поверхности и профилей влажности агропочв

In this article, the impact of volumetric moisture from 0% to 40% (vertical moisture profiles), dry bulk density from 0.4 to 1.8 g/cm3, clay content from 0.15 to 0.55 g/g (agrosoil type), standard deviations heights of surface roughness from 0 to 4 cm of soil on the variations of reflection coefficient in the ultra-wide frequency band from 100-400 MHz to 1.26-2.4 GHz were investigated. The reflection coefficient was calculated for a smooth and rough soil surface. Mironov's two-relaxation dielectric model was used (input parameters: dry bulk density, clay content, volumetric moisture, frequency of electromagnetic wave) to calculating the reflection coefficient. It is shown that the reflection coefficient is an ambiguous function of the clay content and the dry bulk density; the error in retrieving high values of soil moisture can be 5 times higher than for dry soils. In relation to the clay content and the dry bulk density, the soil roughness is the dominant parameter, which uncertainty, significantly effects on the error of soil moisture retrieving. For the considered various vertical profiles of soil moisture, it is shown that the effective thickness of topsoil, which forms the reflection coefficient, does not exceed 2 cm at a sensing frequency above 1 GHz. When the volumetric moisture content of soil surface is more than 28%, the reflection coefficient in the frequency range from 433 MHz to 1.26 GHz does not depend on the vertical distribution of moisture in soil. The conducted studies establish quantitative limitations on the accuracy of soil moisture retrieval for a given error in the initial parameters of the model: the clay content, the dry bulk density, soil surface roughness, which should be taken into account when developing algorithms for remote sensing of agrosoil moisture.

Circular shape MIMO antenna sensor for breast tumor detection

Abstract In this paper, a compact circular shape ultra-wide microstrip antenna is proposed for the detection of breast tumor. The proposed antenna is a two-port MIMO antenna of 1 × 2 elements. The dimensions of the proposed antenna are 34 mm × 18mm × 1.6 mm. It is designed over a lower-cost FR-4 epoxy substrate with a partial ground plane. The antenna is operated between the frequency range of 3.1–9.6 GHz. Isolation between the antenna element is less than −22 dB from 3.1 GHz to 7 GHz and −25 dB between 7 GHz and 10.6 GHz. The obtained ECC of the designed MIMO antenna is less than 0.01 and also DG is almost 10 dB in the entire UWB range. Further, the 3D breast phantom model is also simulated for analysis of the effect of SAR. Due to the variation in the electrical properties of cancerous cells and healthy cells it is possible to identify the cancerous tumor using SAR analysis. The obtained maximum Average SAR value without a tumor is 41.97 W/kg and with a cancerous tumor is 72 W/kg. Also, the variation in reflection coefficient helps to detect the tumor of the same composition but having different locations and having different sizes inside breast phantom. The principal component analysis is done to change the multi-variation in reflection coefficients data value to a single point value for better analysis.

Optimization based design of a wideband metasurface for utilization in a terahertz reflectarray antenna with high efficiency

In this manuscript, two wideband single layer reflectarray antennas are designed utilizing an optimization-based metasurface in terahertz (THz) regime. It is demanded to design a metasurface with wide phase variation range in a broad frequency region of terahertz band. The proposed metasurface is designed based on Random Hill Climbing optimization algorithm whereas a multiobjective fitness function is defined to consider the desired characteristics. A provided link between Matlab and HFSS softwares is utilized to define and simulate various metasurfaces. The finalized cell has considerable wide phase variation ≥ 600 ∘ and notable bandwidth of 30.76% (1.1–1.5 THz) whereas the mean value of magnitude variation of reflection coefficient is −0.42 dB. Two square and circular metasurfaces are designed based on the optimized cell and illuminated using a THz feeding horn antenna. The angles of incident and reflected waves are considered equal to zero. The simulation results confirm 3-dB gain bandwidths of 20.3% and 20.4% for square and circular metasurfaces, respectively. Moreover, the considerable efficiencies of 45.67% and 46.27% are achieved for square and circular arrays, consequently. The maximum gain of square array with 361 elements is 25.9 dB whereas it is equal to 24.9 dB for circular metasurface including 277 unit cells.

Waves in a nonlocal micropolar thermoelastic half-space with voids under dual-phase-lag model

The present article is concerned with the reflection of plane harmonic waves in a nonlocal micropolar thermoelastic medium having void pores in the context of dual-phase-lag and Lord-Shulman models. Two sets of coupled shear waves and three sets of coupled longitudinal waves are shown to exist. When a coupled longitudinal displacement wave is made incident, the reflection coefficients of the various reflected waves and their respective energy ratios are computed analytically and the numerical computation is carried out with the help of MATLAB software. For a particular model, the influence of nonlocal, voids and micropolar parameters on the variations of reflection coefficients and energy ratios of various reflected waves is presented graphically. It is verified that during reflection phenomenon, the sum of energy ratios is equal to unity at each angle of incidence. A comparison between the dual-phase-lag model and Lord-Shulman model is also depicted graphically.

Novel monkey-wrench-shaped microstrip patch sensor for food evaluation and analysis.

Microwave sensor technology is considered to be a non-destructive and hygienic means for food evaluation and analysis. The rapid progress in microwave sensor technologies motivated us to present a novel monkey-wrench-shaped microstrip patch sensor for evaluating food quality. The proposed antenna is considered as a liquid sensor to detect adulteration in liquids by examining the relationship between concentration, shift in resonant frequency, and variation in reflection coefficient. The sensor has a compact size of 17 × 14 mm2 imprinted on an FR4 substrate of thickness 1.57 mm. This microwave system is proposed for monitoring overall milk quality using a microstrip sensor and has considerably good numerical sensitivity and accuracy (13.11% and 88.5% respectively), which makes the system attractive for detecting adulteration. Further, the Q-factor for the proposed sensor is 209 and has a standard deviation less than the difference between non-adulterated and adulterated values, giving resolution high enough to distinguish adulteration with an acceptable statistical accuracy. In this study, different milk categories (buffalo, goat, and cow milk) are considered as liquid samples to detect adulteration by demonstrating the variation in reflection coefficient due to change in dielectric properties for the following different cases: (i) adulteration of milk with water; (ii) adulteration of milk with synthetic milk powder; (iii) adulteration of milk with caustic soda; and (iv) adulteration of milk with vegetable oil. The referred variation in reflection coefficient and resonant frequency is due to a change in the dielectric properties of a liquid when a varying concentration of an adulterant/solute is added to the liquid sample. The simulation and measured results show good agreement that validates the proposed sensor for food adulteration detection with high sensitivity. In terms of performance, the proposed sensor shows accuracy with high spatial resolution and reduced penetration depth to detect the adulteration in various milk samples (i.e. buffalo, goat, and cow milk). © 2021 Society of Chemical Industry.

Triple-Band Single-Layer Rectenna for Outdoor RF Energy Harvesting Applications.

A triple-band single-layer rectenna for outdoor RF energy applications is introduced in this paper. The proposed rectenna operates in the frequency bands of LoRa, GSM-1800, and UMTS-2100 networks. To obtain a triple-band operation, a modified E-shaped patch antenna is used. The receiving module (antenna) of the rectenna system is optimized in terms of its reflection coefficient to match the RF-to-DC rectifier. The final geometry of the proposed antenna is derived by the application of the Moth Search Algorithm and a commercial electromagnetic solver. The impedance matching network of the proposed system is obtained based on a three-step process, including the minimization of the reflection coefficient versus frequency, as well as the minimization of the reflection coefficient variations and the maximization of the DC output voltage versus RF input power. The proposed RF-to-DC rectifier is designed based on the Greinacher topology. The designed rectenna is fabricated on a single layer of FR-4 substrate. Measured results show that our proposed rectenna can harvest RF energy from outdoor (ambient and dedicated) sources with an efficiency of greater than 52%.

Effect of motions on the performance and mooring tension of a floating pontoon-type breakwater

ABSTRACT This study experimentally investigated the performance and hydrodynamic response of a flexible floating pontoon-type breakwater. The floating breakwater consists of ten rubber pontoons with flexible connections. The effect of relative breadth and relative wave height on the wave transmission, reflection and dissipation coefficients has been discussed for various assembly configurations of the floating breakwater. The results show that the flexible multi-pontoon breakwater has better performance with larger relative breadth. The configuration of continuous pontoons without gap has the best performance on wave attenuation for relatively long waves. In short waves, however, better performance was observed on the pontoon configurations of two equal sets with gap. The novelty of this study is figuring out the relationship among the wave reflection coefficient, motion and mooring tension of the breakwater. The results reveal that the variation of reflection coefficient versus relative breadth shows the same trend as that of mooring tension.

Гигантский магниторезистивный эффект в отражении микроволн от сверхрешеток (CoFe)/Cu

Experimental study of microwave giant magnetoresistive effect in wave reflection has been carried out in frequency range from 26 to 38 GHz. The magnitude of the effect is obtained and its magnetic field dependence is defined. The experiments are carried out with (CoFe)/Cu superlattices, which have giant magnetoresistance. Calculations of the magnetic field dependence of microwave reflection coefficient are fulfilled. The measured values of reflection coefficient variations are found to be greater than the calculated ones. This difference is connected with approximation within which the superlattice is replaced by the uniform metallic plate in calculations. A frequency dependence of microwave giant magnetoresistive effect in reflection is also observed. This dependence is explained by the influence of the waveguide impedance where the sample is placed in measurements.

Reflection analysis for Stoneley waves encountering interfacial delamination

Stoneley wave is a kind of ultrasonic guided wave propagating along a solid-solid bonded interface with two different materials. In this paper, the influence of interfacial delamination size on the reflection coefficient of Stoneley waves in a double-layered medium is investigated. According to the energy distribution of Stoneley waves, an appropriate integral region is selected, and the reflection coefficient of Stoneley waves encountering delamination is derived via reciprocity theorem. An example of delamination composed of two arcs is introduced. The effects of delamination radius, delamination width and Stoneley wave wavelength on the reflection coefficient are discussed. It is observed that the reflection coefficient decreases and gradually stabilizes as the delamination radius increases. Meanwhile, the variation of reflection coefficient with the ratio of the delamination width to the Stoneley wave wavelength is half-sine and this can be interpreted by the interference principle. Finally, some experimental validations are carried out on an aluminum-steel plate. The delamination location is tested by pulse-echo approach and the half-sine variation of the reflection coefficient with the ratio of the delamination width to the Stoneley wave wavelength is measured. The variation of reflection coefficient provides a reference for the measurement of the interfacial delamination size in nondestructive testing.

Graphene-based materials for antenna applications

Internet of Things (IoT) has become one of the trending technologies in recent years. With the wide applications and rapid development of wireless communication and IoT, there are growing number of requirements on novel device design, such as flexible antennas and tunable antennas. The demand of transparent and flexible wireless communicational devices is ever-increasing for a wide range of scenarios, such as noninvasive healthcare, real-time wearable electronics, etc. Besides, a highly integrated antenna with tunable bandwidth and low energy consumption is in pressing demands in order to reduce the number of antennas and achieve better signal strength and higher speed signal transmission. Graphene materials have drawn much attention due to its extraordinary optical properties, high electrical and thermal conductivity, and excellent mechanical properties. All of these properties underline that graphene can be considered as a highly competitive material for wearable communication devices. Moreover, the electrical resistance of graphene and graphene oxide could be simply changed by external electric fields, applied strain and environment, which alters the electrical characteristics of the graphene-based microwave devices. Accordingly, graphene materials have a great potential in various reconfigurable or tunable devices. Our group fabricated the first graphene-based flexible and transparent wireless antenna with 2D large single-crystalline graphene and 1D AgNW hybrid material based on the features of graphene, such as high carrier mobility, transparency and flexibility, etc. The antenna exhibited a 75% light transmittance and an ultrawide bandwidth ranging from 5.6 to 12.8 GHz, combining with outstanding durability and stability with an almost negligible variation of reflection coefficients over 1000 bending cycles. Further research confirmed that the existence of graphene harmonized the compatibility between antenna and integrated chips, hence improved the total performance of the radio frequency identification (RFID) tags. Graphene/AgNW-based RFID tag was fabricated with an operating UHF band of 850–960 MHz and a reading distance of 130 cm, showing a great commercial potential. The excellent performance and unique properties of graphene/AgNW-based antenna and RFID tag came from the synergistic effect between 1D and 2D nanomaterials, providing a new vision for the design of next generation wireless electronics. Meanwhile, a slot antenna with tunable bandwidth was proposed. The antenna consisted of a planar slot antenna with graphene ink printed at the gap between the ground and a small patch. The graphene ink was made from the mixture of graphene powder and graphene oxide aqueous dispersion. Graphene oxide sheets functioned as effective surfactants rendering assistance to form uniform printable inks, displayed alterable electrical resistance by optimization of mixing proportions between graphene and graphene oxide. Dried graphene inks displayed tunable electrical resistance under applied DC voltages. The variation in the resistance of graphene ink affected radiation of the slot antenna, resulting in a shift of operating bandwidth. The proposed antenna achieved a shifting bandwidth of 0.54 from 6 to 5.46 GHz after applying DC voltage less than 15 V. Such cost-effective, easily acquired, and printable graphene inks integrated the dual advantages of graphene and graphene oxide. It could be further applied in many other fields of printable electronic devices.

Effect of impedance on the reflection of plane waves in a rotating magneto-thermoelastic solid half-space with diffusion

This research article deals with the propagation of plane waves in a rotating magneto-thermoelastic half-space with diffusion in the context of Lord–Shulman theory of thermoelasticity. The governing equations are formulated for a specialized plane and solved to obtain the velocity equation, which indicates the existence of four coupled plane waves. The wave velocities are computed for a particular medium, and the effect of the diffusion parameter is shown graphically on these waves. Impedance boundary conditions are applied to study the reflection of plane waves from the stress-free and thermally insulated/isothermal surface. Reflection coefficients and energy ratios of the reflected waves are also obtained, and the variations of reflection coefficients and energy ratios against the angle of incidence are shown graphically.

Low Elevation Angle Estimation with Range Super-Resolution in Wideband Radar.

Height detection of a low elevation angle target is crucial in radar applications. Due to the presence of the multiple path reflections, elevation angle estimation is difficult with conventional narrowband radar waveforms. The reflection ground area parameters are especially hard to obtain for modeling. In this paper, we proposed a wideband, low elevation angle estimator based on range super-resolution, achieving a high robustness to variations in reflection coefficients. A relaxation (RELAX) algorithm was applied as the range super-resolution algorithm to separate the direct target echo and the reflected signal thanks to the relatively abundant frequency diversity. The grazing angle was obtained by synthesizing the steering vector of the direct signal and the range structure relationship between the two signal components. Theoretical analysis and simulation results confirmed the improved behavior of the proposed robust estimator in contrast to other conventional algorithms.

A Noninvasive, Electromagnetic, Epidermal Sensing Device for Hemodynamics Monitoring.

Non-intrusive monitoring of blood flow parameters is vital for obtaining physiological and pathophysiological information pertaining to dynamic cardiovascular events and is feasible to achieve via non-invasive, conformal, wearable technologies. Here, we present a proof-of-concept of a fully integrated, high frequency (bandwidth 40 MHz), electromagnetic sensing device for monitoring limb hemodynamics and morphology associated with blood flow. The sensing architecture integrates a novel radio frequency (RF) skin patch resonator embedded with a coplanar outer loop antenna and a scalable, standalone wireless readout hardware based on standing wave ratio (SWR) bridge. The resonator itself is a copper-based open circuit planar Archimedean spiral with a rectangular cross-sectional area, chemically etched on a flexible polyimide substrate. The readout hardware is developed exploiting off-the-shelf components, fabricated on the top of a rigid FR4 substrate. The proposed readout circuit can measure resonant frequency of an RLC network. When energized by the external oscillating RF field via loop antenna, the resonator produces an electromagnetic field response which can be perturbed by dielectric variation inside its field boundary. Through leveraging this principle, the in-vitro experimental results from the benchtop models suggest that the resonator's RF attributes such as resonant frequency shift and magnitude variation of reflection coefficient due to fluid volume displacement can be successfully detected through the proposed hardware architecture. Hence, the system could be an alternative to the conventional, multimodal, non-invasive wearable sensing with an unprecedented capability of ubiquitous fluid phenomena detection from multiple sites of the human body.

Numerical investigation of piston-modal wave resonance in the narrow gap formed by a box in front of a wall

Piston-modal wave resonance between a ship section and a bottom mounted terminal is studied by employing a numerical wave flume based on OpenFOAM® package. A systematic investigation on the piston-modal behavior is performed to characterize the influence of fluid viscosity and flow rotation. Around the resonant frequency, the fluid viscosity and flow rotation not only dissipate the wave amplitude in the narrow gap, but also increase the wave amplitude in the upstream of the box. The dynamic mechanism behind the phenomenon is found to be the interaction between the energy dissipation induced by the fluid vortical flow and energy transformation associated with free surface motion. The increased incident wave amplitude can cause the normalized wave amplitudes and wave forces to deviate more from the potential flow results, while the variation of reflection coefficient is dependent on box-wall geometries. All of these phenomena imply a more significant effect of fluid viscosity and flow rotation with the increase of incident wave amplitude, but the energy dissipation is not the only factor in piston-modal resonance.

Method for low frequency sound reflection coefficient measurements in a compact space

Here, we present a method to measure the quasi-normal reflection coefficients of sound absorbing materials in a compact space. A short incident sound pulse (length < 3ms) is generated by a deconvolution method with the source speaker. Then, a stage-mounted microphone moves across the material surface and records the total (incident + scattered) sound field. By comparing the sound field with and without the presence of the sound absorbing material, the frequency-dependent reflection coefficients can be derived by extracting the corresponding frequency components from the sound pulse. Using this method, we can calculate the reflection coefficients of a 2 ft. by2 ft acoustic panel from 300 Hz to 2500 Hz within a 2 m by2 m by3 m lab space without anechoic coatings. Moreover, this method enables us to investigate the spatial inhomogeneity of the sound absorbing material by studying the amplitude/phase variation of reflection coefficients across the material surface. Compared with conventional measurement techniques for reflection/absorption coefficients, our method has the advantages of low cost, minimal requirements for the measurement environment and the ability to measure the reflection coefficients at different locations. The proposed method can be favorable for measuring reflection coefficients of two-dimensional acoustic panels/metamaterials at low frequencies.

Applying full-azimuth depth processing in the Local Angle Domain for Frequency Absorption versus Azimuth) (FAVAz) analysis to predict permeable, oil-saturated fractures

Predicting the permeability of fractured reservoirs is valuable for both reservoir assessment and drilling planning. Characterization of such systems requires advanced amplitude analysis, mainly based on seismic imaging results of the recorded wavefield. A significant amount of work has been done on the subject over the past few decades. Thomsen (1995) showed the effect of seismic amplitude variations for different fractured media. Pisetsky and Fedorov (1998) showed the influence of the size of cracks and the seismic wave length on the change of reflection coefficient. Ruger (1998) used the Zoeppritz equation to formalize the reflection coefficient variation as a function of the wavefront azimuthal direction with respect to the fracture azimuth. An approximation of the latter by Tsvankin and Grechka (1998) became the basis for AVAz inversion analysis. Studies have also been performed on frequency absorption properties of fluid-saturated and dry fractured layers. Goloshubin (2002) observed that reflections are stronger for fluid-saturated fractured layers than for dry fractured layers at low-frequency ranges. Geek (2008) studied high-frequency absorption vs. wavefront azimuth for dry fractures in the acoustic frequency range for P-waves, and showed that the absorption is insensitive to the azimuth for S-waves. Kozlov (2006) made a comprehensive generalization of the physics of frequency absorption effects in the case of dry and fluid-saturated fractures. In his study he showed that in fractured reservoirs, high fluid permeability has an observable effect of absorption of the low-frequency spectral range for reflected P-waves. This observation was also noted in several exploration areas of Western Siberia (Upper and Middle Jurassic deposits, Davydova, 2004). Despite the research detailed above, predicting and delineating oil-saturated fracture systems using low-frequency absorption analysis has not yet become a standard practice in the industry. This is in large part due to the approximation made by standard processing and imaging methods in creating azimuthal data. To make this process more effective, a true amplitude full-azimuth imaging procedure that decomposes the fully recorded seismic wavefield in the local angle domain is required. This procedure is carried out in-situ, in the depth migrated domain, preserving both reflection azimuth and structural azimuth. Such a technology is the ideal solution for extracting the main faults, building the Structural Tectonic Skeleton (STS), exposing the main fracture orientation, and eventually measuring anisotropic frequency absorption effects. This paper presents a study of carbonate reservoirs in an oilfield in the Middle Volga region of Russia, and suggests a workflow based on imaging and processing in the Local Angle Domain to predict prospective areas of oil-saturated permeable fractured reservoirs.

Feasibility of using near-field microwave reflectometry for monitoring autogenous crack healing in cementitious materials

This study demonstrates the feasibility of using the near-field microwave reflectometry technique to nondestructively monitor the evolution of autogenous crack healing of mortar containing high volume of supplementary cementitious materials. Mortar samples were subjected to controlled compressive loading to generate cracks, and subsequently exposed to wetting/drying cycles to initiate the autogenous crack healing process. Test results indicate that cracked mortar samples exhibit higher point-to-point microwave reflection coefficient variations caused by cracking and moisture ingress (i.e., larger coefficient of variation (COV) values of magnitude of reflection coefficient, |Γ|, obtained from microwave reflectometry). When subjected to wetting/drying cycles, samples with higher crack healing capability are found to undergo less variation in microwave reflection coefficient. Based on the results for cracked samples, the COV trends obtained for microwave reflection properties can be divided into three parts as a function of wetting/drying cycles: part (I) corresponding to a significant point-to-point microwave reflection variations resulting from crack formation and moisture ingress after the first wetting/drying cycle; part (II) indicating the onset of the crack healing process identified by the reduction in the COV values; and part (III) representing slow-down of crack healing process for the regions exposed to microwave radiation as indicated by the relatively constant COV values during additional wetting/drying cycles. Such variations in microwave reflection properties can be linked to changes in moisture transport properties and subsequent crack healing process. To corroborate the microwave reflectometry results, concurrent ultrasonic measurements were conducted on the mortar samples during the self-healing process, and a good correlation was observed between the outcomes of these two test methods. The results of material characterization assessments including capillary water absorption, crack healing quantification, as well as X-ray diffraction and scanning electron microscopy of crack healing products were also used to quantify the crack healing evolution for the investigated mortar samples.