## 4 Results of Numerical and Experimental Approaches  
This section presents a comparative analysis of the thermograms obtained from both numerical simulations and experimental measurements. The numerical results encompass two microwave heating modes--continuous and modulated--and cover all antenna-to-sample angles considered in the study. In parallel, experimental thermograms are provided for two antenna orientations, allowing a direct comparison between modeled and observed thermal responses under varying exposure conditions. Figure 8 illustrates the outcomes of the numerical simulations at selected time points. The thermograms display temperature distributions marked by characteristic stripe patterns, which correspond to the locations of steel reinforcement bars embedded within the concrete. Despite this visual correlation, accurately pinpointing the exact positions of the bars remains challenging. This limitation stems from non-uniform heating, which is significantly affected by the directional radiation pattern of the microwave antenna and the inclined orientation of the samples with respect to the source. The figure further compares thermal fields for both heating strategies--continuous and modulated. The spatial distribution of temperature in both cases remains largely consistent, with no pronounced differences in how heat propagates through the sample. This suggests that microwave power modulation has minimal influence on the resulting temperature patterns within the concrete. Figure 7: Experimental setup visualization showing various inclination angles of the sample relative to the antenna. Moreover, a detailed comparison of the peak temperature values between the two heating modes shows negligible discrepancies, with variations not exceeding a few tenths of a degree Celsius. These results indicate that the intermittent power delivery that is characteristic of modulated heating does not lead to significant cooling during off cycles. Instead, the inherent thermal inertia of the concrete maintains heat accumulation at levels comparable to those achieved with uninterrupted (continuous) power input. In the experimental component of the study, only the modulated heating mode was employed. The applied modulation profile replicated the periodic function used in the simulations (refer to Figure 3), ensuring consistency between the numerical and physical testing conditions. Figure 9 presents the unprocessed infrared measurements for the two experimental configurations: one with the sample oriented at a 30\({}^{\circ}\) angle and the other at 45\({}^{\circ}\) relative to the antenna. These images capture the surface temperature distributions over time, offering direct insight into the development of heating patterns during microwave exposure. To enhance clarity and focus the analysis, the recorded thermographic data  
Figure 8: Temperature maps at the sample surface after 150 s and 300 s of heating, comparing continuous and modulated excitation for four antenna–sample inclination angles: (**a**) 0\({}^{\circ}\), (**b**) 15\({}^{\circ}\), (**c**) 30\({}^{\circ}\), and (**d**) 45\({}^{\circ}\). were cropped to isolate the region of interest--namely, the heated surface of the concrete specimen. Consistent with the numerical results, the experimental thermograms reveal a striped temperature pattern indicative of the embedded steel reinforcement. These patterns highlight the influence of the reinforcement on local heat dissipation, confirming its role in shaping the surface's temperature distribution. However, the images also exhibit signs of non-uniform heating, which can be attributed to the directional radiation characteristics of the horn antenna and the angular positioning of the sample relative to the microwave source. These factors lead to uneven energy distribution across the surface, which, in turn, reduces the sharpness and clarity of the reinforcement's thermal signature in the recorded data.