Table 1.

Performance comparison of the proposed sensor with the literature.

Reference	Design Concept	Frequency Band of Operation	Sensitivity (MHz/Ethanol Percentage)	Selectivity (in dB)	Reproducibility
[6]	Planar resonator	Ku-/K-band	70.72 *	<−8.5 *	NA
[17]	Microstrip BPF	<L-band	2.88 *	NA	NA
[18]	Split ring resonator	L-/S-band	3.86 *	<−6 *	NA
This work	Spiral-coupled resonator	L-/S-band	10.4	<−14	Yes

*—approximated values, NA—data not available.