Table 6.

Comparison of various studies for detecting the concentration between the glucose dissolved in water solutions in terms of sensitivity and concentration range.

Ref.	Sensor	Sample Containers	Sensing Method	Bare Sensor ${\mathit{f}}_{\mathit{o}}$ (GHz)	${\mathit{f}}_0$ mg/dL (GHz)	${\mathit{f}}_{\mathbf{max}}$ (GHz)	$\mathbf{\Delta }\mathit{f}$ (MHz)	Sensitivity (MHz/mg·dL${}^{-1}$)	Normalized Sensitivity Per (mg·dL${}^{-1}$)	Concentration (mg/dL)
[105]	CE-LC resonator	Microfluidic PDMS channel	$f_r$	1.67	1.167	1.39	230 MHz	0.023	1.34 × ${10}^{-5}$	0–10,000 *
[83]	SRR with IDC	Microfluidic PDMS channel	$f_r$ & $S_{21}$	4.18	1.327	1.457	130	0.026	6.22 × ${10}^{-6}$	0–5000
[106]	RF/microwave single-port resonator	Non-invasive	$f_r$ & $S_{11}$	4.8	3.427	3.441	14	0.014	2.92 × ${10}^{-6}$	0–1000
[68]	ENG unit-cell resonator	PDMS cavity	$f_r$ & $S_{21}$	2.09	1.91	2.05	140	1.4/0.014	6.70 × ${10}^{-6}$	0–10,000 *
					1.42	1.59	170	1.7/0.017	8.13 × ${10}^{-6}$
[107]	CSRR	PDMS microfluidic channel and PMMA frame	$f_r$ & $S_{11}$	2.6	2.48	2.5194	39.4	0.4925/0.00493	1.89 × ${10}^{-6}$	500–8000 *
[108]	Open loop resonator	Glass capillary	$f_r$ & Q	2	1.10929	1.10938	0.09	0.000023	1.13 × ${10}^{-8}$	0–4000
[104]	Mediator-free resonator	Droplet on the sensing area	$f_r$ & $S_{21}$	1.5	0.38	0.875	495	0.99	6.60 × 10${}^{-4}$	30–500 *
[65]	RML resonator with IPD	Droplet on the sensing area	$f_r$	9.2	9.14	8.68	460	0.92	1.00 × ${10}^{-4}$	25–500

* The concentration range is changed from mL to dL where 1 dL = 100 mL.