Microfluidic Biosensor Based on Microwave Substrate-Integrated Waveguide Cavity Resonator

Table 2

Comparison of our proposed biosensor with other RF bio/chemical sensors.

Reference	Target biomaterial/chemical	Sensing element/technology	Frequency (GHz)	Frequency shift (MHz)	Physical size (mm × mm)	Electrical size^†
[24]	Acetone, isobutanol, isopropanol, methanol	SIW	8	4.4	23 × 15	0.91 λg × 0.6 λg
[40]^††	DNA hybridization	DSRR	12.35	20, 60	20 × 10	2.56 λg × 1.28 λg
[39]	Cy3 protein G+ PSA antibody	SRR	11.35	20	24 × 11	2.86 λg × 1.31 λg
[38]^†††	Cortisol stress hormone	SRR	10.48	20, 30	20 × 10	2.1 λg × 1.03 λg
[41]	Ethanol, methanol, acetone, propanol, and so forth	SIW	17.08	130	35 × 30	3.03 λg × 2.6 λg
[42]	Blood glucose	SIW slot antenna	8.6	80	80 × 10	7.33 λg × 0.92 λg
[43]	Ethanol	Patch antenna coated with carbon nanotube	5	10, 100	38.1 × 11.1	1.32 λg × 0.38 λg
[44]	Methanol	SIW	10	20, 110	38 × 17	1.88 λg × 0.84 λg
[45]^††††	Dielectric characterization	SIW	7.17	112	63 × 21	2.23 λg × 0.74 λg
This work^†††††	Fibroblast cells	SIW	13.48	20, 170	33 × 28	2.26 λg × 1.92 λg

^†λ_g is the guided wavelength in the structure. ^††20 MHz and 60 MHz shifts in resonance frequency are without and with binding. DSRR represents a double split-ring resonator. ^†††20 MHz and 30 MHz shifts in resonance frequency are relative to anticortisol- and antiprostate-specific antigen, respectively. SRR represents a split-ring resonator. ^††††Mainly proposed as a dielectric characterization sensor, and different chemicals/particles are analyzed; however, utilization of this sensor as a biosensing device is also mentioned/suggested by the corresponding authors. ^{†††††}20 MHz and 170 MHz shifts in resonance frequency are relative to the PBS and empty microwell, respectively.