Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Return loss of the antenna in different concentrations of sugar in water_
| S. No. | Frequency | Return loss (concentration: 20%) | Return loss (concentration: 50%) | Return loss (concentration: 80%) |
|---|---|---|---|---|
| 1 | 2.38 GHz | 23.558 dB | 19.123 dB | 13.022 dB |
| 2 | 2.56 GHz | 24.251 dB | 22.012 dB | 13.223 dB |
| 3 | 2.72 GHz | 24.097 dB | 21.293 dB | 13.144 dB |
| 4 | 2.86 GHz | 22.044 dB | 17.272 dB | 11.962 dB |
Comparison of proposed antenna with existing antennas for salt and sugar detection_
| Reference | Antenna type | Center frequency | Dimensions of the antenna | Substrate parameters |
|---|---|---|---|---|
| Cheng et al. (2014a) | Rectangular microstrip antenna | 2.45 GHz | 0.47λ0 × 0.388λ0 | εr = 2.2, h = 1.575 mm |
| Cheng et al. (2014a) | Circular microstrip antenna | 2.45 GHz | 0.465λ0 × 0.465λ0 | εr = 2.2, h = 1.575 mm |
| Cheng et al. (2014a) | Square microstrip antenna | 2.45 GHz | 0.529λ0 × 0.529λ0 | εr = 2.2, h = 1.575 mm |
| Rahman et al. (2018b) | Circulated psi-shaped patch | 16 GHz | 1.28λ0 × 0.96λ0 | εr = 2.2, h = 1.57 mm |
| Islam et al. (2018) | Crescent-shaped microstrip antenna | 10.6 GHz | 1.13λ0 × 0.777λ0 | εr = 4.6, h = 1.6 mm |
| Rahman et al. (2018a) | Fork-shaped patch | 9.5 GHz | 0.76λ0 × 0.57λ0 | εr = 2.2, h = 1.57 mm |
| Proposed method | Rectangular microstrip antenna | 2.4 GHz | 0.41λ0 × 0.41λ0 | εr = 4.3, h = 1.5 mm |
Optimized dimensions of the compact antenna_
| S. No. | Dimensional parameter | Values |
|---|---|---|
| 1 | L | 25.65 mm |
| 2 | W | 25.65 mm |
| 3 | Lg | 51.3 mm |
| 4 | Wg | 51.3 mm |
| 5 | Lg1 | 25.65 mm |
| 6 | Wg1 | 25.65 mm |
| 7 | Lg2 | 24.41 mm |
| 8 | Wg2 | 5.1525 mm |
| 9 | g | 2.5875 mm |
| 10 | h | 1.5 mm |
| 11 | t | 0.035 mm |
| 12 | εr | 4.3 |
Dimensions of the antenna with and without DGS_
| S. No. | Antenna type | Area of patch | Area of ground plane |
|---|---|---|---|
| 1 | Antenna without DGS | 838.1 mm2 | 3,352.4 mm2 |
| 2 | Antenna with DGS | 657.9 mm2 | 2,631.7 mm2 |
Gain, directivity, and efficiencies of the antenna at 2_4 GHz 2_4 GHz _
| Radiation efficiency | Total efficiency | Max. gain | Max. directivity |
|---|---|---|---|
| −1.84 dB | −1.97 dB | 2.12 dB | 3.95 dBi |
Effect of slot length on various parameters_
| S. No. | Slot length | Resonant frequency | VSWR (at 2.4 GHz) | |S11| (at 2.4 GHz) |
|---|---|---|---|---|
| 1 | 24.95 mm | 2.466 GHz | 1.514 | −13.433 dB |
| 2 | 25.65 mm | 2.402 GHz | 1.389 | −15.768 dB |
| 3 | 26.45 mm | 2.336 GHz | 1.68 | −11.913 dB |
| 4 | 28.95 mm | 2.082 GHz | 4.624 | −3.817 dB |
Return loss of the antenna in different concentrations of salt in water_
| S. No. | Frequency | Return loss (concentration: 20%) | Return loss (concentration: 50%) | Return loss (concentration: 80%) |
|---|---|---|---|---|
| 1 | 2.38 GHz | 23.271 dB | 21.017 dB | 13.334 dB |
| 2 | 2.56 GHz | 23.757 dB | 20.54 dB | 13.281 dB |
| 3 | 2.72 GHz | 24.582 dB | 19.84 dB | 13.046 dB |
| 4 | 2.86 GHz | 23.253 dB | 17.095 dB | 11.691 dB |