New-Tech Europe | Q2 2020 | Digital Edition

Figure 5: A wideband fractal active wearable notch antenna

Figure 4: Radiation pattern of the notch antenna at 3.5GHz

III. WIDEBAND NOTCH ANTENNA, 2GHz to 7.8GHz, for ENERGY HARVESTING APPLICATIONS A wideband notch antenna was printed on RT-DUROID 5880 dielectric substrate with dielectric constant of 2.2 and 1.2mm thick. The notch antenna dimensions are 116.4x71.4mm, as shown in Fig. 2. The antenna bandwidth is around 100% for S11 lower than -6.5dB, as presented in Fig. 3. The notch antenna VSWR is better than 3:1 for frequencies from 2.1GHz to 7.8GHz. The antenna beam width is around 84º. The antenna gain is around 2.5dBi. Fig. 4 present the radiation pattern of the notch antenna at 3.5GHz. These results agrees with measured results. A rectifying circuit is connected to the antenna input. A rechargeable battery is connected to the output of the rectifying circuit. IV. NEW COMPACT WIDEBAND ACTIVE 0.5GHz to 3GHz ENRGY HARVESTING NOTCH ANTENNA Harvested power from RF transmitting links is usually lower than 0.1 µW/ cm2. Active antennas may improve the energy harvesting system efficiency. A

for S11 lower than -5dB. The active notch antenna VSWR is better than 3:1 for frequencies from 0.5GHz to 3GHz. The antenna beam width is around 84º. An E PHEMT LNA surface mount, Low Noise Amplifier, was connected to a notch antenna via an input matching network. An output matching network connects the

wideband active notch Antenna with fractal structure was printed on a 1.2mm thick substrate with dielectric constant of 2.2. The active notch antenna is shown in Fig. 5. The notch antenna dimensions are 74.5x57.1mm. The antenna center frequency is 1.75GHz. The active antenna bandwidth is around 200%

Parameter

specification Remarks

Frequency range 0.4 - 3GHz Gain

26dB @0.4GHz 18dB @2GHz 0.4dB @0.4GHz 0.5dB @2GHz 18.9dBm @0.4GHz 19.1dBm @2GHz 32.1dBm @0.4GHz 33.6dBm @2GHz

Vds=3V; Ids=60mA Vds=3V; Ids=60mA Vds=3V; Ids=60mA Vds=3V; Ids=60mA

N.F

P1dB

OIP3

Max. Input power 17dBm Vgs 0.48V

Vds=3V; Ids=60mA

Vds Ids

3V

60mA

Supply voltage Operating Temp.

+5V

-40 ° c - 80 ° c

Table IV: LNA Amplifier specification

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