We explore the development of an optoelectronic probe for MF/HF/VHF (up to ∼ 37 MHz) radio frequency bands able to display the complete waveforms. It was built from simple, low cost and robust components. A passive loop antenna generates RF current which modulates an ultra-bright LED of display/illumination. The light signals are transmitted along a PMMA plastic optical fibre (POF) to an optical receiver placed in a remote site. All characterization measurements were carried out in the near-field region. Far-field radio transmissions could also be detected. The probe presented at 0.5 MHz tuning-band has shown a 62 dBµV dynamic range and was able to detect down to Hmin ∼ 0.8 nA cm−1 magnetic field amplitude. A new technique for loss compensation of the fibre link is proposed and successfully tested.
This article presents a chipless radio frequency identification (RFID) tag which operates in the frequency span from 0.86 to 2.5 GHz. This new miniature chipless tag is developed to work for Brazilian RFID regulation. It does not require a ground plane and has a compact size of 85.50 × 53.98 mm2, comparable to a credit card. The tag has been measured in a bi and mono‐static arrangement with two double‐ridge horn antennas, with a significantly response at frequency range measurements.
A Abstract -An ultra low cost bias unit operating between 300KHz and 3GHz is simulated and developed using commercial Printed Circuit Board technology (PCB). All Scattering [S] parameters describing transmission loss, reflection and isolation between RF and DC ports are presented. A set of models is realized and characterized presenting excellent results.
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