Fig. 1: Concept of the wireless sensor network.
From: 3D printed sub-terahertz photonic crystal for wireless passive biosensing
a Schematic of the wireless sensors distributed in a room and interrogated by a reader. Airborne pathogens can be detected by the wireless sensors. b Layout of the proposed wireless sensor based on photonic crystal (PhC) slab consisting of a slot resonator, a waveguide, and a dielectric rod antenna (DRA). c Signal processing mechanism in time domain and frequency domain. Signals in time domain and frequency domain are transformed using Fourier transform (FT) and inverse Fourier transform (IFT). Note that the received signal at the reader includes the reflected clutter signal from the room, the sensor, the oscillating signal from the resonator, and the background noise. The clutter signal has a short duration, but a high amplitude overlapping the oscillating signal. It must be removed by a time gate to extract the oscillating signal from the sensor. The resonance spectral shift can be used to detect biomolecules, for instance.
