Pulsed laser-induced crystallization of amorphous Cu2O/Wo3 heterostructures for sub-terahertz waveguide and sub-6 GHz antenna applications

This study presents pulsed laser irradiation (PLI)-induced crystallization of amorphous Cu₂O/WO₃ (CW) heterostructures and evaluates their structural, optical, and electromagnetic behavior for sub-terahertz and sub-6 GHz applications. By varying the PLI fluence from 1.27 to 81.48 kJ cm⁻², crystallization occurred within one second, forming tetragonal phases at low and hexagonal phases at high fluence. Higher fluence increased grain size, porosity, and generated two distinct optical band gaps. Impedance spectroscopy studies in the range of 10 MHz–1.8 GHz revealed cutoff frequencies exceeding 347 GHz, confirming their potential for high-frequency waveguiding which was also confirmed by computer simulations using telegrapher’s equations and network equations. Planar PLI processed samples was implemented as compact rectangular monopole antenna networks and experimentally characterized over 0.01–6.0 GHz. The antennas exhibit multiband and wideband impedance matching, with low fluence resulting in a 3.18 GHz bandwidth (2.52–5.70 GHz) and high fluence showing a narrower 1.80 GHz bandwidth (3.12–4.92 GHz). Distinct resonance behaviors were observed, including deep minima below −20 dB, indicating efficient radiation and good impedance matching. The results demonstrate the suitability of these antennas for sub-6 GHz wireless systems, including 5 G 6 G⁻¹ applications.