Radio frequency heating: assessing its viability for composite tape processing line

This paper assesses the potential of radio frequency (RF) heating as a non-contact, low-power, and localised volumetric heating method for carbon fibre reinforced polymer (CFRP) composite tape processing, with a view toward integration into a larger-scale powder-epoxy tapeline. A stand-alone RF heating module was developed comprising an RF signal generator, a 100 W power amplifier, and a fringing field PCB antenna transducer enclosed within a custom-built Faraday cage. Impedance matchingwas evaluated through measurement of the S11 reflection coefficient using a vector network analyzer and validated with full-wave electromagnetic simulations. The integrated module exhibited multi-band resonance behaviour with reflection coefficients as low as −26 dB and narrow bandwidth matching in the 100 to 200 MHz and 500 to 550 MHz ranges. Frequency sweep experiments identified 112 MHz as the optimal heating frequency within the lower band. At this frequency, the system demonstrated a linear thermal response of approximately 1.46 ◦C/W, achieving measurable heating of carbon fibre tow under low input powers (up to 4 W) providing proof-of-concept demonstration of the system. Electric field strength (EFS) leakage measurements further showed non-linear scaling with input power and up to 98% field attenuation by the Faraday cage enclosure. However, operation at higher matched frequencies (e.g., 483 MHz and 520 MHz) resulted in negligible heating despite being impedance matched, accompanied by elevated EFS leakage levels exceeding 30 V/m at 5Winput power, indicating inefficient energy absorption.These results demonstrate that while impedance matching is necessary for efficient RF heating, it is not alone sufficient to guarantee effective material energy transfer. The study also highlights key system sensitivities to near-field loading conditions and identifies critical design considerations for achieving robust, safe, and energy-efficient RF heating suitable for continuous composite tape manufacturing.