Super-resolution microwave imaging using small loop loaded with spiral resonator

A new microwave sensor for subw ave length imaging is developed and its performance is experimentally verified. The proposed sensor is based on an electrically small loop loaded with a spiral resonator of miniaturized footprint (7.2 mm × 7.2 mm). While the resonance frequency of the sensor is 426 MHz (free-space wavelength λ = 704.2 mm), imaging resolution of around 5 mm (~ A/140) is attained as demonstrated herein.