Minkowski Based Microwave Resonator for Material Detection over Sub-6 GHz 5G Spectrum

Abstract

This paper describes the performance of a low-cost, high-sensitive microwave resonator for 5G modern wireless communication systems operating through sub-6GHz spectrum. Here, the proposed resonator is constructed from a Minkowski fractal open stub that is coupled to an interdigital capacitor. It is fetched to a circular spiral inductor structure with a back loop to increase the resonator quality and it operates at a frequency resonance of 524 MHz. Since the purpose of the study is to apply such technology to characterize liquid properties, the presented resonator is mounted on an FR4 substrate with a thickness of 1.6 mm and an area of 40x60 mm(2). Using CST MWS commercial software, the resulting design dimensions are optimized. The proposed design performance which is demonstrated in terms of S21 magnitude is found to vary significantly by the variations in the photoresistor. Such a property motivated the authors to consider it for material detection as the frequency stability with a photoresistor value change is relative to the light incidence. In such a manner, the achieved results are found to behave linearly without discrepancy due to the effects of diffraction from the resonator layers. This technology is frequently used as a strong contender for a variety of contemporary wireless technologies that may invoke optical-based interface systems.