Electrical modeling of strongly-coupled microstrip resonator arrays for microplasma generation

Summary form only given. Arrays of microstrip resonators have recently been shown to be useful for generating linear arrays of microplasmas. Such arrays show promise for deposition of thin films and ozone generation. Power is shared between the resonators via resonant coupling, allowing a single power input port for the entire array. Coupled-mode theory (CMT) provides an excellent description of weakly-coupled resonators (in our system, those separated by d >; 10 mm). Achieving a relatively uniform distribution of plasma, however, requires placing the microstrips quite close to one another. Typical distances between adjacent microstrip lines are approximately 0.25 mm. Due to this tight spacing, the CMT approximation of weak coupling coefficients relative to the resonator frequencies does not strictly apply to adjacent resonators. Designing large arrays that maintain a uniform distribution of electrical energy requires a better understanding of the characteristics and mechanisms of energy sharing between these closely spaced resonators. In this work we examine several models for strongly-coupled microstrip resonators, including a modified version of coupled-mode theory as well as treating pairs of nearby resonators as single resonant systems. The results of these analyses are compared to both experimental measurements of resonant frequencies and finite element simulations.