Quad spiral microstrip resonator with high quality factor

Abstract

In this paper a simple planar quad spiral microstrip resonator is proposed with high Q, compact size and ease of fabrication. First, its structure consists of quarter wavelength resonator coupled to quad spiral resonators to improve its Q factor. Second, its equivalent circuit is presented. Third, a parametric analysis is deduced to obtain design guidelines for this novel structure. Fourth, two optimized high Q X-band and Ku-band resonators are introduced; one for high resolution microstrip fabrication facility with ultra-high loaded Q reaches 1200 and the other matches the low resolution facilities with high loaded Q of about 400. Finally, the proposed resonator is verified using fabrication and measurements. Measurements are compared to the 3D EM simulations and to the results of other published work. They are found very promising compared to single and dual spirals; above 50% enhancement in loaded Q. This proves the proposed idea and shows the technical penifits compared to the state of the art. Therefore, it could be utilized in modern microwave filters, miniaturized sensors and low phase noise oscillators.