Compact superconducting dual-log spiral resonator with high Q-factor and low power dependence

Abstract

A new dual-log spiral geometry is proposed for microstrip resonators, offering substantial advantages in performance and size reduction at subgigahertz frequencies when realized in superconducting materials. The spiral is logarithmic in line spacing and width such that the width of the spiral line increases smoothly with the increase of the current density, reaching its maximum where the current density is maximum (in its center for 2 resonators). Preliminary results of such a logarithmic ten-turn (2 5 turns) spiral, realized with double-sided YBCO thin film, showed a -factor seven times higher than that of a single ten-turn uniform spiral made of YBCO thin film and 64 times higher than a copper counterpart. The insertion loss of the YBCO dual log-spiral has a high degree of independence of the input power in comparison with a uniform Archimedian spiral, increasing by only 2.5% for a 30-dBm increase of the input power, compared with nearly 31% for the uniform spiral. A simple approximate method, developed for prediction of the resonant frequency of the new resonators, shows a good agreement with the test results.

Accurate design of a compact superconducting microstrip filter

“…As tuning is a time-consuming and repetitious work, researchers have made great efforts to produce high-performance HTS filters without tuning [9,10]. Spiral resonator has been known to have several advantages, including compact size, good simulation accuracy, and insensitivity to the tolerance of fabrication procedures and substrate parameters [11][12][13][14][15]. In this article, we choose a half-wavelength twinspiral resonator to design a high-performance HTS filter.…”

Super-compact left-handed resonator for filter applications

“…Traditionally, microstrip resonators are miniaturized using complex geometries that allow electrically long line to be folded in a small area, [1], or by utilizing photonic bandgap effect, [2]. Recently, metamaterials offered a new perspective to the design of super-compact high-performance resonators and filters, [3].…”

Novel 3D Hilbert microstrip resonators

“…However, miniaturization of planar resonators (while keeping the resonant frequency constant) tends to reduce their quality factor (Q), because of additional dissipative losses caused by the current-density increase. Although this effect can be minimized by using superconductive materials, [1][2][3], new solutions are sought, employing low-cost manufacturing procedures and materials.…”

“…As compared to patch antennas, the slot antenna has wider bandwidth, less conductor loss, and better isolation between the radiating element and feeding network [1]. Related dual-or triple-band slot-antenna designs have been proposed by using a single slot-ring antenna with a narrow rectangular slot [2], parasitic element [3], or stairshaped slot antenna [4]. However, for IEEE 802.11a/b/g and HIPERLAN applications, only the dual-broadband rectangular slot antenna embedded with a U-shaped strip has been presented [5].…”