Search

The goal of this paper is to investigate the electrical properties of photoresist-alumina microcomposites with different portions of ceramic content. Substrates of photoresist-alumina microcomposites are fabricated and a comprehensive analysis is performed to characterize their dielectric constant and dielectric loss tangent at microwave frequencies up to 40 GHz. To evaluate the performance of these materials for microwave applications, the properties of various lithographically fabricated antenna elements are examined and analysed based on the measured electrical properties. The experimental results show that the electrical properties of the photoresist composite are nonlinearly affected by ceramic content and also a minimum percentage of ceramic portion is required to improve the electrical properties of the photoresist composite. For instance, comparison of 0 wt% with 23 wt% SU8-alumina shows that no reduction is achieved for the dielectric loss tangent. Comparison of 38 wt% with 48 wt% SU8-alumina microcomposite shows that the dielectric loss tangent is improved from 0.03 to 0.01 and the dielectric constant is increased from 3.8 to 5.0 at 25 GHz. These improvements can result in superior performance for the photoresist-based microwave components. [ABSTRACT FROM AUTHOR]

Two segmented dielectric-resonator antennas have been investigated. A weighted average model is used to predict the resonant frequency. A simple method is then introduced to optimize the lower segment of the antenna. Finally, a fast and efficient design algorithm is presented. Three examples are used to implement the methods and the algorithm in three different frequency bands. Impedance bandwidths of up to 30% are achieved with the optimum design. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 533–537, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20871 [ABSTRACT FROM AUTHOR]