Microstrip multi-stopband filter based on tree fractal slotted resonator

This paper presents the design and development of a new microstrip multi-stopband filter based on tree fractal slotted resonator. A single square patch with tree fractal slots of different iterations are employed for realizing dual stopband and tri-stopband filters. The tree fractal slotted resonators are generated from conventional square patch using an iterative tree fractal generator method. First, second and third level iterations of the tree fractal slot resonator are used to design dual and tri-stopband filters respectively. The first level iteration introduced for the tree fractal slot realizes dual bands at 2.64 GHz and 3.61 GHz while the second level iteration provides better stopband rejection and insertion loss at 2.57 GHz and 3.56 GHz. The tri-stopband filter generates three resonance frequencies at 1.53 GHz, 2.53 GHz and 3.54 GHz at third level iteration. By varying the slot length and width of the tree fractal slot, the resonant frequencies can be adjusted and stopbands of the proposed filter can be tuned for the desired unwanted frequency to be rejected. The proposed narrowband filters finds application in removing the interference of GPS and Wi-Max narrowband signals from the allotted bands of other wireless communication systems

Art, Maths, Electronics and Micros: The Late Work of Stan Ostoja-Kotkowski

To date, most work on computers in art has focused on the Algorists (1960s–) and on later cyber arts (1990s–). The use of microcomputers is an underexplored area, with the 1980s constituting a particular gap in the knowledge. This article considers the case of Polish-Australian artist, Stan Ostoja-Kotkowski (b. 1922, d. 1994), who after early exposure to computers at the Bell Labs (1967), returned to microcomputers late in his life. He was not a programmer yet used micros in his practice from the early 1980s, first a BBC in his BP Christmas Star commission, and later a 32-bit Archimedes. This he used from 1989 until his death to produce still images with a fractal generator and the ‘paintbox’ program, “Photodesk”. Drawing on archival research and interviews, we focus on three examples of how Ostoja deployed his micro, highlighting the convergence of art, maths, electronics, and a ‘hands-on’ tinkering ethic in his practice. We argue that when considering the history of creative microcomputing, it is imperative to go beyond the field of art itself. In this case, electronics and the hobbyist computing scenes provide crucial contexts.

Computer-Generated Fractal Art

Computer Software Can be a Powerful tool in both the study and creation of fractals. The Snowflake Fractal Generator (Shodor Education Foundation, www.shodor.org) is an appealing example of software that allows students to make fractals similar to the classic Koch snowflake (see fig. 1).