EFFECTS OF AN EPOXY-RESIN-FIBER SUBSTRATE FOR A -SHAPED MICROSTRIP ANTENNA VPLIV Z VLAKNI OJA^ANE EPOKSI PODLAGE PRI -OBLIKI MIKROTRAKASTE ANTENE

A -shaped microstrip antenna using an epoxy-resin-fibre substrate is presented. The proposed antenna consists of a circular slot and two rectangular slots printed on a dielectric resin-fibre substrate and is excited by a 50- microstrip transmission line. A commercially available, high-frequency structural simulator (HFSS) based on the finite-element method (FEM) was used in this investigation. The nearly omni-directional and bidirectional radiation pattern exhibited average gains of 3.12 dBi and 5.44 dBi for the lower band and upper band, respectively. The effects of epoxy-resin-fiber are discussed through comparisons of different substrate materials.