A Comparison of Some Low Cost Laminates for Antennas Operating in the 2.45 GHz ISM Band

An evaluation of some low-cost laminates suitable for microstrip patch antennas is presented. Criteria for the selection of substrates for antenna fabrication are given careful consideration. A coaxial-probe fed linearly-polarized rectangular microstrip patch operating at a frequency of 2.45 GHz was fabricated on four different low cost laminates. The substrates used were polyester, epoxy glass (FR-4), a ceramic filled PTFE composite and a woven glass-reinforced hydrocarbon and ceramic thermoset material. Material properties are discussed and the antenna performances are evaluated and compared to one fabricated on a thick glass-loaded microfiber PTFE substrate. An evaluation of some inexpensive microstrip antenna CAD packages, which employ closed-form expressions based on transmission-line and cavity models, is also given. These models ignore the diffraction effects of a finite ground-plane