Performance Analysis of a Polymer Based Antenna for Cognitive Radio Applications

Microstrip patch antennas are popular due to their appealing characteristics such as low profile, light weight, low cost, ease of fabrication, and integration with RF devices. A narrowband, wide-beam antenna known as a microstrip or patches are created by etching the antenna element pattern in the metal traces that are adhered to insulating dielectric substrates. Most commonly used dielectric substrate is FR4, which has good mechanical and electrical properties but, it possesses very low thermal conductivity. At very low temperature, it becomes less flexible and rigid. Novel polymer substrate materials are proposed to design the patch antennas for cognitive radio applications in S band frequency. Polyethylene based patch antennas are designed using HFSS in three most popular shapes such as rectangular, circular and triangular. The triangular patch with polyethylene substrate achieves the maximum gain with a value of 7.46dB and a maximum directivity of 7.6dB, which is twice the gain from the ordinary FR4 substrate. Proposed materials are more flexible and has shown improvement in terms of gain, directivity and return loss. Further design optimization may be needed to reduce VSWR.