Investigations on Steel as Low Cost Substrate for Low Frequency Patch Antenna

Industry uses different types of materials as microstrip substrates. This paper introduces steel, and thus explores its scope as a microstrip substrate. Its metallic nature creates a barrier, from using it as substrate. A low cost rectangular microstrip patch antenna using a multilayer substrate is proposed here. Martensitic steel of grade 440C and thermocol forms a layered substrate. The magnetic properties of steel and dielectric properties of thermocol helps for achieving good antenna parameters. Designed patch antenna has noticeable return loss of -24dB in 400MHz. Also directional radiation pattern with gain of 0.3dB has been obtained. It shows a narrow bandwidth of 3MHz which is due to the conductivity of steel. VSWR obtained is 1.13 which shows a tremendous matching with transmission line connected to it. The results shows that, newly introduced multilayer material can be used as microstrip substrate for low frequency structures. It can produce almost the same results, which a local substrate can. It can be used for wireless charging using low frequency and thus an application of RF energy harvesting.