Novel low loss thin film materials for wireless 60 GHz application

RXP is a novel and emerging low loss thin core experimental material that has shown promising results as an RF dielectric substrate. In this paper, Ring Resonator Method was utilized to characterize its dielectric properties (relative permittivity and loss tangent) from 30 to 70 GHz frequency domain. BT, a PCB compatible substrate, and RO3003™, an RF organic material, were also characterized for the purpose of comparison. The measured dielectric constant for RXP4 is found to be stable near 3.13, and the loss tangent remains below 0.005. For RXP1, the dielectric constant averages 4.2, and its loss tangent stays below 0.01. To verify application of RXP at higher frequencies, an aperture-coupled patch antenna was designed at 60 GHz and fabricated using three metal layers. The performance of the antenna was found to be comparable to that of Liquid Crystal Polymer (LCP) substrate. The achieved bandwidth was ~3 GHz, and the gain was around 4.7 dBi (simulation results). The measured bandwidth on the fabricated antenna was ~2 GHz. These results show for the first time that RXP can be a good candidate material for wireless 60 GHz application.