RF Transmission Through Unique Environments in Communication Systems
Jean Paul Santos, Evan Mouchard, Athen Pham, Maxim Apalboym, Kamal Bhakta · 2024
Communication systems often experience unique RF environments due to the changing atmospheric environments impinged upon them. More often than not, these negative effects could be attributed to multipath or fading effects due to the rich scattering environment. However, in both legacy and emerging platforms, communication systems experience changing RF environments caused by temperature, chemistry of the environment, and aerodynamics. Therefore, observable effects include significant signal attenuation or antenna detuning from the intended frequency of operation. In this work, a quantitative analysis of an EM wave is performed on attenuation factors and antenna radiation efficiencies in the presence of these atmospheric effects. These effects are modeled as a lossy complex dielectric material using modern modeling and simulation (M&S) software such as CST to assess its dispersive effects. Using Floquet mode simulations, the transmission and reflection effects of such materials are quantified. The work shows that at a particular cutoff frequency, transmission through materials is similar to transmission in air. Next, a broadband S-band and X-band circularly polarized patch antenna was designed with and without the dielectric material. The effects on impedance matching and radiation show possible design changes which could mitigate such effects. Possible solutions and alternatives such as assisted radiation in higher frequency, utilizing the dielectric as an antenna matched layer, and or utilizing epsilon-negative or doublenegative materials to compensate for the attenuation will be shown. The goal of radiating in intended frequencies of interest despite the atmospheric effects is made possible through careful analysis of its effects. Specifically, careful and creative antenna design could lead to significant improvements in link budget despite the presence of significant attenuation.