Relative Permittivity Measurements With SIW Resonant Cavities at mm- Wave Frequencies

In this paper an effective though simple method to accurately characterize dielectric substrate materials at mm-wave frequencies is presented. The method is based on the use of a resonant cavity in SIW technology realized in a substrate made out of the material to characterize. Based on the measured resonant frequency, it is then possible to extract the electrical properties of the material exclusively from the geometry of the cavity. The SIW cavity is fed by two grounded coplanar waveguides to reduce the loading effect of the transmission lines and to avoid errors in the estimations of relative permittivity. The proposed cavity provides a solution for material characterization for emerging 5G-and-beyond applications operating at high frequencies. Measurements have been performed in the frequency range from 10 GHz to 30 GHz, but the design is scalable to lower or higher frequency ranges, if within the possibilities of the manufacturing process of the cavity

Chamber-Decay Time in a mm-Wave Reverberation Chamber

In this work, we present results of a novel mm-wave reverberation chamber, where we discuss the role of the chamber quality factor and chamber decay time, or time constant, for mm-wave applications. For the first time, we analyze the uncertainty due to antenna positioning for these metrics in such a chamber, where we show that the quality factor computed in the frequency domain has a higher uncertainty due to antenna positioning than its time domain counterpart. We describe that the the chamber decay time and quality factor are lower for mm-wave chambers as compared to lower-frequency (sub-6 GHz) chambers, but that they can still function as ideal candidates for metrics revolving around losses

Pushing the Boundaries of Antenna-Efficiency Measurements towards 6G in a mm-Wave Reverberation Chamber

With 6G around the corner, the push for higher-frequency over-the-air testing of antennas is inevitable, where antenna efficiency is one of the key performance metrics. Reverberation chambers can be an ideal tool for performing antenna-efficiency measurements at mm-Wave frequencies, due to its flexibility in placement, and ability to perform rapid and repeatable measurements. However, to the authors’ best knowledge, no work on antenna efficiency above 47 GHz has been published so far. In this work, we show for the first time results of antenna efficiency using the two-antenna method up to 60 GHz, by using a novel mm-Wave reverberation chamber. We also evaluate chamber loss where we predict that larger systems, such as phased-array systems, can be measured inside this chamber as well, and that the current operational frequency range can be extended much further than 60 GHz for antenna-efficiency measurements