Additive manufacturing (AM) has become more important and common in recent years. Advantages of AM include the ability to rapidly design and fabricate samples much faster than traditional manufacturing processes and to create complex internal geometries. Materials are crucial components of microwave systems and proper and accurate measurement of their dielectric properties is important to aid a high level of accuracy in design. There are numerous measurement techniques and finding the most appropriate method is important and requires consideration of all different factors and limitations. One limitation of sample preparation is that the sample size needs to fit in the measurement method. By utilizing the advantage of additive manufacturing, the material can be characterized using different measurement methods. In this paper, the additive manufacturing process and dielectric measurement methods have been critically reviewed. The test specimens for measuring dielectric properties were fabricated using fused filament fabrication (FFF)-based additive manufacturing and were measured using four different commercial dielectric properties measurement instruments including split post dielectric resonator (SPDR), rectangular waveguide, TE01δ cavity resonator, and open resonator. The measured results from the four techniques have been compared and have shown reasonable agreement with measurements within a 10 percent range.

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In this paper, we revisit the classical mechanism to produce [Formula: see text]-dimensional spacetimes via Kaluza–Klein compactification. We made the assumption that the [Formula: see text]-dimensional bulk geometry [Formula: see text] admits a Homothetic Vector Field (HVF) [Formula: see text] relaxing the existence of a zero i.e. [Formula: see text] holds on [Formula: see text] and the homothetic bivector [Formula: see text]. Under these circumstances, we identify the origin of a positive cosmological constant in the [Formula: see text]-dimensional spacetime as the homothetic factor representing a geometrical artifact of late time state of the [Formula: see text]-dimensional bulk spacetime.