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The art of paper folding also known as Origami plays an important role in various research areas of different scientific fields. Origami structures possess many useful characteristics such as reconfigurability, flexibility, deployability, compactness, and multi-functionality. These attributes are inevitable for modern communication systems. Additionally, they provide antenna engineers an extra degree of freedom while blueprinting next-generation designs. One of the desirable features of origami is its folding capability. Using this property, it can be transformed into a two-Dimensional (2D) sheet from a three-Dimensional (3D) structure and vice versa through external stimulus. In recent years, researchers have proposed numerous smart materials to optimize folding behavior. These smart materials extend the functionality of origami technology for designing self-folding structures required in space systems, small scale devices, and self-assembly systems. Origami structures feature many useful characteristics pertinent to modern day design challenges of communication systems such as reconfiguration, flexibility, compactness, and multifunctionality. In this work, a state of the art review is presented on conceptualization, design challenges, and fabrication of light-weight and low-cost deployable origami antennas. Furthermore, to provide critical insights deployment challenges and possible solutions are also provided. It is believed that this work will not only help peers to understand the basic working principles of different origami structures but will also lay the foundation for future research in the evolving field of origami-based antennas. Moreover, the design methodology proposed in this paper will also provide pragmatic solutions for origami antennas suitable for the harsh and rigid environments.

This article reports investigation of self-actuation in phase change material (PCM) germanium telluride (GeTe)-based radio frequency (RF) switches as a limitation to RF power handling. PCM switches are fabricated in-house with multiple design dimensions for evaluation and testing under various RF power levels. RF power handling capability and maximum dc current carrying capacity in the ON-state of the switches is studied for four different device layouts. Self-actuation in the OFF-state is reported at varying input RF power and dc voltage levels. A tradeoff between RF power handling capacity and device performance is discussed, establishing a correlation between design parameters and the power handling. The improved PCM switches exhibit a record high continuous wave (CW) RF power handling capability ranging from +35.5 to +39.2 dBm. [ABSTRACT FROM AUTHOR]

This paper presents the first theoretical and experimental study on the power handling capabilities of electrostatically tunable MEMS cavity filters. The theoretical analysis indicates that the frequency-dependent RF voltage inside a narrowband filter may play an important role in the generation of electromechanical nonlinearities such as frequency response distortion, frequency shift, and bifurcation instability. This analysis also reveals that the filter's power handling capability is dependent on several critical factors, including the capacitive gap, stiffness of the diaphragm actuator, and the overall quality factor (Q) of the evanescent-mode (EVA) resonators. A nonlinear computer-aided design (CAD) model is proposed as a practical tool for capturing the important tradeoffs in high-power design. An EVA tunable resonator and a two-pole 2% filter are fabricated and measured as vehicles to validate the theory and the CAD model. Specifically, a medium-power filter with a tuning range of 2.35–3.21 GHz (1.37:1) and an extracted unloaded quality factor (Q_u) of 356–405 shows measured power levels of 23.4 dBm (0.22 W) before bifurcation instability occurs. The measured IIP3 of this filter are 52.1 dBm. The theory and modeling, backed up by the measurements, provide significant insights into the high-power design of electrostatic tunable cavity filters. [ABSTRACT FROM AUTHOR]

This paper discusses reliability issues in torsional MEMS varactor. Self-actuation due to high ac signals is analyzed, and solutions are proposed. The mode of failure at high actuation voltages is analyzed and established through experiments. Issues like stiction due to high voltages and effect of high residual stress are studied experimentally. [ABSTRACT FROM PUBLISHER]