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Origami inspired antennas have been investigated for their potential as lightweight and efficient multi-purpose reconfigurable antennas for a variety of radio frequency applications. Being able to change antenna frequency, bandwidth and gain simply by folding the antenna structure is certainly attractive, however, challenges must be overcome for real-world applications. Providing sufficient gain is a challenge for small antennas and this issue can be compounded by impedance matching problems resulting from folding the antenna feedlines. Providing sufficient structural strength along with a reliable means to physically fold the antenna can also be a challenge. In this paper a novel origami inspired two-element hexagonal antenna array is investigated for its potential to provide a simple and stable physical structure that demonstrates consistent gain and impedance matching for multiple configurations.

A major component of any communication or wireless sensor is an antenna. There is interest in developing multifunctional and reconfigurable antennas that can morph into different shapes and provide different functionalities. The interest of using one antenna for multiple purposes is usually due to limitations of size and weight, and the increasing need for wireless devices such as wireless power transfer, communication and wireless sensors. Some of the challenges to overcome include having a small form factor, being low-cost and robust, and providing high gain. In this work we are presenting an origami inspired hexagonal shape antenna array. Origami is the art of paper folding and the basis of origami method can be used to design antennas that can be folded and unfold based on deployment need. For example, Kimonis et. al. [1] proposed a power-harvesting cube with the antennas made using inkjet printing. The shape memory hinges are used to change the cube to a flat shape. Another example is the use of a 3D printing method by Shah and Lim [2]. In this paper they designed a push/pull method to change the shape of the array. The initial results of the basic hexagonal antenna elements needed to reconfigure form 2.4 GHz to 5.8 GHz are presented and discussed.

In additive manufacturing, Poly Carbonate-Acrylonitrile Butadiene Styrene (PC-ABS)composite has better mechanical durability and heat-resistance compared to PolyLactic Acid (PLA)thermoplastics. 3-D printed radio frequency (RF)circuits often require being deployed in extreme conditions and hence PC-ABS RF circuits are preferable over PLA RF circuits. In this paper, variations of measured dielectric constant at 1 GHz and 10 GHz were reported for PC-ABS sample cubes based on the printing region on the printing bed surface of a 3-D printer. Also, an error analysis was presented using the measured permittivity at 1 GHz and 10 GHz and the reported average permittivity of PC- ABS from a literature.

Collecting training data from the physical world is usually time-consuming and even dangerous for fragile robots, and thus, recent advances in robot learning advocate the use of simulators as the training platform. Unfortunately, the reality gap between synthetic and real visual data prohibits direct migration of the models trained in virtual worlds to the real world. This paper proposes a modular architecture for tackling the virtual-to-real problem. The proposed architecture separates the learning model into a perception module and a control policy module, and uses semantic image segmentation as the meta representation for relating these two modules. The perception module translates the perceived RGB image to semantic image segmentation. The control policy module is implemented as a deep reinforcement learning agent, which performs actions based on the translated image segmentation. Our architecture is evaluated in an obstacle avoidance task and a target following task. Experimental results show that our architecture significantly outperforms all of the baseline methods in both virtual and real environments, and demonstrates a faster learning curve than them. We also present a detailed analysis for a variety of variant configurations, and validate the transferability of our modular architecture., 7 pages, accepted by IJCAI-18

This article presents the design, simulation, manufacturing, and testing of textile patch antennas for spacesuit applications at the frequency 2.45 GHz. Antennas are designed for dispersed placement on two suit prototypes, NDX-1 and NDX-2, both external to the suit and mounted on the inner wall of a removable, thermal layer. Movement of the wearer, along with the necessity of compact transport and the harsh conditions of the extraterrestrial environment, call for durable and flexible antenna materials. Nickel-copper ripstop was selected as the best material for the patch and ground, and layered ultrafirm fabric stabilizer was used for the dielectric. Spray adhesive joined the patch to substrate to ground. Several rounds of antenna design and manufacture were carried out to create the best-performing design. This design of this patch is 52.122-mm long, 58.375-mm wide, with substrate dimensions of 127.52 mm x 127.52 mm, with a height of 1.6 mm. Simulation and experimental results, including co- and cross-polarization patterns in the E- and H-plane and return loss for planar and conformal antenna configurations are presented and discussed. Results indicate that minimal antenna flexure (radius = 101.6 mm) slightly degrades antenna performance and causes a shift in resonant frequency up to 0.02 GHz. Increased flexure (down to a 43.2-mm radius), did not significantly alter radiation patterns or return loss. Extreme bending (

Techniques of a dual-path error amplifier and two capacitor multipliers for providing on-chip frequency compensation and soft-start function are proposed in this paper. The concept of the dual-path error amplifier is to use two currents to charge and discharge a compensation capacitor simultaneously. As a result, the equivalent capacitance is enlarged significantly with little additional power and silicon area. The dc-dc converter with the dual-path architecture also has great performance in transient response because the compensation capacitor is reduced significantly. For the soft-start function, the subtractive-type and time-average capacitor multipliers are used to relax the restriction of the capacitance and the charging current. Consequently, it is easy to integrate the soft-start capacitance into a chip and the output overshoot voltage can be suppressed. A prototype converter fabricated with TSMC 0.35-μm 2P4M CMOS process verifies the effectiveness of the techniques of a dual-path error amplifier and two capacitor multipliers. Experimental results demonstrate the converter stability, transient response, and soft-start function. The transient recovery time and transient ripple are less than 20 μs and 25 mV, respectively, for the load current swing from 50 to 500 mA. Moreover, the soft-start time is up to 8 ms. With the proposed techniques, the external pins of the dc-dc converters are minimized and their performance is improved significantly.

This paper describes a facile low-toxicity synthesis of two different types of Au nanonests and one binary Au–Pt core–shell nanonest with high yield and excellent uniformity in size and morphology using block copolymer P123 (EO20PO70EO20) as a soft template and the main reductant in an ice water bath. The introduction of a suitable second metallic source, i.e. Pt ions in the present case, was proven to be a unique strategy for effectively governing the reduction sites of P123 for Au nucleation, which leads to significant changes especially in the crystallite size of the grown Au nanonests. The Au nanonests exhibited a distinct morphology-dependent surface plasmon resonance (SPR) that is red-shifted by ∼140 nm from the spherical particles wavelength, and significant surface-enhanced Raman scattering (SERS), allowing the rapid determination of rare malachite green oxalate (MGO).

This paper presents a soft-start circuit that adopts a pulse-skipping control to prevent inrush current and output voltage overshoot during the start-up period of dc-dc converters. The purpose of the pulse-skipping control is to significantly restrain the increasing rate of the reference voltage of the error amplifier. Thanks to the pulse-skipping mechanism and the duty cycle minimization, the soft-start-up time can be extended and the restriction of the charging current and the capacitance can be relaxed. The proposed soft-start circuit is fully integrated on chip without external components, leading to a reduction in PCB area and cost. A current-mode buck converter is implemented with TSMC 0.35-μm 2P4M CMOS process. Simulation results show the output voltage of the buck converter increases smoothly and inrush current is less than 300 mA.