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Microwave absorbion for radar stealth technology is facing challenges for effectiveness in the low frequency region. Here we report a new laser-based method to produce an ultra-wideband metamaterial based microwave absorber with a high sheet resistance uniformity and negative magnetic permeability leading to the highest relative bandwidth and lowest thickness in the L to S band reported so far. Control of electrical sheet resistance uniformity has been achieved to less than 5% deviation for 400 Ω/sq and 6% deviation for 120 Ω/sq, leading to a microwave absorption coefficient between 97.2%-97.7% within 1.56 GHz-18.3GHz bandwidth for incident angles of 0-40, and there is no need for applying energy or an electrical power source during operation. Porous N- and S- doped turbostratic graphene 2D patterns with imbedded magnetic nanoparticles are produced on polyethylene terephthalate simultaneously during laser direct writing. The proposed low frequency, wide band, wide incident angle and high electromagnetic absorption microwave absorber would have the potential for aviation, EMI suppression and 5G applications.

Increasing amounts of attention are being paid to the study of Soft Sensors and Soft Systems. Soft Robotic Systems require input from advances in the field of Soft Sensors. Soft sensors can help a soft robot to perceive and to act upon its immediate environment. The concept of integrating sensing capabilities into soft robotic systems is becoming increasingly important. One challenge is that most of the existing soft sensors have a requirement to be hardwired to power supplies or external data processing equipment. This requirement hinders the ability of a system designer to integrate soft sensors into soft robotic systems. In this article, we design, fabricate, and characterize a new soft sensor, which benefits from a combination of radio-frequency identification (RFID) tag design and microfluidic sensor fabrication technologies. We designed this sensor using the working principle of an RFID transporter antenna, but one whose resonant frequency changes in response to an applied strain. This new microfluidic sensor is intrinsically stretchable and can be reversibly strained. This sensor is a passive and wireless device, and as such, it does not require a power supply and is capable of transporting data without a wired connection. This strain sensor is best understood as an RFID tag antenna; it shows a resonant frequency change from approximately 860 to 800 MHz upon an applied strain change from 0% to 50%. Within the operating frequency, the sensor shows a standoff reading range of >7.5 m (at the resonant frequency). We characterize, experimentally, the electrical performance and the reliability of the fabrication process. We demonstrate a pneumatic soft robot that has four microfluidic sensors embedded in four of its legs, and we describe the implementation circuit to show that we can obtain movement information from the soft robot using our wireless soft sensors.

Increasing amounts of attention are being paid to the study of Soft Sensors and Soft Systems. Soft Robotic Systems require input from advances in the field of Soft Sensors. Soft sensors can help a soft robot to perceive and to act upon its immediate environment. The concept of integrating sensing capabilities into soft robotic systems is becoming increasingly important. One challenge is that mostof the existing soft sensors have a requirement to be hardwired to power supplies, or external dataprocessing equipment. This requirement hinders the ability of a system designer to integrate softsensors into soft robotic systems.In this paper we design, fabricate, and characterise a new soft sensor which benefits from a combination of RFID tag design and microfluidic sensor fabrication technologies. We designed this sensor using the working principle of an RFID transporter antenna, but one whose resonant frequency changes in response to an applied strain. This new microfluidic sensor is intrinsically stretchable and can be reversibly strained. This sensor is a passive and wireless device and as such, it does not require a power supply, and is capable of transporting data without a wired connection. This strain sensor is best understood as an RFID tag antenna; it shows a resonant frequency change from 860MHz to 800MHz upon an applied strain change from 0% to 50%. Within the operating frequency, the sensor shows a stand-off reading range of over 7.5 metres (at the resonant frequency). We characterise, experimentally, the electrical performance and the reliability of the fabrication process. We demonstrate a pneumatic soft robot that has four microfluidic sensors embedded in four of its legs, and we describe the implementation circuit to show that we can obtain movement information from the soft robot using our wireless soft sensors.

In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8-12 GHz) and Ku (12-18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene's application to practical RCS reductions.