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This paper presents high‐power broadband graphene non‐Foster circuit (NFC) enabled Class‐J GaN HEMT power amplifier (PA). A graphene resonant‐tunneling diode (RTD) NFC is proposed to provide negative differential resistance characteristics and to create an effective negative capacitance. The NFC is integrated in the input matching network of the Class‐J GaN HEMT PA to cancel out the transistor input parasitic capacitance so as to enhance PA bandwidth, efficiency, output power, and gain. The PA design is based on Cree's packaged GaN HEMT CGHV40030F biased with drain supply voltage of 50 V at quiescent drain‐to‐source current of 44 mA. The PA operates from 3.4 to 4.0 GHz with center frequency of 3.7 GHz. The effective negative capacitance of the NFC from 3.4 to 4.0 GHz stands at −3.3 to −6.0 pF. An effective capacitance of −3.7 pF has been obtained at 3.7 GHz. The PA has small signal gain of 16.1 dB at 3.7 GHz. Large signal simulation input power sweep from 1 to 33 dBm at 3.7 GHz, indicates that the PA has 57.8% drain efficiency, 54.7% power added efficiency (PAE), 44.6 dBm (28.8 W) output power and 11.6 dB transducer power gain at input power of 33 dBm. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a new compact asymmetric coplanar strip -fed UWB MIMO antenna. The UWB MIMO antenna consists of two identical elements which have quarter elliptical ring radiating element with asymmetric coplanar strip-fed. By designing the antenna using asymmetric coplanar strip-fed, the antenna size can be reduced (its size is only 6 × 2.6 cm2). The distance between the two antenna elements equals 0.37 λ0-The single antenna element is operated at frequencies from 3.1 GHz to 10.6 GHz with reflection coefficient lower than −10 dB. In addition, the designed antenna elements have less than 15 dB coupling isolation between the two input ports. The diversity performance between two antenna elements such as envelope correlation coefficient and diversity gain are investigated and they are within their allowed limits. This analysis confirms that the designed antenna is suitable for portable UWB MIMO applications. The proposed antenna is designed; simulated and measured. There is a good agreement between the simulated and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:31-36, 2017 [ABSTRACT FROM AUTHOR]

A novel ferrite nonreciprocal left-handed (LH) transmission line is presented. The proposed structure is composed of a coplanar waveguide over a ferrite substrate, horizontally magnetized and periodically loaded with only shunt inductors. The line has a nonreciprocal LH propagation with transmission level better than -5 dB with isolation level up to 20 dB over a moderate bandwidth. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2810–2814, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22848 [ABSTRACT FROM AUTHOR]

A binomial low-pass filter provides the flattest passband response but, slow attenuation transition. This letter presents a design for improving the roll-off performance and reducing the size of the filter based on the negative-ℇ property of complementary split ring resonators (CSRRs), whilst maintaining the filter passband performance. The measured results indicate that the proposed structure achieves a flat pass-band with no ripples. Whilst also having a selectivity of 32 dB/GHz, which significantly exceeds the 17 dB/GHz selectivity of the conventional design. Furthermore, the proposed filter has reduced the filter size by 16%. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2406–2409, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22799 [ABSTRACT FROM AUTHOR]

E‐Textiles have gained increasing momentum in wearable electronics recently. Conductive‐yarn‐based embroidered devices, with the advantages of being soft, deformable, breathable, and protective for the skin, play an important role in replacing many metallic counterparts. However, embroidered devices face many new challenges in their design methodology and fabrication processes, such as high resistivity and low Q value of the conductive yarns, as well as deformation of device geometries during wearing. Herein, a strain‐free, deformation‐resilient embroidery process for near field communication (NFC) coil antennas is introduced. Coil geometry can endure extreme deformation by stretching with up to 50% elongation, bending with curvature as small as 16 mm in radius, and can still maintain a relatively small variation in its inductance, resonant frequency, Q value, as well as its energy‐harvesting capabilities. The embroidered coil antenna is used in an NFC‐based battery‐free body sensor system. Experiments demonstrate that the system can maintain a stable performance (voltage supply, temperature sensing, and reading range) under various deformation conditions. [ABSTRACT FROM AUTHOR]