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An X-band power amplifier (PA) implemented in a silicon-germanium (SiGe) heterojunction bipolar transistor technology is presented. The SiGe PA was designed for inverse class-F mode using thin-film microstrip (TFMS) lines, eliminating the use of conventional band-limiting lumped inductors and transformers. Thus, simultaneous high efficiency and minimized in-band variation were achieved for X-band (8–12 GHz) applications. In addition, for boosting peak output power (Pout), the common-base transistor in the PA core was designed to operate in a weak avalanche region, which allowed dynamic collector-to-base voltage to swing beyond the collector-base breakdown voltage with open emitter without performance degradation. The fabricated SiGe PA demonstrates a high power-added efficiency (PAE) of 43.2% and a peak Pout of 24.3 dBm at 10 GHz. Benefitting from the utilization of TFMS lines, the PA exhibits a flat response for both PAE (33.3–44%) and peak Pout (23.1–24.5 dBm) for the entire X-band frequency range. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2868–2871, 2016

The benefits of using through-silicon-vias (TSVs) in silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) low-noise amplifiers (LNAs) over the conventional wire bonding have been investigated for the first time. The parasitics associated with wire bonding can be significantly minimized with TSVs, thereby reducing the LNA performance degradation at the packaging level. To verify simulations and theoretical analysis, a prototype K-band TSV-integrated LNA was implemented in a SiGe HBT platform. The parasitic inductance of TSVs was effectively utilized as an adjustable matching element for the optimum LNA performance. The proposed LNA exhibits minimal degradation compared to the (unpackaged) LNA with probe-supplied ground. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2703–2706, 2015

This article presents a Ku-band switched path type phase shifter in a standard 0.13 µm CMOS technology. The phase shifter consists of phase shifting filter networks, DPDT and SPDT switches, a tuning bit, and digital control logic. The phase coverage of the phase shifter is 354° with the LSB of 5.625°. The measured insertion loss is less than 16 dB. The input and output return losses are more than 12 dB. The RMS phase error and amplitude variation are less than 7.6° and 0.3 dB at 10.7–15 GHz, respectively. When the tuning bit is activated, the RMS phase error of 6.3° and the RMS amplitude variation of 0.4 dB are achieved at 10.7–15 GHz. The input P1dB over ∼11 dBm is achieved at 10–15 GHz. The current consumption is nearly zero with 1.2 V supply voltage. The chip size is 1.46 × 0.82 mm2 including pads. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2120–2124, 2013

This paper presents a 5-bit digital step attenuator (DSA) using a commercial 0.18-μm silicon-on-insulator (SOI) process for the wideband phased array antenna. Both low insertion loss and low root mean square (RMS) phase error and amplitude error are achieved employing two attenuation topologies of the switched path attenuator and the switched T-type attenuator. The attenuation coverage of 31 dB with a least significant bit of 1 dB is achieved at DC to 20 GHz. The RMS phase error and amplitude error are less than 2.5 ° and less than 0.5 dB, respectively. The measured insertion loss of the reference state is less than 5.5 dB at 10 GHz. The input return loss and output return loss are each less than 12 dB at DC to 20 GHz. The current consumption is nearly zero with a voltage supply of 1.8 V. The chip size is 0.93 mm × 0.68 mm, including pads. To the best of the authors’ knowledge, this is the first demonstration of a low phase error DC-to-20-GHz SOI DSA.

A 2.3/3.5 GHz dual-band applicable CMOS power amplifier (PA) is implemented using 0.13-μm CMOS process.To achieve the optimal dual-band characteristics, a switched inductor is used for the driver amplifier (DA) load. To improve the PAE and linearity at back off power, class AB-B combined PA transistor cell is used. The measured maximum output power Psat of the dual-band PA is about 29 dBm and 28 dBm at 2.3 GHz and 3.5 GHz, respectively. The achieved EVM is −30 dB and −26 dB at 23 dBm output power for each band, respectively. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2799–2802, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26437

Nanowires are a focus of research interests as one-dimensional nanosystems and promise exciting applications in nanotechnology, ranging from nanoelectronic devices to cell separation and magnetic labeling in biomedicine. Avariety of methods have been devised to prepare them from magnetic, semiconductor, inorganic, organic, polymer, metallic, and dielectric materials to provide nanowires with novel optical, electrical, catalytic, and magnetic properties. Multilayered or barcode arrangements of nanowires which incorporate different material components are a special case as a result of their spatial arraying, multiple functionalities, and enhanced properties in comparison to those of their single-component counterparts. For instance, Co–Cu barcode nanowires were explored for their high magnetoresistance compared to that of the well-studied thin films, 17] while the coding of magnetic and optical properties in a single wire was targeted for the separation, detection, and transport of cells. Interested in the transport properties and potential applications of nanowires in nanodevices and biomedicine, we have investigated magnetic nanowires by electrodeposition. For biomedical purposes, however, two issues have to be addressed for the implementation of such nanowires, namely surface modification and biocompatibility. In this respect, the synthesis of iron–gold (Fe–Au) nanowires is appealing not only in terms of magnetic properties but also with respect to biological compatibility. On one hand, iron is favored as it is unique in the field of magnetic materials owing to its high magnetization and physicochemical potentiality. It can be easily converted into oxides, which have been thoroughly studied in the form of magnetic nanoparticles in the biomedical field for their magnetic properties and exceptional biocompatibility. On the other hand, gold is a wellestablished material that displays attractive optical properties, biological compatibility, catalytic activity, and excellent surface effects. Thus, it was anticipated that the integration of these two materials into a one-dimensional barcode arrangement on the nanoscale would produce a new nanostructured material that retains the optical and magnetic properties of the respective components, offering synergistically enhanced performance and functionalities which go beyond those of the individual components. Herein, we report the synthesis and characterization of such a kind of multifunctional magnetic–optical Fe–Au barcode nanostructures, that is, nanowires consisting of alternative Fe magnetic and Au optical segments. The Fe–Au barcode nanowires were constructed using anodic alumina oxide (AAO) templates by pulse electrodeposition thus forming iron and gold segments alternatively in a single bath under desired pulse current densities (e.g. 10 mAcm 2 and 0.5 mAcm ) with regulated pulse durations to control the respective segmental lengths (see Experimental Section). The selection of a current density to electrodeposit Fe or Au was based on the evaluation of the composition versus current density profile (Figure 1a), which was acquired from the analysis of the samples each obtained at a given constant current density, by inductively coupled

This article presents a 5-bit broadband digital step attenuator with low insertion loss and phase error using a standard 0.13 μm CMOS process for the phased array antenna.The maximum attenuation of 31 dB with the LSB of 1 dB is achieved at DC-20 GHz. The measured insertion loss of the reference state is