In this letter, a dual band circularly polarized (CP) meta‐structured antenna is designed by −1 mode for L1 band and mu‐zero resonance mode for L2 band, respectively. The antenna consists of two kinds of unit cells which have four unit elements for −1 mode and mu‐zero resonance mode, respectively, in order to utilize the limited space efficiently, and to maximize the gain. Since two modes of −1 mode

Considering the increasingly wide application of optical fiber sensors, this article aims to present an alternative form of interrogation without the use of an optical spectrum analyzer or any other high‐cost devices. The sensor studied here is a long‐period grating being used to measure temperature. The interrogator is composed of optical filters and photodetectors whose responses are processed by

This communication focuses on the Raman spectroscopic characterization of a voltage‐controlled electrospray deposition (VCED) of multiwalled carbon nanotubes (MWCNTs) dispersed from acid refluxed and SDBS (sodium dodecyl benzene sulfonate) assisted carbon nanotube (CNT) dispersion techniques. This versatile method resulted in the direct deposition of CNT films on the surface functionalized target substrates

In this paper, we propose a slot antenna with circularly polarized (CP) characteristics in two frequency bands. The proposed antenna consists of a square wide slot with a square patch in the center and a pair of stubs for radiator asymmetry. The proposed antenna shows right‐hand CP characteristics at 1.88 GHz and left‐hand CP characteristics at 4.41 GHz. The proposed antenna has measured impedance

In this paper, a compact size (16 × 16 mm) of the monocycle pulse generator is proposed for Ultrawide‐band (UWB) impulse radar applications. The proposed circuit is based on the step recovery diodes (SRDs) and has a very simple structure. It consists of a coupling part, short pulse generating part, and monocycle forming part. The performance of the pulse generator is compared against simulation results

In this article, a compact microstrip tri‐band bandpass filter based on a rectangular ring resonator (RRR) and two triangular patch resonators is presented. This filter is designed to operate at 3.5, 5.2, and 8 GHz for WiMAX, wireless local area network (WLAN), and satellite applications respectively. Also, the center frequencies of the first and second passband can be flexibly controlled by tuning

In this article, a planar inverted‐F antenna (PIFA) pair with reflectors for near‐field power transfer at a frequency of 2.45 GHz is proposed. In order to enhance efficiency of power transmission and reduce electromagnetic wave leaked to free space due to the power transmission, the reflectors are installed around the transmitting and receiving antenna pair except on the open side. The transmitting

The paper reports the bandwidth enhancement of a microstrip slot antenna for on‐metal RFID applications. Microstrip patch with a single conductive layer as wideband and conformal antenna is investigated. The proposed bandwidth enhancement is based on stepped‐impedance slot resonator integrated with an inset‐fed microstrip patch. Slots of different electrical lengths and impedances are configured to

In this article, a broadband circularly polarized rectangular dielectric resonator antenna (CP‐RDRA) is explored and reported. The proposed antenna comprises of rectangular dielectric resonator (DR) made up of aluminum oxide placed on a Rogers RT‐5880 substrate and fed by a 50‐Ω microstrip line with a partial ground plane. Microstrip line feed is placed at the right edge of rectangular DR to excite

A multiwavelength semiconductor optical amplifier (SOA) fiber laser based on all‐fiber two‐mode interferometer (TMI) structure is demonstrated. The TMI generates in a comb‐like spectrum with a 1‐nm wavelength spacing and extinction ratio of 5.7 dB. By incorporating a TMI in the laser cavity, stable multiwavelength operation is obtained with 30 output channels from 1570.8 to 1600.8 nm with peak powers

In paper [1], the dimensions of Rs, (Ω) in Table 1 and 2 must be replaced with (kΩ).

In this article, a fiber‐optic sensing scheme based on Stimulated Brillouin scattering effect in a recirculating fiber ring and frequency down‐conversion is proposed and experimentally demonstrated. By employing the recirculating fiber ring structure, high‐order backscattering Stocks light has been generated. The Brillouin frequency shift will be affected by the environmental variations, such as, temperature

In this article, a metamaterial absorber structure is analyzed using the transmission line method (TLM) considering the normal incidence of the wave. The unit cell of the presented absorber structure is a composite geometry providing dual‐band absorption. Peak absorptivities of 95.02% and 99.84% are obtained at 4.215 GHz and 10.95 GHz, respectively. The experimentally validated simulated reflection

A coplanar waveguide‐fed ultra‐wideband (UWB) composite right/left‐handed (CRLH) antenna is presented. It is designed by embedding CRLH unit‐cell on the top side and split‐ring resonator (SRR) on the bottom side of FR4 epoxy substrate. The UWB response is obtained by merging the resonances of CRLH unit‐cell and SRR with two additional resonances due to patch feed‐line and ground plane, respectively

Recently, Plasmonics and metamaterials have been receiving consideration. Spoof surface plasmon polaritons (SSPPs) are a type of electromagnetic surface wave that to a certain limit shares an analogous behavior with surface plasmon polariton (SPP) at microwave frequency domain. The significant point is that the dispersion relation of SSPP is principally controlled by the geometry of the pattern using

This letter presents a low‐power and low‐phase‐noise 5‐GHz VCO fabricated in a standard CMOS 0.18‐μm process. The low power dissipation was achieved by using the PMOS cross‐coupled pair and G m‐boosting topology, and the low phase noise was obtained by adding two pairs of switched capacitor array. The VCO consumed a dc power of 2.92 mW with the supply voltage of 1 V. The measured phase noises were − 104

In this article, a compact super wideband (SWB) high bandwidth dimension ratio (BDR) steering‐shaped antenna is proposed for future wireless communication applications. The proposed antenna consists of a linearly tapered microstrip‐fed circular ring with four elliptical spokes to connect with a central circular disk to form a steering‐shaped radiating patch and a rounded cornered notch‐loaded rectangular

This letter presents a proportional adaptive technique to mitigate the multipath fading effect in advanced wireless communication systems. The designed system consists of a realized ultra‐wideband (UWB) dual antenna array and two universal software radio peripheral (USRP) platforms synchronized by a MIMO cable, with one digital RF phase shifter implemented in the reception chain of one of the two receiving

This paper presents a novel different‐/same‐frequency power combining circuit with high isolation and high frequency selectivity. The proposed design is implemented by integrating the diplexer and the power dividers with simple structure, which consists of a microstrip‐line T‐junction, two bandpass filter with different center frequency, and two pairs of three‐line parallel coupling lines. Source‐load

In this article, two miniaturized, dual‐band, enhanced gain, flexible, low specific absorption rate (SAR) artificial magnetic conductor (AMC) integrated antennas operating at 2.4 GHz ISM and 3.9 GHz WiMAX bands have been proposed. Two compact monopoles with defected stepped ground structures have been used to improve the radiation characteristics while integrated with a common AMC surface. Defected

This article deals with a design and analysis of an 8‐element dipole array for passive coherent location (PCL) systems. The array is composed of eight identical dipole elements that are arranged at a radius of 0.5λ0 from the center to the elements. To verify the performance for the PCL system, the array is fabricated and measured in an outdoor test site. Array performances such as the antenna gain

In this article, a hyperthermia healing system is presented for cancer treatment. To alleviate most of the microwave hyperthermia systems problems, such as high input power, complicated beamforming method, unwanted hot spots for superficial tumors, and bulky profile, a simple repetitive time‐reversal method is proposed to design a low power wearable hyperthermia applicator with low hotspots at 915 MHz

This article indicates a thus far unexplored area of applied research and development to the application and system engineers and researchers from broad engineering backgrounds. Results of a study are presented for measurement of calibrated Radar Cross Section (RCS) of a 9‐mm bullet (projectile) model by using a commercial‐of‐the‐shelf (COTS) millimeter wave Frequency Modulated Continuous Wave (FMCW)

In this article, a compact dual‐port dual‐frequency slot antenna compatible with printed circuit board (PCB) technology is proposed. The antenna has two feed structures for two frequencies with slots and the capacitive matching circuits. The antenna radiates at specific frequency with the matching network and the frequency of the antenna can be adjustable by changing the matching element parameters

Strong and narrowband terahertz (THz) radiation is obtained from a GaAs‐based pseudomorphic high‐electron‐mobility transistor (pHEMT). The radiation properties with respect to the bias conditions and operating temperature are extensively characterized. The maximum emission power is measured to be 63 and 278 μW at room temperature and 77 K, respectively. By using the THz radiation from the pHEMT, a

This article presents a high‐linearity Ka ‐band complementary metal–oxide–semiconductor (CMOS) down‐conversion mixer. The mixer comprises an RF transconductance stage, switching stage, local oscillator buffer, and intermediate frequency (IF) buffer, and employs modified multiple gate transistors for high linearity. The intermodulation and gain characteristics are analyzed, revealing that the proposed

Tran B‐D, Duong T‐V, Tan TD, Tran TT, Vu TA, Vu CT. New phase noise X‐band VCO using perturbed dual‐mode SIW filter. Microw Opt Technol Lett . 2020;62:2866‐2870. DOI: 10.1002/mop.32407 In the article cited above, the correspondence author and address has been changed from. Tuan‐Viet Duong (Radar Institute, Academy of Military Science and Technology, Hanoi, Vietnam; Email: vietroc04@gmail.com) to. Binh‐Duong

A new wideband microstrip antenna, based on the falcate‐shaped patch, with reconfigurable capability at circular‐polarization is presented in this article. To achieve both properties of stable radiation characteristics and impedance matching across a broad bandwidth, the combination of the L‐probe feeding and falcate‐shaped patch is used. An RF‐switch is utilized to excite the L‐probes and generate

A broadband vertically interdigital‐capacitor (VIC) is proposed and fabricated in a 10‐layer low temperature co‐fired ceramic substrate. By interconnecting the open ends of interval fingers, the number of stop‐band structures is reduced and thus the spurs that limit the bandwidth are removed. With the orthogonally placed input/output ports, the amplitudes of transmission coefficient and reflection

With the development of the microelectronics, circuit design has become more and more important. In order to improve the accuracy of circuit design, it is necessary to improve the accuracy of the circuit model. This letter proposes an accurate method based on the Angelov model of the Gallium Nitride (GaN) high electron mobility transistors (HEMTs). For Angelov model, the fitting of DC curve is critically

A modified resistive power divider (RPD) was proposed by Owen and this structure has been shown to have higher isolation than a conventional RPD. However, it has a large insertion loss, which is a disadvantage. No theoretical studies have been published since Owen proposed this unique structure with specific resistor values. Thus far, the improvement of insertion loss has been achieved by trial and

A flexible meander bowtie antenna incorporated with dipole‐like artificial magnetic conductor (AMC) is proposed. Two different types of AMC design are presented for comparison. A new medical transdermal patch is used as the dielectric substrate for both antenna and AMC. The gain enhancement is achieved using a modified dipole‐like unit cell of the AMC. The effect of the substrate thickness and separation

The advances in unmanned aerial vehicles (UAV) and their applications in various areas of military, communications made the researchers focus on the design of compact, wide beam, lightweight antennas. In this article, a novel miniaturized printed dipole antenna with quasi rhombus shape exhibiting an Impedance bandwidth of 113% (within 2:1 VSWR for the frequency range from 6.3 to 23 GHz) is presented

Photonic filters are playing a very important role in many applications, including optical interconnects as well as optical sensing. As silicon photonics has provided a very attractive platform to realize the high integrated intensity and low cost, various silicon‐based on‐chip photonic filters have been proposed and demonstrated in the past decade. In this paper, we give a review of recent progresses

The technique of spray pyrolysis used to prepare the pure thin films NiO and NiO:Cu. In this study, the nickel chloride salt solution (NiCl2⋅6H2O) was used to fabricate thin films deposited on a glass substrate. The structural, optical, and morphological fabricated properties of the samples were investigated. X‐ray diffraction reveals a polycrystalline nickel oxide layer with a crystalline cubic form

Aiming at the increasingly serious water pollution problem, this article proposes a floating waste monitoring method based on the characteristics of millimeter wave radiation. The method is based on the basic principles of microwave radiation and the radiometric characteristics of floating wastes. In this method, we establish a multilayer media model of floating wastes and get the radiometric temperature

This paper presents a compact 180° phase shifter with flat phase difference in a wide bandwidth. It is a hybrid structure based on a stub‐loaded line and a switched‐line phase shifter, in which a kind of periodic dumbbell‐shaped slow wave line and T‐shaped short‐ended stub are introduced for miniaturization. The proposed configuration shows a better broadband performance and compact geometric dimension

A compact four‐way quasi‐rectangular cavity power combiner with high isolation and high power‐combining efficiency is presented. The quasi‐rectangular cavity is employed to realize both impedance transformation and mode conversion. The isolation circuit based on microstrip line technique is utilized to realize high isolation. Besides, a T‐junction is established as a transition from coaxial to microstrip

This letter discusses a complete implementation of high performance voltage‐controlled oscillators using enhanced group delay SIW filters. Through precisely adjusting the perturbing via‐hole position inside dual mode circular cavity resonator, phase noise of the oscillator can be minimized. The planar SIW X‐band voltage‐controlled oscillation prototypes were additionally analyzed, fabricated, and measured

This study presents a planar dual‐channel bandpass microstrip diplexer based on a novel structure. It has the very compact size of 0.0081 λ g 2 (95.7 mm2) fabricated on 0.787 mm dielectric substrate height. Due to the use of close microstrip sections, several coupling capacitors are created. These capacitors can increase the degree of freedom for controlling the diplexer performance while it is optimized

A miniaturized broadband planar monopole multiple‐input‐multiple‐output (MIMO) antenna is proposed for the 3.5 GHz frequency band of the Long‐Term Evolution Advanced application. Two novel broadband metamaterial split‐ring resonator units are used to reduce the mutual coupling of the MIMO antenna, also expanding the antenna impedance bandwidth. The size of the whole antenna is 47.5 mm × 40 mm × 1.6 mm

An antenna array composed of four inclined microstrip Yagi antennas is proposed for a direction finding (DF) system operated in L band. Each element antenna is designed to have a tilted beam toward a central array axis in order to have high gain in the boresight axis of the antenna array. In comparison to a patch antenna array, having the same structure, antenna array gain is improved by a 2.3 dB maximum

This article presents the design and measurement results of a novel wideband circularly polarized 2 × 2 slot antenna array loaded with a metasurface layer. The proposed array exploits circularly polarized elements. Each element is sequentially rotated and fed with an appropriate phase difference to ensure the generation of a circularly polarized wave. The use of metasurface enlarges the impedance bandwidth

Cognitive radio (CR) is designed to achieve intelligent spectrum sensing and sharing, in order to solve spectrum underutilization problem. Conventional CR uses multiple/multiport antenna to switch between UWB and narrow band (NB) frequencies for primary and secondary users. In this article, we propose a compact frequency reconfigurable single port antenna using PIN diodes, to switch between UWB and

A pedestrian‐target detection method based on multiscale convolution features is proposed to solve the problem of the existing target detection algorithms based on convolutional neural networks that cannot effectively adapt to the target scale change, its deformation, and the complex environment. This article analyzes the characteristics of small target, establishes the a three‐layer pyramid network

In this article, a modified complex‐valued convolutional neural network (MCV‐CNN) specifically for interferometric inverse synthetic aperture radar (InISAR) imaging is proposed. Comparing with the fast Fourier transformation‐based and sparsity‐driven imaging algorithms, the MCV‐CNN can achieve super‐resolution and side‐lobe suppression on the imaging results simultaneously within a short time. The

In this article, we utilize the Faster‐Than‐Nyquist (FTN) mechanism combined with the deep neural network (DNN) nonlinear post‐equalization scheme to achieve spectrum compression of the multiband carrierless amplitude phase (CAP) signal in the case of a fixed channel spacing for visible light communication (VLC) system. We found that the number of input layer nodes plays a decisive role in the DNN

This article investigates the design of proton‐exchanged (PE) lithium niobate on insulator configurable photonic multiplexer (CPM). The photonic multiplexer includes two 1 × 1 Mach‐Zehnder modulator and a directional coupler. The performance of the proposed multiplexer is investigated by a 2D finite‐difference beam propagation method for the wavelength range of 1530 to 1570 nm. The results show a uniform

The existing wired intra data center (DC) networks suffer from traffic congestion, low scalability, low flexibility, and increasing power consumption. To solve this problem there is a need to move from wired to wireless intra DC connections. One of the technologies that could provide a solution for the next generation intra DC communication is the use of free space optical (FSO) communication. However

This letter presents a design of very compact asymmetric dual L ‐strip fed split‐ring shaped electromagnetic bandgap (EBG)‐based textile antenna for wireless body area networks (WBAN) applications, operating at frequency 2.45 GHz. The antenna radiator is composed of 2 × 1 array of EBG cells printed on same side of the substrate with partial ground plane to form a compact EBG surface, excited with a

To deal with EM simulations with the low‐frequency evanescent and propagation waves, multi‐order nearly perfectly matched layers (NPML) with complex frequency shifted factor are presented to terminate finite‐difference time‐domain (FDTD) domains. By incorporating the digital signal processing techniques including the bilinear Z‐transform, matched Z‐transform, and direct Z‐transform methods, the proposals

This work proposes a novel method for detecting the concentration of water present in liquid‐water binary mixture in real time with a low cost, portable measurement setup. The sensing element in the proposed system is a two‐port microstrip bandstop resonator based on coupled line open‐ended quarter wavelength section. Voltage control oscillator and power detector ICs are used to generate and detect

In this paper, a balanced dual‐band bandpass filter (BPF) with a high selectivity and intrinsic common‐mode (CM) suppression is presented. The proposed balanced BPF consists of balanced stepped‐impedance microstrip‐slotline transition (BSIMST) structures and two pairs of half‐wavelength split‐ring resonators (SRRs). The designed SRRs can generate two differential‐mode (DM) passbands. By adjusting the

A CPW‐fed, circularly polarized (CP)antenna operating at 2.45 GHz ISM band is investigated for in‐body biotelemetry. Antenna has compact volume of 98mm3 (14 mm × 14 mm × 0.5 mm) and printed on RO 3010 substrate. By using inverted z‐shaped radiator with square ring‐shaped ground, wide impedance bandwidth of 450 MHz (2.25‐2.7 GHz).In addition, it also contributes to excite two orthogonal modes (TM01

In this article, an adjustable microstrip lowpass filter(LPF) with the cut‐off frequency (f c) at 1.59 GHz is designed and fabricated. The proposed structure is composed of a Z‐shaped resonator as basic resonator and a combination of modified T‐shaped and Z‐shaped resonators as suppressor units. To describe a theoretical design, the L‐C equivalent circuit of the basic resonator and also its transfer

A novel electromagnetically coupled c ircular p atch a ntenna (CPA) with an eroded ground plane is proposed for the w ireless l ocal a rea n etwork (WLAN) application. First, a simple CPA is designed for 2.4‐GHz WLAN band. At this frequency, the physical size of the CPA is large. Therefore, a CPA is designed at a higher frequency with much lesser dimensions, and some portion of the ground plane is

A compact K/Ka‐Band dipole antenna element with ball grid array packaging is proposed. The antenna is divided into two parts, one is a cuboid antenna element fabricated on a FR4 printed circuit board, and the other is a grounded coplanar waveguide feed line fabricated on a motherboard. To minimize the size of the antenna element, we use three‐dimensional structure to design the antenna element. The

We demonstrate a 24 GHz hydrology radar system. The continuous‐wave Doppler radar is capable of noncontact and wide‐range surface‐flow velocity detection in various scenarios. The radar receives the reflected echo signal through a directional narrow‐beam antenna. After amplification and demodulation by the proposed low‐noise amplifier and the subharmonic down‐conversion mixer, respectively, the Doppler

A high sensitivity relative humidity sensor based on single mode tapered fiber (SMTF) structure coated with gelatin is reported. The sensing element is composed of a 12‐μm‐diameter fiber taper coated with a thickness of 26‐mm‐length gelatin layer, and is operated at a wavelength of 1550 nm. The sensor is designed based on the intermodal interference effect with high sensitivity (511.33 nW/%RH) and

In this letter, a study of a feeding technique applicable to cylindrical dielectric resonator antennas is presented. The feeding technique analyzed is based on vias glued at the lateral wall of the cylindrical resonator. A series of parametric studies, in terms of the orientation, position and dimensions of the vias, has been carried out to assess the sensitivity to imperfections of the fabrication