A co‐axial waveguide is filled with an anisotropic hyperbolic medium that has a radial negative component of the tensorial permittivity and permeability. This waveguide has no cutoff frequency for propagating transverse electric and transverse magnetic modes. These modes of propagation are described by Bessel functions of first and second kinds (Neumann function) with an imaginary order. This feature

We present a novel and simple scheme to generate high‐quality V‐band (50‐75GHz) vector millimeter‐wave (mm‐wave) based on dual‐parallel Mach‐Zehnder modulators (DPMZM) without resorting to adopting optical filter and precoding. By controlling the bias voltage of the DPMZM and phase shift between the two beams of each sub‐MZM, we can obtain a higher frequency optical vector mm‐wave signal. We have discussed

A fiber optical curvature sensor comprising a concave‐heterotypic cascaded fiber structure built into Sagnac loop is demonstrated experimentally. A section of multimode fiber is sandwiched between the single mode fiber and polarization maintaining fiber in order to construct the concave‐heterotypic cascaded fiber structure. The concave structure presented is used to effectively excite guided modes

In this article, the design of a miniaturized planar antenna using defected ground structure (DGS) and meander line structure for C and X‐band applications is presented. A novel star‐shaped and a rectangle DGS created on the ground plane of lambda/4 fed planar antenna and its effect on the size reduction performance is analyzed. Initially, a simple basic antenna (antenna‐1) operates at 14.9 GHz with

A novel wideband back‐to‐back microstrip‐to‐air‐filled substrate integrated waveguide (AFSIW) transition with controllable band‐pass performance is presented. The wideband transition is constructed by a gradient microstrip and a section of widened partially dielectric‐filled AFSIW. The sharp rejection performance above the pass band is achieved by taking advantage of the notch characteristics of the

In this letter, a new method is proposed to achieve high port isolation and wideband harmonic suppression for two closely placed asymmetric antennas by using integrated filtering structures cascaded on the feeding microstrip lines. The proposed asymmetric antenna pair operates normally at 2.34 to 2.6 GHz and 3.31 to 3.69 GHz, respectively, containing the WLAN band (2.4‐2.484 GHz) and the fifth generation

This article presents a dual notched ultra‐wideband (UWB) bandpass filter (BPF) with good frequency characteristics realized on a low‐cost dielectric. The proposed structure is based on the surface‐to‐surface transition technology, with microstrip lines aligned face‐to‐face on the top, and short‐circuited butterfly shaped coplanar waveguide (CPW) in the ground. The microstrips and CPW are coupled vertically

A simple plastic optical fiber displacement sensor has been demonstrated as a non‐contact color detection device. The sensitivity of the sensor is 0.0228, 0.1718, 0.1122, 0.106, and 0.1267 mW/mm for black, blue, green, red, and white, respectively. The experimental results prove that as the color changes from dark to bright, the peak output power increases proportionally. The proposed sensor is highly

In this study, a wideband right‐handed circularly polarized (RHCP) array of microstrip patch antennas, for direct broadcast satellite (DBS, 12.2‐12.7 GHz) services have been presented. The single element of the array is a two‐dimensional mushroom‐shaped fractal antenna of resonating frequency 12.49 GHz and an impedance bandwidth of 1.12 GHz. The proposed single element is designed by etching a pair

This article presents a dual‐band shared‐aperture antenna. The lower‐band antenna consists of two printed dipoles operated in a 1.6‐2.4 GHz frequency band. An artificial magnetic conductor (AMC) is used to reduce the lower‐band antenna profile. The higher‐band antenna consists of 4 × 2 aperture coupling patches operated in 5.3‐7.1 GHz frequency band and placed between the antenna ground plane and the

A narrow‐band bandpass filter (BPF) based on parallel coupled lines and shorted stubs with very wide upper stopband has been presented. The transmission coefficient and reflection coefficient of the proposed BPF are straightforwardly derived via the input impedances using odd‐ and even‐mode analysis method. The calculation results illustrate that two narrow passbands with very high frequency ratio

A tunable bandpass filter with switchable single‐/dual‐band responses is presented. The single‐band to dual‐band transformation is achieved by controlling frequencies of poles in a passband. The frequencies of poles are adjusting by using a coupled structure with two coupling capacitors. A filter with both 4‐pole single‐band and 2‐pole dual‐band characteristics is built on a Duroid substrate with ε

A compact passive intermodulation calculation method for the nonlinear source with noticeable size is proposed and demonstrated. By approximating the transmission factors of linear carrier and nonlinear passive intermodulation to be the non‐dimensional ratios between the current and power based on the reciprocal calculation principle, the PIM synthetize on a nonlinear source with notable size can ignore

We demonstrate a compact, all‐fiber Q ‐switched hafnium bismuth erbium co‐doped fiber laser based on bismuth‐doped fiber (BDF) as the saturable absorber (SA). The laser cavity was constructed using a homemade hafnium bismuth erbium co‐doped fiber as gain medium. It was found that stable Q ‐switched pulses operating at 1531.74 nm can be readily generated when the 980 nm pump power is raised above the

This article presents a metal cavity‐backed antenna array with high gain and high radiation efficiency. The proposed antenna can be used for the purpose of thermal management. A 28 GHz linear polarized antenna is implemented on a low cost substrate with an aluminum structure that functions as a heat sink. Each antenna element is connected to integrated circuits with a stripline embedded in the printed

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 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

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

A novel wideband filtering dual‐patch antenna with a flat gain response is presented in this letter. This filtering antenna mainly consists of two parts: two patches and an F‐shaped feeding structure. The upper and lower patches are fed by two different horizontally placed narrow strips from the F‐shaped structure. Two patch modes are simultaneously excited within the passband, yielding a 29.3% bandwidth

This article embodies the design and analysis of a novel triple‐band single‐fed circularly polarized (CP) antenna for C‐ and X‐band applications. The proposed antenna covers downlink frequency of C band (3.7‐4.2 GHz) and X band (7.25‐7.3 GHz) for satellite applications. The antenna radiator comprises of F‐shape radiating patch with 50 Ω microstrip feed line. The square strips, slit, and rectangular

A novel resonance method for accurate determining a complex permittivity of the samples over the entire X‐band is proposed. This method uses the difference in the resonant mode perturbation when the sample moves in the field of standing wave of a rectangular resonator thereby leading to changing resonance frequencies and the amplitudes of resonant modes for each position of the sample in the resonator

In this paper, a dual‐polarized antenna that can be used in the 1.7‐2.17 GHz band is proposed. The proposed antenna is a dual‐polarized antenna with parasitic element; it has improved isolation property. The isolation of antenna arrays appears as a synthesis of the isolation of single element and the isolation of adjacent element. The isolation of the antenna array was improved by placing a parasitic

A diamond‐shape stub is proposed to enhance the bandwidth of a resonant type comb‐line array at 60 GHz. For linear polarization, a vertical slit is adopted and its optimal length is determined. Design graphs for the input impedance, quality factor (Q ), and the resonant length of a single cell are presented. A simple demonstration is given that the Q of the array could be reduced by designing a stub

Over the last decade, the wearable electronics has greatly improved and the wearables market is expected to increase exponentially in the next years. Ultra high frequencies (UHF) radio frequency identification (RFID) textile yarns represent one of the most relevant solutions for adding smart functionality into clothes and more generally for any object integrating a textile tag. Among the existing textile

An all‐metal beam scanning metamaterial antenna with polarization transform based on the concept of Risley prism is presented in this paper. The antenna is composed of a feed source and three different all‐metal metamaterial lenses. Each lens consists of numerous cross‐slot metamaterial elements. A full transmission phase range of 360° can be achieved for a transmission efficiency over 99% at 14.25 GHz

A K‐band 4‐channel transmitter IC with fully differential architecture is presented in this paper for beamforming phased‐array system. This IC uses commercial 65 nm CMOS technology. The major building blocks of this IC are 3‐stage medium power amplifiers (MPAs) with resistive feedback network to control the gain, 6‐bit phase shifter with tuning bit, 15 dB attenuators, 4‐way power divider consisting

A novel low‐radar cross section (RCS) microstrip antenna with radiation performance and antenna volume maintained is proposed in this paper. Different from other antenna RCS reduction methods, the proposed antenna applies shaping method on frequency selective surface (FSS) ground plate to achieve further RCS reduction. In order to obtain the effect of subtracting square slots, an antenna with normal

Based on the self‐consistent nonlinear theory, a W‐band continuous wave 30 kW fundamental harmonic gyrotron oscillator is designed and simulated. With a 30.0 kV, 3.0 A electron beam, the output power of more than 35 kW is obtained and the maximum electronic efficiency is equal to 40.3%. The effects of electron beam voltage, beam current, magnetic field intensity, guiding center radius, and velocity

Energy saving and reduction in the emission of carbon dioxide, sulfur, etc. have become one of the prime focus for the deployment of next generation networks. Due to less power consuming, passive optical networks are the best promising solution for such networks. We have proposed different aggressive schemes to reduce the energy consumption viz. no buffer, with buffer, reduced buffer, and reduced buffer

In this letter, a compact multi‐input multi‐output antenna operating at 3300 to 6000 MHz band is presented for 5G mobile terminals. The antenna includes four vertically placed blocks. Each block consists of two driven monopole elements and one parasitic ground branch. The parasitic branch is shared by both elements. It not only serves as radiator, but also is helpful to improve the port isolation in

A continuous‐wave (CW) Doppler radar using two‐tone frequencies is presented for the measurement of short‐range distance. The envelope detection method is proposed to discriminate each frequency signal in the output waveform of the two‐tone CW Doppler radar sensor. The phase difference in each frequency is obtained from the nonlinearly demodulated I/Q baseband signals, following calibration of the

In this research paper, a isosceles triangular radiating patch with two triangular coplanar parasitic elements has been used to design a compact circularly polarized (CP) microstrip patch antenna that can be used for (2.320‐2.345 GHz) satellite digital audio radio systems (SDARS), (2.30‐2.39 GHz) wireless broadband (WiBro), LTE 2300 (2.3‐2.4 GHz), and WIMAX (2.50‐2.69 GHz) application band. Corners

In contrast to most of the previous publications that has addressed the dependency of the defect mode on temperature in planner one‐dimensional photonic crystal, we study this dependency in cylindrical photonic crystal taking into consideration both thermal‐optical and thermal expansion effects. Our analysis, based on the cylindrical transfer matrix, is conducted for both types of polarized electric

Free space optical (FSO) communication has gained significant popularity in recent years due to large bandwidth, license‐free spectrum, high data rates, less power consumption, and low mass requirements. However, system performance strongly depends on atmospheric conditions and ambient noise. In this letter, the duobinary modulation technique is applied and the system performance is investigated in

A wideband and compact rat‐race coupler that covers 3 to 5 GHz is proposed for the fifth‐generation new radio N77/N78/N79 applications. The wideband characteristic is obtained by using cascaded two‐section topology and broadside‐coupled lines at each input/output port. Miniaturization of two‐section rings is achieved using meander microstrip lines. A fractional bandwidth of 50% and a size reduction

When the thin wire whose orientation cannot be parallel to Cartesian axis is modeled by the finite‐difference time‐domain method, the staircasing introduce numerical errors and nonphysical phenomenon. In order to reduce the influence on the induced current, a loaded technique is proposed. The lumped elements are matched at the grid corner based on the contour‐path model. All the electromagnetic difference

A wideband bipolar low‐noise amplifier (LNA) with enhanced linearity operating in 0.5 to 6 GHz frequency range is proposed in this letter. The LNA design is based on a cascode amplifier with an emitter degeneration RC parallel network and a resistive shunt‐shunt feedback which can improve linearity. The cascode topology in conjunction with the preceding series inductor L is utilized to achieve good

In this study, a single layer reflectarray antenna is proposed with variable patch sized unit cells and suggested for enhancing the bandwidth with small overall dimensions for X‐band applications. The novel unit cell consists of double cutted ring geometry. 13 × 13 unit cells reflectarray is covering an 162.5 × 162.5 mm2 ultrathin square substrate with εr = 6.15 dielectric permittivity and 0.042 × λ0

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

A compact monopole antenna with enhanced selectivity is designed based on circular disk monopole antenna and signal interference technique (SIT). It is composed of a circular disk monopole and a SIT‐based filtering structure consisting of two pairs of short‐circuited edge coupled stubs loaded on the feeding line. When the filtering structure is just loaded the feeding line, a filtering monopole antenna

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

In this paper, we propose a method of designing broadside radiation antennas using metamaterial resonators. The antenna consists of a feeding probe and a nested metamaterial resonator (MR), where the latter is located in the near‐field zone of the former and both of them stand on the metallic ground. The nested MR, where a finite‐length comb structure (CS) is circled by a broadside‐coupled split‐ring

In this letter, the characteristic basis functions (CBFs) are utilized to enhance the compressive sensing (CS) technique to analyze the bistatic scattering problems of three‐dimensional targets. The CS technique can efficiently analyze the bistatic scattering problems by establishing an underdetermined linear equation instead of traditional full‐rank dense impedance matrix equation. However, the CS

This article presents a three‐stage 25 to 30 GHz linear CMOS power amplifier (PA) for fifth‐generation (5G) applications. In order to improve the linearity by compensating AM‐AM/AM‐PM distortion, we propose a driver stage RF predistortion technique in which a first drive amplifier (DA) operates in class C mode and a second DA operates in class A mode. By enhancing the linearity with the technique,

A surface‐mount bowtie antenna element with a ball grid array (BGA) packaging is proposed. Compared to a two‐dimensional end‐fire antenna, the proposed surface‐mount antenna element is a discrete three‐dimensional structure for obtaining a broadside radiation pattern. The proposed antenna element is mounted on the motherboard and fed by the balun located at the bottom layer of the motherboard to obtain

A X‐band aperture‐coupled patch antenna based on backed substrate integrated cavity (SIC) and pins‐loaded cross slot with dual linear polarization and high isolation is investigated. Loaded pins are applied to cross aperture to reduce the mutual coupling between the slots. SIC is used to reduce the coupling caused by parallel plate mode. Moreover, one‐cross‐point structure of feed networks is used

This paper presents a CPW‐fed novel structure of dual‐band and dual‐polarized planar antenna consisting of protrudent‐shaped radiator and spiral‐ and cross‐shaped strips loaded ground plane for GPS L1 and SDARS band applications. The right hand circular polarization at GPS L1 and left‐hand circular polarization at SDARS bands were excited by attaching cross‐ and spiral‐shaped strips to the ground plane

This paper presents a wideband high‐gain dual‐circularly‐polarized (CP) antenna with a simple configuration. Instead of improving the gain using the dual‐CP element array, the Fabry‐Perot resonator antenna concept is applied in this work. By designing a dual‐linearly‐polarized Fabry‐Perot resonator antenna and a linear‐to‐circular polarization (LP‐CP) metasurface polarizer separately and combining

A dual notched band MIMO‐UWB antenna is presented in this article. High isolation between radiating elements is achieved with novel elliptical T‐shape stub and dual bands are notched with the help of a novel G‐shape stub; extended from ground plan. The proposed antenna is resonates between 3 and 11 GHz. The size of antenna is 18 × 36 × 1.6 mm3. The antenna is evaluated in term of isolation, envelope

In this article, an improved layout design and a base‐collector undercut etching process have been proposed and demonstrated for a high‐speed InP/InGaAs heterojunction bipolar transistor (HBT). The fabricated HBT using proposed methods has a smaller parasitic base‐collector (B‐C) area, resulting in reduced B‐C capacitance (CBC), a reduction of 36% compared to that in the conventional HBT. A current

A planar, compact UWB MIMO antenna with four elements that accomplish band rejection from 4.91 to 6.41 GHz is presented. Rejection is accomplished using an L‐C stub connected to the ground plane. The length of the stub is changed to reject the band starting from 2.5 GHz to above 8.8 GHz. The perpendicular placement of the elements enables polarization diversity and attains high isolation. Elements

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 g2 (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

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

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 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

Heatsinks are widely utilized to maintain the temperature of the electronic circuit components on the printed circuit board (PCB) within a certain range. Even they are thermally used for maximum cooling; they can also act as a source of electromagnetic (EM) radiation, causing EM interference (EMI) to their surrounding elements in certain cases. In this article, the heatsinks with various fin types

A new scalable small‐signal model for 0.1 μm AlGaN/GaN HEMT up to 110 GHz is presented in this paper. The taps between the gate/drain manifold and fingers on the device has been investigated and included in the equivalent circuit. In addition, to ensure high scalability, a set of scaling rules are presented. A novel extraction procedure for extrinsic capacitances using full‐wave electromagnetic (FW‐EM)

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