A broadband artificial material composed of non-resonant parallel-line unit cells is proposed to enhance the gain an antipodal tapered slot antenna (ATSA). The material, whose effective refractive index lower than that substrate on which printed, will act as a regular lens in beam focusing. In order investigate enhancement effect combination with ATSA made by locating front antenna. Simulation results indicate has been enhanced significantly and increasing dimension radiation direction leads...

This letter presents a broadband cavity-backed circularly polarized (CP) crossed-dipole antenna encircled by novel asymmetrical cross-loop. By using the single parasitic cross-loop, has simple structure and compact configuration. More importantly, it produces additional two CP modes. The suitable combination of crossed dipole crossloop provides operation. measured results show that proposed with an overall dimension 1.1λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

An ultrawideband (UWB) full-metal planar array antenna based on a combination of ridge gap waveguide (RGW) and E-plane groove (E-GGW) is presented for millimeter-wave (mmWave) applications. First, the radiation element double-step double-ridged slot structure proposed designed. By removing vertical walls cavity in H-plane, impedance matching characteristics presents UWB bandwidth 53%. Second, double-layer feeding network achieved by combining RGWs double-side-pin E-GGWs elements. Finally, an...

A 4 × wideband millimeter-wave (mmWave) slot array antenna excited by the TE440 mode based on groove gap waveguide is presented in this paper. vertical located center of cavity and two ridges are used to excite mode. In addition, a pair corrugations acting as soft surface added top improve gain. prototype fabricated measured. The measured simulated results great agreement. show that proposed achieved an impedance bandwidth (|S11| &lt; −10 dB) 26.7% from 26.14 34.2 GHz, maximum gain 17.7 dBi....

A novel flat lens antenna using double-ring slot element is presented. Compared to those conventional high-gain antennas, the proposed can realize greater flexibility in installation with less manufacturing complexity. prime-focus 49-element prototype elements has been fabricated and measured. The highest measured gain 16.7 dBi at center frequency of 6 GHz, a relative bandwidth 15% achieved within 3-dB variations. All experimental results demonstrate that be used as an optimum airborne future.

In this letter, a wideband millimeter-wave (mmWave) planar array antenna with printed ridge gap waveguide (PRGW) feeding network is presented. A bowtie fed by the PRGW employed as radiation element which combines an upside-down electromagnetic bandgap part using lamination. Thus, new structure, proposed achieves stable, wideband, and high-antenna-efficiency performance. prototype of 8 ×8 fabricated measured. The measured results show that has impedance matching bandwidth (|S <sub...

A simple multilayer unit cell has been discussed for circularly polarized transmitarray applications in this letter. This element consists of three layers identical substrates. Each substrate is printed by two sets parallel dipoles orthogonal directions on the opposite sides to realize a proper phase difference. The transmission coefficients have studied balance magnitude against Then, dipole dimensions are analyzed obtain satisfactory transmission. prototype 137 elements designed,...

A novel reflectarray (RA) with ultralow-profile and 2-bit phase quantization beam-steering ability is presented in this article. To reduce the profile, a Leaky-wave feed used to excite RA enhanced illumination efficiency. Moreover, simultaneous sum difference patterns are also obtained provide beam flexibility. The entire thickness of proposed less than 3&#x0025; that conventional front-fed same aperture. increase efficiency RA, unit cell consisting polarizer layer reflection developed,...

A tightly coupled bowtie array antenna at a millimetre‐wave band is presented in the study. The has simple structure and exhibits high performance over an ultra‐wide bandwidth. feeding network designed by using dielectric‐based inverted microstrip gap waveguide technology order to have compact layout. An 8 × planar prototyped. measured results show that proposed achieved overall bandwidth of 55.7% from 18.7 33.15 GHz. maximum gain 21.8 dBi 32.5 GHz, total efficiency above 40% through whole

In this article, a novel design of broadband circularly polarized (CP) folded reflectarray (FRA) antenna is proposed. The CP FRA consists two kinds metasurfaces (MSs) and linearly (LP) open waveguide as the feeding source. bottom MS functions main reflector, which capable realizing cross-polarization conversion beam focusing simultaneously. upper utilized subreflector, could reflect LP wave coming from source transmit its orthogonal counterpart into wave. For demonstration, MS-assisted...

In this work, we fabricate the Mo0.5W0.5S2 by microwave-assisted solvothermal method, and report Q-switched Yb-doped fiber lasers (YDFL) using polymer film tapered as saturable absorbers (SAs). The modulation depth intensity of SA are 5.63% 6.82 MW cm-2. shortest pulse duration maximum single energy 1.22 μs 148.8 nJ for SA, 1.46 339 fiber-taper SA. To best our knowledge, is first on YDFL SAs.

Based on the finite-difference time-domain (FDTD) method, this paper investigates feasibility of using ultra-wideband short-pulse (UWB SP) radar to provide through-wall surveillance. High fidelity data are generated by use FDTD where a two-dimension room with concrete walls is modeled. A space-time domain image-generation algorithm, back projection (BP) utilized transform raw into images. The velocity change in propagation wall alters travel time between transmitter, target, and receiver....

A time-domain beamformer using ultra-wideband short-pulse (UWB SP) signal for through-wall imaging (TWI) applications is proposed in this paper. The impact of the wall on performance radar imaging, such as wave refraction and velocity change, considered design beamformer. Proof verifying provided finite-difference (FDTD)-simulated high fidelity data. Simulation results demonstrate that hidden targets behind can be located accurately both range angle by presented

In this paper, we present a flexible, breathable and optically transparent metasurface with ultra-wideband absorption. The designed double layer of indium tin oxide (ITO) films specific carved structure realizes absorption electromagnetic (EM) isolation in dual-polarization, as well good air permeability. Under the illumination x- y-polarization incidence, has low reflectivity transmission from about 2 to 18 GHz. By employing ITO film based on polyethylene terephthalate (PET), presented also...

In this paper, we report two different saturable absorbers based on WS2 film and Bi2Te3 with similar preparation processes. A high-energy stable Q-switching pulse is achieved in identical cavity configurations for each absorber. modulation depth of 10.17% a maximum single energy 56.50 nJ are obtained when employing the film. However, using obtain higher 23.04% larger 61.80 nJ, dual-wavelength operation was shown at pump power 92 mW.

A Ku broadband OMT for satellite communication applications is designed. This consists of a stepped double ridged waveguide junction, power combiner and an axial branch. It similar to that Bøifot but has no septum pins which increase the complexity structure. The with size 42×44×100 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> can cover from 10.44 GHz 14.93 (35.4% bandwidth). return losses are better than 27 dB isolation greater 70...

A passively Q-switched Er-doped fiber laser based on a novel transition metal sulfide (TMDs) Mo0.5W0.5S2 absorber is reported for the first time. There are two different types of Mo0.5W0.5S2-based saturable absorbers (SAs) that achieve Q-switching operation, one which depositing surface tapered fiber, and maximum single pulse energy 172.91 nJ minimum width 1.42 µs obtained. While other transferring Mo0.5W0.5S2-PVA(polyvinyl alcohol: PVA) SA film onto standard FC/APC end face, high 246.5 1.92...

Numerous studies for non-circular signals are being conducted to improve the performance of systems. However, Non-Circular MUSIC (NC-MUSIC) method include mostly uniform linear arrays and not as much effort has been devoted other configurations. This paper extends Non-circular rectangular array. The simulation shows NC-MUSIC a higher resolution structure array significantly influence on method.

Abstract A simple printed monopole antenna using parasitic loops and defective ground plane is presented for broadband circular polarized (CP) radiation. For this purpose, two square open loops, which install air gaps at the corner close to monopole, are on both sides achieving CP radiation with three minimum axial ratio (AR) points. By a vertical slot horizontal slot, additional AR points can be excited further broaden bandwidth. This design was fabricated, measured results show that...

This paper presents a novel approach to reducing radar cross section (RCS) using 2D multi-layer Van Atta array based on the phase cancellation principle. By controlling of transmission lines wideband shifters, proposed can achieve significant RCS reduction at wide frequency range 8 GHz 11 GHz. Both theoretical calculations and experimental measurements were conducted evaluate performance with shifters. Results showed from various incident angles, demonstrating effectiveness design in...

A dual-frequency retrodirective array is proposed. By using two separated antenna arrays and double balanced passive mixers, the proposed system can achieve retrodirectivity in a bidirectional way. The low-frequency interrogating signal be retransmitted at high frequency, it also work reverse order. has advantages of low cost isolation between retransmitting signals. characteristic make very useful two-way communication system. four-element prototype designed fabricated. Measured results...

A double-layer 2-D monopulse substrate integrated waveguide (SIW) slot array antenna using cavity resonators is proposed in this paper. resonator employed to generate the sum and difference signal at output ports when different input are excited. Then a comparator built up by combining three power divider, which shows simple structure. The simulated results show that achieves an impedance bandwidth (|S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML"...