Recently, manipulation and measurement of quantum states, especially in quantum cavities, have attracted the attention of many researchers in different fields, such as: quantum optics, quantum information, quantum computation, and so on. In this paper a non-demolition method for the measurement of squeezing parameter via atomic Mach-Zehnder interferometer, is presented. An experimental setup was also proposed which included two quantum cavities, in different arms of an atomic Mach-Zehnder interferometer. Each quantum cavity was settled between two classical cavities. Quantum cavities were contained entangled states with arbitrary squeezed photons. It is shown that the outgoing atomic states of Mach-Zehnder interferometer carry on the properties and situation of quantum states of the cavities. The squeezing parameter of photonic state forone of cavities, is obtained by the detection of excited and non-excited probabilities of Mach-Zehnder interferometer's outgoing ports, for a train of incoming two-level Rydberg atoms.

A high isolation broadband dual-polarized omnidirectional antenna comprising two low profile orthogonally polarized omnidirectional radiating elements is presented. A modified monopole using loadings to broaden impedance bandwidth is applied to vertical polarization (VP), while four printed concentrically arranged Yagi-Uda-like antennas are employed for horizontal polarization (HP). Both the simulated and measured results indicate that the operating bands of the proposed antenna with its reflection coefficient less than -10 dB are 1.48 to 3.16 GHz for VP and 1.69 to 2.7 GHz for HP. A good port isolation larger than 40 dB and omnidirectional patterns with the out-of-roundness less than 2 dB in horizontal plane are obtained. This paper explains the radiation mechanism by investigating the simulated surface current distributions for VP element and establishing a radiation model for HP element, and also analyzes the performance of the proposed antenna. This antenna design can be applied to 4G (LTE) communication system.

Last decade has witnessed dramatic advancements in wireless charging distance of magnetic resonant coupling wireless power transfer (MRCWPT) for various portable electronic devices. Driven by the demand of cost-effective and compact system working for multiple receivers, a novel omnidirectional MRCWPT system with a single wire wound spiral transmitter and a single power source is proposed in this work. Besides, an equivalent circuit model is established to derive the power transfer efficiency (PTE) of this novel MRCWPT system. Finite element simulation results have shown that the magnetic field distribution for the proposed model is uniform in all directions. And the PTE of the system depending on the distance between the transmitter and receivers is demonstrated to be independent of the receiving angles. Finally, the theoretical analysis of the simulation results is verified by practical experimental results, which shows that the PTE of the system reaches 60% at the distance of 160 mm and the resonant frequency of 15.5 MHz.

Feature extraction is of significant importance for final results of the through-wall detection procedure. High resolution range profile (HRRP) is related to target reflectivity coefficients which can be used as a new feature for object detection. Compressive sensing (CS) is an emerging technique which enables a sparse signal to be recovered using much fewer measurements. This method can provide a novel way for achieving the HRRP since the target reflectivity coefficients are often known to be sparsely distributed in range cells. In this paper, after a set of input-output patterns that consist of target position and HRRP are obtained, through-wall detection problem is reformulated into a nonlinear regression one, which can be solved by support vector machine (SVM). Numerical simulations demonstrate that the prediction accuracy of target position is related to the number of range cells, the number of observations, and signal-to-noise ratio (SNR). Furthermore, the proposed method performs better than the one using signal amplitude as a feature in terms of smaller estimation error and shows better robustness against noise.

The ability to predict rain characteristics at small space-time scales is important, particularly in the planning, design, and deployment of wireless networks operating at frequencies above 10 GHz. For wide area networks, high space and time resolution rainfall data are often not available, and the cost of such measurements is prohibitive. This paper thus presents a new approach to address this problem using rain radar measurements to obtain rain estimates at finer resolutions than that available from the original measured data. This paper proposes three innovative methodologies: 1) the approach is not directly applied to measured rainfall rate data but focuses on the parameters of fitted lognormal distribution parameters and/or computed rain characteristics for each location; 2) to facilitate the application in wireless communication networks operating above 10 GHz, a set of databases and contour maps of rain parameters spanning North West Europe have been created. These conveniently and efficiently provide rain parameters for any location within the area under study; and 3) the proposed 3D space-time interpolation approach can extrapolate rain parameters at space-time resolutions that are shorter than those found in NIMROD radar databases. The results show that the approach presented in this paper can be used to provide {1 km, 5 mins} space-time rain rate resolution from {5 km, 15 mins} data for the whole North West Europe with error percentages of less than 4%. This is far superior to estimates provided by the International Telecommunication Union recommended model.

We propose a planar chiral metamaterial (PCMM), which can function as a triple-band polarization angle independent 90° polarization rotator. The unit cell of the PCMM is composed of bi-layered mutual twisted Fermat's spiral structure (FSS) resonators with four-fold rotation symmetry. The simulated and measured results show that the PCMM can work in triple-band and convert a linearly polarized (y-/x-polarized) wave to its cross-polarization (x-/y-polarized) or experience a near 90° polarization rotation with a polarization conversion ratio of over 90%. The electric field and surface current distributions of the unit-cell structure are analyzed to study its physics mechanism. Compared with previous CMM-based rotator, our design has more operation frequencies in a single PCMM structure, a relative thinner thickness, and higher Q-factor. Good performances of the PCMM suggest promising applications in the polarization rotator or convertor that need to be integrated with other compact devices.

Moving target ship imaging in large sea area has always been the focus of military and civilian attention. Due to the limitation of pulse repetition frequency (PRF), there is a contradiction between wide mapping band and azimuth accuracy. The nonlinearity of PRF can also cause discontinuity of mapping band. Therefore, this paper proposes a method of digital beamforming-scan on receiving (DBF-SCORE) beam scanning based on airborne phased array radar to achieve the requirement of scene mapping band with lower PRF. The adaptive Capon spectrum estimation is used to dynamically adjust the beam pointing so that it can always point to the moving target for accurate imaging. Considering the nonuniform sampling of the transmitting pulse period of the antenna, the azimuth nonuniform Fourier transform (NUDFT) algorithm is used to re-sample the nonuniform periodic signal of the multi-channel receiving antenna and obtain the uniform spectrum signal. Finally, fine focusing of moving target is achieved by local phase gradient algorithm (PGA) algorithm, and accurate imaging of moving target in large sea area is realized. The validity of the algorithm can be verified by simulation and real data imaging, which can be used for reference in phased array SAR imaging of moving targets.

An asymmetrical cross-shaped microstrip resonator is proposed. It is analyzed on its characteristic impedance and resonant conditions. A first order triband bandstop filter (BSF) and a second order triband BSF are designed using this resonator. Both filters are simulated on Sonnet Suite software. Simulation results show that both filters generate three stopbands at 2.0, 3.0, and 4.5 GHz. The second order BSF is also fabricated and measured using a microwave network analyzer. Simulation and measurement results on the second order BSF agree well.

In this paper, we demonstrate the design of a polarization-independent wideband absorber of light that consists of a perforated graphene sheet on top of a lossless dielectric spacer placed on a metallic reflector. The single layer absorber is duly designed based on impedance matching concept. The simulated results indicate that the structure produces 0.98 THz broad absorption from 1.80 THz to 2.72 THz with absorptivity larger than 90% at the normal incidence. The electromagnetic (EM) field distributions and the plots of surface power loss density have been illustrated to explain the absorption mechanism of the structure. The variation of chemical potential from 0.8 to 1.2 eV keeps 90% absorption bandwidth as much as 1 THz band. The polarization-insensitive feature and the properties under oblique incidence are also investigated. Finally, the interference theory is used to analyze and interpret the broadband absorption mechanism.

Due to the restrictions of low-resolution radar system and the influence of background clutter during the target detection, it is difficult to classify different kinds of low-resolution radar aircraft targets. In this paper, we propose a multifractal correlation method in the optimal fractional Fourier domain found by fractional Fourier transform (FrFT), in which we extract the multifractal correlation features of aircraft target echoes and do target identification combined with the support vector machine. The experimental results show that FrFT can enhance the multifractal correlation characteristics of aircraft target echoes; the multifractal correlation features extracted from the optimal fractional Fourier domain can effectively distinguish different types of aircraft; and the classification and recognition rates of the multifractal correlation method in the optimal fractional Fourier domain are higher than that of the multifractal correlation method in time domain and the multifractal method in the optimal fractional Fourier domain.

Rapid development of the electronic industry has increased the frequency of communication devices which lead to higher intensity of electromagnetic (EM) wave production. Too much exposure of EM wave can cause harm to health besides imposing disturbances in performances of other electronic devices. Hence, this research studies the structural and electromagnetic properties of materials that can act as electromagnetic shielding material at x-band frequency. Different compositions of magnetite powder/Fe₃O₄ (0, 10, 20 and 100 wt.%) were prepared to be dispersed in gypsum powders to form gypsum-magnetite composites. The structural properties of composites were characterized using Scanning Electron Microscopy (SEM) to observe homogeneity of the composites. The X-Ray Diffraction (XRD) was used to determine phase composition of the gypsum-magnetite composites. Scattering parameters of reflection coefficient, S₁₁, and transmission coefficient, S₂₁, were measured using Vector Network Analyzer (VNA). These parameters will be used to calculate the shielding effectiveness (SE) of gypsum-magnetite composite at x-band frequency. The results show that the total SE of the gypsum-magnetite composites were increased by adding magnetite powders.

The generation mechanism of the geomagnetic field perturbations associated with tsunami wave propagation in ocean is examined. The geomagnetic perturbations are produced by electric currents generated in both the seawater and conductive layers of the ionosphere. The electric current in conductive seawater is caused by the seawater motion due totsunami wave propagation whereas the current in the ionospheric plasmais generated by acoustic gravity wave (AGW) incident on the ionosphere from the atmosphere. The AGW is originated from vertical displacements of seawater surface due to the tsunami wave propagation. Although the ionospheric plasma conductivity is much lower than the seawater conductivity, the electric current in the ionosphere can be greater than that in the seawater due to an exponential increase of amplitude of the upward-propagating AGW. Our calculations are indicative of the possibility of space monitoring of tsunami wave based on onboard measurements of the geomagnetic field perturbations.

The aim of this paper is to present a model for a Composite Right-/Left-Handed (CRLH) distributed oscillator. A linear approach is used for the analysis of the circuit. The effects of the losses and of the parasitic elements, both present in the active devices and in the passive components, are included. Analytic formulas for the design of the transmission lines used in the oscillator are given. The model is validated by means of a comparison with previously published measured data.

A rigorous analysis of hexagonal slot with electromagnetically coupled parasitic element is presented in this article. The wide band feature of the antenna highly depends on the shape and location of the parasitic element and tuning stub. It is found that tuning and overlapping of resonating modes at lower frequency band are mainly achieved by parasitic element. The proposed antenna exhibits the bandwidth of 120.83% from 1.45 to 5.8 GHz for S₁₁<-10 dB. The parameters of the antenna and circuit model are studied. The role of individual resonators in circuit modeling is also explained. Series of equations for lower cutoff frequency and other resonating frequencies are deduced after inspecting the surface current distribution. At frequencies 2.27, 4.17, and 5.2 GHz, the simulated and measured far fields are compared.

This article describes multiresonance behaviour to achieve ultra-wideband (UWB) characteristics of a co-planar waveguide (CPW) fed circular patch antenna with a ground plane reflector by using fractal elements and rectangular defective ground structure (RDGS) technique. The patch consists of a circular disc with six ring type fractal elements on the periphery of the disc and slotted defective ground surface (DGS) at the bottom of an FR4_epoxy dielectric substrate to increase the antenna bandwidth. The antenna resonates at frequencies of 5.4 GHz, 9 GHz, & 10.8 GHz with return loss better than -20 dB. The proposed antenna also exhibits UWB characteristics with (≤ -10 dB) impedance bandwidth of 170.4% in the frequency range from 1.8 GHz to 11 GHz. This covers the whole UWB range from 3.1 GHz to10.6 GHz as defined by FCC. The antenna exhibits nearly omnidirectional radiation pattern and a gain ranging from 1 dBi to 6.8 dBi within the operating frequency range (1.8 GHz-11 GHz). An equivalent circuit model of the proposed antenna is developed, and the circuit response is obtained. All the measured results are found in good agreements with the simulated ones. The proposed antenna is suitable for applications in Wi-Fi, IEEE 802.11a Wireless LAN, WiMAX, ISM bands, wireless communications, etc.

Step-like perfect electric conductor (PEC) structures are studied in both electrostatic and electrodynamic cases implementing Method of Moments. The canonical geometries included in these step-like structures such as edges, wedges and corners as well as the unique charge and current behaviors are characterized and discussed. Both 2D and 3D electrostatic problems are studied. In 2D electrostatic problem, a constant is introduced to the traditional 2D Green's function which effectively adjusts the zero potential reference embedded in the Green's function. This modification alleviates the contradiction between 2D and 3D definitions of electrostatic quantities and avoids unrealistic charge solutions obtained by Method of Moments. In 2D electrodynamic problem, the occasional appearance of singular surface current near the step's right angle bends is observed, discussed and then linked with the analytical solution of a canonical wedge scattering problem. Physical Optics approximation is also utilized as a comparison to Method of Moments in solving the 2D scattering problems.

For most of space-frequency joint anti-jamming algorithms, the solution of adaptive steering vector is a high complexity problem. To solve this issue, a space-frequency combined anti-jamming algorithm based on sub-band energy detection (SF-SED) is proposed. At first, the algorithm performs fast Fourier transform (FFT) on the received data of the array antenna and obtains multi-snapshot data of each sub-band through sub-band decomposition. Then, the interference detection statistic and decision threshold are constructed by the energy of the sub-band to judge whether there is an interference in each sub-band. Finally, different methods are used to solve the adaptive weights of the two types of sub-bands according to sub-band classification results. Compared with the related work, the proposed algorithm not only has lower computational complexity, but also has higher output signal-to-interference-and-noise ratio. Theoretical analysis and simulation results demonstrate the anti-jamming performance of the proposed method.

Angular misalignment is an issue for many potential wireless power transfer (WPT) applications. This paper proposes a resonator as an effort to solve this issue. In the beginning, this paper gives an example of quantitative coupling analysis on angular misalignments. Then, it proposes an omnidirectional resonator for electromagnetic coupling WPT system. The proposed resonator is based on the structure of a regular polyhedron. It is constructed of four planar spiral resonators arranged as a regular tetrahedron. The coupling between the proposed resonator and a planar spiral resonator is verified. Both the simulated and measured results show that the coupling coefficient can be kept at a certain level when the omnidirectional resonator rotates around all x, y, and z axes regardless of the orientation of the planar spiral resonator respect to the omnidirectional resonator.

This paper designs, fabricates, and analyzes an inductively-tuned K/Ka band RF MEMS (Radio frequency micro-electro-mechanical-systems) capacitive switches. The MEMS switch employs a defect ground structure (DGS) and an air bridge. Two different MEMS switches, one with air bridges and the other not, are designed. Surface current distribution results of MEMS switches in different states are simulated and discussed. A novel actuation voltage's calculation approach of MEMS switch is proposed. Measured results indicate that the type MEMS switch's actuation voltage is 20 V. For the MEMS switch without air bridges, the isolation is more than 15 dB at 12.5~20 GHz, and the insertion loss is less than 0.28 dB up to 20 GHz. For the MEMS switch with integrated air bridges, the isolation is more than 15 dB at 18.3~40 GHz, and the insertion loss is less than 0.64 dB up to 40 GHz. Circuit models and measured results of the proposed MEMS switches show good agreements. The pull-in and release time of this switch are 99 μs and 49 μs, and the lifetime of this type of switch is more than three million.

Two dual-band microstrip antennas with filtering responses are proposed in this letter. By introducing symmetrical slots (One is a U-shaped slot, and the other is an inverted H-shaped slot) at the edge of rectangle patches, additional resonant modes are induced, and both of the antennas have dual operation bands. More importantly, extra radiation nulls are observed between the two bands. In addition, the proposed antennas are fed by microstrip lines with two pairs of symmetrical open stubs, which offer two more radiation nulls at low frequencies. Thus, dual-band filtering responses for the proposed antennas are obtained. Simulated and measured results show good agreements with unidirectional radiation patterns, as well as high selectivity of realized gains.