In this paper, for the very first time, a general algorithm for designing rectangular microstrip patch antenna, partially loaded with SNG (Single Negative) (MNG (µ Negative) and ENG (ε Negative)) metamaterial has been proposed to achieve better radiation performance. Then, applying our proposed algorithm, theoretically we have predicted novel dual band miniaturized rectangular patch antennas (loaded with MNG metamaterial) for two different bands using unconventional interface resonance mode under fundamental TM010 mode. Then we have proposed a complete design of magnetic inclusions, presenting full wave numerical simulations of the structure, which effectively supports the theoretical expected resonant modes as well as satisfactory radiation pattern performance. Prior to our current work, impossibility of sub-wavelength or electrically small rectangular patch antenna has been demonstrated using ENG metamaterial. However, in this paper, we have indicated a direction towards the real-life implementation of possible miniaturized rectangular patch antennas partially loaded with MNG metamaterial. The algorithm proposed in this paper is the key to choose the appropriate material parameter to design all such antennas.

This study investigates possible lightning threats to naval crafts, especially those sailing in the shallow waters of tropical oceans where thunderstorms prevail throughout the year and Far-East Asian region where dangerous positive lightning is a significant characteristic in winter thunderstorms. It is empathized that sea water acts as nearly a perfect conductor thus lightning electromagnetic transients propagate over the sea with almost zero attenuation of amplitude and high frequency components intact. The ratio between the peak electric fields at 5 km from the lightning channel, after fields propagate over dry soil and over sea water is 0.75. The ratio between the peak electric field derivatives under the same conditions is 0.1. Such small ratios are observed in the magnetic fields and their time derivatives as well. Apart from the conductivity, the topological irregularities of the plane over which propagation takes place also contribute to further attenuation of fields and their time derivatives. This makes marine naval systems more vulnerable to lightning induced effects than their ground-based counterparts. The paper discusses in detail the lapses of existing naval standards in the defense of electrical and electronic systems against both direct lightning currents and induced effects of nearby lightning. Consequently we propose the development of a dedicated standard for the lightning protection of naval systems, with the inclusion of several significant recommendations specified in this paper.

A multimode Brillouin Erbium Fiber Laser BEFL, at 1550 nm band, with in-cavity intensity modulation is demonstrated. The output of the laser is in the form of nanosecond pulses. The longitudinal mode separation is increased, which results in both reducing the number of oscillation modes and, at the same time, changing the output pulses repetition rate to be multiples of the round trip cavity frequency. It is also demonstrated that the number of modes is greatly reduced by the combination of active mode locking and the group velocity dispersion arising from the change in the refractive index at each mode due to the change in its gain within the Brillouin gain bandwidth. A case of a quasi single mode is reached where the output is nearly CW with very low sinusoidal modulation index.

This paper presents a high speed configurable FPGA-based wideband channel sounder with signal bandwidths up to 200 MHz and results of a study of dynamic urban picocell channel. The use of FPGA allows the sounder to be adaptable for measurements in different scenarios. Adaptable options include changes to the waveform, bandwidth, channel sampling rate and real-time averaging to improve signal-to-noise ratio in weak signal conditions. The implemented architecture has led to a 70% reduction in size and weight compared to sounders in use elsewhere making it ideal for mobile channel measurements. The study of an urban picocell channel has shown that dynamic variation due to automotive traffic introduces average signal strength fades of up to 5 dB but causes frequency selective fading with depths of up to 40 dB. Existing channel models assume antenna heights of more than 6 m and path lengths of more than 30 m. Therefore there is a need for shorter path models and this paper proposes a linear picocell channel model for static and dynamic urban environment.

Applying four-dimensional differential-form formalism, a novel class of electromagnetic media, labeled as that of P-media, is introduced in terms of a simple rule. It is shown that it is not possible to define the medium by expressing D and B in terms of E and H, whilst using 3D Gibbsian vectors and dyadics. Moreover, the basic properties of P-media are shown to be complementary to those of the previously known Q-media, which are defined in a somewhat similar manner. It is demonstrated that, for plane waves in a P-medium, there is no restriction to the wave one-form (corresponding to the k-vector). Importantly, the uniaxial P-medium half space also leads to another realization of the recently studied DB boundary conditions. Finally, a generalization of the class of P-media is brie y discussed. It is shown that the dispersion equation of a plane wave in the generalized Pmedium is decomposed into two conditions, each of which corresponds to a certain polarization condition. This occurrence resembles the behaviour of the generalized Q-medium.

We present an efficient way to generate the inverse synthetic aperture radar (ISAR) image of a target at an arbitrary aspect angle using the shooting and bouncing ray (SBR) method, which is much faster than the conventional approach by inverse Fourier transforming the computed scattered fields over frequency and aspect domain. We propose a general image-domain ray-tube integration formula, which contains aspect-dependent factors. The new formula can provide ISAR images of a target rapidly and conveniently in different image planes at different aspect angles in a world coordinate system. The ISAR images of a cube and an aircraft for several aspect angles and different image planes are presented to demonstrate the efficiency and accuracy of the general formula. The proposed method is more significant when large amount of ISAR images of a target are required to build the database for target recognition.

A novel compact square slot antenna design with coplanar waveguide (CPW)-fed for dual-band operation is presented. The proposed antenna is simply composed of a square slot resonator and a monopole radiator. By employing the special square slot structure, the antenna can achieve a new resonance while maintaining a small size. Based on this concept, a prototype of dual-band antenna is designed, fabricated and tested. The experimental results show the antenna has the impedance bandwidths of 400 MHz (2.33-2.73 GHz) and 1020 MHz (3.27-4.29 GHz), covering both WiMAX in the 2.5/3.5 GHz bands and WLAN in the 2.4 GHz band.

In this paper, a reflectarray antenna composed of a combination of double-petal loops of variable size is presented. To evaluate the performance of the designed element, a parametric study is carried out using Ansoft HFSS. For the optimal parametrics, the proposed structure shows an almost linear behavior, while the phase range is in excess of 500°. Then, a prime-focus 77-element reflectarray with this type of element has been designed and implemented. The measured results show that the obtained 1-dBi gain bandwidth of the reflectarray with double-petal loop elements can reach as large as 25% and the highest gain is about 19.3 dBi. Compared with the existing single layer elements (cross and rectangle loop, double rings, etc), microstrip reflectarray with this double-petal loop element can obtain a larger bandwidth.

The major objective of the study was to assess the safety of electric line workers exposed to of a double circuit 132 kV transmission line for different scenarios. The double circuit 132-kV, 60 Hz transmission line has a power rating of 293 MVA and a maximum recorded peak load current of 603 A. The charge simulation and the Biot Savart methods were used by EPRI workstation software to compute the external electric and magnetic fields around a 132 KV transmission line. We used the calculated external electric and magnetic field exposures to determine the induced electric field and induced current densities inside the human body. This was performed using the Finite Difference Time Difference computational algorithm in EMPIRE commercial software, with a 6 mm voxel resolution. We used the Visible Human (VH) to investigate the internal induced electric field and circulating current densities in more than 40 different tissues and organs of the VH. We found that the worker exposure levels to extremely low frequency electromagnetic fields are below the recommended IEEE international standards limits for the studied scenarios. In all scenarios the maximum induced current densities and electric fields were in the bone marrow of the feet.

In this paper, the application of compact non-uniform transmission line transformers (NTLTs) in suppressing and controlling the odd harmonics of the fundamental frequency is presented. A design example showing the complete suppression of the odd harmonics of the fundamental frequency is given. In addition, several compact NTLTs are designed showing the possibility of controlling the existence of a fundamental frequency's odd harmonics. Moreover, multi-band operation using NTLTs is investigated. Specifically, a design example of a miniaturized triple-frequency NTLT is introduced. Based on these compact NTLTs, a 3-way triple-frequency modified Bagley power divider (BPD) with a size reduction of 50%, and a 5-way modified BPD with harmonics suppression and size reduction of 34%, are designed. For verification purposes, both dividers are simulated using the two full-wave simulators IE3D and HFSS. Moreover, the modified 5-way BPD with harmonics suppression is fabricated and measured. Both the simulation and measurement results validate the design approach.

In this study, a very compact, second-order, full differential bandpass filter is presented. To achieve compact circuit area and system-in-package (SiP) applications, the transformer structure is integrated using integrated passive device (IPD) technology on a glass substrate. The coupled resonator synthesis method is used to achieve the bandpass filter design and suitably adjust the tapped feed-lines to obtain good impedance match at all ports. The area (1.27 mm×1.27 mm) of the bandpass filter is effectively reduced, and the performance, as measured by insertion loss (2.5 dB) and CMRR (>30 dB), is still acceptable with such a compact area. Most importantly, this full differential bandpass filter is also suitable for SiP applications, as other studies implemented using glass IPD technology have demonstrated.

After being modulated by a periodic signal, the pulse compression result of the modulated LFM (Linear Frequency Modulation) may have many isolated and sharp peaks. According to this phenomenon, we developed a strip-map SAR (Synthetic Aperture Radar) jammer which modulated both the SAR's fast and slow time LFMs with periodic waveforms. This kind of jamming can forge isolated and bright points in the SAR image, and may confuse the SAR's image processing. The structure of this kind of jammer is simple and easy to be designed comparing to that of a traditional jammer utilizing the coherent jamming. Also it only needs much lower transmitted power than a noise jammer. Finally, the jamming experiences were conducted by utilizing a railway SAR, and the SAR imaging results showed the effectiveness of this kind of jamming.

A novel TM₂₁-mode circularly polarised (CP) annular-ring microstrip antenna (ARMSA) is presented. The annular ring is designed working at TM₂₁ mode, and conical radiation pattern is obtained. At the inner of annular ring, a simple ring-shaped feeding line is arranged to implement impedance matching and CP operation. Therefore, the antenna has good impedance and CP performance, as well as a compact structure. The measured results indicate that the antenna has high low-elevation gains and omnidirectional azimuth coverage. The peak gain reaches 4.3 dBic at elevation angle of 47°, and in the range of 10°-70°, the gain is above 0 dBic. The impedance bandwidth for S₁₁≤-10 dB is 2.3% at 1.601GHz. The proposed antenna can be used in mobile earth-station equipment for satellite positioning and communication systems in global or local.

This paper presents a novel wideband planar dipole antenna with parasitic patches. Of which, acting primarily as directors, the parasitic elements aim to improve the radiation patterns in terms of gain especially at the higher frequencies. For verification, the proposed novel structure was fabricated and measured. The proposed antenna is well-matched with achieved VSWR<2 and has a good radiation performance across the entire operating frequency range of 3-8 GHz.

We analyze the transverse-electric wave propagation through lossless trilayer stacks containing single-negative (SNG) materials in which only one of the two material constants, permittivity (epsilon) or permeability (mu), is negative. We consider the following combinations: ENG/MNG/ENG, ENG/DPS/MNG, DPS/ENG/DPS, and ENG/DPS/ENG, where ENG refers to epsilon-negative, MNG to mu-negative, and DPS to double-positive media. The transfer matrix formalism is applied. Although the waves are evanescent in the SNG media, combining the SNG layers or the SNG and DPS layers, leads to some unusual features, such as the complete tunneling. Since the symmetrical trilayer is equivalent to a single homogeneous layer, the complete tunneling conditions are easily predicted analytically for the trilayer stacks, and we show that in most of cases, they are rather well applicable to the respective bilayer stacks. The field and the Poynting vector distributions are studied in different trilayers and, in some cases, in the respective bilayers. In particular, we show that the complete tunneling is facilitated theoretically in the electrically thin stacks. Similar results could be obtained for the transverse-magnetic waves and the respective dual combinations by using the duality principle.

We numerically demonstrate that the transmission through a deep subwavelength (λ₀/20) aperture in a metal plate could be greatly enhanced owing to the resonance effects of a high permittivity (κ) dielectric cube tightly coupled to the aperture. The transmission enhancement originates from the confinement and re-radiation of the electromagnetic energy impinging onto the high κ cube which operates in the 1st Mie resonance mode, and behaves as an ultra-small magnetic dipole antenna. The complex permittivity of the cube governs the operating frequency and the enhancement in terms of bandwidth and transmissivity maximum. Additionally, based on the isotropic response of the high κ cube with dimensions comparable to the aperture size, the almost independence of the enhancement properties on the illumination polarization and incidence angle was assessed.

Frequency-dependent admittance (J-) inverter is incorporated in synthesis of microstrip trisection filters to achieve a quasi-elliptic function response. In the admittance matrix of the lowpass prototype, certain coupling is modeled by a constant J-inverter multiplied by the complex frequency variable s. Direct synthesis of three lowpass prototypes is presented. Based on the standard lowpass to bandpass transformation, coupled microstrip resonators with both electric and magnetic coupling are devised to implement the J-inverter with desired frequency-dependent characteristics. Tapped-line input/output is used and several transmission zeros can be created in the upper and lower rejection bands. In experiments, a third-order filter with four zeros, a fourth-order circuit with three zeros, and a fourth-order filter with five zeros are designed and fabricated. Measured results are compared with the simulation responses to validate the theory.

Highly dense two-dimensional periodic arrays of nano-scaled silicon pillars present interesting photonic band gaps and the capacity to act as photonic crystals which can mould, manipulate and guide light. We demonstrate finite element modelling of silicon pillars based photonic crystals and their effective use in applications like waveguides, optical power dividers, multiplexers and switches. The optical wave propagation through these structures was thoroughly simulated and analysed, confirming their high efficiency. The band gaps studied through the plane wave expansion method are also presented. Later the fabrication of highly periodic two-dimensional arrays of silicon pillars through the process of etching is also explained. The arrays with pillar radius of 50 nm and lattice constant of 400 nm were successfully utilised as photonic crystal waveguides and their measured results are reported. Moreover, the silicon nanopillars sputtered with noble metals can also display artificial optical properties and act as metamaterials due to the mutual plasmonic coupling effects. We report the theoretical results for the silicon nanopillars based metamaterial high-pass filter.

We propose two metamaterials with sub-wavelength double-slots --- single-side double-slot metamaterial and double-side double-slot metamaterial. The dependence of the electromagnetic resonances and local intensity enhancements on the structural parameters is studied by the finite-difference time-domain technique and the finite element method. Results show that the central-arm of a double-slot structure strongly influences frequency and local intensities at both high- and low-frequency resonances. Very strong field localization can be achieved at the high-frequency resonance and its particular distribution can be well controlled by the width of the central-arm. A double-side double-slot structure can be utilized to separately enhance the high-frequency resonance, while suppressing the low-frequency resonance. The simulation results are discussed in terms of plasmon resonances.

This paper proposes two novel broadband microstrip antennas using coplanar feed-line. By feeding the patch with a suitable shape of the coplanar line in the slot of the patch, the broadband character is achieved. Compared with the antenna fed by a U-shaped feed-line, the antenna with L-shaped feed-line not only has wider bandwidth but also achieves the circular polarization character. The measured bandwidths of 25% and 34% are achieved, and both of the antennas have good radiation characteristics in the work band.