A single-stage ultra-wideband (UWB) CMOS low noise amplifier (LNA) employing interstage matching inductor on conventional cascode inductive source degeneration structure is presented in this paper. The proposed LNA is implemented in 0.18 μm CMOS technology for a 3 to 5 GHz ultra-wideband system. By careful optimization, an interstage inductor can increase the overall broadband gain while maintaining a low level of noise figure of an amplifier. The fabricated prototype has a measured power gain of +12.7 dB, input return loss of 18 dB, output return loss of 3 dB, reverse isolation of 35 dB, noise figure of 4.5 dB and input IP3 of -1 dBm at 4 GHz, while consuming 17 mW of DC dissipation at a 1.8 V supply voltage.

A reconfigurable patch antenna consisting of a square patch with two cross-shaped diagonal slots is presented. The proposed design approach is based on the use of two pairs of switches in order to obtain both frequency and polarization reconfigurability. Specifically, three different polarization states have been obtained: A Right-Hand Circular Polarization, a Left-Hand Circular Polarization and a Linear Polarization. Experimental results, referred to a realization on a FR4 substrate of the layouts corresponding to the useful switch configurations, are reported.

In this paper, a compact, wide fractional bandwidth bandpass filter using a new open slot split ring resonator (OSSRR) defected ground structure and compact microstrip resonating cell (CMRC) is presented. OSSRR is the modified and dual version of the open split ring resonator (OSRR). The band pass filter (BPF) is constructed by cascading lowpass and highpass sections designed using CMRCs and OSSRR respectively. The designed BPF has wide fractional bandwidth of 74%, sharp passband to stopband transition and low passband insertion loss of less than 1 dB. The simulated results are well validated by the experimental results.

A novel compact strip-line fed UWB antenna with band-notched characteristic is proposed. By employing a balanced antipodal structure and strip-line feed, the size of this antenna has been reduced to only 23 mm×27.5 mm with the dielectric substrate of relative permittivity 2.65. Meanwhile, a slot is added onto the radiating patch of the mid metalisation layer to realize the band-notched function, by tuning the length of which suitable rejected frequency band can be obtained. According to the measured results, the proposed antenna has a large bandwidth totally satisfying the requirement of UWB applications (3.1~10.6 GHz) with good stable omnidirectional radiation patterns and gains except in the rejected frequency band (4.9~6.2 GHz). Details of this antenna are described, and the experimental results of the constructed prototype are given, too.

Novel configurations of complementary split ring resonator (CSRR) with dual mesh-shaped couplings and defected ground structures (DGS) are introduced to design the high performance of wide pass-band and stop-band band pass filters (BPF). This paper presents a low insertion loss (-0.82 dB), symmetry and sharper transmission zero level (-51.88 dB), using effective DGS and alternative coupling for CSRR. The filter with center frequency at 1.92 GHz, pass-band from 1.21 GHz to 3.05 GHz (BW = 95.8%) and wider stop-band (extended to 4.2f₀ below -20 dB rejection level) is designed and fabricated. Simulation and measured results including surface current distributions and frequency responses are presented and discussed.

In this paper, a hybrid algorithm combined method of moments (MoM) with particle swarm optimization (PSO) is used to realize low radar cross section (RCS) array synthesis. Both the scattering factor and the radiation factor are involved in the proposed objective function to achieve the promising dipole array with a reduced RCS and satisfied radiation performance. To improve the optimization efficiency, radiation constraint conditions are adopted to avoid unnecessary scattering calculation. The symmetric matrix and block treatment are also used to fill the MoM impedance matrix. The optimization results show that the proposed algorithm is able to achieve RCS reduction of 5.5 dB for dipole array.

A 77 GHz microstrip antenna array with a small surface providing high side and grating lobe suppression is presented. This may serve as a starting point for 77 GHz automotive radar applications. Multiple Wilkinson dividers guarantee both impedance matching at the input port (TX) as well as low return loss for the incoming (RX) signal. Phase shifting is done by adjusting the level of the Wilkinson dividers or by meandered sections of transmission line. The influence of the radiation caused by the feeding network is analyzed and the absolute degradation in side lobe suppression is derived in this paper.

A compact dual-band high-impedance-surface EBG structure is employed as a reflector for a dual-band annular-slot antenna. The reflector comprises an array of miniaturized EBG cells which utilizes square patches augmented by four S-shaped corrugated arms to reduce the resonant frequency of the proposed EBG structure. In order to broaden the bandwidth and adjust the frequency ratio for the dualband EBG structure, a log-periodic spacing between the S-shaped strips is introduced. The combination of microstrip-fed annular slot and EBG reflector provides directional properties for both frequency bands with reduced size and low-profile.

A completely analytical computation of the electromagnetic field produced by an optical fiber helix is presented for the first time. The analysis utilizes the transformation of radially traveling cylindrical waves between two skew cylindrical coordinates systems, that has been previously derived by the author, in order to express the waves radiated by each infinitesimal part of the helix in terms of cylindrical waves around the helix axis and be able to integrate the contributions analytically. Under certain realistic geometrical assumptions, an unperturbed propagation of a single fiber mode is assumed to account for the infinite fiber length, leading to elegant final series expressions in terms of mixed angular-axial Hartree space harmonics, which show clearly the effect of the helical geometry on the field distribution. Analytical formulas are obtained for the field inside and outside the helix cylinder and an interesting two-term decomposition of the outward radiated field is concluded.

A new design technique of microstrip patch antenna is presented in this paper. The proposed antenna design consists of inverted patch structure with air-filled dielectric, direct coaxial probe feed technique and the novel slotted shaped patch. The composite effect of integrating these techniques and by introducing the new multi-slotted patch, offer a low profile, high gain, broadband, and compact antenna element. A wide impedance bandwidth of 27.62% at -10 dB return loss is achieved. The maximum achievable gain is 9.41 dBi. The achievable experimental 3-dB beamwidth (HPBW) in the azimuth and elevation are 60.880 and 390 respectively at centre frequency.

A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/f1=1.33. In order to achieve the dual-frequency operation, a rectangular patch is loaded with a stub at one of its radiating edges. To improve bandwidth at each band, two parasitic patches are coupled to the driven element.

We investigate the electromagnetic properties of three-dimensional (3D) arbitrarily-shaped invisible cloaks based on the analytical field transformation theory instead of the complicated numerical simulations. Very simple closed-form expressions for fields and energy flows have been derived for arbitrarily-shaped 3D cloak, which could help us to investigate the electromagnetic properties of the 3D cloaks rapidly and efficiently. The difference between 2D and 3D cloaks have been compared in detail. Distributions of the fields, power flows and wave polarizations for the 3D case have been discussed inside the cloak. Numerical results have been presented at the cutplanes of cloaks to valid the theoretical analysis, which shows clearly how the incident waves are bent at the inner boundary. In order to further reveal the physical essence of the cloaks, both 3D spherical and ellipsoidal cloaks have been considered based on the analytical method. The common features and the differences for the two structures have been also illustrated in this paper.

This paper proposes a hybrid classifier for polarimetric SAR images. The feature sets consist of span image, the H/A/α decomposition, and the gray-level co-occurrence matrix (GLCM) based texture features. Then, the features are reduced by principle component analysis (PCA). A 3-layer neural network (NN) is constructed, trained by resilient back-propagation (RPROP) method to fasten the training and early stop (ES) method to prevent the overfitting. The results of San Francisco and Flevoland site compared to Wishart Maximum Likelihood and wavelet-based method demonstrate the validness of our method in terms of confusion matrix and overall accuracy. In addition, NNs with and without PCA are compared. Results show the NN with PCA is more accurate and faster.

Design, simulation and measurement results of the integrated compact up-converter MMICs (microwave monolithic integrated circuits) are presented and discussed. The design is performed to achieve low cost and high performance transmitter system for the Ka-band frequency applications. It is designed using anti-parallel diode pair sub-harmonic single sideband mixer and three stage RF (radio frequency) amplifier. Microstrip lines and lumped elements are used together to achieve a compact chip size. The layouts of the circuits are designed with careful EM (electromagnetic) simulations to avoid inter-component couplings and effect of the microstrip bending discontinuities. The chip is operated for the wide bandwidth of the RF frequency from 22-38 GHz. Due to sub-harmonic mixing the required local oscillator frequency (LO) is reduced to half (10-19 GHz) to that of the RF frequency. The conversion gain of the chip is 9-15 dB and P-1dB output power is 7-12 dBm. The single sideband and anti-parallel diode pair suppress the in-band unwanted sideband and second harmonic of the local oscillator (2LO), respectively. The suppression of sideband and 2LO signals is typically 20-35 dB and 20-30 dB, respectively. The size of the chip is as compact as 4.2 mm² on a 100 μm-thick GaAs substrate.

This paper presents a rigorous approach for the propagation of electromagnetic (EM) fields along a helical waveguide with arbitrary profiles in the rectangular cross section. The main objective is to develop a mode model to provide a numerical tool for the calculation of the output fields, output power density, and output power transmission for an arbitrary step's angle and the radius of the cylinder of the helical waveguide. Another objective is to demonstrate the ability of the model to solve practical problems with inhomogeneous dielectric profiles. The method is based on Fourier coefficients of the transverse dielectric profile and those of the input wave profile. Laplace transform is necessary to obtain the comfortable and simple input-output connections of the fields. This model is useful for the analysis of dielectric waveguides in the microwave and the millimeter-wave regimes, for diffused optical waveguides in integrated optics. The output power transmission and the output power density are improved by increasing the step's angle or the radius of the cylinder of the helical waveguide, especially in the cases of space curved waveguides.

In this article, the harmful radiation level of electric field strength from the hostile low-power radio devices causing the intermodulation interference to the AMPS receiver has been predicted. The predicted level becomes the upper limit to avoid the intermodulation interference on the victim device. Our findings show that the quantified upper limit was 79.13[dBμV/m] to mitigate the adverse influence from these low-power radio devices. Our results are based on the calculation, simulation, and measurement for the commercial AMPS chip. Resulting values are in a good agreement within less than 3[dB].

A small 3-Dimensional (3-D) multi-band antenna of "F" shape is proposed for portable phones' applications. The designed configuration of the proposed antenna is different from traditional Planar Inverted-F Antenna (PIFA) radiators. The proposed antenna has the good characteristics of wide band. The ratio of impedance bandwidth to the central frequencies 2.5 and 5.1 GHz is 28.6 % and 9 %, respectively. It can be applied to Bluetooth (BT) 2.4 GHz and Unlicensed NII - 5 GHz, UNII-1 5.1 ~ 5.25 GHz and UNII-2 5.25 ~ 5.35 GHz. The experimental results have fairly good agreement with the simulation data by High Frequency Structure Simulator (HFSS).

We demonstrate complete tunneling of light through large-scale mu-negative media, which has negative permeability but positive permittivity, by constructing a quasi-one-dimensional structure with side branches. For the structure with a single side branch, there always exists a transmission peak which can be easily tuned by varying the parameters of the side branch. For the structure with periodic array of side branches, the transmission peak is enlarged to a band, which exhibits left-handedness, and can be tuned by changing the distance between two neighboring side branches and the length of the side branch.

The concept of Scale-Changing Network is reported for the electromagnetic modeling of complex planar structures composed of a collection of metallic patterns printed on a dielectric surface and whose size covers a large range of scale. Examples of such multi-scale structures are provided by multi-band frequency-selective surfaces, finitesize arrays of non-identical cells and fractal planar objects. Scale-Changing Networks model the electromagnetic coupling between various scale levels in the studied structure and are computed separately. The cascade of Scale-Changing Networks bridges the gap between the smallest and the highest scale levels and allows forming a monolithic (unique) electromagnetic formulation for the global electromagnetic simulation of complex planar structures. Derivation of these networks is presented and key advantages of the electromagnetic approach are reported.