A phase-alignment system is used fully integrate a power amplifier, Cartesian feedback linearization circuitry, and a phasealignment system. The phase-alignment system employs a new technique for offset-free analog multiplication that enables it to function without manual trimming. This paper demonstrates how the phase-alignment system improves the stability margins of the fully integrated Cartesian feedback system. The power amplifier itself, integrated on the same die, operates at 1 GHz and delivers a maximum of 30 dBm of output power into a 50-load. The class AB design for open loop and close loop power amplifier with Cartesian feedback, demonstrated a good linearity of 50 dBc and 80 dBc, respectively. The operating power is 2 W at 1000 MHz frequency.

In this paper a complete analysis to the stability of a microwave oscillator with distributed element resonator is presented. In this type of oscillators, the circuit description changes form ordinary differential equations to partial deferential equations. In this paper a Gunn diode oscillator with distributed elements resonator is analyzed. The instability condition of the startup phase and the stability condition of the steady state oscillation is investigated.

In this paper, a Medium Access Control (MAC) protocol is proposed to investigate Quality of Service (QoS) for multimedia traffic transmitted over Ultra Wide-Band (UWB) networks and increase the system capacity. This enhancement comes from using Wise Algorithm for Link Admission Control (WALAC) which has three suggested versions. The QoS of multimedia transmission is determined in terms of average delay, admission ratio, loss probability, utilization, and the network capacity. In addition, a new parameter is aroused for the network performance. Comparisons between the IEEE 802.15.3a protocol and the proposed one are done. The proposed protocol shows better results in both sparse and dense networks for real time traffic transmission.

A microstrip 180^o phase shifter obtained by a novel design of Microstrip-to-Coplanar Waveguide (CPW)-to-Microstrip transition is presented. The proposed phase shifter is obtained without changing the layer of the second microstrip line. Via holes are used to transfer the current from the top to the bottom substrate layer and vice versa. The presented phase shifter is operating in a wide bandwidth between 5.5 and 18 GHz, with low insertion loss and reflection coefficients. Because the input and output microstrip lines are on the same layer, the presented phase shifter is suitable for a modified class of feeding networks for phased antenna arrays.

In this paper,a fast integral equation method is developed for extracting the inductances in RF ICs,RF MEMs,IC packages,and deep submicron ICs etc. This method combines a recently developed Multilevel Green's Function Interpolation Method (MLGFIM) [1,2] with the volume integral equation discretized using Volume Loop (VL) basis functions. In it,instead of using the filaments model to simulate the currents flowing in the inductors,w e use the conventional SWG basis functions for this kind of basis functions is flexible for problems with complex geometries. The shortest path finding algorithm is also used to find the source loop basis functions. The inductance extractions from the straight line,the spiral inductors,the bump,and the parallel buses in this paper demonstrate the validity and efficiency of this hybrid method.

Mutual external inductance (MEI) associated with fringing magnetic fields in planar transmission lines is a cause of socalled "ground plane noise", which leads to radiation from printed circuit boards in high-speed electronic equipment. Herein, a Method of Edge Currents (MEC) is proposed for calculating the MEI associated with fringing magnetic fields that wrap the ground plane of a microstrip line. This method employs a quasi-magnetostatic approach and direct magnetic field integration, so the resultant MEI is frequencyindependent. It is shown that when infinitely wide ground planes are cut to form ground planes of finite width, the residual surface currents on the tails that are cut off may be redistributed on the edges of the ground planes of finite thickness, forming edge currents. These edge currents shrink to filament currents when the thickness of the ground plane becomes negligible. It is shown that the mutual external inductance is determined by the magnetic flux produced by these edge currents, while the contributions to the magnetic flux by the currents from the signal trace and the finite-size ground plane completely compensate each other. This approach has been applied to estimating the mutual inductance for symmetrical and asymmetrical microstrip lines.

A deep analysis of the directivity enhancement, due to the insertion of a simple linear antenna into a dielectric EBG, is presented. The operative frequency is chosen near a band-gap edge. The planewave expansion method is used in order to obtain the Bloch dispersion diagrams of infinite two-dimensional EBGs. A rigorous cylindricalwave approach is used to analyze two-dimensional EBGs with finite size, excited by a line source. We apply these tools to the analysis of different emitting devices, and propose solutions to improve their performances.

Discrete complex image method is introduced to get a closed-form dyadic Green's function by a sum of spherical waves. However, the simulation result by the traditional discrete complex image method is only valid in near-field for several wavelengths. In this paper, we analyze the form of spectral domain dyadic Green's function in the whole k_ρ plane and the variety of valid range of simulation results by different sampling paths in two-level discrete complex image method. Consequently, for dyadic Green's function, surface wave pole contribution both in spectral domain and spatial domain is clarified. We introduce the automatic incorporation of surface wave poles in discrete complex image method without extracting surface wave poles. The contribution of surface wave poles in spectral domain and spatial domain dyadic Green's function is further confirmed in the new method. Besides, this method can represent dyadic Green's function by spherical waves in the layer where the source and field points are. So it satisfies the splitting requirement and consequently reduces the computational complexity dramatically especially for objects with large scale in ẑ direction.

In this paper, two new line-fed loaded planar antennas are proposed for ultra-wideband applications. The first antenna is a circular patch with a circular ring as a Defected Ground Structure (DGS). A 50 Ohm microstrip line passes through the antenna which is symmetrical between the feed and the load. The impedance bandwidth of the first antenna with S11 < -10 dB is more than 10 GHz, from 3 GHz to more than 13 GHz, in both simulation and measurement. It will be shown that the antenna has quite a stable radiation pattern and also high gain over its bandwidth. The second configuration is a rhomboidal patch which a 50 Ohm microstrip line passes through it. A rhomboidal DGS ring is employed to widen the bandwidth of the proposed antenna. The impedance bandwidth with VSWR < 2 is more than 10 GHz, from 3 GHz to more than 13 GHz, in both simulations and measurement. The second antenna has also quite a stable radiation pattern and high gain values in its frequency band. For these antennas, a wideband 50 Ohm load has been used. Finally, it should be mentioned that the antennas have very compact structures as well as very simple configurations.

The Goos-Hanchen shift on the surface when an optical beam is obliquely incident from one isotropic right-handed material (RHM) into another biaxial anisotropic left-handed material (BALHM) is numerically studied with the finite difference time domain (FDTD) method based on the Drude dispersive models. The analytical expression of the Goos-Hanchen shift is firstly presented, moreo ver the condition for the existence and the sign of the Goos-Hanchen shift are also discussed. According to the theoretical analysis,sev eral sets of constitutive parameters of BA-LHM are considered. The simulated results are in agreement with theoretical results, which validate the theoretical analysis.

A novel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper. This antenna has been demonstrated to provide an UWB with return loss less than -10 dB from 9.5 GHz to 22.4 GHz. The bandwidth is up to 80%, which is quite better than the traditional bow-tie slot antenna. Simulated and measured results are presented.

Reflection and transmission coefficients (R and T) of high frequency waves propagating in the ionosphere are studied taking collisions into account. This was done approximating the expression (1 + Z²)^-1 in the refractive index using binomial expansion and neglecting terms of order higher than Z², where Z is the ratio between the electron collision frequency and the wave frequency. R and T height profiles were assessed using the International Reference Ionosphere, IRI, to estimate the ionosphere plasma parameters. Although no significant differences are found between the estimation with and without collisions, the method employed to include collisions may be useful for other purposes where collisions should be taken into account.

In this paper, an attempt is made to present a theory for the design of handset antennas, which results from the long experience that the authors have in the field of handset antenna design. The proposed theory is based on the well-known skin effect and constructs the antenna using a thin wire model that represent the backbone of the final antenna. The analytical solution for the thin wire model is first obtained, and the main properties (such as the return loss and the radiation properties) of the antenna can then be studied using this analytical solution. Once the antenna backbone is constructed, other elements, such as stubs, patches, etc., can be added to optimize the match at the desired frequency bands. A number of numerical and analytical examples are provided throughout the paper to validate the theory. Different antenna types, such as wire antennas and planar antennas, are tested and designed using the thin wire model. The correspondence between the analytical results and those from the numerical simulations using full-wave solvers agree very well in all examples. The authors also present in this paper a novel design of three small antennas for handset applications, which are based on the simple wire monopole, but in a three-dimensional form. The proposed three-dimensional monopole antennas have multi-band and broadband properties that cover most frequency bands being used for the handset device. The antennas feature remarkable properties while occupying a significantly small space, which makes them strong candidates for handset applications and for the future multi-antenna applications too. 1. INTRODUCTION

Split Ring Resonators (SRR) and Complementary Split Ring Resonators (CSRR) are widely used to design metamaterial structures. These structures when excited by suitable electromagnetic fields have resonance behavior and show unusual properties such as negative permeability and permittivity near the resonance frequency region. In this paper, CSRRs are used to design a bandpass waveguide filter in the X-band. The circuit model of these elements in the waveguide is similar to parallel L and C components that are placed in parallel form in a transmission line. Resonance frequency and bandwidth of LC resonance circuit are adjusted by proper choice of the CSRR geometrical dimensions. Then, to design the miniaturized filter these structures are combined with proper admittance inverter. The admittance inverter is designed such that its electric length is very smaller than the conventional λ/4 transmission line. As a result, a filter is compacted about 66% in comparison to the λ/4 transmission line as admittance inverter. Simulation results by Ansoft HFSS (Based on the Finite Element Method) confirm the results of filter circuit model.

A Neural Network architecture is applied to the problem of Direction of Arrival (DOA) and state of polarization estimation using a uniform circular cross and tri-crossed-dipoles antenna array. A three layer Radial Basis Function Network (RBFN) is trained with input output pairs. The network is then capable of estimating DOA not included in the training set through generalization and the corresponding state of polarization. This approach reduces the extensive computations required by conventional super resolution algorithms such as MUSIC and is easier to implement in real-time applications. The results suggest that the performance of the RBFNN method approaches the exact values. In real time, fast convergence rates of neural networks will allow the array to track mobile sources.

The paper reports on investigations into new schemes for dimensional scaling of the elements of a microstrip reflectarray to obtain a slower slope of the reflected wave phase characteristic. First, the phase response as a function of various shape elements is investigated when only one of their dimensions is varied. Next investigations concern the case when two dimensions or features of the element are scaled in a certain manner simultaneously. In the latter case, it is shown that phase responses of lower slopes with a minimal range reduction can be obtained. The feasibility of this concept is illustrated for dipoles, rectangular patches, and square and circular rings. Comparisons of the obtained results show that twodimensionally scaled square and circular rings offer much better phase responses than those observed for dipoles and patches.

It has long been known that the conical antenna has broadband characteristics and good radiation efficiency. The design considerations in reducing the size of top loaded conical antenna by using posts with lumped resistive loading are presented. The resulting antenna can achieve a VSWR of better than 2.0 over 100-800MHz frequency range. Results indicate that the addition of posts and lumped resistive loading has significant role in designing broadband antennas which are in small size.

This paper presents a design of wireless broadband (WiBro)-multi-input multi-output (MIMO) and personal communication service (PCS) antenna for practical mobile phone. To decrease the mutual coupling of WiBro-MIMO antenna, it is considered on the projected ground structure. In addition, two type PCS antennas for multi-function mobile phone are designed. The proposed antennas are well resonated in each operating frequency band. The measured bandwidths of 3-dimensional (3D) and 2-dimensional (2D) PCS antennas are 110MHz and 130MHz below -10 dB, respectively. The isolations between WiBro-MIMO and two PCS antenna are below -15dB by 2D antenna type and -20dB by 3D antenna type, respectively. The printed IFA has shown a better performance than modified planner IFA with spiral and shorting strip.

This paper introduces a 3 dB tunable symmetric left handed coupled line coupler implemented on ferrite substrate. The proposed coupler is realized in LH coplanar waveguide configuration constructed using interdigital capacitors and meandered line inductors. The analytical analysis and the numerical verification of the proposed couple line coupler are presented. The full wave numerical simulation results for different DC magnetic bias indicate that a tunable left handed coupled line coupler propagation with transmission coefficient up to 3 dB and isolation level more than 25 dB over a wide bandwidth can be achieved.

A new wideband and small size star shaped patch antenna fed capacitively by a small diamond shape patch is proposed. To enhance the impedance bandwidth, posts are incorporated under the patch antenna.HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on the return loss, the E and H-plane radiation patterns and Gain of the proposed antenna are presented at various frequencies.The antenna is able to achieve in the range of 4-8.8 GHz an impedance bandwidth of 81% for return loss of less than -10 dB.