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With the desire for ever-increasing data-rates, coupled with the interest in techniques that offer interference mitigation, much research has focused upon Ultra Wide-Band (UWB) systems that can theoretically realise such benefits. In practice, any UWB system will require an antenna to connect it (the radio) to free-space. Through examples of practical measurements from two different UWB antennas,...
This paper presents the results of an investigation on whether or not a Gaussian beam of uniform polarization, which is non-Maxwellian but which can be easily and quickly generated analytically, can be used in place of a rigorously Maxwellian tapered beam for computing numerically the plane wave scattering coefficients of a slab. First, the paper presents a general technique for computing numerically...
Patch antennas with parasitic subarrays are used to improve the bandwidth of the patch antennas. Parasitic subarrays are coupled to radiating edges, nonradiating edges or all four edges of the patch. These subarrays create new resonance frequencies which interfere with the main resonance frequency and improve the bandwidth. Gupta et al. [1] used segmentation method to optimize the gap dimensions and...
The ACE Network of Excellence brings together 45 of the antennas groups in Europe with the aim of improving the research collaboration and interaction across Europe. The activity area on millimetric antennas and integrated antennas involves 12 of these. This paper briefly introduces the operation of the activity in the Network and then overviews the current research and development taking place in...
Fractal geometry has been developed within the last quarter century for understanding geometries that cannot be easily defined by Euclidian geometry. Fractal geometry encompasses an iterative methodology for defining structures. A simple geometrical transformation is performed on a starting structure and the result is fed back into this same transformation many times.
In the present paper, a lumped element equivalent circuit including frequency dependent losses is developed to model a transmission line that is routed above an electromagnetic bandgap (EBG) structure. The EBG is used as a power/ground plane in the power distribution network of a typical digital circuit. The developed model for the transmission line is ported into the simulation testbench for analysis...
The new concept of Coherently Radiating Periodic Structures, CORPS, has been presented. In this case, it has been applied to the design of antenna arrays.
Feeding structures for the one-turn single-arm Archemedian Spiral Slot Antenna are proposed to improve the impedance matching bandwidth, while maintaining good axial ratio bandwidth. Examples of antenna prototypes with the radiating slot and the feeding strip integrated on the same dielectric substrate are presented and demonstrate the bandwidth improvements of the proposed feeding structure over...
Solving electromagnetic scattering and radiation problems with moment methods or finite element methods over a large frequency band gives accurate results, but it is often too time-consuming. So we propose a fast auto-adaptive method to optimize the computational electromagnetics solver applied in the case of various radiating and dielectric structures. This method is able to generate the electromagnetic...
This paper presents the design of antenna arrays of patches fed by microstrip hybrid branchline couplers in reflection mode as phase shifters. This topology permits the reduction of the number of FET, PIN diode or MEMS switches by two when compared with classic array feeding techniques. Two antenna prototypes are simulated, fabricated and measured. The results show beam steering capability over a...
The goal of this paper is to present a beam steering multi-band base station antenna for mobile communications without RF components (phase shifters, amplifiers, …) or Butler matrix. This base station antenna associates a omni-directional antenna to a cylindrical controllable metallic Electromagnetic Band Gap (EBG) material. The main characteristic of this lattice is to include PIN diodes along the...
The objective of this paper is to present a Chaff cloud Radar Cross Section (RCS) model, able to characterize battle ship autoprotection systems under operational configurations.
Ultrawideband (UWB) signal transmission in Si integrated circuits was performed by use of wireless interconnects. Linear dipole antennas fabricated on a Si substrate showed UWB characteristics in the frequency range of 5–20 GHz. The signal attenuation rates of Gaussian monocycle pulse through 10 Ωcm and 2.29 kΩcm substrates were −0.08 mV/chip and −0.03 mV/chip, respectively. Pseudo random binary signals...
The use of semiconductors as substrate in microwave devices is becoming more common in the design and implementation of low-cost integrated circuits. The presence of a lossy substrate and the loss-reduction techniques, through modification of the interconnect geometry, result in significant frequency dependence of the per-unit-length (p.u.l) parameters of the transmission line. In this paper, an approach...
This letter presents the concept and design of a complete system of data transmission in medical indoor environnement. The system is built around a module of acquisition using analog to digital conversion and time domain multiple access. The 24 GHz carrier is generated by a 12 GHz local oscillator followed by a frequency multiplier associated with appropriate harmonic filter. The design an concept...
In this work, we reported on an antenna design with a complete microstrip feed suited for near-field microwave imaging centered at 6GHz. The antenna is compact and has a planar structure. Future work will be directed toward studying the antenna efficiency and fidelity for different values of surface resistivity. In addition, the antenna will be studied in an array configuration for near-field imaging...
In this paper, the effects of t vector for GPOF approximation of a Green's function for a single layered microstrip structure have been evaluated. In order to do this, effects of T0 and dt variations and also the simple polynomial profile of non-uniform sampling strategy have been evaluated. The best value for each computation can be determined separately using different compromising policies between...
The effects of flat conductor and dielectric back planes on the performance of a finite rectangular microstrip antenna are studied. It is shown that both back plane types have similar effects on the near and far fields of the microstrip antenna. Also, it is shown that the resonant frequency, input resistance at resonance and directivity of the microstrip antenna change periodically by increasing the...
This paper proposes an extension of the conventional electric model of Marcuvitz for 2D cylindrical metallic wires. The proposed approach, obtained using the Method of Moments (MoM) has been employed in conjunction the Marcuvitz model to simulate the case of an EBG metallic structure of finite dimensions. The results show a good concordance with full wave simulations.
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