The advancement in wireless communications requires the integration of multiple radios into a single platform to maximize connectivity. In this paper, design process reconfigurable antennas is discussed. Reconfigurable are proposed cover different services that operate over wide frequency range. They show significant promise addressing new system requirements. exhibit ability modify their geometries and behavior adapt changes surrounding conditions. can deliver same throughput as...

This letter reports the concept and development of first optically controlled reconfigurable antenna for millimeter-wave (mm-wave) applications. It is based on a slotted-waveguide array two photoconductive switches, which are used to control slot electrical length. novel photonics-based strategy enables frequency tunability radiation pattern reconfiguration through 28- 38-GHz bands. Numerical simulations experimental results illustrate its applicability mm-wave indoor The measured gain...

Telecommunications have been in constant evolution during past decades. Among the technological innovations, use of digital technologies is very relevant. Digital communication systems proven their efficiency and brought a new element chain signal transmitting receiving, processor. This device offers to radio equipments flexibility programmable system. Nowadays, behavior system can be modified by simply changing its software. gave rising model called Software Defined Radio (or...

The objective of this paper is to illustrate that electromagnetic macro modeling can properly predict the path-loss exponent in mobile cellular wireless communication. This represents variation path loss with distance from base-station antenna. Specifically, we communication three, preceded by a slow-fading region, and followed fringe where four. sizes these regions are determined heights transmitting antennas receiving antennas. Theoretically, illustrated through analysis radiation vertical...

The estimation of the spectrum usage from point view number users and modulation types is addressed in this paper. techniques used here are based on Support Vector Machines (SVM). SVMs machine learning strategies which use a robust cost function alternative to widely Least Squares that apply regularization provides control complexity resulting estimators. As result, estimators against interferences nongaussian noise present excellent generalization properties where data available for small....

In this paper we present a Software Defined Radio (SDR) platform, composed by USRP hardware and GNU Radio, as new approach for teaching telecommunications at schools of Electrical Engineering. The proposed makes the preparation an experiment faster using modern communications architectures, which significantly reduce occurrence errors during setup test beds well. This gives students opportunity to focus their efforts on learning techniques algorithms. Furthermore, intend make easier...

The analysis of a new printed antenna is presented and discussed. This consists monopole, with one or two sleeves on each side, fed by coplanar waveguide (CPW) line. Switches are used to control the length monopole tune resonant frequencies antenna. In case double-sleeved antenna, switch connect disconnect second sleeve in cactus Measurement results show that maintains dipole-like radiation patterns for all different

A Multi-class Support Vector Classifier (SVC) is proposed for planar array failure diagnosis. Extracted feature information from the far field intensity of used to train and test multi-class SVC, so one can detect location failed elements in an also level failure.

This letter presents a novel approach to design highly efficient multioctave bandwidth power amplifiers (PAs). The fundamental load impedances are slightly detuned out of their optimum values reduce the in-band harmonics influence on output and power-added efficiency. matching network includes 4:1 planar Guanella transformer for wide low complexity. In frequency band 0.5-2.7 GHz, PA achieves 9.2 ± 1.2 dB gain more than 20-W power. drain efficiency varies from 56% 70% over bandwidth.

A new reconfigurable multi band microstrip antenna is presented in this paper. The patch has the shape of a 6 armed star printed on hexagonal substrate. reconfigurability obtained by inserting small switches rectangular slots cut patch. Different switch configurations were investigated and different functionalities obtained. many practical applications, like GSM, wireless LAN, WIMAX other systems, as illustrated detail herein. changes its application according to which are activated.

This paper addresses the functional reliability and complexity of reconfigurable antennas using graph models. The correlation between for any given antenna is defined. Two methods are proposed to reduce failures improve antennas. caused by reconfiguration technique or surrounding environment. These failure reduction tested examples which verify these methods.

This paper presents a new technique for the implementation of reconfigurable antenna system. The reconfigurability is based on integrating laser diodes within substrate. are used to shine light photoconductive switches that connect different radiating elements structure. A prototype fabricated and tested. good agreement between simulation measurement data noticed.

Three antennas for Wi-Fi 802.11n applications are presented. The first antenna is a dual-band operating at the 2.4 GHz and 5.5 bands. This conceived from zero-order resonating wire metamaterial antenna. By making judicious choice capacitances inductances of mode antenna, new metamaterial-inspired can resonate two distinct frequencies. simulated gain 2 dBi 4 lower upper band, respectively. others designed compact folded monopole with 0.5 gain, dipole gain. They were using CST Microwave Studio...

In this paper we present a new quadrifilar helix antenna designed for CubeSat applications. The presented in covers the UHF bandwidth between 250 MHz and 500 MHz. is fed with four ports exhibits circular polarization as well an acceptable gain over desired frequency range.

This letter addresses the optimization and complexity reduction of switch-reconfigured antennas. A new technique based on graph models is investigated. used to minimize redundancy in a reconfigurable antenna structure reduce its complexity. modeling rule for antennas proposed, examples are presented.

In this work, a Quasi-Yagi antenna is designed to operate at 2.4 GHz for RFID applications. The proposed device composed by surrounded fractal metamaterial structures placed strategic positions, improving bandwidth and enhancing the tunability desired frequency. Design guidelines combination of antennas are presented. obtained results show that use in systems very promising.

In this paper, it is presented the design of a low power temperature sensor for protection smart cards from security attacks at corners their operating range. The usually use failure generation techniques abnormal environmental conditions. They normally result in malfunctions card processor, allowing additional access to information happen. purpose effectively protect chip art tampering range -20 °C 120 with small area and consumption circuit. designed Cadence TSMC using System on Chip (SoC)...

Radio frequency identification (RFID) is an emerging technology with many different applications. In this paper, results obtained from the use of active RFID system for trucks access control will be presented. Using a directive antenna reader and middleware RSSI feature, it possible to make much more accurate than in conventional approaches, avoiding most reading problems making robust. A comparison between without these resources shown text.

In this contribution, a design, implementation, and experimental results of highly efficient, multi-octave bandwidth power amplifier (PA) using 25 W packaged GaN-HEMT are presented. Source/load-pull setup is used to extract the optimum source/load impedances across 1.1 – 2.7 GHz. The harmonics impact considered improve efficiency. Utilizing characteristics FET transistor leads modify fundamental load low frequency range, which have higher gain compared high minimize influence harmonics. This...

This work presents the design and performance characteristics of a novel antenna array structure. The prototype is composed by three equal quasi-Yagi antennas 120/spl deg/ shifted, due to this new layout allow configuration radiation pattern, forming directional patterns with high directivity, keeping same as isolated element has in band terms. was designed for working at 2.4 GHz optimized include 1.9 GHz, GSM-USA standard. simulation optimization were done commercial software using MoM...

In this paper, graph models and Neural Networks (NNs) are applied to reconfigurable antennas both techniques analyzed be used for cognitive radio applications. The use of NNs synthesize different antenna configurations the optimize performance such addressed investigated. application tools on has proven beneficial in applications where software control fast response required. Thus incorporation an FPGA (Field Programmable Gate Array) creates a self adjusting defined that can many wireless...

Cognitive radios have been proposed for opportunistic users to make use of the frequency bands allocated licensed users. For this be possible, spectrum sensing should performed in search free bands. In work, is investigated based on energy detection. Scenarios are studied where noise distribution Gaussian and scenarios considering uncertainty. The behavior probability detection as a function false alarm parameterized number samples signal-to-noise ratio (SNR) presented.

This work describes two methods for improving the directivity of an edge coupled microstrip based coupler with weak coupling. The proposed couplers have a coupling factor about −30 dB. interdigital capacitors achieved excess loss 0.5 dB fractional bandwidth 44 % and 25 second structure uses floating stubs between lines, which increases up to 67% same directivity. insertion structures is lower than 0.3