Papers by Keyword: Smart Antenna

Abstract: Injection-locking technique is receiving increasing interest in industrial applications, which is especially suitable for smart antenna array, but relative experiments are complicated. The article focuses on the theory and experiment of the technique. Firstly, section 2 reviews the theory of injection-locking technique, and summarizes two useful conclusions on injection-locking bandwidth and phase difference adjusting bound of the phenomena. Secondly, section 3 describes experiments using commercial microwave integrated circuit (MMIC) voltage controlled oscillator (VCO), which is reduces the experimental conditions. Experiments results perform very well.

Abstract: A smart antenna using 4x4 Butler matrix for 5.8 GHz band is designed. The antenna array has four inputs and is excited by the Butler matrix feeding network to electronically steer the beams in desired directions. The architecture of the Butler matrix beamforming network is designed without using cross couplers, in fact the array antenna will be surrounded by the hybrid couplers, and it leads to decrease losses due to the crossing lines. The designed prototype is simulated on Rogers RT /duroid 5880 substrate with a relative permittivity of 2.2 using ADS momentum software.

Abstract: A 5.8 GHz band smart antenna system of 4-elements microstrip linear array antenna with Butler matrix beamforming network is designed. The Butler matrix smart antenna is designed for WLAN applications using microstrip technology. System’s design and optimization was based on computer simulations using ADS momentum. The Butler matrix components like the hybrids couplers, the cross-couplers, and the phase shifters are designed and optimized one by one to get the best performances. The prototype is simulated on Rogers RT /duroid 5880 substrate with a relative permittivity of 2.2 and height of 0.787mm. Finally, the isolations of the Butler ports, the power distributions at the outputs, the return loss and the radiation pattern are presented in detail, in order to prove the system’s performance.

Abstract: The multi-access interference and quality of communication system can be greatly improved by beam forming technology when the smart antenna is adopted. This paper investigates the performance improvement given by a multi-antenna receiver on a mobile terminal , and a link level simulation scheme is presented based on TD-SCDMA system. The performance of dual smart antenna under different circumstance is analyzed, and three different adaptive algorithms are compared under the specifically modeled multipath fading channel. The simulation results show that a dual-antenna arrangement on a mobile terminal can achieve better performance than a conventional single antenna.

Abstract: Because the direction of a single antenna is limited, and for strengthening the direct radiant ability of the antenna, we will put the weaker direction antennas together in some way to constitute an antenna array system. The antenna array is also called the array antenna or a disperse antenna array. The antenna cell can be the symmetry center-fed dipole, the aperture antenna, the circle antenna or other forms of the antennas whose direction are limited. In practice, the antenna array is almost constituted of similar antenna cells. I have mainly completed the antenna array direction diagram in conditions of some kinds of parameters. And at last, I get the useful results for practice. This also provides theories basis for the analysis of smart antenna.

Abstract: With the rapid development of China's TD-SCDMA system, how to qualitative and quantitative to judge intelligent antenna electromagnetic radiation pollution is a problem to be solved. Due to the special working principle of smart antenna, the second generation communication system spectrometer and field intensity meter measurement method is a complicated and difficult to operate. This paper introduces a design suitable for TD smart antenna measurement system: this system can realize in single user or multiple users at the same time and the TD base station set up calls link of multi-point synchronous signal intensity measurement. The measurement results of our system are very close to the measurement results of spectrometer field intensitys and can reasonable reflect TD stations around the extent of the electromagnetic radiation. This method of our system is easy, cheap and maneuverable

Abstract: In reality, wireless communication channels are designed to serve for multiple users while multipath propagation interference (MPI) and other problems are deteriorating the quality of service, especially when modern wireless communication demands higher data rate giving that less and less radio spectrum resources are available. Compared to conventional techniques trying to solve the related problems, smart antenna (SA) may have shed new light on the solutions of these issues. The forming of broadcast beam of SA is studied in this paper. Firstly, the mathematical formulas for the forming of directional broadcast beam by the method of baseband-amplitude-weighting are derived, according to which the corresponding circuit diagram is given. Then the forming method for broadcast beam for SA by combining several directional radio beams is presented. Moreover, the computer simulation results of SA with 6 array elements are provided to demonstrate the accuracy and achievability of this beam-forming method.

Abstract: In this paper,we design a uniform circular array beamforming device of 16 yuan based on the least squares SLC-LSCMA algorithm (based on the linear subspace constrained least squares cma) high stability and rapid convergence for the foundation. The design of the complete beam-forming the SLC-LSCMA algorithm by plural, time-multiplier and accumulators, which uses less resources and faster than the traditional algorithm. The beamforming device uses hardware description language of Verilog HDL , and wires on the QUARTUS II 8.0. Finally the beamforming device is downloaded to the Alteras EP2C35F672C6, and its timing simulation can be run properly in the 50MHz clock frequency. This design can be widely used in mobile communication and satellite communications.

Abstract: In this paper RF MEMS switchis designed for dielectric-embedded electronically switched multiple-beam (DE-ESMB) antenna array. To achieve small stiffness without buckling, a novel bidirectional Z-shaped thermal actuator is used instead of V-shaped thermal actuator, which can generate large displacement and high contact force at low actuation voltage. With the actuation current from-0.6 A to 0.6 A, the electrothermal actuator can achieve a bidirectional motion in a dynamic range of-10.08 μm to 10.17 μm.RF performances are improved by suspending the structure 25 μm from the substrate using MetalMumps process. An ON state insertion loss of-0.14 dB at 10 GHz and an OFF state isolation of-67 dB at 10 GHz are achieved on low resistivity silicon substrate.

Abstract: Head of Line (HOL) blocking and deaf node problem are the main challenges in the smart antenna system in wireless ad hoc networks. To resolve these difficulties, we propose a novel packet scheduling algorithm based on the Directional Network Allocation Vector (DNAV). In the new algorithm, we divide the surrounding space of a tagged node into interference regions and free regions, and then transmit packets selected in turn from the data queue if there is an appropriately free region. The proposed algorithm can eliminate the deaf node problem and resolve the HOL blocking efficiently. Higher throughput and lower network delay are obtained by adapting to the dynamic network topology than other methods. The simulation results confirm the validity of the proposed algorithm.