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There are several disadvantages in the current electromagnetic theory of reverberation chamber analysis. The first disadvantage is that the current theory can only estimate number of electromagnetic modes and statistic uniform field distribution under high order modes circumstance inside a reverberation chamber, not give a systematic electromagnetic analysis of operating reverberation chamber. The...
A digital processing system for digital forming antenna (DFM) has been implemented using a digital signal processor (DSP). We are developing a beam former for a real-time system. The beam former provides multi-beam synthesis and beam selection for the DBF antenna
A novel kind of dual-band microstrip patch antenna is presented in this paper. We obtained dual-band operation by embedding a pair of L-shaped slots. It is easy to adjust the higher and the lower band by changing the parameters of the antenna, respectively. The proposed antenna can satisfy WLAN greatly
A circular cylindrical dipole and a Yagi-Uda antenna with an elliptical sphere radome of rotation have been exactly analyzed by using the method of moments (MoM). The good agreement of the numerical results with those from related references has shown the correctness of this MoM modeling. The numerical results show that the antenna radome will influence the antenna characteristics significantly, especially...
In order to effectively reduce the mutual interference among different transmitting antennas in multiple-antenna communication systems, accurate and effective channel estimation is important. In this paper, a general multi-path MIMO channel model is considered, and a closed-form estimation variance as a function of sequence length, family size and zero correlation zone (ZCZ) is derived for MIMO systems...
In this paper, an extended AM-FM MWOL model in the context of WLAN interference management is discussed. The MWOL model incorporates the frequency wander effect, which has not been addressed in the existing MWO models. The simulation result provided by this model match real measurements quite well. The MWOL envelope may change considerably when received at different WLAN channels. The results from...
To overcome the shortcomings of traditionally SNMP-based centralized network management, a mobile agent-based hierarchical network management model was presented. Its construction and work procedure were illustrated and compared with those of the traditionally SNMP. A conclusion was drawn that this model has such advantages as less bandwidth consumption and higher flexibility than the initial one,...
Effective usage and management of radio resources in the future wireless systems are discussed in this paper, which addresses to applications in the smart relay for wireless and mobile broadband radio and to smart antennas. The latter is expected to have a significant impact on the effective use of the spectrum. In this paper some ideas concerning dynamically allocated frequency spectrum assignment...
This paper presents a method, which can automatically implement the Mallat's filtering algorithm in WT (wavelet transform) coefficient's maxima domain. It can automatically find the maxima which corresponding to the same edges through all the scales (which we called the same edge maxima (SE-maxima) in this paper), and can be applied in many field for signal's automatic detection and de-noising. Also,...
In this paper, a method that combines the microwave network theory with MoM-FDTD algorithm to calculate the isolation between antennas involving dielectric objects is presented. First, a novel iteration procedure of a hybrid method combining the method of moments with the finite-difference time-domain method is employed to simulate the antennas with dielectric objects. Then, the network theory is...
Cold characteristics of W-band folded waveguide slow-wave structure used in micro-TWT are analyzed using the electromagnetic software MAFIA, including dispersion relation and coupling impedance. And the simulation results show good agreement with their theory formula analysis. In this paper the on-axis coupling impedance is directly calculated from its definition equation using MAFIA
The following topics were dealt with: wireless communications; microwave electronics; antenna; EMC; electromagnetic wave propagation theory; signal processing; coding; and waveforms;
This paper presents a decision feedback subband generalized sidelobe canceller (GSC), in which the design of the statistically optimum filter bank decomposition of the signals passing through the lower branch of the GSC as well as the signal after the decision feedback based on the minimum mean-square error criterion is addressed. The new beamformer not only renders superior interference cancellation...
A full monolithic low-phase-noise wide-tuning-range voltage-control-oscillator (VCO) designed for a dual-band homodyne transceiver for WLAN applications is presented in this paper. The circuit is designed and implemented in a commercial 0.35 SiGe BiCMOS process. MOS varactor is used to realize a wide tuning range. Measured VCO circuit specifications feature a 440 MHz tuning range around 2.45 GHz,...
In this paper, the properties of cylindrical and rectangular DRAs are reviewed and applications of the antennas to polarization control, polarization diversity, and direction of arrival determination are described. Theoretical and experimental results show that cylindrical and rectangular DRAs have useful radiation and impedance characteristics, which are determined by the permittivity of the dielectric...
Constant modulus (CM) is an important criterion in multiuser detection. Since the CM cost functions are non-convex and local minima exist. It is necessary to confine the searching space. In the paper we study the constraints for CM-based multiuser detection. A new constraint based on the MMSE criterion is proposed. Simulation results show the proposed algorithm is superior to some existing linearly...
A combined WLAN (wireless local area network) and RFID (radio frequency identification) system and its application in joint total asset visibility (JTAV) are studied. The working principle, choices of working frequencies and terminal roaming of this system as well as smart storage and in-transit visibility (ITV) of JTAV are discussed. The application of such JTAV in Qingxin County of Guangdong Province...
This paper describes a method for tuning an HTS filter at the cryogenic temperature. Sonnet software was used for simulating the distribution of current density. Dielectric tuning screws were used to regulate the redistribution of electromagnetic field, so that the response characteristics of the filter can be improved. For matching the designed result, this technique allows correcting the deviation...
Luneberg lens is prevalently studied, for it may be a unique solution for low profile broadband and wide angle scanning applications. From the view of application, this paper studied the tolerance problems during being manufactured, using the computation method combining spherical vector wave functions and the reciprocity theorem. The effects of the shell number air gaps between the layers and dielectric...
In this paper, measurement procedures of propagation loss and examination results between propagation loss and distance in 70 GHz band are reported For the propagation loss, differences of approximate equations in the various environments, such as LoS and NLoS, and relation between an antenna beam width and an attenuation coefficient for distance are discussed
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