Full-wave analysis of circular guiding structures completely filled with ferrite by using the finite difference frequency domain method is presented. The ferrite is assumed to be azimuthally magnetized to remanence. Emphasis is placed on the TE 0m modes that are rotationally symmetric. These modes exhibit nonreciprocal behavior that could be exploited to build phase shifters and microwave isolators. Dispersion diagrams for these modes are given for both forward and reverse waves, and the effect of various ferrite parameters is studied. It is shown that the dispersion diagram may exhibit a region of negative slope, which gives rise to backward wave. V V C 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE 00: 000-000, 2009.
In this article, a general full-wave two dimensional finite difference frequency domain (2D-FDFD) method is presented that could be used to analyze general circular multi-layered multi-conductor guiding structures. The FDFD method is mainly used to get the dispersion curves for these structures. The results which are obtained using the FDFD equations come through solving an eigen-value problem, where the obtained eigen-values and eigen-vectors are used to produce the propagation constants, distribution of the fields and the characteristic impedances for these structures. Several examples ranging from simple coaxial lines to coupled circular microstrip lines are presented. The FDFD results are compared with those obtained through other analytical and numerical techniques.
This paper presents the advantages of using a wideband spectrum adopting multi-carrier to improve targets localization within a simulated indoor environment using the Time of Arrival (TOA) technique. The study investigates the effect of using various spectrum bandwidths and a different number of carriers on localization accuracy. Also, the paper considers the influence of the transmitters’ positions in line-of-sight (LOS) and non-LOS propagation scenarios. It was found that the accuracy of the proposed method depends on the number of sub-carriers, the allocated bandwidth (BW), and the number of access points (AP). In the case of using large BW with a large number of subcarriers, the algorithm was effective to reduce localization errors compared to the conventional TOA technique. The performance degrades and becomes similar to the conventional TOA technique while using a small BW and a low number of subcarriers.
An exact design for seven-way Bagley power divider (7-way BPD) is introduced. The objective of this article is to derive general closed-form expressions for the impedances between adjacent ports for unequal-split 7-way BPD. The values of the impedances control the output power ratio. Full derivation of S-parameters followed by exact impedance equations will be presented. A parametric study in addition to several examples will be given to validate the proposed derivation
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