Radiation and scattering from ferrite-tuned cavity-backed slot antennas: theory and experiment

Polycarpou, Anastasis C.; Balanis, C.A.; Aberle, J.T.; Birtcher, Craig R.

doi:10.1109/8.719973

Cited by 29 publications

(29 citation statements)

References 17 publications

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“…However, the actual magnetic field distributions are not uniform; therefore, the assumption of the uniform fields was introduced by averaging these distributions. Although the results presented in [12] are in good agreement with measurements, we were able to show that by removing the above-mentioned assumptions it is possible to obtain slightly more accurate predictions at the expense of a more complex procedure [13].…”

Section: What Has Been Done?supporting

confidence: 52%

“…• Demonstrate that the procedures used in [12] and [14] are unable to provide adequate accuracy in designs with severe non-uniformities in the magnetic bias field.…”

Section: What Am I Going To Do?mentioning

confidence: 99%

“…Non-uniform biasing is achieved by subjecting the ferrite material to a severely non-uniform applied magnetic field. The input impedance of such an antenna is computed using procedures outlined in [12], [14], and the by solving the antenna radiation problem using the hybrid FEM/MoM technique or pure FEM outlined in Chapter 2. To solve this problem, it is necessary to know the frequency dependent permeability tensor for the ferrite material.…”

Section: How Am I Going To Do It?mentioning

confidence: 99%

“…Computation of the uniform field is based on the average applied field and the ballistic demagnetizing factor. This approach was used in [12], and it will be briefly discussed in Section 4.1. Non-uniform internal magnetic field can be computed in a number of ways with varying degree of accuracy.…”

Section: How Am I Going To Do It?mentioning

confidence: 99%

“…Non-uniform internal magnetic field can be computed in a number of ways with varying degree of accuracy. One way is to follow the procedure of [12], but replace the average applied field with the actual field distribution and the ballistic (scalar) demagnetizing factor with its tensorial form. This approach was examined in [13] and will be omitted here.…”

Section: How Am I Going To Do It?mentioning

confidence: 99%

See 4 more Smart Citations

Analysis, Simulation and Measurements of CBS Antennas Loaded With Non-Uniformly Biased Ferrite Material

Kononov

Balanis

Birtcher

2012

IEEE Trans. Antennas Propagat.

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When ferrite materials are used in antenna designs, they introduce some interesting and unique performance characteristics. One of the attractive features, for example, is the ability to reconfigure the center frequency of the antenna. In addition, ferrite materials also introduce a number of challenges in the modeling and simulation of such antennas.In order for the ferrite material to be useful in an antenna design, it usually is subjected to an external magnetic field. This field induces the internal magnetic field inside the ferrite material. The internal field plays a pivotal role in the radiation characteristics of the antenna. Thus, from the numerical point of view, accurate computation of this field is critical to the overall accuracy of the analysis. Usually the internal field is non-uniform and its computation is often a rather complex and nontrivial task. Therefore, to facilitate the modeling, simplifying assumptions, which introduce some kind of averaging, are often made.In this study, ferrite-loaded cavity-backed slot antennas are used to demonstrate that averaging procedures can lead to very unsatisfactory results. For instance, it is common practice to assume that the external field is uniform by averaging its distribution. One of the pivotal points in this study is the demonstration that the external magnetic field plays a very significant role and should be included in the modeling without averaging, if the accurate results are to be attained. Results presented in this study clearly support this argument. A procedure which avoids such averaging is presented and verified by comparing simulations with measurements. In contrast to the previous formulations, the modeling methodology developed in this dissertation leads to accurate results which compare very well with measurements for both uniform and non-uniform field distributions. The utility of this methodology is especially evident for the case when the magnetic field is severely non-uniform. i

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Section: What Has Been Done?supporting

confidence: 52%

“…• Demonstrate that the procedures used in [12] and [14] are unable to provide adequate accuracy in designs with severe non-uniformities in the magnetic bias field.…”

Section: What Am I Going To Do?mentioning

confidence: 99%