Bandwidth Limitations of TEM Cells due to Resonances

Hill, D.A.

doi:10.1080/16070658.1983.11689323

Cited by 68 publications

(26 citation statements)

References 15 publications

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“…The nonuniformity of the field pattern does not produce absorption rates differing significantly from those for the uniform-exposure case. This was proved for cylinders by showing that the absorption rates measured for five different thin cylinders in our TEM cell agreed within 20% with calculations assuming uniform exposure [Hill, 1983, Table IV] .…”

Section: Exposuresmentioning

confidence: 63%

The effect of frequency and grounding on whole‐body absorption of humans in E‐polarized radiofrequency fields

Hill¹

1984

Bioelectromagnetics

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The radiofrequency absorption rates of five male human volunteers have been measured from 3 to 41 MHz. The subjects were exposed at about 10 microW /cm2 inside a very large transverse electromagnetic (TEM) cell and never absorbed more than 1 W. Both the EKH and EHK orientations were employed under both free-space and grounded conditions. Absorption rates for the EKH orientation exceed those of the EHK orientation by 40% in free space, but only by 6% when grounded. The absorption rates for the grounded men vary with frequency, f, as f1.9 from 3 to 25 MHz and then level off at peak. The free-space absorption rates vary as f1.7 from 3 to 18 MHz and as f2.9 from 18 to 41 MHz. The average measured absorption rates at 10 MHz exceed the average of the standard model calculations by a factor of three (for free space) or four (grounded). The average man, when exposed grounded in an EKH orientation to the maximum permitted exposure levels under ANSI standard C95 .1-1982, will absorb 0.58 +/- 0.14 W/kg over most of the 3 to 41-MHz frequency range. This slightly exceeds the whole-body maximum of 0.40 W/kg underlying the standard.

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Section: Exposuresmentioning

confidence: 63%

The effect of frequency and grounding on whole‐body absorption of humans in E‐polarized radiofrequency fields

Hill¹

1984

Bioelectromagnetics

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“…The upper frequency limit for a TEM cell is determined by the appearance of high-order modes. Hill [5] has shown that significant perturbation of the internal fields within the structure exists primarily at certain discrete frequencies where resonances of the higher order mode fields occur. However, it is generally desirable to operate the TEM cell well below these cut off frequencies.…”

Section: Introductionmentioning

confidence: 99%

Quasi‐static analysis of electric and magnetic fields in tem cell

Chang

1989

Journal of the Chinese Institute of Engineers

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A method is presented whereby the electric and magnetic fields within a rectangular coaxial transmission line (TEM cell) can easily be obtained. The analysis is based on the variational technique in the space domain combined with the Green's function method. Numerical data are presented for the characteristic impedance and for the field distributions within the cell. The results calculated by the present method are found to be in good agreement with those in open literature.

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“…It is particularly advantageous when comparing it with the previously mentioned methods, because it allows the setting up of the equipment under test (EUT) in a uniform electric field. The TEM cell and the GTEM cell (a modified type of TEM cell) are nowadays widely used [2][3][4][5][6]. The reverberating chamber method (4) is applied for immunity tests at high frequency.…”

Section: Introductionmentioning

confidence: 99%

Immunity testing cell using a rectangular loop resonator comprised of a conducting channel plate and a capacitive gap

Saito

Saegusa

Hasebe

2003

Electron. Comm. Jpn. Pt. I

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SUMMARYTEM cells that are popular in immunity measurements require high operating power. In this paper, an immunity testing cell using a rectangular loop resonator is proposed. The testing cell is expected to generate high electric field strength at comparatively low power. The resonator comprises a conducting channel plate and a capacitive gap set onto the ground plane. The testing cell has a size of 1/10 wavelength at the testing frequency and therefore is suitable for immunity testing at low frequency. In this study, the electric and magnetic field distribution inside two different types of proposed resonators are analyzed by the FDTD method. Comparison of analytical and experimental results shows a close match. The electric field strength inside the two resonator types is increased by 31.2 and 14.3 dB, respectively, relative to that of the TEM cell of similar size. In the latter type of resonator the electric field deviation inside a square area of 100 mm length is suppressed to 2 dB. Moreover, the resonator covered with a shield case for practical use shows an increase of 11.2 dB in the electric field strength over the level of the similar size TEM cell. The amplitude deviation remains the same as that of the bare resonator.

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Bandwidth Limitations of TEM Cells due to Resonances

Cited by 68 publications

References 15 publications

The effect of frequency and grounding on whole‐body absorption of humans in E‐polarized radiofrequency fields

The effect of frequency and grounding on whole‐body absorption of humans in E‐polarized radiofrequency fields

Quasi‐static analysis of electric and magnetic fields in tem cell

Immunity testing cell using a rectangular loop resonator comprised of a conducting channel plate and a capacitive gap

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