Radiation and Scattering of Waves

Felsen, Leopold B.; Marcuvitz, N.

doi:10.1109/9780470546307

Cited by 1,792 publications

(1,748 citation statements)

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“…The time-harmonic analytical expressions for the non-null EM field components E ϕ , H ρ , and H z generated on the surface of the medium can be obtained from those corresponding to source and field points located respectively at heights h and −z above the medium by setting h = 0 and z = 0. Thus, with the time-harmonic factor e jωt suppressed for better clarity, the EM field components may be expressed as [2,8,[15][16][17] …”

Section: Theorymentioning

confidence: 99%

Exact Electromagnetic Field Excited by a Vertical Magnetic Dipole on the Surface of a Lossy Half-Space

Parise¹

2010

PIER B

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Abstract-A rigorous analytical procedure is developed that allows the exact evaluation of the complete integral representations for the time-harmonic electromagnetic (EM) field components generated by a vertical magnetic dipole (VMD) lying on the surface of a flat and homogeneous lossy half-space. Closed-form expressions for the radial distributions of the EM field components induced on the surface of the half-space are provided in terms of exponential functions and modified Bessel functions. Such expressions make it possible to overcome the limitations implied by the previously published quasi-static solutions, which are valid only in the low-frequency range. Numerical results are presented to show where the quasi-static approximations deviate from the exact solutions for a given homogeneous medium as frequency is changed. The computed amplitude and phase frequency spectra of the EM field components demonstrate that the quasi-static approach produces inaccurate results at frequencies higher than 1 MHz, and that, in particular, it leads to underestimating the EM field strength. Finally, it is also shown that at a frequency equal to or greater than 10 MHz excellent results in terms of accuracy may be obtained by using the high-frequency asymptotic forms of the exact solutions.

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Section: Theorymentioning

confidence: 99%

Exact Electromagnetic Field Excited by a Vertical Magnetic Dipole on the Surface of a Lossy Half-Space

Parise¹

2010

PIER B

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“…At first the integral is cast into a form in which the range of integration extends from −∞ to ∞. Proceeding as discussed in [19] allows to derive the following representation for E ϕ (r, z) alternative to (1):…”

Section: Theorymentioning

confidence: 99%

“…where E x and E y are given by (18) and (19). The SAR is computed at depth z = 3.5 cm from the fat-muscle boundary, assuming that the coil has six turns, with a 1 = a 4 = 2 cm, a 2 = a 5 = 2.2 cm, and a 3 = a 6 = 2.4 cm, and carries a current I = 3 A at 27.12 MHz.…”

Section: Figure-eight Geometrymentioning

confidence: 99%

High-Order Electromagnetic Modeling of Shortwave Inductive Diathermy Effects

Parise¹,

Cristina²

2009

PIER

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Abstract-A high-order closed-form solution for the specific absorption rate (SAR) distribution induced inside a plane geometry fatmuscle tissue by a shortwave diathermy induction coil is presented. The solution is derived starting from the complete integral expressions for the electromagnetic field components generated by a currentcarrying circular loop located horizontally above a stratified earth. It is valid in a wide frequency range, and is flexible to any multi-turn coil configuration. The spatial distribution of the SAR induced in the muscle tissue by a flat round coil is computed by using the proposed formulation, the zero-order quasi-static one, and the finite difference time domain (FDTD) method. Excellent agreement is demonstrated to exist between the results provided by the new approach and those achieved through FDTD simulations. On the contrary, the performed computations show that the zero-order solution leads to over-estimate the SAR. The performances of the round and figure-eight coil geometries are compared. Despite of what has been argued in previously published papers, it turns out that the figure-eight coil is less energetically efficient than the round one. The work in the present paper is an extension of a previous work.

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“…Due to the needs of TD solutions, many efforts have been applied [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Typical TD approaches include using fast Fourier transform (FFT) or analytical time transform (ATT) [16,17] to directly inverse FD solutions into TD, finite difference time domain (FDTD) [18], TD integral approaches [19] and TD uniform geometrical theory of diffractions (TD-UTD) [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

A Discrete Time Electromagnetic Formulization and Its Applications

Tuan¹,

Chou²

2008

PIER

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Abstract-This paper presents a formulization of time domain (TD) discrete electromagnetic (EM) solution to provide an effective analysis over a variety of EM problems. This procedure first represents the time responses of EM fields in terms of a set of selected basis functions. Their coefficients are then employed to create matrix-form Maxwell's equations with forms analogous to frequency domain (FD) Maxwell's equations, which allows one to formulate TD solutions via utilizing their corresponding FD solutions that are existing and generally much mature. This work provides general characteristics with parts previously described in the discrete-time EM theory [20,21] and, most importantly, provides rigorous theoretical derivations in formulating the TD solutions.

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Radiation and Scattering of Waves

Cited by 1,792 publications

References 0 publications

Exact Electromagnetic Field Excited by a Vertical Magnetic Dipole on the Surface of a Lossy Half-Space

Exact Electromagnetic Field Excited by a Vertical Magnetic Dipole on the Surface of a Lossy Half-Space

High-Order Electromagnetic Modeling of Shortwave Inductive Diathermy Effects

A Discrete Time Electromagnetic Formulization and Its Applications

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