Modal cutoff in coaxial transmission lines of conical and cylindrical geometries// IEEE MTT-S International Microwave Symposium Digest, Boulder, USA, May 20–25, 2001: 1229–1232. WEIL C M, RIDDLE B F, NOVOTNY D R, et al. Calibration of broadband RF field probes using a coaxial conical transmission line// Proceedings of 14th International Conference on Microwaves Radar and Wireless Communicationse, Boulder, USA, May 20–22, 2002: 404–407. A new broadband RF field standard using a coaxial transmission line of conical geometry: progress report// Proceedings of 23rd AMTA Meeting, Denver, USA, October, 2001: 14–19. IEEE Transaction on Intrumentation and Measurement, 2009, 58(4): 1109–1113. Characterization method of electric field probe by using transfer standard in GTEM cell. Probe response to a non-uniform e-field in a TEM cell// Conference on Precision Electromagnetic Measurements, Daejeon, Korea, June 13–18, 2010: 327–328. On the use of TEM cells for the calibration of power frequency electric field meters. New York: The Institute of Electrical and Electronics Engineers Inc., 2005. IEEE Std 1309TM - 2005 IEEE Standard for Calibration of Electromagnetic Field Sensors and Probes, Excluding Antennas, from 9 kHz to 40 GHz. Standards Development Committee of the IEEE Electromagnetic Compatibility Society, American National Standards Institute. This paper presents numerical calculation data and theoretical analysis to design key structural parameters for the co-conical transverse electromagnetic wave cell(co-conical TEM cell). The simulation plots show that transmission of high-order modes appears with electromagnetic wave reflection, then different high-order mode transmission has different cut-off region and each cut-off region is determined by its cut-off wavelength.
#Schelkunoff electromagnetic waves software#
The propagation process of the first three transmitting modes wave is simulated in CST-MWS software from the same structured co-conical. Relationship between roots and high-order modes transmission is analyzed, when the half angles of inner conductor and outer conductor are θ 1=1.5136° and θ 2=8° respectively, the co-conical cell has better performance for fewer transmitting high-order modes. The associated Legendre control functions of high-order modes are calculated by using recursion methodology and the numerical calculation roots are presented with different half angles of inner and outer conductor. For designing a high performance cell, a mathematic model of high-order modes transmission is built according to the geometrical construction of co-conical. Existing research is only qualitative because of the complexity of theoretical calculations.
For this reason we feel that these methods are preferable to those based on the Kirchhoff formula.In order to solve the problem of broadband field probes calibration with only selected discrete frequencies above 1 GHz, a sweep-frequency calibration technology based on a coaxial conical(co-conical) cell is researched.
The calculations of diffracted fields and radiation fields, based either on the Equivalence Principle or on the more general Induction Theorem, depend upon a priori verifiable approximations to the actual fields in the neighborhoods of the sources of the diffracted and radiated waves. If, on the other hand, this formula is applied to some auxiliary vector potential from which the diffracted field is subsequently deduced by differentiation, the result (although consistent with Maxwell's equations) depends on the particular choice of the auxiliary vector and in some instances, at least, is obviously unreasonable (Appendix III). If the Kirchhoff formula is applied directly to the field intensities of the incident wave over the aperture, the diffracted field is found to be inconsistent with Maxwell's equations. Inasmuch as it is rarely possible to treat diffraction of electromagnetic waves exactly, the Kirchhoff formulation of Huygens' Principle has been frequently used in approximate calculations.
0 kommentar(er)
