摘要:

Coupled-line digital frequency multipliers are described from the frequency domain behaviour, where certain discrete frequency components of input pulses are eliminated and others are passed with minimum attenuation. The simulated waveforms from measured data are found to be in good agreement with experiments. The proposed multipliers can function under TEM wave propagation. The effect of unequal phase velocities is also considered.

DOI:10.1049/ip-h-2.1992.0049

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A method for the computation of radiation patterns of microstrip antennas on substrates of finite dimensions by a combination of the mixed potential integral equation technique (MPIE) for patch antennas and the weak form of the conjugate gradient — fast Fourier transform (WCG-FFT) method for the scattering by the finite ground plane is presented. The computation is carried out in three steps. The MPIE formulation is first used for the accurate evaluation of the current distribution on the conducting surface of the patch. Using these currents as primary sources, equivalent polarisation currents in the dielectric slab are then evaluated. These two steps are based on the infinite grounded dielectric slab assumption. Finally the current distribution on the finite ground plane is determined using the WCG-FFT method. Since matrix inversion is not involved in the last step, the method is very convenient for treating small to moderate size ground planes. An alternative approach for the derivation of far field patterns of microstrip antennas on an infinite grounded dielectric slab using the volume equivalence theorem and image theory is also presented. Numerical results of radiation patterns have been verified experimentally.

DOI:10.1049/ip-h-2.1992.0050

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Characteristic mode theory is presented as a method of calculating the characteristic currents, the equivalent magnetic current, the radiation patterns, and the field everywhere (especially in the aperture region) of an infinitely long, thin, perfectly conducting cylinder with an infinitely long slot illuminated by a uniform transverse magnetic (TM) plane wave to the slot. The characteristic modes obtained are the solution of an eigenvalue equation representing the continuity of the tangential component of the magnetic field in the slot.

DOI:10.1049/ip-h-2.1992.0051

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A modified indirect boundary element formulation is developed following a weighted residual approach. In this formulation, the fictitious source density, which appears in the integral equations of the method, is distributed on a surface which is exteriorly separated from the physical field boundary of the problem. The method does not require the evaluation of singular integrals and produces undeteriorated solutions at geometric discontinuities. The technique is applied to two-dimensional electromagnetic potential problems, and several examples are investigated.

DOI:10.1049/ip-h-2.1992.0052

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Metallic tape is commonly used to cover the interpanel gaps which occur in panelled compact-range reflectors. It is therefore of interest to study the effect of the scattering by the tape on the field in the target zone of the range. An analytical solution is presented for the target zone fields scattered by 2D metallic tapes. It is formulated by the generalised scattering matrix technique in conjunction with the Wiener-Hopf procedure. An extension to treat 3D tapes can be accomplished using the 2D solution via the equivalent current concept. The analytical solution is compared with a reference moment method solution to confirm the accuracy of the former.

DOI:10.1049/ip-h-2.1992.0053

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Whispering gallery modes in high permittivity right cylindrical dielectric resonators are shown to be very useful at millimetre wavelengths since they offer a highQfactor and their oversized dimensions make them easy to manufacture. Using a dielectric waveguide model, simple expressions are generated that accurately predict the resonant frequencies of the WGE whispering gallery modes within right cylindrical dielectric resonators placed on a dielectric integrated circuit substrate of lower permittivity. Theoretical and experimental results are given and the accuracy of the proposed model is shown to be good.

DOI:10.1049/ip-h-2.1992.0054

出版商:IEE    

年代:1992

数据来源: IET