In the present work some novel techniques for an efficient numerical analysis of printed microwave circuits and antennas etched in layered media have been proposed.

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CONCLUSIONS

In the present work some novel techniques for an efficient numerical analysis of printed microwave circuits and antennas etched in layered media have been proposed.

In the first chapter a detailed description of a fast and reliable procedure to evaluate the Green’s function for a multilayered dielectric environment has been provided. In particular the proposed method is able to face the difficulty with the numerical computation of the Sommerfeld Integral related to the oscillatory and slowly decaying nature of its integrand.

This useful groundwork has been employed in the second section for a versatile implementation of an electromagnetic “full-wave” solver implementing the Method of Moments for the analysis of printed circuits and antennas etched in multilayered media.

In the third chapter, a new interpolation technique for the MoM impedance matrices associated with planar microstrip structures has been presented. The proposed scheme relies on a cubic spline polynomial fitting approach and extracts analytically the Green’s function singular behavior when the distance between source and observation point is extremely small. Though not discussed here, the developed technique can be applied to the electromagnetic analysis of three-dimensional conducting object situated in a planar-stratified layered medium. The algorithm has been applied to some common planar microstrip problems in order to prove the accuracy and the numerical efficiency of the presented scheme obtaining always accurate results even at frequencies near the resonances and with a considerable time saving.

In the last chapter, some novel schemes for an efficient MoM analysis of

planar patch arrays and microstrip circuits involving a large number of

unknowns have been proposed. Several different examples have been

reported in order to prove the accuracy and numerical efficiency of

developed techniques. An excellent agreement for the S-parameters and

the related results has been achieved between the new and the direct

method. In particular, we have developed a new CBFM two-step strategy

for the analysis of microstrip circuits etched in layered media. The CBFM-

EMA, which is employed for the preliminary design, replaces the stratified

medium with a semi-infinite homogeneous grounded slab whose Green’s

Functions can be derived analytically. The proposed approach leads to a

CONCLUSIONS

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considerable time-saving when compared to the conventional approach thanks to the analytical nature of the equivalent Green’s Function which is composed only of the direct ray and a reflected one due to the ground plane image for this case. This method is well suited for rapid prototyping of a circuit with reasonable accuracy.

Once this first step has produced the initial design, a more accurate

approach, the CBFM-SP, is involved for a more accurate analysis. The

CBFM-SP employs the same approach exploited in the first step to evaluate

the CBFs but uses the rigorous spectral domain DGFs (which can be

evaluated analytically) to determine the expansion coefficients leading to

more accurate results with respect to the CBFM-EMA and results faster

than classical techniques for analyzing problems with a large number of

unknowns.