Synthesis Method for Low Ripple 1-D and 2-D Uniform Microwave Field via Spatial Spectrum Low-Pass Filtering

Uniform microwave field (UMF) plays an important role in medical, industrial and measurement in recent decades. It is a challenging problem to avoid Gibbs phenomenon in synthesizing UMF since the infinite spectrum component. In this letter, an analytical synthesis method based on spatial spectrum low-pass filtering (SSLPF) is presented to shape low ripple UMF. The angular spectrum projection (ASP) principle is used as the foundation and combined with Fejer and Gauss-Weierstrass summation theory, which have better convergence than Fourier summation, to the reconstruction of low ripple UMF. Thereby, the proposed method not only keeps the analyticity of ASP but also has a better effect on reducing the ripple. Finally, several full-wave simulations are provided and the results demonstrate the validity and efficiency of the proposed method.