Design and implementation of 3-D recursive digital filters by applying spectral transformations to LC filter networks

A spectral transformation technique is proposed for the design of three-dimensional recursive digital filters having planar and beam frequency responses. Circuit-theoretic concepts are used to generate stable 3-D continuous-domain networks from a corresponding one-dimensional prototype network. Implementation schemes are developed in the discrete domain that convert the 3-D analog network into a 3-D wave digital filter (WDF). The proposed 3-D discrete beam and planar filters offer significant advantages over direct-form realizations including the low-sensitivity properties of the WDF and simplicity of the structure. It is concluded that the proposed methods are well suited for VLSI hardware implementation and may be helpful in proceeding to real-time 3-D filters