Capacitance Calculation of Long Straight Line Conductors Using the Method of Moments

The Method of Moments for calculating capacitance of long straight line conductors is a classical numerical computation technique in electromagnetic field analysis. This method is primarily used to solve capacitance characteristics of conductors in electrostatic fields, particularly suitable for conductor systems with simple geometric shapes. Regarding computational principles, the Method of Moments discretizes the conductor surface into multiple small segments, assuming uniform charge distribution on each segment. It then establishes corresponding integral equations, transforming continuous problems into discrete matrix equations. By solving this matrix equation, the charge distribution on the conductor surface can be obtained, subsequently calculating the system's capacitance value. For simple geometries like long straight conductors, the computation process can be significantly simplified. Due to the linear symmetry of the conductor, one-dimensional discretization can be employed, substantially reducing computational complexity. In MATLAB implementation, key steps include: setting conductor geometric parameters, discretization processing, coefficient matrix construction, linear equation system solving, and final capacitance value calculation. The implementation typically involves functions like `linspace` for segmentation, matrix operations using backslash operator or `linsolve`, and potential custom functions for Green's function integration. Practical applications require attention to the ratio between conductor radius and length, as this parameter significantly affects calculation accuracy. Simultaneously, discretization density must be appropriately chosen - overly dense discretization increases computational burden while sparse discretization compromises precision. Code implementation should include parameter validation checks and convergence testing loops. This computational method has extensive application value in electromagnetic engineering fields such as transmission line analysis and antenna design, providing important theoretical references for engineering design. The MATLAB code structure typically follows a modular approach with clear separation between geometry setup, matrix assembly, and solution phases for maintainability.