Conformal Mapping for Multiple Terminals

TL;DR

This paper introduces a conformal mapping technique for multiple terminals, enabling more accurate solutions in electrostatics and optics by properly handling additional boundaries within the mapped domain.

Contribution

It presents a novel conformal mapping method for multiple terminals, improving accuracy over previous two-terminal approaches in practical applications.

Findings

More precise electrostatic actuator modeling with three electrodes.

Enhanced light beam splitter design with three ports.

Method effectively incorporates multiple boundaries without influencing the solution.

Abstract

Conformal mapping is an important mathematical tool in many physical and engineering fields, especially in electrostatics, fluid mechanics, classical mechanics, and transformation optics. However in the existing textbooks and literatures, it is only adopted to solve the problems which have only two terminals. Two terminals with electric potential differences, pressure difference, optical path difference, etc., can be mapped conformally onto a solvable structure, e.g., a rectangle, where the two terminals are mapped onto two opposite edges of the rectangle. Here we show a conformal mapping method for multiple terminals, which is more common in practical applications. Through accurate analysis of the boundary conditions, additional terminals or boundaries are folded in the inner of the mapped rectangle. Then the solution will not be influenced. The method is described in several typical situations and two application examples are detailed. The first example is an electrostatic actuator with three electrodes. A previous literature dealt with this problem by approximately treat the three electrodes as two electrodes. Based on the proposed method, a preciser result is achieved in our paper. The second example is a light beam splitter designed by transformation optics, which is recently attracting growing interests around the world. The splitter has three ports, one for input and two for output. Based on the proposed method, a relatively simple and precise solution compared with previously reported results is obtained.