Rigorous Calculations of Lumped Electrical Parameters for a Microstrip Interdigitated Electrode Structure
Abstract
This research investigates a microstrip interdigitated electrode structure used in integrated circuit sensors and presents an electrical model for the device. The structure is assumed to: (1) have a periodic arrangement of interdigitated electrodes, (2) have electrodes of sufficient length to ignore effects created by the ends of the structure, (3) be operating at a sufficiently low frequency, where the potential is essentially constant along the electrode's length and where the substrate is essentially a conductor, and finally (4) have five layers of homogeneous, isotropic, non-magnetic material in the plane transverse to the structure's length. Within these constraints, the problem focuses on solving for the potential distribution using Laplace's equation. The electrical model developed consists of three elements--a capacitance from each of two electrodes to ground, a capacitance between the electrodes, and a resistance through the sensor coating. The values for the individual elements are found from the potential solution. Potential functions, in the form of infinite Fourier series, are developed for each layer within a periodic cell. The coefficients of the Fourier series are determined by matching boundary conditions across interfaces between the material layers. These coefficients are estimated numerically by truncating the infinite series, and solving a linear system of equations. Results are presented for a variety of cell parameters (cell dimensions and material properties), which illustrate the dependence of the individual elements on these cell parameters. Theses. (JHD)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA215337
Entities
People
- Henry P. Leal
Organizations
- Air Force Institute of Technology