Performance Analysis of On-Chip Coplanar Waveguide for In Vivo Dielectric Analysis

Integrated on-chip coplanar waveguides (CPWs) can be used as integrated dielectric sensors for chemical and physical material analyses. The experimentally estimated dielectric properties can vary depending on the measurement technique; physical characteristics, such as the dimensions of the transmission line; and the length of the test material. A critical component in the design of these systems involves the careful design of chip CPW dimensions in order to achieve acceptable accuracy. Minimizing CPW dimensions is important for medical applications where the size of the chip is a critical parameter. This paper presents the following: 1) the methods to estimate dielectric properties from CPW measurements; 2) the effect of the dimensions of the CPW sensor and the properties of test materials on the estimation of the complex permittivity; and 3) the measured dielectric properties in the 1-30-GHz range to verify the performance of the proposed system. The presented results highlight the importance of the careful consideration of the length of the CPW, the thickness of the metal layer, and the materials' thicknesses and lengths when designing a CPW for integrated on-chip sensors for the measurement of dielectric properties.