Wideband voltage source design for EIT systems

The excitation source is a major component in bio-impedance measurement systems. Electrical Impedance Tomography can be performed by injecting current and measuring the resulting voltages, or by applying voltages and measuring the current developed. Interesting characteristics of breast tissues mostly lie above 1 MHz; therefore a wideband excitation source covering higher frequencies (i.e. above 1 MHz) is required. This paper proposes a voltage controlled voltage source (VCVS), which can be used over a wide bandwidth (100 Hz-20 MHz). This paper describes the performance of the designed EIT voltage source for different load conditions and load capacitances. The objective of this research is to establish a viable bandwidth envelope that can be used to design a constant EIT voltage source over a wide bandwidth for practical implementation. Simulation data obtained using Pspice is used to demonstrate the high-bandwidth performance of the source.