Analysis of transmission characteristics of a circular pipe with two open ends

In this paper, we extend the modal formulation to characterize the transmission characteristics of a circular pipe with two open ends. Our interest in this problem stems from the possibility of using an open pipe as a transmission medium to propagate waves through an opaque wall at radar frequencies. We begin this study by developing an approximate solution for the transmitted field through a circular pipe with two open ends due to an incident plane wave. Transmission data are then collected in the laboratory using a circular metal pipe and the results are compared to simulation. It is shown that our formulation agrees well with the measurement data and therefore can be used as a good approximation to the transmission through a circular pipe with two open ends.