Transmission-line model for rectangular microstrip antennas

Microstrip antennas have a physical structure derived from microstrip trans mission lines. Therefore a transmission-line model is the first and most obvious choice for the analysis and the design of microstrip antennas. However, the transmission-line model is often regarded as a simplified and somewhat dated theory. This is true for the original, simple transmission-line model; but the accuracy of the improved transmission-line model is comparable to that of other more complicated methods. Even mutual coupling between rectangular micro strip antennas can be calculated in a fairly accurate and very efficient way with the transmission-line approach. The concept of the transmission-line model can be applied to any microstrip antenna configuration for which separation of variables is possible. In this chapter we will devote our attention entirely to rectangular (and square) microstrip antennas.