Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 108

If the excitation source is connected only to the j^th port and the response is seen at the i^th port, while all other ports are terminated in their characteristic impedances, it leads to . It shows that the excitation is zero at all ports, except at the j^th port. The transmitted power, i.e. the scattered power, from the j^th port is available at all ports, i = 1, 2, …, k. However, at the j^th port, a part of the incident power appears as the reflected power. The transmission coefficient, S_ij for the power transfer from the j^th port to the i^th port is defined as

(3.1.42)

Normally, the network has identical port impedances and equal to the system impedance, i.e. Z_0i = Z_0j = Z₀. Equation (3.1.40) is written in compact form as

(3.1.43)

The elements of the [S] matrix are determined using equations (3.1.41) and (3.1.42).