Radio Frequency Circuit Design, 2nd Edition

APPENDIX ETermination of a Transistor Port with a Load

In the three-port circuit in Fig. E.1 one of the three ports is terminated with an impedance that has a reflection coefficient relative to the reference impedance Z_ref:

(E.1)

FIGURE E.1 Three-port with source terminated with r_s.

In this expression the subscript i represents s, g, or d, depending on whether the device connection is common source, gate, or drain terminated with Z_s, Z_g, or Z_d . For example, r_s = a₂/b₂ in Fig. E.1 or b₂ = a₂/r_s . This is substituted in the appropriate place in the following equations. The incident and scattered waves from the three-port circuit are

(E.2)

(E.3)

(E.4)

When one of the ports is terminated with r_i, then the circuit really is a two port. The scattering parameters for the common source, gate, and drain connection follow:

Common Source

(E.5)

(E.6)

(E.7) ...