R type switch and its three different states. 7.3. T-type Switch The T-switch is another type of multiport switch that provides a high degree of flexibility in the redundancy network design [13]. It consists of four ports and six signal paths with three operational states, as shown in Fig.5. Each state has two conducting paths connecting to two pairs of ports. In State I, Ports 1 and 3, and Ports 2 and 4 are connected. In State II, Ports 1 and 4, and Ports 2 and 3 are connected. In State III, the two RF signals crossover to provide connectivity between Ports 1 and 2, and 3 and 4. The application of the T-type switch in redundancy networks is very attractive as it provides one more routing that simplifies the integration of switch matrices considerably. The latest measured data indicates that, for all of the states, the insertion and return losses are better than 1.5 dB and 20 dB, respectively. The isolation also is better than 28 dB up to 30 GHz [14].