Performance Of A Low Loss Tunable Coupling Ratio Multiple Tap Network

The introduction of linear networks with greater than 20 nodes has been inhibited by the loss associated with conventional discrete couplers. Typical excess and insertion loss are 0.5 dB and 1.0 dB respectively. This paper describes the development of a low loss, tunable coupling ratio tap which enables the expansion of linear networks to a hundred nodes or more. It analyzes the characteristics of the coupler and shows the impact on system design and performance.