Approximate Synthesis of Tem Mode Transmission-Type Directional Filters

An approximate synthesis technique is described for TEM mode transmission-type directional filters for which only a hand-held electronic calculator is required to compute the element values. In the example given the element values differ by less than 1.5% from the values calculated by an exact technique. The sole disadvantage of this approximate method is that one cannot accurately predict the response of the filter in the very far stopband.