Microwave crossovers based on coupled line couplers

Annotation: The microwave crossovers with a pair of directional couplers based on coupled lines with a tight 3-dB coupling are analyzed. On the basis of three types (contra-, co-, and trans-) directional couplers connected in three schemes: tandem, cascade and parallel, respectively, crossovers with a total coupling of 0 dB are constructed. The frequency characteristics of a crossover based on trans-directional coupler are presented for the first time. Modeling and computer simulation have shown that tandem crossovers based on the contra-directional couplers have the superiority in terms of the working frequency band (with a decoupling level of more than 15 dB) with a bandwidth of 73% versus 26 and 25% for cascade and parallel crossovers based on (co- and trans-) directional couplers, respectively. The results can be used when finding the optimal crossover design solution that meets the specified technical requirements.

Keywords: microwave crossover, coupled lines, directional coupler, contra-directional coupler, co-directional coupler, trans-directional coupler, tandem connection, cascade connection, parallel connection