A stripline re-entrant coupler network for cofired multilayer microwave circuits

A stripline coupler network is presented that is suitable for cofired multilayer circuit applications. The network contains a tandem arrangement of two re-entrant coupler structures that can provide tight coupling (3 dB) and is insensitive to conductor registration or misalignments. In addition, circuit modeling and EM simulation for a coupler design using Low Temperature Cofired Ceramic (LTCC) is presented along with experimental results.