Microstrip-slotline components for microwave IC's

Evidence is presented that the microstrip-slotline coupler can be used instead of the microstrip coupled transmission line (CTL) in situations requiring tight coupling, i.e., 1.5 to 4 dB. The paper presents examples of new microwave passive components which are directly derived from the idea of the microstrip-slotline coupler. Attention is given to the three-section maximally flat 3-dB coupler and to the filtering section obtained as a result of opening the coupled and through ports of the microstrip-slotline four-port. In conclusion, microstrip-slotline coupler sections capable of achieving tight coupling are useful in constructing multielement, wideband couplers and bandpass filters.