Solving Resonance Problems in Transitions: End-Launch Connector Considerations for Coaxial-to-Microstrip Transitions

Coaxial-to-microstrip transitions are usually a required part of microwave and millimeter-wave products that feature microstrip-based circuit designs. The transitions not only facilitate device testing; they also benefit system assembly and integration. To meet the growing demand for high-speed data rates from wireless communication systems, broadband behavior has become a desired feature for microstrip-based circuits as well as their coaxial-to-microstrip transitions. The conventional design for coaxial-to-microstrip transitions suffers severe insertion loss at higher frequencies. This problem adds inaccuracy to broadband measurements when the equipment requires minimum power. The design also fails to deliver maximum power to radiators for high-frequency measurements when the transition is involved in the feed network for planar antennas. Therefore, improving the high-frequency performance of coaxial-to-microstrip transitions has become an important subject for microwave engineering.