Extending the operation frequencies of standard coaxial-to-microstrip connectors

A new connector for coaxial-to-microstrip transitions is proposed. The structure designed for the transformation of the electromagnetic field distributions of a coaxial line and a microstrip line consists of two blocks split from a metallic ring and two parallel arrays of via holes embedded in the substrate of the microstrip line. Insertion loss caused by a field discontinuity at their transition is reduced, particularly at higher frequencies. Thus, the transmission passband of the transition is extended. A prototype of the new connector is prepared and its transition to a microstrip line with two embedded via arrays is simulated and measured for a design example. The results indicate that the proposed design can improve the 1-dB passband of the transition by more than 60% compared to the conventional design.