Millimeter wave (mmWave) is an interesting research area in recent years. Transition connectors are key components of mmWave passive systems. The commercially available cable connectors are lossy and expensive in mmWave frequencies. In this paper, various PCB-based transition connectors for 2.92mm and SMPM have been designed, fabricated and measured. The measured results show high performance transitions in terms of impedance matching and insertion loss below 0.85dB up to 40 GHz. The proposed designs are low cost, low loss and applicable for interconnection and test measurement purposes in various mmWave wireless technologies such as 5G, radar and satellite communications up to 40 GHz.