A new half cymbal style piezoelectric-metal composite structure (HCPCS) membrane is proposed and utilized for piezoelectric synthetic jet actuator (PSJA) to increase its output jet velocity. PSJA specimens with both plane and HCPCS membranes were manufactured. An experimental system with hot-wire anemometer was setup to test the jet velocity. The frequency responses of time-averaged jet velocity were measured for both HCPCS diaphragms and plane membranes. The time-averaged velocity distributions were collected along the exit centerline. Experiments indicate that the HCPCS structure brings a promotion of vibration displacement distortion of diaphragm and stronger driving capability, and that the mean jet velocities synthesized from the optimal HCPCS PSJAs are higher than the optimal plane membrane one. Hilbert-Huang Transform was employed to analyze the instantaneous energy distribution characteristics of the jet. The analysis was done for signals along the centerline. The results show that HHT is an effective method for fluid field analysis.