In　this　article,　an　analytical　equivalent　circuit　model　is　established　for　the　piezoelectric　micromachined　ultrasonic　transducer　(PMUT)　cell　and　array　with　a　combination　of　the　annular　and　circular　diaphragms　used　for　structural　optimization　and　complex　array　design.　Based　on　this　model,　a　comprehensive　analysis　is　conducted　on　the　acoustic-structural　coupling　of　an　annular　and　circular　diaphragm-coupled　PMUT　(AC-PMUT)　with　a　new　excitation　method.　The　model-derived　results　are　in　good　agreement　with　the　simulation　and　experimental　results.　Then,　an　optimized　design　has　been　presented　to　achieve　high-output　pressure　and　a　good　array　working　performance.　In　summary,　a　comparison　of　the　array　working　performance　is　conducted　between　the　arrays　that　consist　of　AC-PMUTs　and　traditional　circular　diaphragm　PMUTs　(C-PMUTs).　The　results　indicate　that　the　AC-PMUT　array　has　a　much　lower　crosstalk　effect　than　that　of　the　traditional　C-PMUT　array.　By　this　means,　the　AC-PMUT　array　can　fully　use　the　high　vibration　amplitude　achieved　by　each　AC-PMUT　cell　to　improve　its　output　ability.　As　a　result,　the　highest　ultrasonic　output　pressure　generated　by　the　AC-PMUT　array　in　its　resonant　condition　can　achieve　an　increase　of　155%,　compared　with　that　generated　by　the　C-PMUT　array.　©　1986-2012　IEEE.