**Abstract**

Metal-matrix embedded phononic crystals (MMEPCs) can be applied for noise and vibration reduction. Metal-matrix embedded phononic crystals (MMEPCs) consisting of double-sided stubs (single "hard" stubs/composite stubs) were introduced. The introduced MMEPCs are deposited on a twodimensional locally resonant phononic crystal plate that consists of an array of rubber fillers embedded in a steel plate. The lower frequency complete bandgap will be produced in the MMEPCs with composite stubs by decoupling the spring-mass system of the resonator by means of the rubber filler. Then, the out-of-plane bandgap and the in-plane bandgap can be adjusted into the same lowest frequency range by the composite stubs. The broad complete bandgap will be produced in the metal-matrix embedded phononic crystals with single "hard" stubs by producing new kinds of resonance modes (in-plane and out-of-plane analogous-rigid modes) by introducing the single "hard" stubs, and then the out-of-plane bandgap and the in-plane bandgap can be broadened into the same frequency range by the single "hard" stubs. The proposed MMEPCs can be used for noise and vibration reduction.

**Keywords:** metal-matrix embedded phononic crystals, lower frequency complete bandgap, broad complete bandgap, forming mechanisms of the bandgap, noise, vibration reduction
