In view of providing consistent power to remotely situated microelectronic devices, this paper proposes a full‐length cavity‐based novel segmented doubly clamped piezoelectric energy harvester (DCPEH). The paper starts with the analysis of different possible configurations of segmented DCPEH beam corresponding to single, double, and triple cavity systems involvement. It has been observed that for full‐length single cavity involvement, the segmented DCPEH beam is resonate at minimum value (70 Hz) of resonance frequency. However, the observed value of output power response (76 mW) at such low resonant frequency is not so appropriate. Therefore, the performance of full‐length cavity‐based segmented DCPEH beam has been further investigated for series and parallel composite structural design of PMN‐35%PT (M1) and PZT‐5H (M2) piezoelectric materials. The improved value of output power (313 mW) response at low (68.8 Hz) resonant frequency has been achieved with M2‐M1 series composite form of piezoelectric materials.