The near detector (ND280) located 280 m down the neutrino beam at the J-PARC accelerator is currently being upgraded and equipped with new sub-detectors, including a Super Fine-Grained Scintillator detector (FGD) and two High-Angle Time Projection Chambers (HA-TPCs). The readout planes of the HAT-TPCs are equipped with a new Micromegas readout technology (ERAM – Encapsulated Resistive Anode Module) that utilizes a resistive foil covering the reading pads, acting as a 2D RC network and allowing a better determination of the deposited charges position. In order to ensure that the HA-TPCs satisfy the required performances for the ND280 Upgrade (space point resolution better than 600 μm and dE/dx resolution smaller than 10%), the ERAM detectors have been characterized with X-rays sources and by exposing them to the DESY electron beam [1]. In this poster we will present the results obtained during these tests, demonstrating that the performances of the ERAM detectors largely fulfil the requirements for the ND280 Upgrade.