This paper proposes a novel textile antenna with body humidity sensing function for communication by body area network (BAN) applications. The chosen design of aperture coupled antenna which is weakly coupled to an interdigitated capacitor (IDC) that serves the dual purpose of antenna in the 2.5 GHz band (Industrial, Scientific and Medical (ISM), the latter enabled by a film of polyimide deposited on the IDC surface and the sensing function. The simulated and measured results show that the IDC antenna sensor has a good radiation pattern for every 10g of tissue. A change in the dielectric permittivity of the antenna is transduced into a variation of resonant frequency due to polyimide s high sensitivity towards humidity. We demonstrate the measured sensing performance at different relative humidity concentrations.