This paper presents the design of low cost FR4 substrate trapezoidal patch microstrip feed antenna array for low frequency wireless medical applications. Initially, single element trapezoidal patch antenna having size of 70 × 30 mm2 has been designed and then the 2 × 2 array has been achieved for bandwidth improvement with low loss in same dimension. The array resonates at 1.891 GHz with impedance bandwidth of 80 MHz and low return loss of − 26.19 dB. The VSWR of 1.103 validate the activeness of the proposed antenna array having maximum surface current 133.1 (A/m) and directivity of 4.48 dBi. The antenna array exhibit the H-Field strength of 160.52 (A/m) and E-Field of 36,093.4 (V/m) prove the radiation capability at low frequency on body application. The antenna has been simulated in low frequency L band from 1 to 2 GHz and compared with other works in literature. The radiation property of proposed array validate it uses in low frequency biological imaging application for visual representation of interior body for medical diagnosis and interventions.