Abstract-In this paper, a 2 × 1 duplex antenna array with small frequency space and high isolation between transmitting and receiving bands is presented. The duplex antenna array element consists of a pair of radiating patches for bidirectional radiation, a set of microstrip resonator and H-slot resonator coupled to the patches for transmitting, and the other set of microstrip and H-slot resonators coupled to the patches for receiving. The H slots are designed for the operations of coupling and the elements of the bandpass filters. The two antenna elements of the 2 × 1 array are connected by transmitting and receiving channels microstrip power-split resonators. The array achieves a compact size and high performances in terms of high isolation and small Tx-Rx frequency space. Higher than 30 dB and 40 dB ports isolation at 1.94-1.99 GHz and 2.43-2.52 GHz is realized. And the Tx-Rx frequency space Δf = (f r − f t ) is smaller than 0.23 times of the central frequency (f r + f t )/2.