A microstrip tri-band bandpass fllter (BPF) based on three embedded bending stub resonators (EBSRs) is proposed in this paper. Three resonant paths that resonate at three difierent frequencies can achieve three passbands. The lumped circuit models of the proposed fllter are given for designing. The fllter is extremely compact, whose area is about 0:047‚g £ 0:12‚g. There are two transmission zeros located between the flrst two passbands and a transmission zero between the second and third passbands, which results in good selectivity. For demonstrating the proposed fllter structure, a fllter at 0.9/2.14/3.6GHz is designed and fabricated. The measured results are well agreed with simulated ones, which indicate the validity.