Dual-band dual-mode bandpass filters with good selectivity and wide upper-stop- band performance based on circular ring resonator is presented. The two first-order degenerate modes are excited and split to form the first passband, while one of the third-order degenerate modes forms the second passband together with a second-order degenerate mode. After installing two parallel-coupled-line sections on a ring at the two ports with 90◦ -separation, five transmission zeroes are produced for the rejections between the two passbands and in the stopband. A dual- band filter with the two transmission poles in each passband is designed and measured, the measured filter shows good agreement with the simulated.