In this paper, a compact and tunable dual-band microstrip bandpass filter is proposed for WiMAX and WLAN applications. The filter is designed using a combination of ring-shaped, parenthesis-shaped, and semi-circular resonators to achieve a simple structure with enhanced performance. The proposed configuration enables independent tuning of the second passband frequency by adjusting only a single geometrical parameter, without modifying the overall structure. The filter is designed to operate at center frequencies of 3.6 GHz and 5.7 GHz. Simulation and measurement results show that the proposed filter exhibits low insertion loss (0.81 dB and 0.9 dB), high return loss (20.54 dB and 20.68 dB), sharp roll-off characteristics, and wide stopband suppression extending up to 12 GHz. Compared to previously reported works, the proposed filter offers a simpler structure, improved tunability, and competitive performance in terms of size and frequency response. The good agreement between simulated and measured results validates the effectiveness of the proposed design.