A compact microstrip elliptic function bandpass filter (BPF) is introduced in this article. The techniques, etching slot and adding open stubs with capacitive loading, are applied to enhance the self-inductance and self-capacitance of the hexagonal open-loop resonators, which increases the electrical length of the resonator. At the same time, the capacitive coupling between two hexagonal resonators is enhanced. Size reduction and improved insertion-loss performances are obtained. Compared to the conventional design, the center frequency and insertion loss of the proposed filters are reduced by 28 percent and 3.1 dB, respectively. The measurements show that the proposed filter, called Type II, has a fractional bandwidth of 23 percent at the center frequency of 1.84 GHz and its insertion loss in the passband is less than 1.5 dB. The BPF occupies only 12 x 21.2 mm.