中文摘要：

基于新型的加载非对称开路枝节的阶梯阻抗谐振器，设计了一种具有高频率选择性的单频微带滤波器。该滤波器采用非对称的开路枝节作为容性负载，抑制高次杂散频率，具有较宽的上阻带，中心频率（2．4GHz）处的插入损耗为0．6dB。与传统结构相比，该滤波器在相同的谐振频率下尺寸减小了45％。调整新型阶梯阻抗谐振器的尺寸，还能实现中心频率为3．5GHz单频和2．4GHz／3．5GHz双频带通滤波器。

英文摘要：

A novel microstrip bandpass filter using stepped impedance resonators（SIRs） with asymmetric open stubqoaded is presented in this paper. The proposed filter which operates at 2.4 GHz with low insertion loss of 0.6 dB uses asymmetric open stubs as capacitive loads, resulting in higher-order spurious frequencies suppression and wider upper stopband. Compared with the traditional filter based on stepped impedance resonators at the same resonant frequency, the proposed filter can significantly reduce the circuit size of 45 %. By changing the geometric dimensions of the asymmetric open stub-loaded SIRs,which can achieve single-band bandpass filter at the centre frequency of 3.5 GHz and dual-band bandpass filter at the centre frequency of 2.4 GHz/3.5 GHz.