論文ID: 13.20161049
A novel ultra-wideband (UWB) bandpass filter with high selectivity and compact size is proposed in this letter. The major architecture of this filter is a coplanar waveguide (CPW)-microstrip-CPW transition from broadband balun mechanism. This structure has UWB bandpass characteristic and a transmission zero at its lower transition band. And some complementary split ring resonators (CSRR) are added in the ground of microstrip. A transmission zero located in upper transition band of filter is introduced by these CSRRs. Besides, the size of filter is only 0.25λg×0.36λg (λg is the guided wavelength of 6.85GHz). Finally, a filter prototype is fabricated and measured. The measured results show that its 3dB passband covers 2.9 to 11 GHz. And two transmission zeros are located at 2.45 GHz and 11.45GHz, which means the proposed filter presents high selectivity of 0.9 skirt factor.
