This article presents a compact microstrip bandpass filter (BPF) design for the 2.45 and 5.25 GHz wireless local-area network (WLAN) applications. U-shaped quarter-wavelength stepped-impedance resonators (λ/4 SIRs), for which the circuit size is small and the second resonant frequency can be tuned over a wide range, are adopted in the BPF design. It is shown that the first spurious passbands of the resultant filters are farther away from their second passbands than are those of the corresponding filters using half-wavelength SIRs. Experiments on a second-order and a fourth-order BPF are conducted for validating the filter performance. Good agreement between the measured and the simulated results are observed.
關聯:
Microwave and Optical Technology Lett., 49(1): 164-168
