The invention provides a high-selectivity dual-
passband filter based on a triangular hairpin ring
resonator and a manufacturing method, and solves the problems that an existing dual-
passband filter is large in circuit size, poor in
passband control flexibility and insufficient in selectivity. The filter comprises a
transmission line substrate, two
microstrip feeder lines, two
microstrip feeder lines and two triangular hairpin ring resonators. The resonators are connected through double hairpin structures to form a dual-mode
resonator, are symmetrically distributed about the
coupling gap, and realize
electromagnetic coupling with the
transmission line through the
coupling gap. Two passbands are respectively formed by odd-mode
resonance and even-mode
resonance, and a transmission zero point is generated between the passbands by adjusting a
coupling gap, so that the isolation and the selectivity are effectively improved. The overall size of the filter is only 17.45 mm * 8.7 mm, the dual-passband characteristic with the
center frequency of 4.36 GHz and 6.85 GHz is achieved, the
insertion loss is smaller than 0.2 dB, the
return loss is superior to-20 dB, and the filter has the advantages of being small in size, high in selectivity, controllable in passband and the like. The method is suitable for the
wireless communication fields of double-frequency
wireless local area network (WLAN),
satellite communication and the like.