LAUSR

ABSTRACT A new compact dual-band rejection filter using multilayered stepped impedance loaded-resonator (SILR) is proposed in this article. The stepped impedance loaded-resonator is a dual-mode resonator. The filter structure is compose of two circuits patterned on three layers using two substrates. On the bottom double layer substrate, two SILRs are designed and coupled to generate and control the bandwidths of the first and second bandstops. To achieve the frequency response of the desired filter, a signal path transmission line is realized on a top single layer substrate and vertically coupled to the bottom substrate circuit. To validate the developed approach, a dual-band rejection filter is designed and fabricated to reject the frequencies of 2.4 GHz WLAN and 3.5 GHz WiMax systems. The simulated and measured responses are in good agreement. The resulted filter offers small size, good isolation passband and high selectivity performance with favourite transmission poles around the desired rejection bands.