Double-Layered T-Shape Loaded Hairpin Resonator for High Performance Characteristic Dual-Band BPF Design

A simple high performance compact dual-band bandpass filter is developed in this paper based on multilayered T-shape loaded hairpin resonator (T-SLHR). The filter circuit is constructed using two substrates. On the first ground plane substrate, two T-SLHRs are analyzed and electrically coupled through a space gap S to accomplish the desired dual passbands. To acquire the filtering response, an input/output grounded hairpin-stub is patterned on a second ungrounded-substrate and broadside coupled to the T-SLHRs. To validate the proposed concept, a dual-band BPF is realized for a multi-wireless network system working at 2.4 GHz and 3.5 GHz center frequencies. Indeed, the T-SLHR is analyzed based on odd-even theory to generate the specified frequencies. Furthermore, a block-diagram to explain the coupling mechanism of the expected filter behavior is suggested. Moreover, the simulated filter is manufactured and its measurement and simulation results are compared and discussed. The produced filter has quite small area less than 126 mm 2 , high skirt roll-off selectivity and good isolation rejection band.