Miniaturized Dual-Band Bandpass Filter Using Multilayered Dual-Mode Resonator


This paper presents a miniaturized dual-band bandpass filter using two coupled dual-mode resonators (DMRs). The dual-mode resonator is a short-circuited stub loaded square loop resonator. The concept of miniaturization achieved using multilayered technology. Therefore, the filter circuits are achieved in three layers. On the first layer, two coupled dual-mode resonators are designed and shorted to a ground layer to specify the required passbands. Next, a second layer employs two shorted quarter wavelength stubs coupled through one via hole are capacitively coupled to the first layer circuit to achieve the filtering response. For our demonstration, a multi-band bandpass filter is designed to serve a multifunctional wireless system has centre frequencies of 1.9 GHz GSM and 3.5 GHz WiMax systems. The filter is implemented and simulated using the momentum simulator of the Advanced Design System (ADS) software package. The filter response has two second-order passbands with four transmission zeros leads to a high skirt selectivity. The filter circuit area is very small, less than 37 mm2 terminating the feeding ports.